[LU-20062] BUG: unable to handle page fault for address in vvp_dump_pgcache_seq_open()

• Type: Bug
• Resolution: Fixed
• Priority: Medium
• Fix Version/s: Lustre 2.18.0
• Severity: 3
• Assignee: Alex Zhuravlev
• Reporter: Alex Zhuravlev

Description

[   81.674805] BUG: unable to handle page fault for address: 000000020000011c
[   81.674808] #PF: supervisor read access in kernel mode
[   81.674809] #PF: error_code(0x0000) - not-present page
[   81.674810] PGD 144a18067 P4D 144a18067 PUD 0 
[   81.674813] Oops: 0000 [#1] SMP
[   81.674815] CPU: 0 PID: 8778 Comm: lctl Tainted: G        W  O      -------  ---  5.14.0 #24
[   81.674817] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.17.0-4.fc41 04/01/2014
[   81.674819] RIP: 0010:do_raw_spin_lock+0x1/0xa0
[   81.674825] Code: 09 00 00 48 8d 88 f0 0b 00 00 48 c7 c7 18 8b ed 91 e8 85 75 6e 00 e9 3b 2c 6f 00 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 55 <8b> 47 04 48 89 fd 3d ad 4e ad de 75 47 48 8b 55 10 65 48 8b 04 25
[   81.674826] RSP: 0018:ffff999a0507bca0 EFLAGS: 00010286
[   81.674828] RAX: ffffffff914d7760 RBX: ffff999a04d4b3a0 RCX: 0000000000000000
[   81.674829] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000200000118
[   81.674830] RBP: 0000000200000000 R08: 0000000000000001 R09: 0000000000000000
[   81.674831] R10: ffffffffffffffff R11: ffff999a443152e8 R12: 0000000200000118
[   81.674831] R13: ffff999a21cb4d98 R14: ffff999a21ca0ea0 R15: ffff999a0ad4dc00
[   81.674834] FS:  00007fbde752c940(0000) GS:ffff999b50800000(0000) knlGS:0000000000000000
[   81.674835] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   81.674836] CR2: 000000020000011c CR3: 000000012020f000 CR4: 0000000000350eb0
[   81.674839] Call Trace:
[   81.674841]  <TASK>
[   81.674843]  ? __die_body.cold+0x1a/0x1f
[   81.674847]  ? page_fault_oops+0x65/0x1d0
[   81.674851]  ? exc_page_fault+0x65/0x240
[   81.674855]  ? asm_exc_page_fault+0x22/0x30
[   81.674858]  ? rhashtable_walk_enter+0x30/0xc0
[   81.674861]  ? do_raw_spin_lock+0x1/0xa0
[   81.674863]  rhashtable_walk_enter+0x30/0xc0
[   81.674867]  vvp_dump_pgcache_seq_open+0x69/0x90 [lustre]
[   81.674901]  full_proxy_open+0x142/0x1c0
[   81.674905]  ? open_proxy_open+0xd0/0xd0
[   81.674906]  do_dentry_open+0x13a/0x430
[   81.674910]  path_openat+0x6cc/0x890
[   81.674913]  ? trace_contention_end+0x29/0xc0
[   81.674916]  ? lock_release+0x1c7/0x2e0
[   81.674918]  do_filp_open+0x9a/0x120
[   81.674921]  ? lock_release+0x1c7/0x2e0
[   81.674923]  ? do_raw_spin_unlock+0x46/0x90
[   81.674924]  ? _raw_spin_unlock+0x1a/0x30
[   81.674927]  ? alloc_fd+0x126/0x1e0
[   81.674930]  do_sys_openat2+0x75/0xa0
[   81.674933]  __x64_sys_openat+0x40/0x70

this is lctl get_param racing with mount