[dm-devel] A crash caused by the commit 0dd84b319352bb8ba64752d4e45396d8b13e6018

[Mikulas Patocka]

Hi

There's a crash in the test shell/lvchange-rebuild-raid.sh when running 
the lvm testsuite. It can be reproduced by running "make check_local 
T=shell/lvchange-rebuild-raid.sh" in a loop.

The crash happens in the kernel 6.0 and 6.1-rc3, but not in 5.19.

I bisected the crash and it is caused by the commit 
0dd84b319352bb8ba64752d4e45396d8b13e6018.

I uploaded my .config here (it's 12-core virtual machine): 
https://people.redhat.com/~mpatocka/testcases/md-crash-config/config.txt

Mikulas

[   78.478417] BUG: kernel NULL pointer dereference, address: 0000000000000000
[   78.479166] #PF: supervisor write access in kernel mode
[   78.479671] #PF: error_code(0x0002) - not-present page
[   78.480171] PGD 11557f0067 P4D 11557f0067 PUD 0
[   78.480626] Oops: 0002 [#1] PREEMPT SMP
[   78.481001] CPU: 0 PID: 73 Comm: kworker/0:1 Not tainted 6.1.0-rc3 #5
[   78.481661] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014
[   78.482471] Workqueue: kdelayd flush_expired_bios [dm_delay]
[   78.483021] RIP: 0010:mempool_free+0x47/0x80
[   78.483455] Code: 48 89 ef 5b 5d ff e0 f3 c3 48 89 f7 e8 32 45 3f 00 48 63 53 08 48 89 c6 3b 53 04 7d 2d 48 8b 43 10 8d 4a 01 48 89 df 89 4b 08 <48> 89 2c d0 e8 b0 45 3f 00 48 8d 7b 30 5b 5d 31 c9 ba 01 00 00 00
[   78.485220] RSP: 0018:ffff88910036bda8 EFLAGS: 00010093
[   78.485719] RAX: 0000000000000000 RBX: ffff8891037b65d8 RCX: 0000000000000001
[   78.486404] RDX: 0000000000000000 RSI: 0000000000000202 RDI: ffff8891037b65d8
[   78.487080] RBP: ffff8891447ba240 R08: 0000000000012908 R09: 00000000003d0900
[   78.487764] R10: 0000000000000000 R11: 0000000000173544 R12: ffff889101a14000
[   78.488451] R13: ffff8891562ac300 R14: ffff889102b41440 R15: ffffe8ffffa00d05
[   78.489146] FS:  0000000000000000(0000) GS:ffff88942fa00000(0000) knlGS:0000000000000000
[   78.489913] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   78.490474] CR2: 0000000000000000 CR3: 0000001102e99000 CR4: 00000000000006b0
[   78.491165] Call Trace:
[   78.491429]  <TASK>
[   78.491640]  clone_endio+0xf4/0x1c0 [dm_mod]
[   78.492072]  clone_endio+0xf4/0x1c0 [dm_mod]
[   78.492505]  __submit_bio+0x76/0x120
[   78.492859]  submit_bio_noacct_nocheck+0xb6/0x2a0
[   78.493325]  flush_expired_bios+0x28/0x2f [dm_delay]
[   78.493808]  process_one_work+0x1b4/0x300
[   78.494211]  worker_thread+0x45/0x3e0
[   78.494570]  ? rescuer_thread+0x380/0x380
[   78.494957]  kthread+0xc2/0x100
[   78.495279]  ? kthread_complete_and_exit+0x20/0x20
[   78.495743]  ret_from_fork+0x1f/0x30
[   78.496096]  </TASK>
[   78.496326] Modules linked in: brd dm_delay dm_raid dm_mod af_packet uvesafb cfbfillrect cfbimgblt cn cfbcopyarea fb font fbdev tun autofs4 binfmt_misc configfs ipv6 virtio_rng virtio_balloon rng_core virtio_net pcspkr net_failover failover qemu_fw_cfg button mousedev raid10 raid456 libcrc32c async_raid6_recov async_memcpy async_pq raid6_pq async_xor xor async_tx raid1 raid0 md_mod sd_mod t10_pi crc64_rocksoft crc64 virtio_scsi scsi_mod evdev psmouse bsg scsi_common [last unloaded: brd]
[   78.500425] CR2: 0000000000000000
[   78.500752] ---[ end trace 0000000000000000 ]---
[   78.501214] RIP: 0010:mempool_free+0x47/0x80
[   78.501633] Code: 48 89 ef 5b 5d ff e0 f3 c3 48 89 f7 e8 32 45 3f 00 48 63 53 08 48 89 c6 3b 53 04 7d 2d 48 8b 43 10 8d 4a 01 48 89 df 89 4b 08 <48> 89 2c d0 e8 b0 45 3f 00 48 8d 7b 30 5b 5d 31 c9 ba 01 00 00 00
[   78.503420] RSP: 0018:ffff88910036bda8 EFLAGS: 00010093
[   78.503921] RAX: 0000000000000000 RBX: ffff8891037b65d8 RCX: 0000000000000001
[   78.504611] RDX: 0000000000000000 RSI: 0000000000000202 RDI: ffff8891037b65d8
[   78.505374] RBP: ffff8891447ba240 R08: 0000000000012908 R09: 00000000003d0900
[   78.506075] R10: 0000000000000000 R11: 0000000000173544 R12: ffff889101a14000
[   78.506766] R13: ffff8891562ac300 R14: ffff889102b41440 R15: ffffe8ffffa00d05
[   78.507481] FS:  0000000000000000(0000) GS:ffff88942fa00000(0000) knlGS:0000000000000000
[   78.508273] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   78.508837] CR2: 0000000000000000 CR3: 0000001102e99000 CR4: 00000000000006b0
[   78.509542] note: kworker/0:1[73] exited with preempt_count 1
[   78.510427] md/raid10:mdX: active with 4 out of 8 devices
[   96.902910] sysrq: Resetting