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scope out targeted usage of non-heuristic-based integer overflow checking #35

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thestinger opened this issue May 18, 2017 · 0 comments
Open

scope out targeted usage of non-heuristic-based integer overflow checking #35

thestinger opened this issue May 18, 2017 · 0 comments
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@thestinger
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thestinger commented May 18, 2017 •
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Similar to #34 (see explanation there) but for -fsanitize=integer and subsets of it. Unsigned integer overflow is well-defined but still quite suspicious and intended overflows would ideally be marked. Some subsystems might buy into doing this and using it for debugging and fuzzing. Signed integer overflow is usually undefined, but the kernel makes it well-defined via -fno-strict-overflow so it's almost just as hard to push for that. Marking the intended overflows is not that much to ask for though and it can be done in a way that's pretty. The no_sanitize attribute exists for doing it at the function level but ideally they'd be marked on a case-by-case basis with the _builtin*_overflow intrinsics via wrappers making them sane to use for this.

This will provide a lot more coverage than SIZE_OVERFLOW and uncover a lot more issues, so it's a lot more work and should be targeted in scope.
thestinger pushed a commit that referenced this issue Jun 24, 2017
@AlanStern @gregkh
USB: gadgetfs, dummy-hcd, net2280: fix locking for callbacks
20360f1 
commit f16443a upstream.

Using the syzkaller kernel fuzzer, Andrey Konovalov generated the
following error in gadgetfs:

> BUG: KASAN: use-after-free in __lock_acquire+0x3069/0x3690
> kernel/locking/lockdep.c:3246
> Read of size 8 at addr ffff88003a2bdaf8 by task kworker/3:1/903
>
> CPU: 3 PID: 903 Comm: kworker/3:1 Not tainted 4.12.0-rc4+ #35
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
> Workqueue: usb_hub_wq hub_event
> Call Trace:
>  __dump_stack lib/dump_stack.c:16 [inline]
>  dump_stack+0x292/0x395 lib/dump_stack.c:52
>  print_address_description+0x78/0x280 mm/kasan/report.c:252
>  kasan_report_error mm/kasan/report.c:351 [inline]
>  kasan_report+0x230/0x340 mm/kasan/report.c:408
>  __asan_report_load8_noabort+0x19/0x20 mm/kasan/report.c:429
>  __lock_acquire+0x3069/0x3690 kernel/locking/lockdep.c:3246
>  lock_acquire+0x22d/0x560 kernel/locking/lockdep.c:3855
>  __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
>  _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151
>  spin_lock include/linux/spinlock.h:299 [inline]
>  gadgetfs_suspend+0x89/0x130 drivers/usb/gadget/legacy/inode.c:1682
>  set_link_state+0x88e/0xae0 drivers/usb/gadget/udc/dummy_hcd.c:455
>  dummy_hub_control+0xd7e/0x1fb0 drivers/usb/gadget/udc/dummy_hcd.c:2074
>  rh_call_control drivers/usb/core/hcd.c:689 [inline]
>  rh_urb_enqueue drivers/usb/core/hcd.c:846 [inline]
>  usb_hcd_submit_urb+0x92f/0x20b0 drivers/usb/core/hcd.c:1650
>  usb_submit_urb+0x8b2/0x12c0 drivers/usb/core/urb.c:542
>  usb_start_wait_urb+0x148/0x5b0 drivers/usb/core/message.c:56
>  usb_internal_control_msg drivers/usb/core/message.c:100 [inline]
>  usb_control_msg+0x341/0x4d0 drivers/usb/core/message.c:151
>  usb_clear_port_feature+0x74/0xa0 drivers/usb/core/hub.c:412
>  hub_port_disable+0x123/0x510 drivers/usb/core/hub.c:4177
>  hub_port_init+0x1ed/0x2940 drivers/usb/core/hub.c:4648
>  hub_port_connect drivers/usb/core/hub.c:4826 [inline]
>  hub_port_connect_change drivers/usb/core/hub.c:4999 [inline]
>  port_event drivers/usb/core/hub.c:5105 [inline]
>  hub_event+0x1ae1/0x3d40 drivers/usb/core/hub.c:5185
>  process_one_work+0xc08/0x1bd0 kernel/workqueue.c:2097
>  process_scheduled_works kernel/workqueue.c:2157 [inline]
>  worker_thread+0xb2b/0x1860 kernel/workqueue.c:2233
>  kthread+0x363/0x440 kernel/kthread.c:231
>  ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:424
>
> Allocated by task 9958:
>  save_stack_trace+0x1b/0x20 arch/x86/kernel/stacktrace.c:59
>  save_stack+0x43/0xd0 mm/kasan/kasan.c:513
>  set_track mm/kasan/kasan.c:525 [inline]
>  kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:617
>  kmem_cache_alloc_trace+0x87/0x280 mm/slub.c:2745
>  kmalloc include/linux/slab.h:492 [inline]
>  kzalloc include/linux/slab.h:665 [inline]
>  dev_new drivers/usb/gadget/legacy/inode.c:170 [inline]
>  gadgetfs_fill_super+0x24f/0x540 drivers/usb/gadget/legacy/inode.c:1993
>  mount_single+0xf6/0x160 fs/super.c:1192
>  gadgetfs_mount+0x31/0x40 drivers/usb/gadget/legacy/inode.c:2019
>  mount_fs+0x9c/0x2d0 fs/super.c:1223
>  vfs_kern_mount.part.25+0xcb/0x490 fs/namespace.c:976
>  vfs_kern_mount fs/namespace.c:2509 [inline]
>  do_new_mount fs/namespace.c:2512 [inline]
>  do_mount+0x41b/0x2d90 fs/namespace.c:2834
>  SYSC_mount fs/namespace.c:3050 [inline]
>  SyS_mount+0xb0/0x120 fs/namespace.c:3027
>  entry_SYSCALL_64_fastpath+0x1f/0xbe
>
> Freed by task 9960:
>  save_stack_trace+0x1b/0x20 arch/x86/kernel/stacktrace.c:59
>  save_stack+0x43/0xd0 mm/kasan/kasan.c:513
>  set_track mm/kasan/kasan.c:525 [inline]
>  kasan_slab_free+0x72/0xc0 mm/kasan/kasan.c:590
>  slab_free_hook mm/slub.c:1357 [inline]
>  slab_free_freelist_hook mm/slub.c:1379 [inline]
>  slab_free mm/slub.c:2961 [inline]
>  kfree+0xed/0x2b0 mm/slub.c:3882
>  put_dev+0x124/0x160 drivers/usb/gadget/legacy/inode.c:163
>  gadgetfs_kill_sb+0x33/0x60 drivers/usb/gadget/legacy/inode.c:2027
>  deactivate_locked_super+0x8d/0xd0 fs/super.c:309
>  deactivate_super+0x21e/0x310 fs/super.c:340
>  cleanup_mnt+0xb7/0x150 fs/namespace.c:1112
>  __cleanup_mnt+0x1b/0x20 fs/namespace.c:1119
>  task_work_run+0x1a0/0x280 kernel/task_work.c:116
>  exit_task_work include/linux/task_work.h:21 [inline]
>  do_exit+0x18a8/0x2820 kernel/exit.c:878
>  do_group_exit+0x14e/0x420 kernel/exit.c:982
>  get_signal+0x784/0x1780 kernel/signal.c:2318
>  do_signal+0xd7/0x2130 arch/x86/kernel/signal.c:808
>  exit_to_usermode_loop+0x1ac/0x240 arch/x86/entry/common.c:157
>  prepare_exit_to_usermode arch/x86/entry/common.c:194 [inline]
>  syscall_return_slowpath+0x3ba/0x410 arch/x86/entry/common.c:263
>  entry_SYSCALL_64_fastpath+0xbc/0xbe
>
> The buggy address belongs to the object at ffff88003a2bdae0
>  which belongs to the cache kmalloc-1024 of size 1024
> The buggy address is located 24 bytes inside of
>  1024-byte region [ffff88003a2bdae0, ffff88003a2bdee0)
> The buggy address belongs to the page:
> page:ffffea0000e8ae00 count:1 mapcount:0 mapping:          (null)
> index:0x0 compound_mapcount: 0
> flags: 0x100000000008100(slab|head)
> raw: 0100000000008100 0000000000000000 0000000000000000 0000000100170017
> raw: ffffea0000ed3020 ffffea0000f5f820 ffff88003e80efc0 0000000000000000
> page dumped because: kasan: bad access detected
>
> Memory state around the buggy address:
>  ffff88003a2bd980: fb fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>  ffff88003a2bda00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> >ffff88003a2bda80: fc fc fc fc fc fc fc fc fc fc fc fc fb fb fb fb
>                                                                 ^
>  ffff88003a2bdb00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>  ffff88003a2bdb80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> ==================================================================

What this means is that the gadgetfs_suspend() routine was trying to
access dev->lock after it had been deallocated.  The root cause is a
race in the dummy_hcd driver; the dummy_udc_stop() routine can race
with the rest of the driver because it contains no locking.  And even
when proper locking is added, it can still race with the
set_link_state() function because that function incorrectly drops the
private spinlock before invoking any gadget driver callbacks.

The result of this race, as seen above, is that set_link_state() can
invoke a callback in gadgetfs even after gadgetfs has been unbound
from dummy_hcd's UDC and its private data structures have been
deallocated.

include/linux/usb/gadget.h documents that the ->reset, ->disconnect,
->suspend, and ->resume callbacks may be invoked in interrupt context.
In general this is necessary, to prevent races with gadget driver
removal.  This patch fixes dummy_hcd to retain the spinlock across
these calls, and it adds a spinlock acquisition to dummy_udc_stop() to
prevent the race.

The net2280 driver makes the same mistake of dropping the private
spinlock for its ->disconnect and ->reset callback invocations.  The
patch fixes it too.

Lastly, since gadgetfs_suspend() may be invoked in interrupt context,
it cannot assume that interrupts are enabled when it runs.  It must
use spin_lock_irqsave() instead of spin_lock_irq().  The patch fixes
that bug as well.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Reported-and-tested-by: Andrey Konovalov <andreyknvl@google.com>
Acked-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
thestinger pushed a commit that referenced this issue Jul 3, 2017
@AlanStern @gregkh
USB: gadgetfs, dummy-hcd, net2280: fix locking for callbacks
f16443a 
Using the syzkaller kernel fuzzer, Andrey Konovalov generated the
following error in gadgetfs:

> BUG: KASAN: use-after-free in __lock_acquire+0x3069/0x3690
> kernel/locking/lockdep.c:3246
> Read of size 8 at addr ffff88003a2bdaf8 by task kworker/3:1/903
>
> CPU: 3 PID: 903 Comm: kworker/3:1 Not tainted 4.12.0-rc4+ #35
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
> Workqueue: usb_hub_wq hub_event
> Call Trace:
>  __dump_stack lib/dump_stack.c:16 [inline]
>  dump_stack+0x292/0x395 lib/dump_stack.c:52
>  print_address_description+0x78/0x280 mm/kasan/report.c:252
>  kasan_report_error mm/kasan/report.c:351 [inline]
>  kasan_report+0x230/0x340 mm/kasan/report.c:408
>  __asan_report_load8_noabort+0x19/0x20 mm/kasan/report.c:429
>  __lock_acquire+0x3069/0x3690 kernel/locking/lockdep.c:3246
>  lock_acquire+0x22d/0x560 kernel/locking/lockdep.c:3855
>  __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
>  _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151
>  spin_lock include/linux/spinlock.h:299 [inline]
>  gadgetfs_suspend+0x89/0x130 drivers/usb/gadget/legacy/inode.c:1682
>  set_link_state+0x88e/0xae0 drivers/usb/gadget/udc/dummy_hcd.c:455
>  dummy_hub_control+0xd7e/0x1fb0 drivers/usb/gadget/udc/dummy_hcd.c:2074
>  rh_call_control drivers/usb/core/hcd.c:689 [inline]
>  rh_urb_enqueue drivers/usb/core/hcd.c:846 [inline]
>  usb_hcd_submit_urb+0x92f/0x20b0 drivers/usb/core/hcd.c:1650
>  usb_submit_urb+0x8b2/0x12c0 drivers/usb/core/urb.c:542
>  usb_start_wait_urb+0x148/0x5b0 drivers/usb/core/message.c:56
>  usb_internal_control_msg drivers/usb/core/message.c:100 [inline]
>  usb_control_msg+0x341/0x4d0 drivers/usb/core/message.c:151
>  usb_clear_port_feature+0x74/0xa0 drivers/usb/core/hub.c:412
>  hub_port_disable+0x123/0x510 drivers/usb/core/hub.c:4177
>  hub_port_init+0x1ed/0x2940 drivers/usb/core/hub.c:4648
>  hub_port_connect drivers/usb/core/hub.c:4826 [inline]
>  hub_port_connect_change drivers/usb/core/hub.c:4999 [inline]
>  port_event drivers/usb/core/hub.c:5105 [inline]
>  hub_event+0x1ae1/0x3d40 drivers/usb/core/hub.c:5185
>  process_one_work+0xc08/0x1bd0 kernel/workqueue.c:2097
>  process_scheduled_works kernel/workqueue.c:2157 [inline]
>  worker_thread+0xb2b/0x1860 kernel/workqueue.c:2233
>  kthread+0x363/0x440 kernel/kthread.c:231
>  ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:424
>
> Allocated by task 9958:
>  save_stack_trace+0x1b/0x20 arch/x86/kernel/stacktrace.c:59
>  save_stack+0x43/0xd0 mm/kasan/kasan.c:513
>  set_track mm/kasan/kasan.c:525 [inline]
>  kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:617
>  kmem_cache_alloc_trace+0x87/0x280 mm/slub.c:2745
>  kmalloc include/linux/slab.h:492 [inline]
>  kzalloc include/linux/slab.h:665 [inline]
>  dev_new drivers/usb/gadget/legacy/inode.c:170 [inline]
>  gadgetfs_fill_super+0x24f/0x540 drivers/usb/gadget/legacy/inode.c:1993
>  mount_single+0xf6/0x160 fs/super.c:1192
>  gadgetfs_mount+0x31/0x40 drivers/usb/gadget/legacy/inode.c:2019
>  mount_fs+0x9c/0x2d0 fs/super.c:1223
>  vfs_kern_mount.part.25+0xcb/0x490 fs/namespace.c:976
>  vfs_kern_mount fs/namespace.c:2509 [inline]
>  do_new_mount fs/namespace.c:2512 [inline]
>  do_mount+0x41b/0x2d90 fs/namespace.c:2834
>  SYSC_mount fs/namespace.c:3050 [inline]
>  SyS_mount+0xb0/0x120 fs/namespace.c:3027
>  entry_SYSCALL_64_fastpath+0x1f/0xbe
>
> Freed by task 9960:
>  save_stack_trace+0x1b/0x20 arch/x86/kernel/stacktrace.c:59
>  save_stack+0x43/0xd0 mm/kasan/kasan.c:513
>  set_track mm/kasan/kasan.c:525 [inline]
>  kasan_slab_free+0x72/0xc0 mm/kasan/kasan.c:590
>  slab_free_hook mm/slub.c:1357 [inline]
>  slab_free_freelist_hook mm/slub.c:1379 [inline]
>  slab_free mm/slub.c:2961 [inline]
>  kfree+0xed/0x2b0 mm/slub.c:3882
>  put_dev+0x124/0x160 drivers/usb/gadget/legacy/inode.c:163
>  gadgetfs_kill_sb+0x33/0x60 drivers/usb/gadget/legacy/inode.c:2027
>  deactivate_locked_super+0x8d/0xd0 fs/super.c:309
>  deactivate_super+0x21e/0x310 fs/super.c:340
>  cleanup_mnt+0xb7/0x150 fs/namespace.c:1112
>  __cleanup_mnt+0x1b/0x20 fs/namespace.c:1119
>  task_work_run+0x1a0/0x280 kernel/task_work.c:116
>  exit_task_work include/linux/task_work.h:21 [inline]
>  do_exit+0x18a8/0x2820 kernel/exit.c:878
>  do_group_exit+0x14e/0x420 kernel/exit.c:982
>  get_signal+0x784/0x1780 kernel/signal.c:2318
>  do_signal+0xd7/0x2130 arch/x86/kernel/signal.c:808
>  exit_to_usermode_loop+0x1ac/0x240 arch/x86/entry/common.c:157
>  prepare_exit_to_usermode arch/x86/entry/common.c:194 [inline]
>  syscall_return_slowpath+0x3ba/0x410 arch/x86/entry/common.c:263
>  entry_SYSCALL_64_fastpath+0xbc/0xbe
>
> The buggy address belongs to the object at ffff88003a2bdae0
>  which belongs to the cache kmalloc-1024 of size 1024
> The buggy address is located 24 bytes inside of
>  1024-byte region [ffff88003a2bdae0, ffff88003a2bdee0)
> The buggy address belongs to the page:
> page:ffffea0000e8ae00 count:1 mapcount:0 mapping:          (null)
> index:0x0 compound_mapcount: 0
> flags: 0x100000000008100(slab|head)
> raw: 0100000000008100 0000000000000000 0000000000000000 0000000100170017
> raw: ffffea0000ed3020 ffffea0000f5f820 ffff88003e80efc0 0000000000000000
> page dumped because: kasan: bad access detected
>
> Memory state around the buggy address:
>  ffff88003a2bd980: fb fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>  ffff88003a2bda00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> >ffff88003a2bda80: fc fc fc fc fc fc fc fc fc fc fc fc fb fb fb fb
>                                                                 ^
>  ffff88003a2bdb00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>  ffff88003a2bdb80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> ==================================================================

What this means is that the gadgetfs_suspend() routine was trying to
access dev->lock after it had been deallocated.  The root cause is a
race in the dummy_hcd driver; the dummy_udc_stop() routine can race
with the rest of the driver because it contains no locking.  And even
when proper locking is added, it can still race with the
set_link_state() function because that function incorrectly drops the
private spinlock before invoking any gadget driver callbacks.

The result of this race, as seen above, is that set_link_state() can
invoke a callback in gadgetfs even after gadgetfs has been unbound
from dummy_hcd's UDC and its private data structures have been
deallocated.

include/linux/usb/gadget.h documents that the ->reset, ->disconnect,
->suspend, and ->resume callbacks may be invoked in interrupt context.
In general this is necessary, to prevent races with gadget driver
removal.  This patch fixes dummy_hcd to retain the spinlock across
these calls, and it adds a spinlock acquisition to dummy_udc_stop() to
prevent the race.

The net2280 driver makes the same mistake of dropping the private
spinlock for its ->disconnect and ->reset callback invocations.  The
patch fixes it too.

Lastly, since gadgetfs_suspend() may be invoked in interrupt context,
it cannot assume that interrupts are enabled when it runs.  It must
use spin_lock_irqsave() instead of spin_lock_irq().  The patch fixes
that bug as well.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Reported-and-tested-by: Andrey Konovalov <andreyknvl@google.com>
CC: <stable@vger.kernel.org>
Acked-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
thestinger pushed a commit that referenced this issue Aug 30, 2017
@ebiggers @gregkh
mm/madvise.c: fix freeing of locked page with MADV_FREE
4823f46 
commit 263630e upstream.

If madvise(..., MADV_FREE) split a transparent hugepage, it called
put_page() before unlock_page().

This was wrong because put_page() can free the page, e.g. if a
concurrent madvise(..., MADV_DONTNEED) has removed it from the memory
mapping. put_page() then rightfully complained about freeing a locked
page.

Fix this by moving the unlock_page() before put_page().

This bug was found by syzkaller, which encountered the following splat:

    BUG: Bad page state in process syzkaller412798  pfn:1bd800
    page:ffffea0006f60000 count:0 mapcount:0 mapping:          (null) index:0x20a00
    flags: 0x200000000040019(locked|uptodate|dirty|swapbacked)
    raw: 0200000000040019 0000000000000000 0000000000020a00 00000000ffffffff
    raw: ffffea0006f60020 ffffea0006f60020 0000000000000000 0000000000000000
    page dumped because: PAGE_FLAGS_CHECK_AT_FREE flag(s) set
    bad because of flags: 0x1(locked)
    Modules linked in:
    CPU: 1 PID: 3037 Comm: syzkaller412798 Not tainted 4.13.0-rc5+ #35
    Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
    Call Trace:
     __dump_stack lib/dump_stack.c:16 [inline]
     dump_stack+0x194/0x257 lib/dump_stack.c:52
     bad_page+0x230/0x2b0 mm/page_alloc.c:565
     free_pages_check_bad+0x1f0/0x2e0 mm/page_alloc.c:943
     free_pages_check mm/page_alloc.c:952 [inline]
     free_pages_prepare mm/page_alloc.c:1043 [inline]
     free_pcp_prepare mm/page_alloc.c:1068 [inline]
     free_hot_cold_page+0x8cf/0x12b0 mm/page_alloc.c:2584
     __put_single_page mm/swap.c:79 [inline]
     __put_page+0xfb/0x160 mm/swap.c:113
     put_page include/linux/mm.h:814 [inline]
     madvise_free_pte_range+0x137a/0x1ec0 mm/madvise.c:371
     walk_pmd_range mm/pagewalk.c:50 [inline]
     walk_pud_range mm/pagewalk.c:108 [inline]
     walk_p4d_range mm/pagewalk.c:134 [inline]
     walk_pgd_range mm/pagewalk.c:160 [inline]
     __walk_page_range+0xc3a/0x1450 mm/pagewalk.c:249
     walk_page_range+0x200/0x470 mm/pagewalk.c:326
     madvise_free_page_range.isra.9+0x17d/0x230 mm/madvise.c:444
     madvise_free_single_vma+0x353/0x580 mm/madvise.c:471
     madvise_dontneed_free mm/madvise.c:555 [inline]
     madvise_vma mm/madvise.c:664 [inline]
     SYSC_madvise mm/madvise.c:832 [inline]
     SyS_madvise+0x7d3/0x13c0 mm/madvise.c:760
     entry_SYSCALL_64_fastpath+0x1f/0xbe

Here is a C reproducer:

    #define _GNU_SOURCE
    #include <pthread.h>
    #include <sys/mman.h>
    #include <unistd.h>

    #define MADV_FREE	8
    #define PAGE_SIZE	4096

    static void *mapping;
    static const size_t mapping_size = 0x1000000;

    static void *madvise_thrproc(void *arg)
    {
        madvise(mapping, mapping_size, (long)arg);
    }

    int main(void)
    {
        pthread_t t[2];

        for (;;) {
            mapping = mmap(NULL, mapping_size, PROT_WRITE,
                           MAP_POPULATE|MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);

            munmap(mapping + mapping_size / 2, PAGE_SIZE);

            pthread_create(&t[0], 0, madvise_thrproc, (void*)MADV_DONTNEED);
            pthread_create(&t[1], 0, madvise_thrproc, (void*)MADV_FREE);
            pthread_join(t[0], NULL);
            pthread_join(t[1], NULL);
            munmap(mapping, mapping_size);
        }
    }

Note: to see the splat, CONFIG_TRANSPARENT_HUGEPAGE=y and
CONFIG_DEBUG_VM=y are needed.

Google Bug Id: 64696096

Link: http://lkml.kernel.org/r/20170823205235.132061-1-ebiggers3@gmail.com
Fixes: 854e9ed ("mm: support madvise(MADV_FREE)")
Signed-off-by: Eric Biggers <ebiggers@google.com>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
thestinger pushed a commit that referenced this issue Sep 3, 2017
@ebiggers @torvalds
mm/madvise.c: fix freeing of locked page with MADV_FREE
263630e 
If madvise(..., MADV_FREE) split a transparent hugepage, it called
put_page() before unlock_page().

This was wrong because put_page() can free the page, e.g. if a
concurrent madvise(..., MADV_DONTNEED) has removed it from the memory
mapping. put_page() then rightfully complained about freeing a locked
page.

Fix this by moving the unlock_page() before put_page().

This bug was found by syzkaller, which encountered the following splat:

    BUG: Bad page state in process syzkaller412798  pfn:1bd800
    page:ffffea0006f60000 count:0 mapcount:0 mapping:          (null) index:0x20a00
    flags: 0x200000000040019(locked|uptodate|dirty|swapbacked)
    raw: 0200000000040019 0000000000000000 0000000000020a00 00000000ffffffff
    raw: ffffea0006f60020 ffffea0006f60020 0000000000000000 0000000000000000
    page dumped because: PAGE_FLAGS_CHECK_AT_FREE flag(s) set
    bad because of flags: 0x1(locked)
    Modules linked in:
    CPU: 1 PID: 3037 Comm: syzkaller412798 Not tainted 4.13.0-rc5+ #35
    Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
    Call Trace:
     __dump_stack lib/dump_stack.c:16 [inline]
     dump_stack+0x194/0x257 lib/dump_stack.c:52
     bad_page+0x230/0x2b0 mm/page_alloc.c:565
     free_pages_check_bad+0x1f0/0x2e0 mm/page_alloc.c:943
     free_pages_check mm/page_alloc.c:952 [inline]
     free_pages_prepare mm/page_alloc.c:1043 [inline]
     free_pcp_prepare mm/page_alloc.c:1068 [inline]
     free_hot_cold_page+0x8cf/0x12b0 mm/page_alloc.c:2584
     __put_single_page mm/swap.c:79 [inline]
     __put_page+0xfb/0x160 mm/swap.c:113
     put_page include/linux/mm.h:814 [inline]
     madvise_free_pte_range+0x137a/0x1ec0 mm/madvise.c:371
     walk_pmd_range mm/pagewalk.c:50 [inline]
     walk_pud_range mm/pagewalk.c:108 [inline]
     walk_p4d_range mm/pagewalk.c:134 [inline]
     walk_pgd_range mm/pagewalk.c:160 [inline]
     __walk_page_range+0xc3a/0x1450 mm/pagewalk.c:249
     walk_page_range+0x200/0x470 mm/pagewalk.c:326
     madvise_free_page_range.isra.9+0x17d/0x230 mm/madvise.c:444
     madvise_free_single_vma+0x353/0x580 mm/madvise.c:471
     madvise_dontneed_free mm/madvise.c:555 [inline]
     madvise_vma mm/madvise.c:664 [inline]
     SYSC_madvise mm/madvise.c:832 [inline]
     SyS_madvise+0x7d3/0x13c0 mm/madvise.c:760
     entry_SYSCALL_64_fastpath+0x1f/0xbe

Here is a C reproducer:

    #define _GNU_SOURCE
    #include <pthread.h>
    #include <sys/mman.h>
    #include <unistd.h>

    #define MADV_FREE	8
    #define PAGE_SIZE	4096

    static void *mapping;
    static const size_t mapping_size = 0x1000000;

    static void *madvise_thrproc(void *arg)
    {
        madvise(mapping, mapping_size, (long)arg);
    }

    int main(void)
    {
        pthread_t t[2];

        for (;;) {
            mapping = mmap(NULL, mapping_size, PROT_WRITE,
                           MAP_POPULATE|MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);

            munmap(mapping + mapping_size / 2, PAGE_SIZE);

            pthread_create(&t[0], 0, madvise_thrproc, (void*)MADV_DONTNEED);
            pthread_create(&t[1], 0, madvise_thrproc, (void*)MADV_FREE);
            pthread_join(t[0], NULL);
            pthread_join(t[1], NULL);
            munmap(mapping, mapping_size);
        }
    }

Note: to see the splat, CONFIG_TRANSPARENT_HUGEPAGE=y and
CONFIG_DEBUG_VM=y are needed.

Google Bug Id: 64696096

Link: http://lkml.kernel.org/r/20170823205235.132061-1-ebiggers3@gmail.com
Fixes: 854e9ed ("mm: support madvise(MADV_FREE)")
Signed-off-by: Eric Biggers <ebiggers@google.com>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: <stable@vger.kernel.org>	[v4.5+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
thestinger pushed a commit that referenced this issue May 21, 2018
@gregkh
nsh: fix infinite loop
2e32778 
[ Upstream commit af50e4b ]

syzbot caught an infinite recursion in nsh_gso_segment().

Problem here is that we need to make sure the NSH header is of
reasonable length.

BUG: MAX_LOCK_DEPTH too low!
turning off the locking correctness validator.
depth: 48  max: 48!
48 locks held by syz-executor0/10189:
 #0:         (ptrval) (rcu_read_lock_bh){....}, at: __dev_queue_xmit+0x30f/0x34c0 net/core/dev.c:3517
 #1:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #1:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #2:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #2:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #3:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #3:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #4:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #4:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #5:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #5:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #6:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #6:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #7:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #7:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #8:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #8:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #9:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #9:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #10:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #10:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #11:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #11:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #12:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #12:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #13:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #13:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #14:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #14:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #15:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #15:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #16:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #16:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #17:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #17:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #18:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #18:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #19:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #19:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #20:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #20:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #21:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #21:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #22:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #22:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #23:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #23:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #24:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #24:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #25:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #25:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #26:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #26:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #27:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #27:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #28:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #28:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #29:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #29:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #30:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #30:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #31:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #31:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
dccp_close: ABORT with 65423 bytes unread
 #32:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #32:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #33:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #33:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #34:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #34:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #35:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #35:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #36:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #36:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #37:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #37:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #38:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #38:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #39:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #39:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #40:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #40:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #41:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #41:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #42:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #42:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #43:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #43:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #44:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #44:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #45:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #45:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #46:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #46:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #47:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #47:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
INFO: lockdep is turned off.
CPU: 1 PID: 10189 Comm: syz-executor0 Not tainted 4.17.0-rc2+ #26
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1b9/0x294 lib/dump_stack.c:113
 __lock_acquire+0x1788/0x5140 kernel/locking/lockdep.c:3449
 lock_acquire+0x1dc/0x520 kernel/locking/lockdep.c:3920
 rcu_lock_acquire include/linux/rcupdate.h:246 [inline]
 rcu_read_lock include/linux/rcupdate.h:632 [inline]
 skb_mac_gso_segment+0x25b/0x720 net/core/dev.c:2789
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 __skb_gso_segment+0x3bb/0x870 net/core/dev.c:2865
 skb_gso_segment include/linux/netdevice.h:4025 [inline]
 validate_xmit_skb+0x54d/0xd90 net/core/dev.c:3118
 validate_xmit_skb_list+0xbf/0x120 net/core/dev.c:3168
 sch_direct_xmit+0x354/0x11e0 net/sched/sch_generic.c:312
 qdisc_restart net/sched/sch_generic.c:399 [inline]
 __qdisc_run+0x741/0x1af0 net/sched/sch_generic.c:410
 __dev_xmit_skb net/core/dev.c:3243 [inline]
 __dev_queue_xmit+0x28ea/0x34c0 net/core/dev.c:3551
 dev_queue_xmit+0x17/0x20 net/core/dev.c:3616
 packet_snd net/packet/af_packet.c:2951 [inline]
 packet_sendmsg+0x40f8/0x6070 net/packet/af_packet.c:2976
 sock_sendmsg_nosec net/socket.c:629 [inline]
 sock_sendmsg+0xd5/0x120 net/socket.c:639
 __sys_sendto+0x3d7/0x670 net/socket.c:1789
 __do_sys_sendto net/socket.c:1801 [inline]
 __se_sys_sendto net/socket.c:1797 [inline]
 __x64_sys_sendto+0xe1/0x1a0 net/socket.c:1797
 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Fixes: c411ed8 ("nsh: add GSO support")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Jiri Benc <jbenc@redhat.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Acked-by: Jiri Benc <jbenc@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
anthraxx referenced this issue in anthraxx/linux-hardened May 22, 2018
@gregkh
nsh: fix infinite loop
8151fe6 
[ Upstream commit af50e4b ]

syzbot caught an infinite recursion in nsh_gso_segment().

Problem here is that we need to make sure the NSH header is of
reasonable length.

BUG: MAX_LOCK_DEPTH too low!
turning off the locking correctness validator.
depth: 48  max: 48!
48 locks held by syz-executor0/10189:
 #0:         (ptrval) (rcu_read_lock_bh){....}, at: __dev_queue_xmit+0x30f/0x34c0 net/core/dev.c:3517
 #1:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #1:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #2:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #2:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #3:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #3:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #4:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #4:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #5:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #5:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #6:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #6:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #7:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #7:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #8:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #8:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #9:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #9:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #10:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #10:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #11:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #11:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #12:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #12:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #13:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #13:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #14:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #14:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #15:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #15:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #16:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #16:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #17:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #17:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #18:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #18:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #19:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #19:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #20:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #20:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #21:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #21:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #22:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #22:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #23:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #23:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #24:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #24:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #25:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #25:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #26:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #26:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #27:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #27:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #28:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #28:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #29:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #29:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #30:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #30:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #31:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #31:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
dccp_close: ABORT with 65423 bytes unread
 #32:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #32:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #33:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #33:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #34:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #34:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #35:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #35:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #36:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #36:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #37:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #37:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #38:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #38:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #39:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #39:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #40:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #40:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #41:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #41:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #42:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #42:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #43:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #43:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #44:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #44:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #45:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #45:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #46:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #46:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
 #47:         (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
 #47:         (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
INFO: lockdep is turned off.
CPU: 1 PID: 10189 Comm: syz-executor0 Not tainted 4.17.0-rc2+ #26
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1b9/0x294 lib/dump_stack.c:113
 __lock_acquire+0x1788/0x5140 kernel/locking/lockdep.c:3449
 lock_acquire+0x1dc/0x520 kernel/locking/lockdep.c:3920
 rcu_lock_acquire include/linux/rcupdate.h:246 [inline]
 rcu_read_lock include/linux/rcupdate.h:632 [inline]
 skb_mac_gso_segment+0x25b/0x720 net/core/dev.c:2789
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
 skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
 __skb_gso_segment+0x3bb/0x870 net/core/dev.c:2865
 skb_gso_segment include/linux/netdevice.h:4025 [inline]
 validate_xmit_skb+0x54d/0xd90 net/core/dev.c:3118
 validate_xmit_skb_list+0xbf/0x120 net/core/dev.c:3168
 sch_direct_xmit+0x354/0x11e0 net/sched/sch_generic.c:312
 qdisc_restart net/sched/sch_generic.c:399 [inline]
 __qdisc_run+0x741/0x1af0 net/sched/sch_generic.c:410
 __dev_xmit_skb net/core/dev.c:3243 [inline]
 __dev_queue_xmit+0x28ea/0x34c0 net/core/dev.c:3551
 dev_queue_xmit+0x17/0x20 net/core/dev.c:3616
 packet_snd net/packet/af_packet.c:2951 [inline]
 packet_sendmsg+0x40f8/0x6070 net/packet/af_packet.c:2976
 sock_sendmsg_nosec net/socket.c:629 [inline]
 sock_sendmsg+0xd5/0x120 net/socket.c:639
 __sys_sendto+0x3d7/0x670 net/socket.c:1789
 __do_sys_sendto net/socket.c:1801 [inline]
 __se_sys_sendto net/socket.c:1797 [inline]
 __x64_sys_sendto+0xe1/0x1a0 net/socket.c:1797
 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Fixes: c411ed8 ("nsh: add GSO support")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Jiri Benc <jbenc@redhat.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Acked-by: Jiri Benc <jbenc@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
randomhydrosol pushed a commit to randomhydrosol/linux-hardened that referenced this issue Nov 9, 2018
s390/kasan: increase instrumented stack size to 64k
9fed920 
Increase kasan instrumented kernel stack size from 32k to 64k. Other
architectures seems to get away with just doubling kernel stack size under
kasan, but on s390 this appears to be not enough due to bigger frame size.
The particular pain point is kasan inlined checks (CONFIG_KASAN_INLINE
vs CONFIG_KASAN_OUTLINE). With inlined checks one particular case hitting
stack overflow is fs sync on xfs filesystem:

 #0 [9a0681e8]  704 bytes  check_usage at 34b1fc
 GrapheneOS#1 [9a0684a8]  432 bytes  check_usage at 34c710
 GrapheneOS#2 [9a068658]  1048 bytes  validate_chain at 35044a
 GrapheneOS#3 [9a068a70]  312 bytes  __lock_acquire at 3559fe
 GrapheneOS#4 [9a068ba8]  440 bytes  lock_acquire at 3576ee
 GrapheneOS#5 [9a068d60]  104 bytes  _raw_spin_lock at 21b44e0
 GrapheneOS#6 [9a068dc8]  1992 bytes  enqueue_entity at 2dbf72
 GrapheneOS#7 [9a069590]  1496 bytes  enqueue_task_fair at 2df5f0
 GrapheneOS#8 [9a069b68]  64 bytes  ttwu_do_activate at 28f438
 GrapheneOS#9 [9a069ba8]  552 bytes  try_to_wake_up at 298c4c
 GrapheneOS#10 [9a069dd0]  168 bytes  wake_up_worker at 23f97c
 GrapheneOS#11 [9a069e78]  200 bytes  insert_work at 23fc2e
 GrapheneOS#12 [9a069f40]  648 bytes  __queue_work at 2487c0
 GrapheneOS#13 [9a06a1c8]  200 bytes  __queue_delayed_work at 24db28
 GrapheneOS#14 [9a06a290]  248 bytes  mod_delayed_work_on at 24de84
 GrapheneOS#15 [9a06a388]  24 bytes  kblockd_mod_delayed_work_on at 153e2a0
 GrapheneOS#16 [9a06a3a0]  288 bytes  __blk_mq_delay_run_hw_queue at 158168c
 GrapheneOS#17 [9a06a4c0]  192 bytes  blk_mq_run_hw_queue at 1581a3c
 GrapheneOS#18 [9a06a580]  184 bytes  blk_mq_sched_insert_requests at 15a2192
 GrapheneOS#19 [9a06a638]  1024 bytes  blk_mq_flush_plug_list at 1590f3a
 GrapheneOS#20 [9a06aa38]  704 bytes  blk_flush_plug_list at 1555028
 GrapheneOS#21 [9a06acf8]  320 bytes  schedule at 219e476
 GrapheneOS#22 [9a06ae38]  760 bytes  schedule_timeout at 21b0aac
 GrapheneOS#23 [9a06b130]  408 bytes  wait_for_common at 21a1706
 GrapheneOS#24 [9a06b2c8]  360 bytes  xfs_buf_iowait at fa1540
 GrapheneOS#25 [9a06b430]  256 bytes  __xfs_buf_submit at fadae6
 GrapheneOS#26 [9a06b530]  264 bytes  xfs_buf_read_map at fae3f6
 GrapheneOS#27 [9a06b638]  656 bytes  xfs_trans_read_buf_map at 10ac9a8
 GrapheneOS#28 [9a06b8c8]  304 bytes  xfs_btree_kill_root at e72426
 GrapheneOS#29 [9a06b9f8]  288 bytes  xfs_btree_lookup_get_block at e7bc5e
 GrapheneOS#30 [9a06bb18]  624 bytes  xfs_btree_lookup at e7e1a6
 GrapheneOS#31 [9a06bd88]  2664 bytes  xfs_alloc_ag_vextent_near at dfa070
 GrapheneOS#32 [9a06c7f0]  144 bytes  xfs_alloc_ag_vextent at dff3ca
 GrapheneOS#33 [9a06c880]  1128 bytes  xfs_alloc_vextent at e05fce
 GrapheneOS#34 [9a06cce8]  584 bytes  xfs_bmap_btalloc at e58342
 GrapheneOS#35 [9a06cf30]  1336 bytes  xfs_bmapi_write at e618de
 GrapheneOS#36 [9a06d468]  776 bytes  xfs_iomap_write_allocate at ff678e
 GrapheneOS#37 [9a06d770]  720 bytes  xfs_map_blocks at f82af8
 GrapheneOS#38 [9a06da40]  928 bytes  xfs_writepage_map at f83cd6
 GrapheneOS#39 [9a06dde0]  320 bytes  xfs_do_writepage at f85872
 GrapheneOS#40 [9a06df20]  1320 bytes  write_cache_pages at 73dfe8
 GrapheneOS#41 [9a06e448]  208 bytes  xfs_vm_writepages at f7f892
 GrapheneOS#42 [9a06e518]  88 bytes  do_writepages at 73fe6a
 GrapheneOS#43 [9a06e570]  872 bytes  __writeback_single_inode at a20cb6
 GrapheneOS#44 [9a06e8d8]  664 bytes  writeback_sb_inodes at a23be2
 GrapheneOS#45 [9a06eb70]  296 bytes  __writeback_inodes_wb at a242e0
 GrapheneOS#46 [9a06ec98]  928 bytes  wb_writeback at a2500e
 GrapheneOS#47 [9a06f038]  848 bytes  wb_do_writeback at a260ae
 GrapheneOS#48 [9a06f388]  536 bytes  wb_workfn at a28228
 GrapheneOS#49 [9a06f5a0]  1088 bytes  process_one_work at 24a234
 GrapheneOS#50 [9a06f9e0]  1120 bytes  worker_thread at 24ba26
 GrapheneOS#51 [9a06fe40]  104 bytes  kthread at 26545a
 GrapheneOS#52 [9a06fea8]             kernel_thread_starter at 21b6b62

To be able to increase the stack size to 64k reuse LLILL instruction
in __switch_to function to load 64k - STACK_FRAME_OVERHEAD - __PT_SIZE
(65192) value as unsigned.

Reported-by: Benjamin Block <bblock@linux.ibm.com>
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
anthraxx referenced this issue in anthraxx/linux-hardened Jan 28, 2019
@roxell @gregkh
arm64: perf: set suppress_bind_attrs flag to true
85a3e68 
[ Upstream commit 81e9fa8 ]

The armv8_pmuv3 driver doesn't have a remove function, and when the test
'CONFIG_DEBUG_TEST_DRIVER_REMOVE=y' is enabled, the following Call trace
can be seen.

[    1.424287] Failed to register pmu: armv8_pmuv3, reason -17
[    1.424870] WARNING: CPU: 0 PID: 1 at ../kernel/events/core.c:11771 perf_event_sysfs_init+0x98/0xdc
[    1.425220] Modules linked in:
[    1.425531] CPU: 0 PID: 1 Comm: swapper/0 Tainted: G        W         4.19.0-rc7-next-20181012-00003-ge7a97b1ad77b-dirty #35
[    1.425951] Hardware name: linux,dummy-virt (DT)
[    1.426212] pstate: 80000005 (Nzcv daif -PAN -UAO)
[    1.426458] pc : perf_event_sysfs_init+0x98/0xdc
[    1.426720] lr : perf_event_sysfs_init+0x98/0xdc
[    1.426908] sp : ffff00000804bd50
[    1.427077] x29: ffff00000804bd50 x28: ffff00000934e078
[    1.427429] x27: ffff000009546000 x26: 0000000000000007
[    1.427757] x25: ffff000009280710 x24: 00000000ffffffef
[    1.428086] x23: ffff000009408000 x22: 0000000000000000
[    1.428415] x21: ffff000009136008 x20: ffff000009408730
[    1.428744] x19: ffff80007b20b400 x18: 000000000000000a
[    1.429075] x17: 0000000000000000 x16: 0000000000000000
[    1.429418] x15: 0000000000000400 x14: 2e79726f74636572
[    1.429748] x13: 696420656d617320 x12: 656874206e692065
[    1.430060] x11: 6d616e20656d6173 x10: 2065687420687469
[    1.430335] x9 : ffff00000804bd50 x8 : 206e6f7361657220
[    1.430610] x7 : 2c3376756d705f38 x6 : ffff00000954d7ce
[    1.430880] x5 : 0000000000000000 x4 : 0000000000000000
[    1.431226] x3 : 0000000000000000 x2 : ffffffffffffffff
[    1.431554] x1 : 4d151327adc50b00 x0 : 0000000000000000
[    1.431868] Call trace:
[    1.432102]  perf_event_sysfs_init+0x98/0xdc
[    1.432382]  do_one_initcall+0x6c/0x1a8
[    1.432637]  kernel_init_freeable+0x1bc/0x280
[    1.432905]  kernel_init+0x18/0x160
[    1.433115]  ret_from_fork+0x10/0x18
[    1.433297] ---[ end trace 27fd415390eb9883 ]---

Rework to set suppress_bind_attrs flag to avoid removing the device when
CONFIG_DEBUG_TEST_DRIVER_REMOVE=y, since there's no real reason to
remove the armv8_pmuv3 driver.

Cc: Arnd Bergmann <arnd@arndb.de>
Co-developed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Anders Roxell <anders.roxell@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
anthraxx referenced this issue in anthraxx/linux-hardened Jan 28, 2019
@roxell @gregkh
arm64: perf: set suppress_bind_attrs flag to true
6f88ff1 
[ Upstream commit 81e9fa8 ]

The armv8_pmuv3 driver doesn't have a remove function, and when the test
'CONFIG_DEBUG_TEST_DRIVER_REMOVE=y' is enabled, the following Call trace
can be seen.

[    1.424287] Failed to register pmu: armv8_pmuv3, reason -17
[    1.424870] WARNING: CPU: 0 PID: 1 at ../kernel/events/core.c:11771 perf_event_sysfs_init+0x98/0xdc
[    1.425220] Modules linked in:
[    1.425531] CPU: 0 PID: 1 Comm: swapper/0 Tainted: G        W         4.19.0-rc7-next-20181012-00003-ge7a97b1ad77b-dirty #35
[    1.425951] Hardware name: linux,dummy-virt (DT)
[    1.426212] pstate: 80000005 (Nzcv daif -PAN -UAO)
[    1.426458] pc : perf_event_sysfs_init+0x98/0xdc
[    1.426720] lr : perf_event_sysfs_init+0x98/0xdc
[    1.426908] sp : ffff00000804bd50
[    1.427077] x29: ffff00000804bd50 x28: ffff00000934e078
[    1.427429] x27: ffff000009546000 x26: 0000000000000007
[    1.427757] x25: ffff000009280710 x24: 00000000ffffffef
[    1.428086] x23: ffff000009408000 x22: 0000000000000000
[    1.428415] x21: ffff000009136008 x20: ffff000009408730
[    1.428744] x19: ffff80007b20b400 x18: 000000000000000a
[    1.429075] x17: 0000000000000000 x16: 0000000000000000
[    1.429418] x15: 0000000000000400 x14: 2e79726f74636572
[    1.429748] x13: 696420656d617320 x12: 656874206e692065
[    1.430060] x11: 6d616e20656d6173 x10: 2065687420687469
[    1.430335] x9 : ffff00000804bd50 x8 : 206e6f7361657220
[    1.430610] x7 : 2c3376756d705f38 x6 : ffff00000954d7ce
[    1.430880] x5 : 0000000000000000 x4 : 0000000000000000
[    1.431226] x3 : 0000000000000000 x2 : ffffffffffffffff
[    1.431554] x1 : 4d151327adc50b00 x0 : 0000000000000000
[    1.431868] Call trace:
[    1.432102]  perf_event_sysfs_init+0x98/0xdc
[    1.432382]  do_one_initcall+0x6c/0x1a8
[    1.432637]  kernel_init_freeable+0x1bc/0x280
[    1.432905]  kernel_init+0x18/0x160
[    1.433115]  ret_from_fork+0x10/0x18
[    1.433297] ---[ end trace 27fd415390eb9883 ]---

Rework to set suppress_bind_attrs flag to avoid removing the device when
CONFIG_DEBUG_TEST_DRIVER_REMOVE=y, since there's no real reason to
remove the armv8_pmuv3 driver.

Cc: Arnd Bergmann <arnd@arndb.de>
Co-developed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Anders Roxell <anders.roxell@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
anthraxx referenced this issue in anthraxx/linux-hardened Jan 28, 2019
@roxell @gregkh
arm64: perf: set suppress_bind_attrs flag to true
2e7abfb 
[ Upstream commit 81e9fa8 ]

The armv8_pmuv3 driver doesn't have a remove function, and when the test
'CONFIG_DEBUG_TEST_DRIVER_REMOVE=y' is enabled, the following Call trace
can be seen.

[    1.424287] Failed to register pmu: armv8_pmuv3, reason -17
[    1.424870] WARNING: CPU: 0 PID: 1 at ../kernel/events/core.c:11771 perf_event_sysfs_init+0x98/0xdc
[    1.425220] Modules linked in:
[    1.425531] CPU: 0 PID: 1 Comm: swapper/0 Tainted: G        W         4.19.0-rc7-next-20181012-00003-ge7a97b1ad77b-dirty #35
[    1.425951] Hardware name: linux,dummy-virt (DT)
[    1.426212] pstate: 80000005 (Nzcv daif -PAN -UAO)
[    1.426458] pc : perf_event_sysfs_init+0x98/0xdc
[    1.426720] lr : perf_event_sysfs_init+0x98/0xdc
[    1.426908] sp : ffff00000804bd50
[    1.427077] x29: ffff00000804bd50 x28: ffff00000934e078
[    1.427429] x27: ffff000009546000 x26: 0000000000000007
[    1.427757] x25: ffff000009280710 x24: 00000000ffffffef
[    1.428086] x23: ffff000009408000 x22: 0000000000000000
[    1.428415] x21: ffff000009136008 x20: ffff000009408730
[    1.428744] x19: ffff80007b20b400 x18: 000000000000000a
[    1.429075] x17: 0000000000000000 x16: 0000000000000000
[    1.429418] x15: 0000000000000400 x14: 2e79726f74636572
[    1.429748] x13: 696420656d617320 x12: 656874206e692065
[    1.430060] x11: 6d616e20656d6173 x10: 2065687420687469
[    1.430335] x9 : ffff00000804bd50 x8 : 206e6f7361657220
[    1.430610] x7 : 2c3376756d705f38 x6 : ffff00000954d7ce
[    1.430880] x5 : 0000000000000000 x4 : 0000000000000000
[    1.431226] x3 : 0000000000000000 x2 : ffffffffffffffff
[    1.431554] x1 : 4d151327adc50b00 x0 : 0000000000000000
[    1.431868] Call trace:
[    1.432102]  perf_event_sysfs_init+0x98/0xdc
[    1.432382]  do_one_initcall+0x6c/0x1a8
[    1.432637]  kernel_init_freeable+0x1bc/0x280
[    1.432905]  kernel_init+0x18/0x160
[    1.433115]  ret_from_fork+0x10/0x18
[    1.433297] ---[ end trace 27fd415390eb9883 ]---

Rework to set suppress_bind_attrs flag to avoid removing the device when
CONFIG_DEBUG_TEST_DRIVER_REMOVE=y, since there's no real reason to
remove the armv8_pmuv3 driver.

Cc: Arnd Bergmann <arnd@arndb.de>
Co-developed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Anders Roxell <anders.roxell@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
anthraxx referenced this issue in anthraxx/linux-hardened Jul 29, 2019
@gregkh
block: null_blk: fix race condition for null_del_dev
c8f75e7 
[ Upstream commit 7602843 ]

Dulicate call of null_del_dev() will trigger null pointer error like below.
The reason is a race condition between nullb_device_power_store() and
nullb_group_drop_item().

  CPU#0                         CPU#1
  ----------------              -----------------
  do_rmdir()
   >configfs_rmdir()
    >client_drop_item()
     >nullb_group_drop_item()
                                nullb_device_power_store()
				>null_del_dev()

      >test_and_clear_bit(NULLB_DEV_FL_UP
       >null_del_dev()
       ^^^^^
       Duplicated null_dev_dev() triger null pointer error

				>clear_bit(NULLB_DEV_FL_UP

The fix could be keep the sequnce of clear NULLB_DEV_FL_UP and null_del_dev().

[  698.613600] BUG: unable to handle kernel NULL pointer dereference at 0000000000000018
[  698.613608] #PF error: [normal kernel read fault]
[  698.613611] PGD 0 P4D 0
[  698.613619] Oops: 0000 [#1] SMP PTI
[  698.613627] CPU: 3 PID: 6382 Comm: rmdir Not tainted 5.0.0+ #35
[  698.613631] Hardware name: LENOVO 20LJS2EV08/20LJS2EV08, BIOS R0SET33W (1.17 ) 07/18/2018
[  698.613644] RIP: 0010:null_del_dev+0xc/0x110 [null_blk]
[  698.613649] Code: 00 00 00 5b 41 5c 41 5d 41 5e 41 5f 5d c3 0f 0b eb 97 e8 47 bb 2a e8 0f 1f 80 00 00 00 00 0f 1f 44 00 00 55 48 89 e5 41 54 53 <8b> 77 18 48 89 fb 4c 8b 27 48 c7 c7 40 57 1e c1 e8 bf c7 cb e8 48
[  698.613654] RSP: 0018:ffffb887888bfde0 EFLAGS: 00010286
[  698.613659] RAX: 0000000000000000 RBX: ffff9d436d92bc00 RCX: ffff9d43a9184681
[  698.613663] RDX: ffffffffc11e5c30 RSI: 0000000068be6540 RDI: 0000000000000000
[  698.613667] RBP: ffffb887888bfdf0 R08: 0000000000000001 R09: 0000000000000000
[  698.613671] R10: ffffb887888bfdd8 R11: 0000000000000f16 R12: ffff9d436d92bc08
[  698.613675] R13: ffff9d436d94e630 R14: ffffffffc11e5088 R15: ffffffffc11e5000
[  698.613680] FS:  00007faa68be6540(0000) GS:ffff9d43d14c0000(0000) knlGS:0000000000000000
[  698.613685] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  698.613689] CR2: 0000000000000018 CR3: 000000042f70c002 CR4: 00000000003606e0
[  698.613693] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  698.613697] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  698.613700] Call Trace:
[  698.613712]  nullb_group_drop_item+0x50/0x70 [null_blk]
[  698.613722]  client_drop_item+0x29/0x40
[  698.613728]  configfs_rmdir+0x1ed/0x300
[  698.613738]  vfs_rmdir+0xb2/0x130
[  698.613743]  do_rmdir+0x1c7/0x1e0
[  698.613750]  __x64_sys_rmdir+0x17/0x20
[  698.613759]  do_syscall_64+0x5a/0x110
[  698.613768]  entry_SYSCALL_64_after_hwframe+0x44/0xa9

Signed-off-by: Bob Liu <bob.liu@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
anthraxx referenced this issue in anthraxx/linux-hardened Jul 29, 2019
@gregkh
block: null_blk: fix race condition for null_del_dev
7b6ee18 
[ Upstream commit 7602843 ]

Dulicate call of null_del_dev() will trigger null pointer error like below.
The reason is a race condition between nullb_device_power_store() and
nullb_group_drop_item().

  CPU#0                         CPU#1
  ----------------              -----------------
  do_rmdir()
   >configfs_rmdir()
    >client_drop_item()
     >nullb_group_drop_item()
                                nullb_device_power_store()
				>null_del_dev()

      >test_and_clear_bit(NULLB_DEV_FL_UP
       >null_del_dev()
       ^^^^^
       Duplicated null_dev_dev() triger null pointer error

				>clear_bit(NULLB_DEV_FL_UP

The fix could be keep the sequnce of clear NULLB_DEV_FL_UP and null_del_dev().

[  698.613600] BUG: unable to handle kernel NULL pointer dereference at 0000000000000018
[  698.613608] #PF error: [normal kernel read fault]
[  698.613611] PGD 0 P4D 0
[  698.613619] Oops: 0000 [#1] SMP PTI
[  698.613627] CPU: 3 PID: 6382 Comm: rmdir Not tainted 5.0.0+ #35
[  698.613631] Hardware name: LENOVO 20LJS2EV08/20LJS2EV08, BIOS R0SET33W (1.17 ) 07/18/2018
[  698.613644] RIP: 0010:null_del_dev+0xc/0x110 [null_blk]
[  698.613649] Code: 00 00 00 5b 41 5c 41 5d 41 5e 41 5f 5d c3 0f 0b eb 97 e8 47 bb 2a e8 0f 1f 80 00 00 00 00 0f 1f 44 00 00 55 48 89 e5 41 54 53 <8b> 77 18 48 89 fb 4c 8b 27 48 c7 c7 40 57 1e c1 e8 bf c7 cb e8 48
[  698.613654] RSP: 0018:ffffb887888bfde0 EFLAGS: 00010286
[  698.613659] RAX: 0000000000000000 RBX: ffff9d436d92bc00 RCX: ffff9d43a9184681
[  698.613663] RDX: ffffffffc11e5c30 RSI: 0000000068be6540 RDI: 0000000000000000
[  698.613667] RBP: ffffb887888bfdf0 R08: 0000000000000001 R09: 0000000000000000
[  698.613671] R10: ffffb887888bfdd8 R11: 0000000000000f16 R12: ffff9d436d92bc08
[  698.613675] R13: ffff9d436d94e630 R14: ffffffffc11e5088 R15: ffffffffc11e5000
[  698.613680] FS:  00007faa68be6540(0000) GS:ffff9d43d14c0000(0000) knlGS:0000000000000000
[  698.613685] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  698.613689] CR2: 0000000000000018 CR3: 000000042f70c002 CR4: 00000000003606e0
[  698.613693] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  698.613697] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  698.613700] Call Trace:
[  698.613712]  nullb_group_drop_item+0x50/0x70 [null_blk]
[  698.613722]  client_drop_item+0x29/0x40
[  698.613728]  configfs_rmdir+0x1ed/0x300
[  698.613738]  vfs_rmdir+0xb2/0x130
[  698.613743]  do_rmdir+0x1c7/0x1e0
[  698.613750]  __x64_sys_rmdir+0x17/0x20
[  698.613759]  do_syscall_64+0x5a/0x110
[  698.613768]  entry_SYSCALL_64_after_hwframe+0x44/0xa9

Signed-off-by: Bob Liu <bob.liu@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
anthraxx referenced this issue in anthraxx/linux-hardened Jul 29, 2019
@gregkh
block: null_blk: fix race condition for null_del_dev
c538dfa 
[ Upstream commit 7602843 ]

Dulicate call of null_del_dev() will trigger null pointer error like below.
The reason is a race condition between nullb_device_power_store() and
nullb_group_drop_item().

  CPU#0                         CPU#1
  ----------------              -----------------
  do_rmdir()
   >configfs_rmdir()
    >client_drop_item()
     >nullb_group_drop_item()
                                nullb_device_power_store()
				>null_del_dev()

      >test_and_clear_bit(NULLB_DEV_FL_UP
       >null_del_dev()
       ^^^^^
       Duplicated null_dev_dev() triger null pointer error

				>clear_bit(NULLB_DEV_FL_UP

The fix could be keep the sequnce of clear NULLB_DEV_FL_UP and null_del_dev().

[  698.613600] BUG: unable to handle kernel NULL pointer dereference at 0000000000000018
[  698.613608] #PF error: [normal kernel read fault]
[  698.613611] PGD 0 P4D 0
[  698.613619] Oops: 0000 [#1] SMP PTI
[  698.613627] CPU: 3 PID: 6382 Comm: rmdir Not tainted 5.0.0+ #35
[  698.613631] Hardware name: LENOVO 20LJS2EV08/20LJS2EV08, BIOS R0SET33W (1.17 ) 07/18/2018
[  698.613644] RIP: 0010:null_del_dev+0xc/0x110 [null_blk]
[  698.613649] Code: 00 00 00 5b 41 5c 41 5d 41 5e 41 5f 5d c3 0f 0b eb 97 e8 47 bb 2a e8 0f 1f 80 00 00 00 00 0f 1f 44 00 00 55 48 89 e5 41 54 53 <8b> 77 18 48 89 fb 4c 8b 27 48 c7 c7 40 57 1e c1 e8 bf c7 cb e8 48
[  698.613654] RSP: 0018:ffffb887888bfde0 EFLAGS: 00010286
[  698.613659] RAX: 0000000000000000 RBX: ffff9d436d92bc00 RCX: ffff9d43a9184681
[  698.613663] RDX: ffffffffc11e5c30 RSI: 0000000068be6540 RDI: 0000000000000000
[  698.613667] RBP: ffffb887888bfdf0 R08: 0000000000000001 R09: 0000000000000000
[  698.613671] R10: ffffb887888bfdd8 R11: 0000000000000f16 R12: ffff9d436d92bc08
[  698.613675] R13: ffff9d436d94e630 R14: ffffffffc11e5088 R15: ffffffffc11e5000
[  698.613680] FS:  00007faa68be6540(0000) GS:ffff9d43d14c0000(0000) knlGS:0000000000000000
[  698.613685] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  698.613689] CR2: 0000000000000018 CR3: 000000042f70c002 CR4: 00000000003606e0
[  698.613693] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  698.613697] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  698.613700] Call Trace:
[  698.613712]  nullb_group_drop_item+0x50/0x70 [null_blk]
[  698.613722]  client_drop_item+0x29/0x40
[  698.613728]  configfs_rmdir+0x1ed/0x300
[  698.613738]  vfs_rmdir+0xb2/0x130
[  698.613743]  do_rmdir+0x1c7/0x1e0
[  698.613750]  __x64_sys_rmdir+0x17/0x20
[  698.613759]  do_syscall_64+0x5a/0x110
[  698.613768]  entry_SYSCALL_64_after_hwframe+0x44/0xa9

Signed-off-by: Bob Liu <bob.liu@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
anthraxx referenced this issue in anthraxx/linux-hardened Feb 13, 2020
@vcgomes @gregkh
taprio: Fix still allowing changing the flags during runtime
d544302 
[ Upstream commit a9d6227 ]

Because 'q->flags' starts as zero, and zero is a valid value, we
aren't able to detect the transition from zero to something else
during "runtime".

The solution is to initialize 'q->flags' with an invalid value, so we
can detect if 'q->flags' was set by the user or not.

To better solidify the behavior, 'flags' handling is moved to a
separate function. The behavior is:
 - 'flags' if unspecified by the user, is assumed to be zero;
 - 'flags' cannot change during "runtime" (i.e. a change() request
 cannot modify it);

With this new function we can remove taprio_flags, which should reduce
the risk of future accidents.

Allowing flags to be changed was causing the following RCU stall:

[ 1730.558249] rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
[ 1730.558258] rcu: 	  6-...0: (190 ticks this GP) idle=922/0/0x1 softirq=25580/25582 fqs=16250
[ 1730.558264] 		  (detected by 2, t=65002 jiffies, g=33017, q=81)
[ 1730.558269] Sending NMI from CPU 2 to CPUs 6:
[ 1730.559277] NMI backtrace for cpu 6
[ 1730.559277] CPU: 6 PID: 0 Comm: swapper/6 Tainted: G            E     5.5.0-rc6+ #35
[ 1730.559278] Hardware name: Gigabyte Technology Co., Ltd. Z390 AORUS ULTRA/Z390 AORUS ULTRA-CF, BIOS F7 03/14/2019
[ 1730.559278] RIP: 0010:__hrtimer_run_queues+0xe2/0x440
[ 1730.559278] Code: 48 8b 43 28 4c 89 ff 48 8b 75 c0 48 89 45 c8 e8 f4 bb 7c 00 0f 1f 44 00 00 65 8b 05 40 31 f0 68 89 c0 48 0f a3 05 3e 5c 25 01 <0f> 82 fc 01 00 00 48 8b 45 c8 48 89 df ff d0 89 45 c8 0f 1f 44 00
[ 1730.559279] RSP: 0018:ffff9970802d8f10 EFLAGS: 00000083
[ 1730.559279] RAX: 0000000000000006 RBX: ffff8b31645bff38 RCX: 0000000000000000
[ 1730.559280] RDX: 0000000000000000 RSI: ffffffff9710f2ec RDI: ffffffff978daf0e
[ 1730.559280] RBP: ffff9970802d8f68 R08: 0000000000000000 R09: 0000000000000000
[ 1730.559280] R10: 0000018336d7944e R11: 0000000000000001 R12: ffff8b316e39f9c0
[ 1730.559281] R13: ffff8b316e39f940 R14: ffff8b316e39f998 R15: ffff8b316e39f7c0
[ 1730.559281] FS:  0000000000000000(0000) GS:ffff8b316e380000(0000) knlGS:0000000000000000
[ 1730.559281] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1730.559281] CR2: 00007f1105303760 CR3: 0000000227210005 CR4: 00000000003606e0
[ 1730.559282] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 1730.559282] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 1730.559282] Call Trace:
[ 1730.559282]  <IRQ>
[ 1730.559283]  ? taprio_dequeue_soft+0x2d0/0x2d0 [sch_taprio]
[ 1730.559283]  hrtimer_interrupt+0x104/0x220
[ 1730.559283]  ? irqtime_account_irq+0x34/0xa0
[ 1730.559283]  smp_apic_timer_interrupt+0x6d/0x230
[ 1730.559284]  apic_timer_interrupt+0xf/0x20
[ 1730.559284]  </IRQ>
[ 1730.559284] RIP: 0010:cpu_idle_poll+0x35/0x1a0
[ 1730.559285] Code: 88 82 ff 65 44 8b 25 12 7d 73 68 0f 1f 44 00 00 e8 90 c3 89 ff fb 65 48 8b 1c 25 c0 7e 01 00 48 8b 03 a8 08 74 0b eb 1c f3 90 <48> 8b 03 a8 08 75 13 8b 05 be a8 a8 00 85 c0 75 ed e8 75 48 84 ff
[ 1730.559285] RSP: 0018:ffff997080137ea8 EFLAGS: 00000202 ORIG_RAX: ffffffffffffff13
[ 1730.559285] RAX: 0000000000000001 RBX: ffff8b316bc3c580 RCX: 0000000000000000
[ 1730.559286] RDX: 0000000000000001 RSI: 000000002819aad9 RDI: ffffffff978da730
[ 1730.559286] RBP: ffff997080137ec0 R08: 0000018324a6d387 R09: 0000000000000000
[ 1730.559286] R10: 0000000000000400 R11: 0000000000000001 R12: 0000000000000006
[ 1730.559286] R13: ffff8b316bc3c580 R14: 0000000000000000 R15: 0000000000000000
[ 1730.559287]  ? cpu_idle_poll+0x20/0x1a0
[ 1730.559287]  ? cpu_idle_poll+0x20/0x1a0
[ 1730.559287]  do_idle+0x4d/0x1f0
[ 1730.559287]  ? complete+0x44/0x50
[ 1730.559288]  cpu_startup_entry+0x1b/0x20
[ 1730.559288]  start_secondary+0x142/0x180
[ 1730.559288]  secondary_startup_64+0xb6/0xc0
[ 1776.686313] nvme nvme0: I/O 96 QID 1 timeout, completion polled

Fixes: 4cfd577 ("taprio: Add support for txtime-assist mode")
Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
anthraxx referenced this issue in anthraxx/linux-hardened Mar 17, 2020
@vcgomes @gregkh
taprio: Fix still allowing changing the flags during runtime
b9b5a76 
[ Upstream commit a9d6227 ]

Because 'q->flags' starts as zero, and zero is a valid value, we
aren't able to detect the transition from zero to something else
during "runtime".

The solution is to initialize 'q->flags' with an invalid value, so we
can detect if 'q->flags' was set by the user or not.

To better solidify the behavior, 'flags' handling is moved to a
separate function. The behavior is:
 - 'flags' if unspecified by the user, is assumed to be zero;
 - 'flags' cannot change during "runtime" (i.e. a change() request
 cannot modify it);

With this new function we can remove taprio_flags, which should reduce
the risk of future accidents.

Allowing flags to be changed was causing the following RCU stall:

[ 1730.558249] rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
[ 1730.558258] rcu: 	  6-...0: (190 ticks this GP) idle=922/0/0x1 softirq=25580/25582 fqs=16250
[ 1730.558264] 		  (detected by 2, t=65002 jiffies, g=33017, q=81)
[ 1730.558269] Sending NMI from CPU 2 to CPUs 6:
[ 1730.559277] NMI backtrace for cpu 6
[ 1730.559277] CPU: 6 PID: 0 Comm: swapper/6 Tainted: G            E     5.5.0-rc6+ #35
[ 1730.559278] Hardware name: Gigabyte Technology Co., Ltd. Z390 AORUS ULTRA/Z390 AORUS ULTRA-CF, BIOS F7 03/14/2019
[ 1730.559278] RIP: 0010:__hrtimer_run_queues+0xe2/0x440
[ 1730.559278] Code: 48 8b 43 28 4c 89 ff 48 8b 75 c0 48 89 45 c8 e8 f4 bb 7c 00 0f 1f 44 00 00 65 8b 05 40 31 f0 68 89 c0 48 0f a3 05 3e 5c 25 01 <0f> 82 fc 01 00 00 48 8b 45 c8 48 89 df ff d0 89 45 c8 0f 1f 44 00
[ 1730.559279] RSP: 0018:ffff9970802d8f10 EFLAGS: 00000083
[ 1730.559279] RAX: 0000000000000006 RBX: ffff8b31645bff38 RCX: 0000000000000000
[ 1730.559280] RDX: 0000000000000000 RSI: ffffffff9710f2ec RDI: ffffffff978daf0e
[ 1730.559280] RBP: ffff9970802d8f68 R08: 0000000000000000 R09: 0000000000000000
[ 1730.559280] R10: 0000018336d7944e R11: 0000000000000001 R12: ffff8b316e39f9c0
[ 1730.559281] R13: ffff8b316e39f940 R14: ffff8b316e39f998 R15: ffff8b316e39f7c0
[ 1730.559281] FS:  0000000000000000(0000) GS:ffff8b316e380000(0000) knlGS:0000000000000000
[ 1730.559281] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1730.559281] CR2: 00007f1105303760 CR3: 0000000227210005 CR4: 00000000003606e0
[ 1730.559282] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 1730.559282] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 1730.559282] Call Trace:
[ 1730.559282]  <IRQ>
[ 1730.559283]  ? taprio_dequeue_soft+0x2d0/0x2d0 [sch_taprio]
[ 1730.559283]  hrtimer_interrupt+0x104/0x220
[ 1730.559283]  ? irqtime_account_irq+0x34/0xa0
[ 1730.559283]  smp_apic_timer_interrupt+0x6d/0x230
[ 1730.559284]  apic_timer_interrupt+0xf/0x20
[ 1730.559284]  </IRQ>
[ 1730.559284] RIP: 0010:cpu_idle_poll+0x35/0x1a0
[ 1730.559285] Code: 88 82 ff 65 44 8b 25 12 7d 73 68 0f 1f 44 00 00 e8 90 c3 89 ff fb 65 48 8b 1c 25 c0 7e 01 00 48 8b 03 a8 08 74 0b eb 1c f3 90 <48> 8b 03 a8 08 75 13 8b 05 be a8 a8 00 85 c0 75 ed e8 75 48 84 ff
[ 1730.559285] RSP: 0018:ffff997080137ea8 EFLAGS: 00000202 ORIG_RAX: ffffffffffffff13
[ 1730.559285] RAX: 0000000000000001 RBX: ffff8b316bc3c580 RCX: 0000000000000000
[ 1730.559286] RDX: 0000000000000001 RSI: 000000002819aad9 RDI: ffffffff978da730
[ 1730.559286] RBP: ffff997080137ec0 R08: 0000018324a6d387 R09: 0000000000000000
[ 1730.559286] R10: 0000000000000400 R11: 0000000000000001 R12: 0000000000000006
[ 1730.559286] R13: ffff8b316bc3c580 R14: 0000000000000000 R15: 0000000000000000
[ 1730.559287]  ? cpu_idle_poll+0x20/0x1a0
[ 1730.559287]  ? cpu_idle_poll+0x20/0x1a0
[ 1730.559287]  do_idle+0x4d/0x1f0
[ 1730.559287]  ? complete+0x44/0x50
[ 1730.559288]  cpu_startup_entry+0x1b/0x20
[ 1730.559288]  start_secondary+0x142/0x180
[ 1730.559288]  secondary_startup_64+0xb6/0xc0
[ 1776.686313] nvme nvme0: I/O 96 QID 1 timeout, completion polled

Fixes: 4cfd577 ("taprio: Add support for txtime-assist mode")
Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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