Division by zero in kernel (uart) with latest kernels #123

lintweaker · 2012-09-25T15:52:45Z

I am seeing "Devision by zero" backtraces at bootup with the latest kernels (#168 and #171). They do not harm but should not be there.
This is on raspbian (2012-09-12 image) fully updated.

[ 0.777928] Console: switching to colour frame buffer device 210x65
[ 0.802400] ------------[ cut here ]------------
[ 0.802600] WARNING: at drivers/tty/serial/serial_core.c:402 uart_get_baud_rate+0xe8/0x150()
[ 0.802813] Modules linked in:
[ 0.802953] from
[ 0.803213] from
[ 0.803490] from
[ 0.803762] from
[ 0.804040] from
[ 0.804305] from
[ 0.804579] from
[ 0.804866] from
[ 0.805159] from
[ 0.805444] from
[ 0.805719] from
[ 0.806031] ---[ end trace f3b9c4fa506cdf51 ]---
[ 0.806184] Division by zero in kernel.
[ 0.806351] from
[ 0.806604] from
[ 0.806854] from
[ 0.807122] from
[ 0.807392] from
[ 0.807677] from
[ 0.807974] from
[ 0.808255] from
[ 0.808531] from
[ 0.808769] Division by zero in kernel.
[ 0.808927] from
[ 0.809173] from
[ 0.809425] from
[ 0.809701] from
[ 0.818354] from
[ 0.826964] from
[ 0.835695] from
[ 0.844527] from
[ 0.853444] from
[ 0.862465] from
[ 0.871573] kgdb: Registered I/O driver kgdboc.

licaon-kter · 2012-09-25T20:00:58Z

modified cmdline.txt? config.txt?

DrivenLogic · 2012-09-25T23:29:24Z

It would be a fair assumption to think that config.txt was used by the kernel for UART settings.... however UART clock speed is hard coded in the RPi kernel... only the GPU bootloader reads the settings in config.txt in regards to UART.

See this issue:
#105

There has been some recent work on the GPU mailbox stuff by @popcornmix: adae199#arch/arm/mach-bcm2708/include/mach/vcio.h

But I can't see spot anything new in regards to UART?

AFAIK the current hardcoded clock value is right at the bottom of this header: https://github.com/raspberrypi/linux/blob/rpi-3.2.27/arch/arm/mach-bcm2708/include/mach/platform.h

lintweaker · 2012-09-26T15:16:50Z

ah, yes. Found the culprit. Due to additions in cmdline.txt a had a misformed 'console=ttyAMA0,115200' part, it read 'onsole=ttyAMA0,115200'. That driver should really check its input...

commit 10164c2 upstream. Fix driver new_id sysfs-attribute removal deadlock by making sure to not hold any locks that the attribute operations grab when removing the attribute. Specifically, usb_serial_deregister holds the table mutex when deregistering the driver, which includes removing the new_id attribute. This can lead to a deadlock as writing to new_id increments the attribute's active count before trying to grab the same mutex in usb_serial_probe. The deadlock can easily be triggered by inserting a sleep in usb_serial_deregister and writing the id of an unbound device to new_id during module unload. As the table mutex (in this case) is used to prevent subdriver unload during probe, it should be sufficient to only hold the lock while manipulating the usb-serial driver list during deregister. A racing probe will then either fail to find a matching subdriver or fail to get the corresponding module reference. Since v3.15-rc1 this also triggers the following lockdep warning: ====================================================== [ INFO: possible circular locking dependency detected ] 3.15.0-rc2 #123 Tainted: G W ------------------------------------------------------- modprobe/190 is trying to acquire lock: (s_active#4){++++.+}, at: [<c0167aa0>] kernfs_remove_by_name_ns+0x4c/0x94 but task is already holding lock: (table_lock){+.+.+.}, at: [<bf004d84>] usb_serial_deregister+0x3c/0x78 [usbserial] which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (table_lock){+.+.+.}: [<c0075f84>] __lock_acquire+0x1694/0x1ce4 [<c0076de8>] lock_acquire+0xb4/0x154 [<c03af3cc>] _raw_spin_lock+0x4c/0x5c [<c02bbc24>] usb_store_new_id+0x14c/0x1ac [<bf007eb4>] new_id_store+0x68/0x70 [usbserial] [<c025f568>] drv_attr_store+0x30/0x3c [<c01690e0>] sysfs_kf_write+0x5c/0x60 [<c01682c0>] kernfs_fop_write+0xd4/0x194 [<c010881c>] vfs_write+0xbc/0x198 [<c0108e4c>] SyS_write+0x4c/0xa0 [<c000f880>] ret_fast_syscall+0x0/0x48 -> #0 (s_active#4){++++.+}: [<c03a7a28>] print_circular_bug+0x68/0x2f8 [<c0076218>] __lock_acquire+0x1928/0x1ce4 [<c0076de8>] lock_acquire+0xb4/0x154 [<c0166b70>] __kernfs_remove+0x254/0x310 [<c0167aa0>] kernfs_remove_by_name_ns+0x4c/0x94 [<c0169fb8>] remove_files.isra.1+0x48/0x84 [<c016a2fc>] sysfs_remove_group+0x58/0xac [<c016a414>] sysfs_remove_groups+0x34/0x44 [<c02623b8>] driver_remove_groups+0x1c/0x20 [<c0260e9c>] bus_remove_driver+0x3c/0xe4 [<c026235c>] driver_unregister+0x38/0x58 [<bf007fb4>] usb_serial_bus_deregister+0x84/0x88 [usbserial] [<bf004db4>] usb_serial_deregister+0x6c/0x78 [usbserial] [<bf005330>] usb_serial_deregister_drivers+0x2c/0x4c [usbserial] [<bf016618>] usb_serial_module_exit+0x14/0x1c [sierra] [<c009d6cc>] SyS_delete_module+0x184/0x210 [<c000f880>] ret_fast_syscall+0x0/0x48 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(table_lock); lock(s_active#4); lock(table_lock); lock(s_active#4); *** DEADLOCK *** 1 lock held by modprobe/190: #0: (table_lock){+.+.+.}, at: [<bf004d84>] usb_serial_deregister+0x3c/0x78 [usbserial] stack backtrace: CPU: 0 PID: 190 Comm: modprobe Tainted: G W 3.15.0-rc2 #123 [<c0015e10>] (unwind_backtrace) from [<c0013728>] (show_stack+0x20/0x24) [<c0013728>] (show_stack) from [<c03a9a54>] (dump_stack+0x24/0x28) [<c03a9a54>] (dump_stack) from [<c03a7cac>] (print_circular_bug+0x2ec/0x2f8) [<c03a7cac>] (print_circular_bug) from [<c0076218>] (__lock_acquire+0x1928/0x1ce4) [<c0076218>] (__lock_acquire) from [<c0076de8>] (lock_acquire+0xb4/0x154) [<c0076de8>] (lock_acquire) from [<c0166b70>] (__kernfs_remove+0x254/0x310) [<c0166b70>] (__kernfs_remove) from [<c0167aa0>] (kernfs_remove_by_name_ns+0x4c/0x94) [<c0167aa0>] (kernfs_remove_by_name_ns) from [<c0169fb8>] (remove_files.isra.1+0x48/0x84) [<c0169fb8>] (remove_files.isra.1) from [<c016a2fc>] (sysfs_remove_group+0x58/0xac) [<c016a2fc>] (sysfs_remove_group) from [<c016a414>] (sysfs_remove_groups+0x34/0x44) [<c016a414>] (sysfs_remove_groups) from [<c02623b8>] (driver_remove_groups+0x1c/0x20) [<c02623b8>] (driver_remove_groups) from [<c0260e9c>] (bus_remove_driver+0x3c/0xe4) [<c0260e9c>] (bus_remove_driver) from [<c026235c>] (driver_unregister+0x38/0x58) [<c026235c>] (driver_unregister) from [<bf007fb4>] (usb_serial_bus_deregister+0x84/0x88 [usbserial]) [<bf007fb4>] (usb_serial_bus_deregister [usbserial]) from [<bf004db4>] (usb_serial_deregister+0x6c/0x78 [usbserial]) [<bf004db4>] (usb_serial_deregister [usbserial]) from [<bf005330>] (usb_serial_deregister_drivers+0x2c/0x4c [usbserial]) [<bf005330>] (usb_serial_deregister_drivers [usbserial]) from [<bf016618>] (usb_serial_module_exit+0x14/0x1c [sierra]) [<bf016618>] (usb_serial_module_exit [sierra]) from [<c009d6cc>] (SyS_delete_module+0x184/0x210) [<c009d6cc>] (SyS_delete_module) from [<c000f880>] (ret_fast_syscall+0x0/0x48) Signed-off-by: Johan Hovold <jhovold@gmail.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz>

commit 10164c2 upstream. Fix driver new_id sysfs-attribute removal deadlock by making sure to not hold any locks that the attribute operations grab when removing the attribute. Specifically, usb_serial_deregister holds the table mutex when deregistering the driver, which includes removing the new_id attribute. This can lead to a deadlock as writing to new_id increments the attribute's active count before trying to grab the same mutex in usb_serial_probe. The deadlock can easily be triggered by inserting a sleep in usb_serial_deregister and writing the id of an unbound device to new_id during module unload. As the table mutex (in this case) is used to prevent subdriver unload during probe, it should be sufficient to only hold the lock while manipulating the usb-serial driver list during deregister. A racing probe will then either fail to find a matching subdriver or fail to get the corresponding module reference. Since v3.15-rc1 this also triggers the following lockdep warning: ====================================================== [ INFO: possible circular locking dependency detected ] 3.15.0-rc2 #123 Tainted: G W ------------------------------------------------------- modprobe/190 is trying to acquire lock: (s_active#4){++++.+}, at: [<c0167aa0>] kernfs_remove_by_name_ns+0x4c/0x94 but task is already holding lock: (table_lock){+.+.+.}, at: [<bf004d84>] usb_serial_deregister+0x3c/0x78 [usbserial] which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (table_lock){+.+.+.}: [<c0075f84>] __lock_acquire+0x1694/0x1ce4 [<c0076de8>] lock_acquire+0xb4/0x154 [<c03af3cc>] _raw_spin_lock+0x4c/0x5c [<c02bbc24>] usb_store_new_id+0x14c/0x1ac [<bf007eb4>] new_id_store+0x68/0x70 [usbserial] [<c025f568>] drv_attr_store+0x30/0x3c [<c01690e0>] sysfs_kf_write+0x5c/0x60 [<c01682c0>] kernfs_fop_write+0xd4/0x194 [<c010881c>] vfs_write+0xbc/0x198 [<c0108e4c>] SyS_write+0x4c/0xa0 [<c000f880>] ret_fast_syscall+0x0/0x48 -> #0 (s_active#4){++++.+}: [<c03a7a28>] print_circular_bug+0x68/0x2f8 [<c0076218>] __lock_acquire+0x1928/0x1ce4 [<c0076de8>] lock_acquire+0xb4/0x154 [<c0166b70>] __kernfs_remove+0x254/0x310 [<c0167aa0>] kernfs_remove_by_name_ns+0x4c/0x94 [<c0169fb8>] remove_files.isra.1+0x48/0x84 [<c016a2fc>] sysfs_remove_group+0x58/0xac [<c016a414>] sysfs_remove_groups+0x34/0x44 [<c02623b8>] driver_remove_groups+0x1c/0x20 [<c0260e9c>] bus_remove_driver+0x3c/0xe4 [<c026235c>] driver_unregister+0x38/0x58 [<bf007fb4>] usb_serial_bus_deregister+0x84/0x88 [usbserial] [<bf004db4>] usb_serial_deregister+0x6c/0x78 [usbserial] [<bf005330>] usb_serial_deregister_drivers+0x2c/0x4c [usbserial] [<bf016618>] usb_serial_module_exit+0x14/0x1c [sierra] [<c009d6cc>] SyS_delete_module+0x184/0x210 [<c000f880>] ret_fast_syscall+0x0/0x48 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(table_lock); lock(s_active#4); lock(table_lock); lock(s_active#4); *** DEADLOCK *** 1 lock held by modprobe/190: #0: (table_lock){+.+.+.}, at: [<bf004d84>] usb_serial_deregister+0x3c/0x78 [usbserial] stack backtrace: CPU: 0 PID: 190 Comm: modprobe Tainted: G W 3.15.0-rc2 #123 [<c0015e10>] (unwind_backtrace) from [<c0013728>] (show_stack+0x20/0x24) [<c0013728>] (show_stack) from [<c03a9a54>] (dump_stack+0x24/0x28) [<c03a9a54>] (dump_stack) from [<c03a7cac>] (print_circular_bug+0x2ec/0x2f8) [<c03a7cac>] (print_circular_bug) from [<c0076218>] (__lock_acquire+0x1928/0x1ce4) [<c0076218>] (__lock_acquire) from [<c0076de8>] (lock_acquire+0xb4/0x154) [<c0076de8>] (lock_acquire) from [<c0166b70>] (__kernfs_remove+0x254/0x310) [<c0166b70>] (__kernfs_remove) from [<c0167aa0>] (kernfs_remove_by_name_ns+0x4c/0x94) [<c0167aa0>] (kernfs_remove_by_name_ns) from [<c0169fb8>] (remove_files.isra.1+0x48/0x84) [<c0169fb8>] (remove_files.isra.1) from [<c016a2fc>] (sysfs_remove_group+0x58/0xac) [<c016a2fc>] (sysfs_remove_group) from [<c016a414>] (sysfs_remove_groups+0x34/0x44) [<c016a414>] (sysfs_remove_groups) from [<c02623b8>] (driver_remove_groups+0x1c/0x20) [<c02623b8>] (driver_remove_groups) from [<c0260e9c>] (bus_remove_driver+0x3c/0xe4) [<c0260e9c>] (bus_remove_driver) from [<c026235c>] (driver_unregister+0x38/0x58) [<c026235c>] (driver_unregister) from [<bf007fb4>] (usb_serial_bus_deregister+0x84/0x88 [usbserial]) [<bf007fb4>] (usb_serial_bus_deregister [usbserial]) from [<bf004db4>] (usb_serial_deregister+0x6c/0x78 [usbserial]) [<bf004db4>] (usb_serial_deregister [usbserial]) from [<bf005330>] (usb_serial_deregister_drivers+0x2c/0x4c [usbserial]) [<bf005330>] (usb_serial_deregister_drivers [usbserial]) from [<bf016618>] (usb_serial_module_exit+0x14/0x1c [sierra]) [<bf016618>] (usb_serial_module_exit [sierra]) from [<c009d6cc>] (SyS_delete_module+0x184/0x210) [<c009d6cc>] (SyS_delete_module) from [<c000f880>] (ret_fast_syscall+0x0/0x48) Signed-off-by: Johan Hovold <jhovold@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Fix driver new_id sysfs-attribute removal deadlock by making sure to not hold any locks that the attribute operations grab when removing the attribute. Specifically, usb_serial_deregister holds the table mutex when deregistering the driver, which includes removing the new_id attribute. This can lead to a deadlock as writing to new_id increments the attribute's active count before trying to grab the same mutex in usb_serial_probe. The deadlock can easily be triggered by inserting a sleep in usb_serial_deregister and writing the id of an unbound device to new_id during module unload. As the table mutex (in this case) is used to prevent subdriver unload during probe, it should be sufficient to only hold the lock while manipulating the usb-serial driver list during deregister. A racing probe will then either fail to find a matching subdriver or fail to get the corresponding module reference. Since v3.15-rc1 this also triggers the following lockdep warning: ====================================================== [ INFO: possible circular locking dependency detected ] 3.15.0-rc2 #123 Tainted: G W ------------------------------------------------------- modprobe/190 is trying to acquire lock: (s_active#4){++++.+}, at: [<c0167aa0>] kernfs_remove_by_name_ns+0x4c/0x94 but task is already holding lock: (table_lock){+.+.+.}, at: [<bf004d84>] usb_serial_deregister+0x3c/0x78 [usbserial] which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (table_lock){+.+.+.}: [<c0075f84>] __lock_acquire+0x1694/0x1ce4 [<c0076de8>] lock_acquire+0xb4/0x154 [<c03af3cc>] _raw_spin_lock+0x4c/0x5c [<c02bbc24>] usb_store_new_id+0x14c/0x1ac [<bf007eb4>] new_id_store+0x68/0x70 [usbserial] [<c025f568>] drv_attr_store+0x30/0x3c [<c01690e0>] sysfs_kf_write+0x5c/0x60 [<c01682c0>] kernfs_fop_write+0xd4/0x194 [<c010881c>] vfs_write+0xbc/0x198 [<c0108e4c>] SyS_write+0x4c/0xa0 [<c000f880>] ret_fast_syscall+0x0/0x48 -> #0 (s_active#4){++++.+}: [<c03a7a28>] print_circular_bug+0x68/0x2f8 [<c0076218>] __lock_acquire+0x1928/0x1ce4 [<c0076de8>] lock_acquire+0xb4/0x154 [<c0166b70>] __kernfs_remove+0x254/0x310 [<c0167aa0>] kernfs_remove_by_name_ns+0x4c/0x94 [<c0169fb8>] remove_files.isra.1+0x48/0x84 [<c016a2fc>] sysfs_remove_group+0x58/0xac [<c016a414>] sysfs_remove_groups+0x34/0x44 [<c02623b8>] driver_remove_groups+0x1c/0x20 [<c0260e9c>] bus_remove_driver+0x3c/0xe4 [<c026235c>] driver_unregister+0x38/0x58 [<bf007fb4>] usb_serial_bus_deregister+0x84/0x88 [usbserial] [<bf004db4>] usb_serial_deregister+0x6c/0x78 [usbserial] [<bf005330>] usb_serial_deregister_drivers+0x2c/0x4c [usbserial] [<bf016618>] usb_serial_module_exit+0x14/0x1c [sierra] [<c009d6cc>] SyS_delete_module+0x184/0x210 [<c000f880>] ret_fast_syscall+0x0/0x48 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(table_lock); lock(s_active#4); lock(table_lock); lock(s_active#4); *** DEADLOCK *** 1 lock held by modprobe/190: #0: (table_lock){+.+.+.}, at: [<bf004d84>] usb_serial_deregister+0x3c/0x78 [usbserial] stack backtrace: CPU: 0 PID: 190 Comm: modprobe Tainted: G W 3.15.0-rc2 #123 [<c0015e10>] (unwind_backtrace) from [<c0013728>] (show_stack+0x20/0x24) [<c0013728>] (show_stack) from [<c03a9a54>] (dump_stack+0x24/0x28) [<c03a9a54>] (dump_stack) from [<c03a7cac>] (print_circular_bug+0x2ec/0x2f8) [<c03a7cac>] (print_circular_bug) from [<c0076218>] (__lock_acquire+0x1928/0x1ce4) [<c0076218>] (__lock_acquire) from [<c0076de8>] (lock_acquire+0xb4/0x154) [<c0076de8>] (lock_acquire) from [<c0166b70>] (__kernfs_remove+0x254/0x310) [<c0166b70>] (__kernfs_remove) from [<c0167aa0>] (kernfs_remove_by_name_ns+0x4c/0x94) [<c0167aa0>] (kernfs_remove_by_name_ns) from [<c0169fb8>] (remove_files.isra.1+0x48/0x84) [<c0169fb8>] (remove_files.isra.1) from [<c016a2fc>] (sysfs_remove_group+0x58/0xac) [<c016a2fc>] (sysfs_remove_group) from [<c016a414>] (sysfs_remove_groups+0x34/0x44) [<c016a414>] (sysfs_remove_groups) from [<c02623b8>] (driver_remove_groups+0x1c/0x20) [<c02623b8>] (driver_remove_groups) from [<c0260e9c>] (bus_remove_driver+0x3c/0xe4) [<c0260e9c>] (bus_remove_driver) from [<c026235c>] (driver_unregister+0x38/0x58) [<c026235c>] (driver_unregister) from [<bf007fb4>] (usb_serial_bus_deregister+0x84/0x88 [usbserial]) [<bf007fb4>] (usb_serial_bus_deregister [usbserial]) from [<bf004db4>] (usb_serial_deregister+0x6c/0x78 [usbserial]) [<bf004db4>] (usb_serial_deregister [usbserial]) from [<bf005330>] (usb_serial_deregister_drivers+0x2c/0x4c [usbserial]) [<bf005330>] (usb_serial_deregister_drivers [usbserial]) from [<bf016618>] (usb_serial_module_exit+0x14/0x1c [sierra]) [<bf016618>] (usb_serial_module_exit [sierra]) from [<c009d6cc>] (SyS_delete_module+0x184/0x210) [<c009d6cc>] (SyS_delete_module) from [<c000f880>] (ret_fast_syscall+0x0/0x48) Signed-off-by: Johan Hovold <jhovold@gmail.com> Cc: stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit 10164c2 upstream. Fix driver new_id sysfs-attribute removal deadlock by making sure to not hold any locks that the attribute operations grab when removing the attribute. Specifically, usb_serial_deregister holds the table mutex when deregistering the driver, which includes removing the new_id attribute. This can lead to a deadlock as writing to new_id increments the attribute's active count before trying to grab the same mutex in usb_serial_probe. The deadlock can easily be triggered by inserting a sleep in usb_serial_deregister and writing the id of an unbound device to new_id during module unload. As the table mutex (in this case) is used to prevent subdriver unload during probe, it should be sufficient to only hold the lock while manipulating the usb-serial driver list during deregister. A racing probe will then either fail to find a matching subdriver or fail to get the corresponding module reference. Since v3.15-rc1 this also triggers the following lockdep warning: ====================================================== [ INFO: possible circular locking dependency detected ] 3.15.0-rc2 #123 Tainted: G W ------------------------------------------------------- modprobe/190 is trying to acquire lock: (s_active#4){++++.+}, at: [<c0167aa0>] kernfs_remove_by_name_ns+0x4c/0x94 but task is already holding lock: (table_lock){+.+.+.}, at: [<bf004d84>] usb_serial_deregister+0x3c/0x78 [usbserial] which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (table_lock){+.+.+.}: [<c0075f84>] __lock_acquire+0x1694/0x1ce4 [<c0076de8>] lock_acquire+0xb4/0x154 [<c03af3cc>] _raw_spin_lock+0x4c/0x5c [<c02bbc24>] usb_store_new_id+0x14c/0x1ac [<bf007eb4>] new_id_store+0x68/0x70 [usbserial] [<c025f568>] drv_attr_store+0x30/0x3c [<c01690e0>] sysfs_kf_write+0x5c/0x60 [<c01682c0>] kernfs_fop_write+0xd4/0x194 [<c010881c>] vfs_write+0xbc/0x198 [<c0108e4c>] SyS_write+0x4c/0xa0 [<c000f880>] ret_fast_syscall+0x0/0x48 -> #0 (s_active#4){++++.+}: [<c03a7a28>] print_circular_bug+0x68/0x2f8 [<c0076218>] __lock_acquire+0x1928/0x1ce4 [<c0076de8>] lock_acquire+0xb4/0x154 [<c0166b70>] __kernfs_remove+0x254/0x310 [<c0167aa0>] kernfs_remove_by_name_ns+0x4c/0x94 [<c0169fb8>] remove_files.isra.1+0x48/0x84 [<c016a2fc>] sysfs_remove_group+0x58/0xac [<c016a414>] sysfs_remove_groups+0x34/0x44 [<c02623b8>] driver_remove_groups+0x1c/0x20 [<c0260e9c>] bus_remove_driver+0x3c/0xe4 [<c026235c>] driver_unregister+0x38/0x58 [<bf007fb4>] usb_serial_bus_deregister+0x84/0x88 [usbserial] [<bf004db4>] usb_serial_deregister+0x6c/0x78 [usbserial] [<bf005330>] usb_serial_deregister_drivers+0x2c/0x4c [usbserial] [<bf016618>] usb_serial_module_exit+0x14/0x1c [sierra] [<c009d6cc>] SyS_delete_module+0x184/0x210 [<c000f880>] ret_fast_syscall+0x0/0x48 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(table_lock); lock(s_active#4); lock(table_lock); lock(s_active#4); *** DEADLOCK *** 1 lock held by modprobe/190: #0: (table_lock){+.+.+.}, at: [<bf004d84>] usb_serial_deregister+0x3c/0x78 [usbserial] stack backtrace: CPU: 0 PID: 190 Comm: modprobe Tainted: G W 3.15.0-rc2 #123 [<c0015e10>] (unwind_backtrace) from [<c0013728>] (show_stack+0x20/0x24) [<c0013728>] (show_stack) from [<c03a9a54>] (dump_stack+0x24/0x28) [<c03a9a54>] (dump_stack) from [<c03a7cac>] (print_circular_bug+0x2ec/0x2f8) [<c03a7cac>] (print_circular_bug) from [<c0076218>] (__lock_acquire+0x1928/0x1ce4) [<c0076218>] (__lock_acquire) from [<c0076de8>] (lock_acquire+0xb4/0x154) [<c0076de8>] (lock_acquire) from [<c0166b70>] (__kernfs_remove+0x254/0x310) [<c0166b70>] (__kernfs_remove) from [<c0167aa0>] (kernfs_remove_by_name_ns+0x4c/0x94) [<c0167aa0>] (kernfs_remove_by_name_ns) from [<c0169fb8>] (remove_files.isra.1+0x48/0x84) [<c0169fb8>] (remove_files.isra.1) from [<c016a2fc>] (sysfs_remove_group+0x58/0xac) [<c016a2fc>] (sysfs_remove_group) from [<c016a414>] (sysfs_remove_groups+0x34/0x44) [<c016a414>] (sysfs_remove_groups) from [<c02623b8>] (driver_remove_groups+0x1c/0x20) [<c02623b8>] (driver_remove_groups) from [<c0260e9c>] (bus_remove_driver+0x3c/0xe4) [<c0260e9c>] (bus_remove_driver) from [<c026235c>] (driver_unregister+0x38/0x58) [<c026235c>] (driver_unregister) from [<bf007fb4>] (usb_serial_bus_deregister+0x84/0x88 [usbserial]) [<bf007fb4>] (usb_serial_bus_deregister [usbserial]) from [<bf004db4>] (usb_serial_deregister+0x6c/0x78 [usbserial]) [<bf004db4>] (usb_serial_deregister [usbserial]) from [<bf005330>] (usb_serial_deregister_drivers+0x2c/0x4c [usbserial]) [<bf005330>] (usb_serial_deregister_drivers [usbserial]) from [<bf016618>] (usb_serial_module_exit+0x14/0x1c [sierra]) [<bf016618>] (usb_serial_module_exit [sierra]) from [<c009d6cc>] (SyS_delete_module+0x184/0x210) [<c009d6cc>] (SyS_delete_module) from [<c000f880>] (ret_fast_syscall+0x0/0x48) Signed-off-by: Johan Hovold <jhovold@gmail.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz>

Since commit 0f04cf8 ("drm/exynos: fix wrong pipe calculation for crtc"), fimd_clear_channel() can be called when is_drm_iommu_supported() returns true. In this case, the kernel is going to be panicked because crtc is not set yet. [ 1.211156] [drm] Initialized drm 1.1.0 20060810 [ 1.216785] Unable to handle kernel NULL pointer dereference at virtual address 00000350 [ 1.223415] pgd = c0004000 [ 1.226086] [00000350] *pgd=00000000 [ 1.229649] Internal error: Oops: 5 [#1] PREEMPT SMP ARM [ 1.234940] Modules linked in: [ 1.237982] CPU: 2 PID: 1 Comm: swapper/0 Not tainted 4.0.0-rc1-00062-g7a7cc79-dirty #123 [ 1.246136] Hardware name: SAMSUNG EXYNOS (Flattened Device Tree) [ 1.252214] task: ee8c8000 ti: ee8d0000 task.ti: ee8d0000 [ 1.257606] PC is at fimd_wait_for_vblank+0x8/0xc8 [ 1.262370] LR is at fimd_bind+0x138/0x1a8 [ 1.266450] pc : [<c02fb63c>] lr : [<c02fb834>] psr: 20000113 [ 1.266450] sp : ee8d1d28 ip : 00000000 fp : 00000000 [ 1.277906] r10: 00000001 r9 : c09d693c r8 : c0a2d6a8 [ 1.283114] r7 : 00000034 r6 : 00000001 r5 : ee0bb400 r4 : ee244c10 [ 1.289624] r3 : 00000000 r2 : 00000000 r1 : 00000001 r0 : 00000000 [ 1.296135] Flags: nzCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment kernel [ 1.303426] Control: 10c5387d Table: 4000404a DAC: 00000015 [ 1.309154] Process swapper/0 (pid: 1, stack limit = 0xee8d0210) [ 1.315143] Stack: (0xee8d1d28 to 0xee8d2000) [ 1.319486] 1d20: 00000000 c0113d18 ee0bb400 ee0bb400 ee245c30 eebbe210 [ 1.327645] 1d40: ee008a40 ee244c10 ee0bb400 00000001 00000034 c02fb834 00000000 c030a858 [ 1.335804] 1d60: ee244a10 eeb60780 ee008a40 eeb60740 ee0bb400 c03030d0 00000000 00000000 [ 1.343963] 1d80: ee244a10 ee0bb400 00000000 eeb60740 eeb60810 00000000 00000000 c02f6ba4 [ 1.352123] 1da0: ee0bb400 00000000 00000000 c02e0500 ee244a00 c0a04a14 ee0bb400 c02e1de4 [ 1.360282] 1dc0: 00000000 c030a858 00000002 eeb60820 eeb60820 00000002 eeb60780 c03033d4 [ 1.368441] 1de0: c06e9cec 00000000 ee244a10 eeb60780 c0a056f8 c03035fc c0a04b24 c0a04b24 [ 1.376600] 1e00: ee244a10 00000001 c0a049d0 c02f6d34 c0ad462c eeba0790 00000000 ee244a10 [ 1.384759] 1e20: ffffffed c0a049d0 00000000 c03090b0 ee244a10 c0ad462c c0a2d840 c03077a0 [ 1.392919] 1e40: eeb5e880 c024b738 000008db ee244a10 c0a049d0 ee244a44 00000000 c09e71d8 [ 1.401078] 1e60: 000000c6 c0307a6c c0a049d0 00000000 c03079e0 c0305ea8 ee826e5c ee1dc7b4 [ 1.409237] 1e80: c0a049d0 eeb5e880 c0a058a8 c0306e2c c0896204 c0a049d0 c06e9d10 c0a049d0 [ 1.417396] 1ea0: c06e9d10 c0ad4600 00000000 c0308360 00000000 00000003 c06e9d10 c02f6e14 [ 1.425555] 1ec0: 00000000 c0896204 ffffffff 00000000 00000000 00000000 00000000 00000000 [ 1.433714] 1ee0: 00000000 00000000 c02f6d5c c02f6d5c 00000000 eeb5d740 c09e71d8 c0008a30 [ 1.441874] 1f00: ef7fca5e 00000000 00000000 00000066 00000000 ee8d1f28 c003ff1c c02514e8 [ 1.450033] 1f20: 60000113 ffffffff c093906c ef7fca5e 000000c6 c004018c 00000000 c093906c [ 1.458192] 1f40: c08a9690 c093840c 00000006 00000006 c09eb2ac c09c0d74 00000006 c09c0d54 [ 1.466351] 1f60: c0a3d680 c09745a0 c09d693c 000000c6 00000000 c0974db4 00000006 00000006 [ 1.474510] 1f80: c09745a0 ffffffff 00000000 c0692e00 00000000 00000000 00000000 00000000 [ 1.482669] 1fa0: 00000000 c0692e08 00000000 c000f040 00000000 00000000 00000000 00000000 [ 1.490828] 1fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 [ 1.498988] 1fe0: 00000000 00000000 00000000 00000000 00000013 00000000 ffffffff ffffffff [ 1.507159] [<c02fb63c>] (fimd_wait_for_vblank) from [<c02fb834>] (fimd_bind+0x138/0x1a8) [ 1.515313] [<c02fb834>] (fimd_bind) from [<c03030d0>] (component_bind_all+0xc4/0x20c) [ 1.523209] [<c03030d0>] (component_bind_all) from [<c02f6ba4>] (exynos_drm_load+0xa0/0x140) [ 1.531632] [<c02f6ba4>] (exynos_drm_load) from [<c02e0500>] (drm_dev_register+0xa0/0xf4) [ 1.539788] [<c02e0500>] (drm_dev_register) from [<c02e1de4>] (drm_platform_init+0x44/0xcc) [ 1.548121] [<c02e1de4>] (drm_platform_init) from [<c03033d4>] (try_to_bring_up_master.part.1+0xc8/0x104) [ 1.557668] [<c03033d4>] (try_to_bring_up_master.part.1) from [<c03035fc>] (component_master_add_with_match+0xd0/0x118) [ 1.568431] [<c03035fc>] (component_master_add_with_match) from [<c02f6d34>] (exynos_drm_platform_probe+0xf0/0x118) [ 1.578847] [<c02f6d34>] (exynos_drm_platform_probe) from [<c03090b0>] (platform_drv_probe+0x48/0x98) [ 1.588052] [<c03090b0>] (platform_drv_probe) from [<c03077a0>] (driver_probe_device+0x140/0x380) [ 1.596902] [<c03077a0>] (driver_probe_device) from [<c0307a6c>] (__driver_attach+0x8c/0x90) [ 1.605321] [<c0307a6c>] (__driver_attach) from [<c0305ea8>] (bus_for_each_dev+0x54/0x88) [ 1.613480] [<c0305ea8>] (bus_for_each_dev) from [<c0306e2c>] (bus_add_driver+0xec/0x200) [ 1.621640] [<c0306e2c>] (bus_add_driver) from [<c0308360>] (driver_register+0x78/0xf4) [ 1.629625] [<c0308360>] (driver_register) from [<c02f6e14>] (exynos_drm_init+0xb8/0x11c) [ 1.637785] [<c02f6e14>] (exynos_drm_init) from [<c0008a30>] (do_one_initcall+0xac/0x1ec) [ 1.645950] [<c0008a30>] (do_one_initcall) from [<c0974db4>] (kernel_init_freeable+0x194/0x268) [ 1.654626] [<c0974db4>] (kernel_init_freeable) from [<c0692e08>] (kernel_init+0x8/0xe4) [ 1.662699] [<c0692e08>] (kernel_init) from [<c000f040>] (ret_from_fork+0x14/0x34) [ 1.670246] Code: eaffffd5 c09df884 e92d40f0 e24dd01c (e5905350) [ 1.676408] ---[ end trace 804468492f306a6f ]--- [ 1.680948] Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b [ 1.680948] [ 1.690035] CPU1: stopping [ 1.692727] CPU: 1 PID: 0 Comm: swapper/1 Tainted: G D 4.0.0-rc1-00062-g7a7cc79-dirty #123 [ 1.702097] Hardware name: SAMSUNG EXYNOS (Flattened Device Tree) [ 1.708192] [<c0016c84>] (unwind_backtrace) from [<c00129bc>] (show_stack+0x10/0x14) [ 1.715908] [<c00129bc>] (show_stack) from [<c0696f58>] (dump_stack+0x78/0xc8) [ 1.723108] [<c0696f58>] (dump_stack) from [<c0015020>] (handle_IPI+0x16c/0x2b4) [ 1.730485] [<c0015020>] (handle_IPI) from [<c00086bc>] (gic_handle_irq+0x64/0x6c) [ 1.738036] [<c00086bc>] (gic_handle_irq) from [<c00134c0>] (__irq_svc+0x40/0x74) [ 1.745498] Exception stack(0xee8fdf98 to 0xee8fdfe0) [ 1.750533] df80: 00000000 00000000 [ 1.758695] dfa0: ee8fdfe8 c0021780 c09df938 00000015 10c0387d c0a3d988 4000406a c09df8d4 [ 1.766853] dfc0: c0a27a74 c09df94 01000000 ee8fdfe0 c00101c0 c00101c4 60000113 ffffffff [ 1.775015] [<c00134c0>] (__irq_svc) from [<c00101c4>] (arch_cpu_idle+0x30/0x3c) [ 1.782397] [<c00101c4>] (arch_cpu_idle) from [<c005e804>] (cpu_startup_entry+0x180/0x324) [ 1.790639] [<c005e804>] (cpu_startup_entry) from [<40008764>] (0x40008764) [ 1.797579] CPU0: stopping [ 1.800272] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G D 4.0.0-rc1-00062-g7a7cc79-dirty #123 [ 1.809642] Hardware name: SAMSUNG EXYNOS (Flattened Device Tree) [ 1.815730] [<c0016c84>] (unwind_backtrace) from [<c00129bc>] (show_stack+0x10/0x14) [ 1.823450] [<c00129bc>] (show_stack) from [<c0696f58>] (dump_stack+0x78/0xc8) [ 1.830653] [<c0696f58>] (dump_stack) from [<c0015020>] (handle_IPI+0x16c/0x2b4) [ 1.838030] [<c0015020>] (handle_IPI) from [<c00086bc>] (gic_handle_irq+0x64/0x6c) [ 1.845581] [<c00086bc>] (gic_handle_irq) from [<c00134c0>] (__irq_svc+0x40/0x74) [ 1.853043] Exception stack(0xc09ddf60 to 0xc09ddfa8) [ 1.858081] df60: 00000000 00000000 c09ddfb0 c0021780 c09df938 00000001 ffffffff c0a3d680 [ 1.866239] df80: c09c0dec c09df8d4 c0a27a74 c09df94 01000000 c09ddfa8 c00101c0 c00101c4 [ 1.874396] dfa0: 60000113 ffffffff [ 1.877872] [<c00134c0>] (__irq_svc) from [<c00101c4>] (arch_cpu_idle+0x30/0x3c) [ 1.885251] [<c00101c4>] (arch_cpu_idle) from [<c005e804>] (cpu_startup_entry+0x180/0x324) [ 1.893499] [<c005e804>] (cpu_startup_entry) from [<c0974bc8>] (start_kernel+0x324/0x37c) [ 1.901655] [<c0974bc8>] (start_kernel) from [<40008074>] (0x40008074) [ 1.908161] CPU3: stopping [ 1.910855] CPU: 3 PID: 0 Comm: swapper/3 Tainted: G D 4.0.0-rc1-00062-g7a7cc79-dirty #123 [ 1.920225] Hardware name: SAMSUNG EXYNOS (Flattened Device Tree) [ 1.926313] [<c0016c84>] (unwind_backtrace) from [<c00129bc>] (show_stack+0x10/0x14) [ 1.934034] [<c00129bc>] (show_stack) from [<c0696f58>] (dump_stack+0x78/0xc8) [ 1.941237] [<c0696f58>] (dump_stack) from [<c0015020>] (handle_IPI+0x16c/0x2b4) [ 1.948613] [<c0015020>] (handle_IPI) from [<c00086bc>] (gic_handle_irq+0x64/0x6c) [ 1.956165] [<c00086bc>] (gic_handle_irq) from [<c00134c0>] (__irq_svc+0x40/0x74) [ 1.963626] Exception stack(0xee901f98 to 0xee901fe0) [ 1.968661] 1f80: 00000000 00000000 [ 1.976823] 1fa0: ee901fe8 c0021780 c09df938 00000015 10c0387d c0a3d988 4000406a c09df8d4 [ 1.984982] 1fc0: c0a27a74 c09df94 01000000 ee901fe0 c00101c0 c00101c4 60000113 ffffffff [ 1.993143] [<c00134c0>] (__irq_svc) from [<c00101c4>] (arch_cpu_idle+0x30/0x3c) [ 2.000522] [<c00101c4>] (arch_cpu_idle) from [<c005e804>] (cpu_startup_entry+0x180/0x324) [ 2.008765] [<c005e804>] (cpu_startup_entry) from [<40008764>] (0x40008764) [ 2.015710] ---[ end Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b Signed-off-by: Hyungwon Hwang <human.hwang@samsung.com> Signed-off-by: Inki Dae <inki.dae@samsung.com>

Don't use kmap_atomic() for doorbell & process descriptor access. This patch fixes the BUG shown below, where the thread could sleep while holding a kmap_atomic mapping. In order not to need to call kmap_atomic() in this code path, we now set up a permanent kernel mapping of the shared doorbell and process-descriptor page, and use that in all doorbell and process-descriptor related code. BUG: scheduling while atomic: gem_close_race/1941/0x00000002 Modules linked in: hid_generic usbhid i915 asix usbnet libphy mii i2c_algo_bit drm_kms_helper cfbfillrect syscopyarea cfbimgblt sysfillrect sysimgblt fb_sys_fops cfbcopyarea drm coretemp i2c_hid hid video pinctrl_sunrisepoint pinctrl_intel acpi_pad nls_iso8859_1 e1000e ptp psmouse pps_core ahci libahci CPU: 0 PID: 1941 Comm: gem_close_race Tainted: G U 4.4.0-160121+ #123 Hardware name: Intel Corporation Skylake Client platform/Skylake AIO DDR3L RVP10, BIOS SKLSE2R1.R00.X100.B01.1509220551 09/22/2015 0000000000013e40 ffff880166c27a78 ffffffff81280d02 ffff880172c13e40 ffff880166c27a88 ffffffff810c203a ffff880166c27ac8 ffffffff814ec808 ffff88016b7c6000 ffff880166c28000 00000000000f4240 0000000000000001 Call Trace: [<ffffffff81280d02>] dump_stack+0x4b/0x79 [<ffffffff810c203a>] __schedule_bug+0x41/0x4f [<ffffffff814ec808>] __schedule+0x5a8/0x690 [<ffffffff814ec927>] schedule+0x37/0x80 [<ffffffff814ef3fd>] schedule_hrtimeout_range_clock+0xad/0x130 [<ffffffff81090be0>] ? hrtimer_init+0x10/0x10 [<ffffffff814ef3f1>] ? schedule_hrtimeout_range_clock+0xa1/0x130 [<ffffffff814ef48e>] schedule_hrtimeout_range+0xe/0x10 [<ffffffff814eef9b>] usleep_range+0x3b/0x40 [<ffffffffa01ec109>] i915_guc_wq_check_space+0x119/0x210 [i915] [<ffffffffa01da47c>] intel_logical_ring_alloc_request_extras+0x5c/0x70 [i915] [<ffffffffa01cdbf1>] i915_gem_request_alloc+0x91/0x170 [i915] [<ffffffffa01c1c07>] i915_gem_do_execbuffer.isra.25+0xbc7/0x12a0 [i915] [<ffffffffa01cb785>] ? i915_gem_object_get_pages_gtt+0x225/0x3c0 [i915] [<ffffffffa01d1fb6>] ? i915_gem_pwrite_ioctl+0xd6/0x9f0 [i915] [<ffffffffa01c2e68>] i915_gem_execbuffer2+0xa8/0x250 [i915] [<ffffffffa00f65d8>] drm_ioctl+0x258/0x4f0 [drm] [<ffffffffa01c2dc0>] ? i915_gem_execbuffer+0x340/0x340 [i915] [<ffffffff8111590d>] do_vfs_ioctl+0x2cd/0x4a0 [<ffffffff8111eac2>] ? __fget+0x72/0xb0 [<ffffffff81115b1c>] SyS_ioctl+0x3c/0x70 [<ffffffff814effd7>] entry_SYSCALL_64_fastpath+0x12/0x6a ------------[ cut here ]------------ v4: Only tear down doorbell & kunmap() client object if we actually succeeded in allocating a client object (Tvrtko Ursulin) Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=93847 Original-version-by: Alex Dai <yu.dai@intel.com> Signed-off-by: Dave Gordon <david.s.gordon@intel.com> Cc: Tvtrko Ursulin <tvrtko.ursulin@intel.com> Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>

mem_cgroup_css_alloc() was returning NULL on failure while cgroup core expected it to return an ERR_PTR value leading to the following NULL deref after a css allocation failure. Fix it by return ERR_PTR(-ENOMEM) instead. I'll also update cgroup core so that it can handle NULL returns. mkdir: page allocation failure: order:6, mode:0x240c0c0(GFP_KERNEL|__GFP_COMP|__GFP_ZERO) CPU: 0 PID: 8738 Comm: mkdir Not tainted 4.7.0-rc3+ #123 ... Call Trace: dump_stack+0x68/0xa1 warn_alloc_failed+0xd6/0x130 __alloc_pages_nodemask+0x4c6/0xf20 alloc_pages_current+0x66/0xe0 alloc_kmem_pages+0x14/0x80 kmalloc_order_trace+0x2a/0x1a0 __kmalloc+0x291/0x310 memcg_update_all_caches+0x6c/0x130 mem_cgroup_css_alloc+0x590/0x610 cgroup_apply_control_enable+0x18b/0x370 cgroup_mkdir+0x1de/0x2e0 kernfs_iop_mkdir+0x55/0x80 vfs_mkdir+0xb9/0x150 SyS_mkdir+0x66/0xd0 do_syscall_64+0x53/0x120 entry_SYSCALL64_slow_path+0x25/0x25 ... BUG: unable to handle kernel NULL pointer dereference at 00000000000000d0 IP: init_and_link_css+0x37/0x220 PGD 34b1e067 PUD 3a109067 PMD 0 Oops: 0002 [#1] SMP Modules linked in: CPU: 0 PID: 8738 Comm: mkdir Not tainted 4.7.0-rc3+ #123 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.9.2-20160422_131301-anatol 04/01/2014 task: ffff88007cbc5200 ti: ffff8800666d4000 task.ti: ffff8800666d4000 RIP: 0010:[<ffffffff810f2ca7>] [<ffffffff810f2ca7>] init_and_link_css+0x37/0x220 RSP: 0018:ffff8800666d7d90 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: ffffffff810f2499 RSI: 0000000000000000 RDI: 0000000000000008 RBP: ffff8800666d7db8 R08: 0000000000000003 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: ffff88005a5fb400 R13: ffffffff81f0f8a0 R14: ffff88005a5fb400 R15: 0000000000000010 FS: 00007fc944689700(0000) GS:ffff88007fc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f3aed0d2b80 CR3: 000000003a1e8000 CR4: 00000000000006f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: cgroup_apply_control_enable+0x1ac/0x370 cgroup_mkdir+0x1de/0x2e0 kernfs_iop_mkdir+0x55/0x80 vfs_mkdir+0xb9/0x150 SyS_mkdir+0x66/0xd0 do_syscall_64+0x53/0x120 entry_SYSCALL64_slow_path+0x25/0x25 Code: 89 f5 48 89 fb 49 89 d4 48 83 ec 08 8b 05 72 3b d8 00 85 c0 0f 85 60 01 00 00 4c 89 e7 e8 72 f7 ff ff 48 8d 7b 08 48 89 d9 31 c0 <48> c7 83 d0 00 00 00 00 00 00 00 48 83 e7 f8 48 29 f9 81 c1 d8 RIP init_and_link_css+0x37/0x220 RSP <ffff8800666d7d90> CR2: 00000000000000d0 ---[ end trace a2d8836ae1e852d1 ]--- Link: http://lkml.kernel.org/r/20160621165740.GJ3262@mtj.duckdns.org Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Vladimir Davydov <vdavydov@virtuozzo.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Michal Hocko <mhocko@suse.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

commit ea3a964 upstream. mem_cgroup_css_alloc() was returning NULL on failure while cgroup core expected it to return an ERR_PTR value leading to the following NULL deref after a css allocation failure. Fix it by return ERR_PTR(-ENOMEM) instead. I'll also update cgroup core so that it can handle NULL returns. mkdir: page allocation failure: order:6, mode:0x240c0c0(GFP_KERNEL|__GFP_COMP|__GFP_ZERO) CPU: 0 PID: 8738 Comm: mkdir Not tainted 4.7.0-rc3+ #123 ... Call Trace: dump_stack+0x68/0xa1 warn_alloc_failed+0xd6/0x130 __alloc_pages_nodemask+0x4c6/0xf20 alloc_pages_current+0x66/0xe0 alloc_kmem_pages+0x14/0x80 kmalloc_order_trace+0x2a/0x1a0 __kmalloc+0x291/0x310 memcg_update_all_caches+0x6c/0x130 mem_cgroup_css_alloc+0x590/0x610 cgroup_apply_control_enable+0x18b/0x370 cgroup_mkdir+0x1de/0x2e0 kernfs_iop_mkdir+0x55/0x80 vfs_mkdir+0xb9/0x150 SyS_mkdir+0x66/0xd0 do_syscall_64+0x53/0x120 entry_SYSCALL64_slow_path+0x25/0x25 ... BUG: unable to handle kernel NULL pointer dereference at 00000000000000d0 IP: init_and_link_css+0x37/0x220 PGD 34b1e067 PUD 3a109067 PMD 0 Oops: 0002 [#1] SMP Modules linked in: CPU: 0 PID: 8738 Comm: mkdir Not tainted 4.7.0-rc3+ #123 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.9.2-20160422_131301-anatol 04/01/2014 task: ffff88007cbc5200 ti: ffff8800666d4000 task.ti: ffff8800666d4000 RIP: 0010:[<ffffffff810f2ca7>] [<ffffffff810f2ca7>] init_and_link_css+0x37/0x220 RSP: 0018:ffff8800666d7d90 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: ffffffff810f2499 RSI: 0000000000000000 RDI: 0000000000000008 RBP: ffff8800666d7db8 R08: 0000000000000003 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: ffff88005a5fb400 R13: ffffffff81f0f8a0 R14: ffff88005a5fb400 R15: 0000000000000010 FS: 00007fc944689700(0000) GS:ffff88007fc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f3aed0d2b80 CR3: 000000003a1e8000 CR4: 00000000000006f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: cgroup_apply_control_enable+0x1ac/0x370 cgroup_mkdir+0x1de/0x2e0 kernfs_iop_mkdir+0x55/0x80 vfs_mkdir+0xb9/0x150 SyS_mkdir+0x66/0xd0 do_syscall_64+0x53/0x120 entry_SYSCALL64_slow_path+0x25/0x25 Code: 89 f5 48 89 fb 49 89 d4 48 83 ec 08 8b 05 72 3b d8 00 85 c0 0f 85 60 01 00 00 4c 89 e7 e8 72 f7 ff ff 48 8d 7b 08 48 89 d9 31 c0 <48> c7 83 d0 00 00 00 00 00 00 00 48 83 e7 f8 48 29 f9 81 c1 d8 RIP init_and_link_css+0x37/0x220 RSP <ffff8800666d7d90> CR2: 00000000000000d0 ---[ end trace a2d8836ae1e852d1 ]--- Link: http://lkml.kernel.org/r/20160621165740.GJ3262@mtj.duckdns.org Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Vladimir Davydov <vdavydov@virtuozzo.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Michal Hocko <mhocko@suse.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>

[ Upstream commit 1106638 ] When slub_debug=O is set. It is possible to clear debug flags for an "unmergeable" slab cache in kmem_cache_open(). It makes the "unmergeable" cache became "mergeable" in sysfs_slab_add(). These caches will generate their "unique IDs" by create_unique_id(), but it is possible to create identical unique IDs. In my experiment, sgpool-128, names_cache, biovec-256 generate the same ID ":Ft-0004096" and the kernel reports "sysfs: cannot create duplicate filename '/kernel/slab/:Ft-0004096'". To repeat my experiment, set disable_higher_order_debug=1, CONFIG_SLUB_DEBUG_ON=y in kernel-4.14. Fix this issue by setting unmergeable=1 if slub_debug=O and the the default slub_debug contains any no-merge flags. call path: kmem_cache_create() __kmem_cache_alias() -> we set SLAB_NEVER_MERGE flags here create_cache() __kmem_cache_create() kmem_cache_open() -> clear DEBUG_METADATA_FLAGS sysfs_slab_add() -> the slab cache is mergeable now sysfs: cannot create duplicate filename '/kernel/slab/:Ft-0004096' ------------[ cut here ]------------ WARNING: CPU: 0 PID: 1 at fs/sysfs/dir.c:31 sysfs_warn_dup+0x60/0x7c Modules linked in: CPU: 0 PID: 1 Comm: swapper/0 Tainted: G W 4.14.0-rc7ajb-00131-gd4c2e9f-dirty #123 Hardware name: linux,dummy-virt (DT) task: ffffffc07d4e0080 task.stack: ffffff8008008000 PC is at sysfs_warn_dup+0x60/0x7c LR is at sysfs_warn_dup+0x60/0x7c pc : lr : pstate: 60000145 Call trace: sysfs_warn_dup+0x60/0x7c sysfs_create_dir_ns+0x98/0xa0 kobject_add_internal+0xa0/0x294 kobject_init_and_add+0x90/0xb4 sysfs_slab_add+0x90/0x200 __kmem_cache_create+0x26c/0x438 kmem_cache_create+0x164/0x1f4 sg_pool_init+0x60/0x100 do_one_initcall+0x38/0x12c kernel_init_freeable+0x138/0x1d4 kernel_init+0x10/0xfc ret_from_fork+0x10/0x18 Link: http://lkml.kernel.org/r/1510365805-5155-1-git-send-email-miles.chen@mediatek.com Signed-off-by: Miles Chen <miles.chen@mediatek.com> Acked-by: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <alexander.levin@verizon.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

For a failing smc_listen_rdma_finish() smc_listen_decline() is called. If fallback is possible, the new socket is already enqueued to be accepted in smc_listen_decline(). Avoid enqueuing a second time afterwards in this case, otherwise the smc_create_lgr_pending lock is released twice: [ 373.463976] WARNING: bad unlock balance detected! [ 373.463978] 4.18.0-rc7+ #123 Tainted: G O [ 373.463979] ------------------------------------- [ 373.463980] kworker/1:1/30 is trying to release lock (smc_create_lgr_pending) at: [ 373.463990] [<000003ff801205fc>] smc_listen_work+0x22c/0x5d0 [smc] [ 373.463991] but there are no more locks to release! [ 373.463991] other info that might help us debug this: [ 373.463993] 2 locks held by kworker/1:1/30: [ 373.463994] #0: 00000000772cbaed ((wq_completion)"events"){+.+.}, at: process_one_work+0x1ec/0x6b0 [ 373.464000] #1: 000000003ad0894a ((work_completion)(&new_smc->smc_listen_work)){+.+.}, at: process_one_work+0x1ec/0x6b0 [ 373.464003] stack backtrace: [ 373.464005] CPU: 1 PID: 30 Comm: kworker/1:1 Kdump: loaded Tainted: G O 4.18.0-rc7uschi+ #123 [ 373.464007] Hardware name: IBM 2827 H43 738 (LPAR) [ 373.464010] Workqueue: events smc_listen_work [smc] [ 373.464011] Call Trace: [ 373.464015] ([<0000000000114100>] show_stack+0x60/0xd8) [ 373.464019] [<0000000000a8c9bc>] dump_stack+0x9c/0xd8 [ 373.464021] [<00000000001dcaf8>] print_unlock_imbalance_bug+0xf8/0x108 [ 373.464022] [<00000000001e045c>] lock_release+0x114/0x4f8 [ 373.464025] [<0000000000aa87fa>] __mutex_unlock_slowpath+0x4a/0x300 [ 373.464027] [<000003ff801205fc>] smc_listen_work+0x22c/0x5d0 [smc] [ 373.464029] [<0000000000197a68>] process_one_work+0x2a8/0x6b0 [ 373.464030] [<0000000000197ec2>] worker_thread+0x52/0x410 [ 373.464033] [<000000000019fd0e>] kthread+0x15e/0x178 [ 373.464035] [<0000000000aaf58a>] kernel_thread_starter+0x6/0xc [ 373.464052] [<0000000000aaf584>] kernel_thread_starter+0x0/0xc [ 373.464054] INFO: lockdep is turned off. Signed-off-by: Ursula Braun <ubraun@linux.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>

[ Upstream commit a9fd095 ] Leaving dev_init_lock mutex locked in probe causes BUG and a WARNING when kernel is compiled with CONFIG_PROVE_LOCKING. Convert mutex to completion which silences those warnings and improves code readability. Fix below errors when connecting the USB WiFi dongle: brcmfmac: brcmf_fw_alloc_request: using brcm/brcmfmac43143 for chip BCM43143/2 BUG: workqueue leaked lock or atomic: kworker/0:2/0x00000000/434 last function: hub_event 1 lock held by kworker/0:2/434: #0: 18d5dcdf (&devinfo->dev_init_lock){+.+.}, at: brcmf_usb_probe+0x78/0x550 [brcmfmac] CPU: 0 PID: 434 Comm: kworker/0:2 Not tainted 4.19.23-00084-g454a789-dirty #123 Hardware name: Freescale i.MX6 Quad/DualLite (Device Tree) Workqueue: usb_hub_wq hub_event [<8011237c>] (unwind_backtrace) from [<8010d74c>] (show_stack+0x10/0x14) [<8010d74c>] (show_stack) from [<809c4324>] (dump_stack+0xa8/0xd4) [<809c4324>] (dump_stack) from [<8014195c>] (process_one_work+0x710/0x808) [<8014195c>] (process_one_work) from [<80141a80>] (worker_thread+0x2c/0x564) [<80141a80>] (worker_thread) from [<80147bcc>] (kthread+0x13c/0x16c) [<80147bcc>] (kthread) from [<801010b4>] (ret_from_fork+0x14/0x20) Exception stack(0xed1d9fb0 to 0xed1d9ff8) 9fa0: 00000000 00000000 00000000 00000000 9fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 9fe0: 00000000 00000000 00000000 00000000 00000013 00000000 ====================================================== WARNING: possible circular locking dependency detected 4.19.23-00084-g454a789-dirty #123 Not tainted ------------------------------------------------------ kworker/0:2/434 is trying to acquire lock: e29cf799 ((wq_completion)"events"){+.+.}, at: process_one_work+0x174/0x808 but task is already holding lock: 18d5dcdf (&devinfo->dev_init_lock){+.+.}, at: brcmf_usb_probe+0x78/0x550 [brcmfmac] which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&devinfo->dev_init_lock){+.+.}: mutex_lock_nested+0x1c/0x24 brcmf_usb_probe+0x78/0x550 [brcmfmac] usb_probe_interface+0xc0/0x1bc really_probe+0x228/0x2c0 __driver_attach+0xe4/0xe8 bus_for_each_dev+0x68/0xb4 bus_add_driver+0x19c/0x214 driver_register+0x78/0x110 usb_register_driver+0x84/0x148 process_one_work+0x228/0x808 worker_thread+0x2c/0x564 kthread+0x13c/0x16c ret_from_fork+0x14/0x20 (null) -> #1 (brcmf_driver_work){+.+.}: worker_thread+0x2c/0x564 kthread+0x13c/0x16c ret_from_fork+0x14/0x20 (null) -> #0 ((wq_completion)"events"){+.+.}: process_one_work+0x1b8/0x808 worker_thread+0x2c/0x564 kthread+0x13c/0x16c ret_from_fork+0x14/0x20 (null) other info that might help us debug this: Chain exists of: (wq_completion)"events" --> brcmf_driver_work --> &devinfo->dev_init_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&devinfo->dev_init_lock); lock(brcmf_driver_work); lock(&devinfo->dev_init_lock); lock((wq_completion)"events"); *** DEADLOCK *** 1 lock held by kworker/0:2/434: #0: 18d5dcdf (&devinfo->dev_init_lock){+.+.}, at: brcmf_usb_probe+0x78/0x550 [brcmfmac] stack backtrace: CPU: 0 PID: 434 Comm: kworker/0:2 Not tainted 4.19.23-00084-g454a789-dirty #123 Hardware name: Freescale i.MX6 Quad/DualLite (Device Tree) Workqueue: events request_firmware_work_func [<8011237c>] (unwind_backtrace) from [<8010d74c>] (show_stack+0x10/0x14) [<8010d74c>] (show_stack) from [<809c4324>] (dump_stack+0xa8/0xd4) [<809c4324>] (dump_stack) from [<80172838>] (print_circular_bug+0x210/0x330) [<80172838>] (print_circular_bug) from [<80175940>] (__lock_acquire+0x160c/0x1a30) [<80175940>] (__lock_acquire) from [<8017671c>] (lock_acquire+0xe0/0x268) [<8017671c>] (lock_acquire) from [<80141404>] (process_one_work+0x1b8/0x808) [<80141404>] (process_one_work) from [<80141a80>] (worker_thread+0x2c/0x564) [<80141a80>] (worker_thread) from [<80147bcc>] (kthread+0x13c/0x16c) [<80147bcc>] (kthread) from [<801010b4>] (ret_from_fork+0x14/0x20) Exception stack(0xed1d9fb0 to 0xed1d9ff8) 9fa0: 00000000 00000000 00000000 00000000 9fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 9fe0: 00000000 00000000 00000000 00000000 00000013 00000000 Signed-off-by: Piotr Figiel <p.figiel@camlintechnologies.com> Signed-off-by: Kalle Valo <kvalo@codeaurora.org> Signed-off-by: Sasha Levin <sashal@kernel.org>

[ Upstream commit a9fd095 ] Leaving dev_init_lock mutex locked in probe causes BUG and a WARNING when kernel is compiled with CONFIG_PROVE_LOCKING. Convert mutex to completion which silences those warnings and improves code readability. Fix below errors when connecting the USB WiFi dongle: brcmfmac: brcmf_fw_alloc_request: using brcm/brcmfmac43143 for chip BCM43143/2 BUG: workqueue leaked lock or atomic: kworker/0:2/0x00000000/434 last function: hub_event 1 lock held by kworker/0:2/434: #0: 18d5dcdf (&devinfo->dev_init_lock){+.+.}, at: brcmf_usb_probe+0x78/0x550 [brcmfmac] CPU: 0 PID: 434 Comm: kworker/0:2 Not tainted 4.19.23-00084-g454a789-dirty raspberrypi#123 Hardware name: Freescale i.MX6 Quad/DualLite (Device Tree) Workqueue: usb_hub_wq hub_event [<8011237c>] (unwind_backtrace) from [<8010d74c>] (show_stack+0x10/0x14) [<8010d74c>] (show_stack) from [<809c4324>] (dump_stack+0xa8/0xd4) [<809c4324>] (dump_stack) from [<8014195c>] (process_one_work+0x710/0x808) [<8014195c>] (process_one_work) from [<80141a80>] (worker_thread+0x2c/0x564) [<80141a80>] (worker_thread) from [<80147bcc>] (kthread+0x13c/0x16c) [<80147bcc>] (kthread) from [<801010b4>] (ret_from_fork+0x14/0x20) Exception stack(0xed1d9fb0 to 0xed1d9ff8) 9fa0: 00000000 00000000 00000000 00000000 9fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 9fe0: 00000000 00000000 00000000 00000000 00000013 00000000 ====================================================== WARNING: possible circular locking dependency detected 4.19.23-00084-g454a789-dirty raspberrypi#123 Not tainted ------------------------------------------------------ kworker/0:2/434 is trying to acquire lock: e29cf799 ((wq_completion)"events"){+.+.}, at: process_one_work+0x174/0x808 but task is already holding lock: 18d5dcdf (&devinfo->dev_init_lock){+.+.}, at: brcmf_usb_probe+0x78/0x550 [brcmfmac] which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> raspberrypi#2 (&devinfo->dev_init_lock){+.+.}: mutex_lock_nested+0x1c/0x24 brcmf_usb_probe+0x78/0x550 [brcmfmac] usb_probe_interface+0xc0/0x1bc really_probe+0x228/0x2c0 __driver_attach+0xe4/0xe8 bus_for_each_dev+0x68/0xb4 bus_add_driver+0x19c/0x214 driver_register+0x78/0x110 usb_register_driver+0x84/0x148 process_one_work+0x228/0x808 worker_thread+0x2c/0x564 kthread+0x13c/0x16c ret_from_fork+0x14/0x20 (null) -> raspberrypi#1 (brcmf_driver_work){+.+.}: worker_thread+0x2c/0x564 kthread+0x13c/0x16c ret_from_fork+0x14/0x20 (null) -> #0 ((wq_completion)"events"){+.+.}: process_one_work+0x1b8/0x808 worker_thread+0x2c/0x564 kthread+0x13c/0x16c ret_from_fork+0x14/0x20 (null) other info that might help us debug this: Chain exists of: (wq_completion)"events" --> brcmf_driver_work --> &devinfo->dev_init_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&devinfo->dev_init_lock); lock(brcmf_driver_work); lock(&devinfo->dev_init_lock); lock((wq_completion)"events"); *** DEADLOCK *** 1 lock held by kworker/0:2/434: #0: 18d5dcdf (&devinfo->dev_init_lock){+.+.}, at: brcmf_usb_probe+0x78/0x550 [brcmfmac] stack backtrace: CPU: 0 PID: 434 Comm: kworker/0:2 Not tainted 4.19.23-00084-g454a789-dirty raspberrypi#123 Hardware name: Freescale i.MX6 Quad/DualLite (Device Tree) Workqueue: events request_firmware_work_func [<8011237c>] (unwind_backtrace) from [<8010d74c>] (show_stack+0x10/0x14) [<8010d74c>] (show_stack) from [<809c4324>] (dump_stack+0xa8/0xd4) [<809c4324>] (dump_stack) from [<80172838>] (print_circular_bug+0x210/0x330) [<80172838>] (print_circular_bug) from [<80175940>] (__lock_acquire+0x160c/0x1a30) [<80175940>] (__lock_acquire) from [<8017671c>] (lock_acquire+0xe0/0x268) [<8017671c>] (lock_acquire) from [<80141404>] (process_one_work+0x1b8/0x808) [<80141404>] (process_one_work) from [<80141a80>] (worker_thread+0x2c/0x564) [<80141a80>] (worker_thread) from [<80147bcc>] (kthread+0x13c/0x16c) [<80147bcc>] (kthread) from [<801010b4>] (ret_from_fork+0x14/0x20) Exception stack(0xed1d9fb0 to 0xed1d9ff8) 9fa0: 00000000 00000000 00000000 00000000 9fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 9fe0: 00000000 00000000 00000000 00000000 00000013 00000000 Signed-off-by: Piotr Figiel <p.figiel@camlintechnologies.com> Signed-off-by: Kalle Valo <kvalo@codeaurora.org> Signed-off-by: Sasha Levin <sashal@kernel.org>

commit 380a009 upstream. We got issue as follows when run syzkaller: [ 167.936972] EXT4-fs error (device loop0): __ext4_remount:6314: comm rep: Abort forced by user [ 167.938306] EXT4-fs (loop0): Remounting filesystem read-only [ 167.981637] Assertion failure in ext4_getblk() at fs/ext4/inode.c:847: '(EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY) || handle != NULL || create == 0' [ 167.983601] ------------[ cut here ]------------ [ 167.984245] kernel BUG at fs/ext4/inode.c:847! [ 167.984882] invalid opcode: 0000 [#1] PREEMPT SMP KASAN PTI [ 167.985624] CPU: 7 PID: 2290 Comm: rep Tainted: G B 5.16.0-rc5-next-20211217+ #123 [ 167.986823] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ?-20190727_073836-buildvm-ppc64le-16.ppc.fedoraproject.org-3.fc31 04/01/2014 [ 167.988590] RIP: 0010:ext4_getblk+0x17e/0x504 [ 167.989189] Code: c6 01 74 28 49 c7 c0 a0 a3 5c 9b b9 4f 03 00 00 48 c7 c2 80 9c 5c 9b 48 c7 c6 40 b6 5c 9b 48 c7 c7 20 a4 5c 9b e8 77 e3 fd ff <0f> 0b 8b 04 244 [ 167.991679] RSP: 0018:ffff8881736f7398 EFLAGS: 00010282 [ 167.992385] RAX: 0000000000000094 RBX: 1ffff1102e6dee75 RCX: 0000000000000000 [ 167.993337] RDX: 0000000000000001 RSI: ffffffff9b6e29e0 RDI: ffffed102e6dee66 [ 167.994292] RBP: ffff88816a076210 R08: 0000000000000094 R09: ffffed107363fa09 [ 167.995252] R10: ffff88839b1fd047 R11: ffffed107363fa08 R12: ffff88816a0761e8 [ 167.996205] R13: 0000000000000000 R14: 0000000000000021 R15: 0000000000000001 [ 167.997158] FS: 00007f6a1428c740(0000) GS:ffff88839b000000(0000) knlGS:0000000000000000 [ 167.998238] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 167.999025] CR2: 00007f6a140716c8 CR3: 0000000133216000 CR4: 00000000000006e0 [ 167.999987] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 168.000944] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 168.001899] Call Trace: [ 168.002235] <TASK> [ 168.007167] ext4_bread+0xd/0x53 [ 168.007612] ext4_quota_write+0x20c/0x5c0 [ 168.010457] write_blk+0x100/0x220 [ 168.010944] remove_free_dqentry+0x1c6/0x440 [ 168.011525] free_dqentry.isra.0+0x565/0x830 [ 168.012133] remove_tree+0x318/0x6d0 [ 168.014744] remove_tree+0x1eb/0x6d0 [ 168.017346] remove_tree+0x1eb/0x6d0 [ 168.019969] remove_tree+0x1eb/0x6d0 [ 168.022128] qtree_release_dquot+0x291/0x340 [ 168.023297] v2_release_dquot+0xce/0x120 [ 168.023847] dquot_release+0x197/0x3e0 [ 168.024358] ext4_release_dquot+0x22a/0x2d0 [ 168.024932] dqput.part.0+0x1c9/0x900 [ 168.025430] __dquot_drop+0x120/0x190 [ 168.025942] ext4_clear_inode+0x86/0x220 [ 168.026472] ext4_evict_inode+0x9e8/0xa22 [ 168.028200] evict+0x29e/0x4f0 [ 168.028625] dispose_list+0x102/0x1f0 [ 168.029148] evict_inodes+0x2c1/0x3e0 [ 168.030188] generic_shutdown_super+0xa4/0x3b0 [ 168.030817] kill_block_super+0x95/0xd0 [ 168.031360] deactivate_locked_super+0x85/0xd0 [ 168.031977] cleanup_mnt+0x2bc/0x480 [ 168.033062] task_work_run+0xd1/0x170 [ 168.033565] do_exit+0xa4f/0x2b50 [ 168.037155] do_group_exit+0xef/0x2d0 [ 168.037666] __x64_sys_exit_group+0x3a/0x50 [ 168.038237] do_syscall_64+0x3b/0x90 [ 168.038751] entry_SYSCALL_64_after_hwframe+0x44/0xae In order to reproduce this problem, the following conditions need to be met: 1. Ext4 filesystem with no journal; 2. Filesystem image with incorrect quota data; 3. Abort filesystem forced by user; 4. umount filesystem; As in ext4_quota_write: ... if (EXT4_SB(sb)->s_journal && !handle) { ext4_msg(sb, KERN_WARNING, "Quota write (off=%llu, len=%llu)" " cancelled because transaction is not started", (unsigned long long)off, (unsigned long long)len); return -EIO; } ... We only check handle if NULL when filesystem has journal. There is need check handle if NULL even when filesystem has no journal. Signed-off-by: Ye Bin <yebin10@huawei.com> Reviewed-by: Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/20211223015506.297766-1-yebin10@huawei.com Signed-off-by: Theodore Ts'o <tytso@mit.edu> Cc: stable@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit 380a009 upstream. We got issue as follows when run syzkaller: [ 167.936972] EXT4-fs error (device loop0): __ext4_remount:6314: comm rep: Abort forced by user [ 167.938306] EXT4-fs (loop0): Remounting filesystem read-only [ 167.981637] Assertion failure in ext4_getblk() at fs/ext4/inode.c:847: '(EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY) || handle != NULL || create == 0' [ 167.983601] ------------[ cut here ]------------ [ 167.984245] kernel BUG at fs/ext4/inode.c:847! [ 167.984882] invalid opcode: 0000 [raspberrypi#1] PREEMPT SMP KASAN PTI [ 167.985624] CPU: 7 PID: 2290 Comm: rep Tainted: G B 5.16.0-rc5-next-20211217+ raspberrypi#123 [ 167.986823] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ?-20190727_073836-buildvm-ppc64le-16.ppc.fedoraproject.org-3.fc31 04/01/2014 [ 167.988590] RIP: 0010:ext4_getblk+0x17e/0x504 [ 167.989189] Code: c6 01 74 28 49 c7 c0 a0 a3 5c 9b b9 4f 03 00 00 48 c7 c2 80 9c 5c 9b 48 c7 c6 40 b6 5c 9b 48 c7 c7 20 a4 5c 9b e8 77 e3 fd ff <0f> 0b 8b 04 244 [ 167.991679] RSP: 0018:ffff8881736f7398 EFLAGS: 00010282 [ 167.992385] RAX: 0000000000000094 RBX: 1ffff1102e6dee75 RCX: 0000000000000000 [ 167.993337] RDX: 0000000000000001 RSI: ffffffff9b6e29e0 RDI: ffffed102e6dee66 [ 167.994292] RBP: ffff88816a076210 R08: 0000000000000094 R09: ffffed107363fa09 [ 167.995252] R10: ffff88839b1fd047 R11: ffffed107363fa08 R12: ffff88816a0761e8 [ 167.996205] R13: 0000000000000000 R14: 0000000000000021 R15: 0000000000000001 [ 167.997158] FS: 00007f6a1428c740(0000) GS:ffff88839b000000(0000) knlGS:0000000000000000 [ 167.998238] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 167.999025] CR2: 00007f6a140716c8 CR3: 0000000133216000 CR4: 00000000000006e0 [ 167.999987] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 168.000944] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 168.001899] Call Trace: [ 168.002235] <TASK> [ 168.007167] ext4_bread+0xd/0x53 [ 168.007612] ext4_quota_write+0x20c/0x5c0 [ 168.010457] write_blk+0x100/0x220 [ 168.010944] remove_free_dqentry+0x1c6/0x440 [ 168.011525] free_dqentry.isra.0+0x565/0x830 [ 168.012133] remove_tree+0x318/0x6d0 [ 168.014744] remove_tree+0x1eb/0x6d0 [ 168.017346] remove_tree+0x1eb/0x6d0 [ 168.019969] remove_tree+0x1eb/0x6d0 [ 168.022128] qtree_release_dquot+0x291/0x340 [ 168.023297] v2_release_dquot+0xce/0x120 [ 168.023847] dquot_release+0x197/0x3e0 [ 168.024358] ext4_release_dquot+0x22a/0x2d0 [ 168.024932] dqput.part.0+0x1c9/0x900 [ 168.025430] __dquot_drop+0x120/0x190 [ 168.025942] ext4_clear_inode+0x86/0x220 [ 168.026472] ext4_evict_inode+0x9e8/0xa22 [ 168.028200] evict+0x29e/0x4f0 [ 168.028625] dispose_list+0x102/0x1f0 [ 168.029148] evict_inodes+0x2c1/0x3e0 [ 168.030188] generic_shutdown_super+0xa4/0x3b0 [ 168.030817] kill_block_super+0x95/0xd0 [ 168.031360] deactivate_locked_super+0x85/0xd0 [ 168.031977] cleanup_mnt+0x2bc/0x480 [ 168.033062] task_work_run+0xd1/0x170 [ 168.033565] do_exit+0xa4f/0x2b50 [ 168.037155] do_group_exit+0xef/0x2d0 [ 168.037666] __x64_sys_exit_group+0x3a/0x50 [ 168.038237] do_syscall_64+0x3b/0x90 [ 168.038751] entry_SYSCALL_64_after_hwframe+0x44/0xae In order to reproduce this problem, the following conditions need to be met: 1. Ext4 filesystem with no journal; 2. Filesystem image with incorrect quota data; 3. Abort filesystem forced by user; 4. umount filesystem; As in ext4_quota_write: ... if (EXT4_SB(sb)->s_journal && !handle) { ext4_msg(sb, KERN_WARNING, "Quota write (off=%llu, len=%llu)" " cancelled because transaction is not started", (unsigned long long)off, (unsigned long long)len); return -EIO; } ... We only check handle if NULL when filesystem has journal. There is need check handle if NULL even when filesystem has no journal. Signed-off-by: Ye Bin <yebin10@huawei.com> Reviewed-by: Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/20211223015506.297766-1-yebin10@huawei.com Signed-off-by: Theodore Ts'o <tytso@mit.edu> Cc: stable@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

scx: Fix a couple follow ups to recent struct_ops changes

[ Upstream commit 4174867 ] When trying to insert a 10MB kernel module kept in a virtio-fs with cache disabled, the following warning was reported: ------------[ cut here ]------------ WARNING: CPU: 1 PID: 404 at mm/page_alloc.c:4551 ...... Modules linked in: CPU: 1 PID: 404 Comm: insmod Not tainted 6.9.0-rc5+ #123 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) ...... RIP: 0010:__alloc_pages+0x2bf/0x380 ...... Call Trace: <TASK> ? __warn+0x8e/0x150 ? __alloc_pages+0x2bf/0x380 __kmalloc_large_node+0x86/0x160 __kmalloc+0x33c/0x480 virtio_fs_enqueue_req+0x240/0x6d0 virtio_fs_wake_pending_and_unlock+0x7f/0x190 queue_request_and_unlock+0x55/0x60 fuse_simple_request+0x152/0x2b0 fuse_direct_io+0x5d2/0x8c0 fuse_file_read_iter+0x121/0x160 __kernel_read+0x151/0x2d0 kernel_read+0x45/0x50 kernel_read_file+0x1a9/0x2a0 init_module_from_file+0x6a/0xe0 idempotent_init_module+0x175/0x230 __x64_sys_finit_module+0x5d/0xb0 x64_sys_call+0x1c3/0x9e0 do_syscall_64+0x3d/0xc0 entry_SYSCALL_64_after_hwframe+0x4b/0x53 ...... </TASK> ---[ end trace 0000000000000000 ]--- The warning is triggered as follows: 1) syscall finit_module() handles the module insertion and it invokes kernel_read_file() to read the content of the module first. 2) kernel_read_file() allocates a 10MB buffer by using vmalloc() and passes it to kernel_read(). kernel_read() constructs a kvec iter by using iov_iter_kvec() and passes it to fuse_file_read_iter(). 3) virtio-fs disables the cache, so fuse_file_read_iter() invokes fuse_direct_io(). As for now, the maximal read size for kvec iter is only limited by fc->max_read. For virtio-fs, max_read is UINT_MAX, so fuse_direct_io() doesn't split the 10MB buffer. It saves the address and the size of the 10MB-sized buffer in out_args[0] of a fuse request and passes the fuse request to virtio_fs_wake_pending_and_unlock(). 4) virtio_fs_wake_pending_and_unlock() uses virtio_fs_enqueue_req() to queue the request. Because virtiofs need DMA-able address, so virtio_fs_enqueue_req() uses kmalloc() to allocate a bounce buffer for all fuse args, copies these args into the bounce buffer and passed the physical address of the bounce buffer to virtiofsd. The total length of these fuse args for the passed fuse request is about 10MB, so copy_args_to_argbuf() invokes kmalloc() with a 10MB size parameter and it triggers the warning in __alloc_pages(): if (WARN_ON_ONCE_GFP(order > MAX_PAGE_ORDER, gfp)) return NULL; 5) virtio_fs_enqueue_req() will retry the memory allocation in a kworker, but it won't help, because kmalloc() will always return NULL due to the abnormal size and finit_module() will hang forever. A feasible solution is to limit the value of max_read for virtio-fs, so the length passed to kmalloc() will be limited. However it will affect the maximal read size for normal read. And for virtio-fs write initiated from kernel, it has the similar problem but now there is no way to limit fc->max_write in kernel. So instead of limiting both the values of max_read and max_write in kernel, introducing use_pages_for_kvec_io in fuse_conn and setting it as true in virtiofs. When use_pages_for_kvec_io is enabled, fuse will use pages instead of pointer to pass the KVEC_IO data. After switching to pages for KVEC_IO data, these pages will be used for DMA through virtio-fs. If these pages are backed by vmalloc(), {flush|invalidate}_kernel_vmap_range() are necessary to flush or invalidate the cache before the DMA operation. So add two new fields in fuse_args_pages to record the base address of vmalloc area and the condition indicating whether invalidation is needed. Perform the flush in fuse_get_user_pages() for write operations and the invalidation in fuse_release_user_pages() for read operations. It may seem necessary to introduce another field in fuse_conn to indicate that these KVEC_IO pages are used for DMA, However, considering that virtio-fs is currently the only user of use_pages_for_kvec_io, just reuse use_pages_for_kvec_io to indicate that these pages will be used for DMA. Fixes: a62a8ef ("virtio-fs: add virtiofs filesystem") Signed-off-by: Hou Tao <houtao1@huawei.com> Tested-by: Jingbo Xu <jefflexu@linux.alibaba.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org>

lintweaker closed this as completed Sep 26, 2012

0lxb pushed a commit to 0lxb/rpi_linux that referenced this issue Jan 30, 2024

Merge pull request raspberrypi#123 from sched-ext/structops_follow_ups

30b6fa8

scx: Fix a couple follow ups to recent struct_ops changes

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Division by zero in kernel (uart) with latest kernels #123

Division by zero in kernel (uart) with latest kernels #123

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lintweaker commented Sep 26, 2012

Division by zero in kernel (uart) with latest kernels #123

Division by zero in kernel (uart) with latest kernels #123

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lintweaker commented Sep 26, 2012