kernel panic VERIFY(!RW_LOCK_HELD(&dn->dn_struct_rwlock))

[tuomari]

System information

Type	Version/Name
Distribution Name	Debian
Distribution Version	8.4
Linux Kernel	4.9.13
Architecture	amd64
ZFS Version	0.7.0-rc3_138_gef1bdf3
SPL Version	0.7.0-rc3_4_ge0aacd9

Describe the problem you're observing

I have been hitting #5429 every two days for a month or so. I updated kernel from 4.9.1 to 4.9.13 and fetched latest ZFS and SPL, and after that the system stayed up for a week, which was quite a surprise.

After a week, or so of running a seemingly stable system, I got a new panic from the system, which seems different than #5429.

Describe how to reproduce the problem

For now I have not reproduced this problem. I will keep running my apparently somewhat mysterious payload, and report if I hit this again.

Include any warning/errors/backtraces from the system logs

Mar 21 02:49:06 helvi kernel: [711380.522726] VERIFY(!RW_LOCK_HELD(&dn->dn_struct_rwlock)) failed
Mar 21 02:49:06 helvi kernel: [711380.522783] PANIC at dnode.c:158:dnode_dest()
Mar 21 02:49:06 helvi kernel: [711380.522829] Showing stack for process 7064
Mar 21 02:49:06 helvi kernel: [711380.522833] CPU: 4 PID: 7064 Comm: dbu_evict Tainted: P           O    4.9.13.iudex.kvm.ovs.1 #2
Mar 21 02:49:06 helvi kernel: [711380.522834] Hardware name: System manufacturer System Product Name/Z8NA-D6(C), BIOS 1303    05/10/2012
Mar 21 02:49:06 helvi kernel: [711380.522837]  ffffc90004017b90 ffffffff813269eb ffffffffa0e08261 000000000000009e
Mar 21 02:49:06 helvi kernel: [711380.522841]  ffffc90004017ba0 ffffffffa06e6b2f ffffc90004017d20 ffffffffa06e6be7
Mar 21 02:49:06 helvi kernel: [711380.522845]  0000000000000000 ffff880800000028 ffffc90004017d30 ffffc90004017cd0
Mar 21 02:49:06 helvi kernel: [711380.522848] Call Trace:
Mar 21 02:49:06 helvi kernel: [711380.522857]  [<ffffffff813269eb>] dump_stack+0x4d/0x72
Mar 21 02:49:06 helvi kernel: [711380.522873]  [<ffffffffa06e6b2f>] spl_dumpstack+0x3f/0x50 [spl]
Mar 21 02:49:06 helvi kernel: [711380.522881]  [<ffffffffa06e6be7>] spl_panic+0xa7/0xd0 [spl]
Mar 21 02:49:06 helvi kernel: [711380.522887]  [<ffffffff811cbe8c>] ? __slab_free+0x9c/0x2a0
Mar 21 02:49:06 helvi kernel: [711380.522896]  [<ffffffffa06e98b0>] ? __cv_destroy+0x50/0x240 [spl]
Mar 21 02:49:06 helvi kernel: [711380.522996]  [<ffffffffa0ca0b65>] dnode_dest+0x865/0x870 [zfs]
Mar 21 02:49:06 helvi kernel: [711380.523004]  [<ffffffffa06e02e0>] spl_kmem_cache_free+0x40/0x260 [spl]
Mar 21 02:49:06 helvi kernel: [711380.523063]  [<ffffffffa0ca198c>] dnode_destroy+0x1ec/0x310 [zfs]
Mar 21 02:49:06 helvi kernel: [711380.523124]  [<ffffffffa0ca1b23>] dnode_buf_evict_async+0x73/0x140 [zfs]
Mar 21 02:49:06 helvi kernel: [711380.523133]  [<ffffffffa06e402b>] taskq_thread+0x29b/0x590 [spl]
Mar 21 02:49:06 helvi kernel: [711380.523139]  [<ffffffff810d11e0>] ? wake_up_q+0x70/0x70
Mar 21 02:49:06 helvi kernel: [711380.523147]  [<ffffffffa06e3d90>] ? taskq_thread_should_stop+0x80/0x80 [spl]
Mar 21 02:49:06 helvi kernel: [711380.523149]  [<ffffffff810c70e9>] kthread+0xe9/0x100
Mar 21 02:49:06 helvi kernel: [711380.523152]  [<ffffffff810c7000>] ? kthread_park+0x60/0x60
Mar 21 02:49:06 helvi kernel: [711380.523156]  [<ffffffff816d6c52>] ret_from_fork+0x22/0x30
```

[tuomari]

The system has been stable for a while. Assuming this fixed.