[LU-12324] zero transno on transaction commit

• Type: Bug
• Resolution: Fixed
• Priority: Critical
• Fix Version/s: Lustre 2.13.0, Lustre 2.12.3
• Affects Version/s: Lustre 2.13.0, Lustre 2.12.1
• Severity: 3
• Assignee: Oleg Drokin
• Reporter: Oleg Drokin

Description

It was observed that when we have changelogs enabled there's a getxattr path that can create a transaction even if getxattr itself only wants the xattr size and there's no reply buffer

This results in a NULL pointer deref in lustre_msg_set_transno because rq_rep is NULL like this:

[ 1826.910143] RIP: 0010:[<ffffffffc0e5012c>]  [<ffffffffc0e5012c>] lustre_msg_set_transno+0xc/0xa0 [ptlrpc]
[ 1826.922696] RSP: 0018:ffff8e7d974df940  EFLAGS: 00010282
[ 1826.930429] RAX: 0000002700000008 RBX: ffff8e5d4c5bb000 RCX: ffff8e5d4e9280b0
[ 1826.940192] RDX: 0000000000000000 RSI: 0000002700000008 RDI: 0000000000000000
[ 1826.949927] RBP: ffff8e7d974df950 R08: ffff8e7d913d8a40 R09: 0000000000000030
[ 1826.959650] R10: 0000000000000000 R11: ffff8e7d974df72e R12: ffff8e7d97477000
[ 1826.969402] R13: ffff8e7d913d8a40 R14: ffff8e7db37c1c80 R15: 0000000000000000
[ 1826.979089] FS:  0000000000000000(0000) GS:ffff8e7dbdfc0000(0000) knlGS:0000000000000000
[ 1826.989827] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1826.997935] CR2: 0000000000000008 CR3: 0000001ffc266000 CR4: 00000000003607e0
[ 1827.007585] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 1827.017224] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 1827.026817] Call Trace:
[ 1827.031220]  [<ffffffffc0eaaeba>] tgt_last_rcvd_update+0x21a/0xc90 [ptlrpc]
[ 1827.040631]  [<ffffffffc0ae4d07>] ? libcfs_debug_msg+0x57/0x80 [libcfs]
[ 1827.049674]  [<ffffffffc0eb011d>] tgt_txn_stop_cb+0x19d/0x490 [ptlrpc]
[ 1827.058593]  [<ffffffffc0c25071>] dt_txn_hook_stop+0x81/0xd0 [obdclass]
[ 1827.067570]  [<ffffffffc1269854>] osd_trans_stop+0x134/0x850 [osd_ldiskfs]
[ 1827.076823]  [<ffffffffc0bdc283>] ? llog_cat_add_rec+0x233/0x8b0 [obdclass]
[ 1827.086182]  [<ffffffffc0eca602>] top_trans_stop+0x92/0x930 [ptlrpc]
[ 1827.094806]  [<ffffffff9d0f944f>] ? __getnstimeofday64+0x3f/0xd0
[ 1827.103028]  [<ffffffffc147c5e9>] lod_trans_stop+0x259/0x340 [lod]
[ 1827.111424]  [<ffffffffc151b7ba>] mdd_trans_stop+0x2a/0x46 [mdd]
[ 1827.119589]  [<ffffffffc150f340>] mdd_xattr_get+0x2f0/0x5c0 [mdd]
[ 1827.127864]  [<ffffffffc13caf71>] mdt_getxattr+0x951/0x12c0 [mdt]
[ 1827.136094]  [<ffffffffc0c22f7f>] ? lu_object_find_at+0x20f/0x2b0 [obdclass]
[ 1827.145358]  [<ffffffffc13b477c>] mdt_tgt_getxattr+0x1c/0x30 [mdt]
[ 1827.153671]  [<ffffffffc0eb741a>] tgt_request_handle+0x92a/0x1370 [ptlrpc]
[ 1827.162737]  [<ffffffffc0e5cfeb>] ptlrpc_server_handle_request+0x23b/0xaa0 [ptlrpc]
[ 1827.172666]  [<ffffffffc0e59618>] ? ptlrpc_wait_event+0x98/0x340 [ptlrpc]
[ 1827.181578]  [<ffffffff9d0cf682>] ? default_wake_function+0x12/0x20
[ 1827.189891]  [<ffffffff9d0c52ab>] ? __wake_up_common+0x5b/0x90
[ 1827.197740]  [<ffffffffc0e60732>] ptlrpc_main+0xa92/0x1e40 [ptlrpc]
[ 1827.206078]  [<ffffffffc0e5fca0>] ? ptlrpc_register_service+0xe30/0xe30 [ptlrpc]
[ 1827.215631]  [<ffffffff9d0bb621>] kthread+0xd1/0xe0
[ 1827.222337]  [<ffffffff9d0bb550>] ? insert_kthread_work+0x40/0x40
[ 1827.230379]  [<ffffffff9d7205f7>] ret_from_fork_nospec_begin+0x21/0x21
[ 1827.238877]  [<ffffffff9d0bb550>] ? insert_kthread_work+0x40/0x40

Comments

[Gerrit Updater]

Oleg Drokin ([e-mail]) merged in patch https://review.whamcloud.com/35010/
Subject: LU-12324 mdd: Do not record xattr size get in changelogs
Project: fs/lustre-release
Branch: b2_12
Current Patch Set:
Commit: f94aecf16859e2e0dcd999eb8862227e50671ee8

[Gerrit Updater]

Minh Diep ([e-mail]) uploaded a new patch: https://review.whamcloud.com/35010
Subject: LU-12324 mdd: Do not record xattr size get in changelogs
Project: fs/lustre-release
Branch: b2_12
Current Patch Set: 1
Commit: 234dfa5cdefc631b14de3db6030fb7823c680732

[Peter Jones]

Landed for 2.13

[Gerrit Updater]

Oleg Drokin ([e-mail]) merged in patch https://review.whamcloud.com/34936/
Subject: LU-12324 mdd: Do not record xattr size get in changelogs
Project: fs/lustre-release
Branch: master
Current Patch Set:
Commit: 8f2599c599011a50549cdc79f0b3379239cf4f0c

[Gerrit Updater]

Oleg Drokin ([e-mail]) uploaded a new patch: https://review.whamcloud.com/34936
Subject: LU-12324 mdd: Do not record xattr size get in changelogs
Project: fs/lustre-release
Branch: master
Current Patch Set: 1
Commit: 978a35803fb1d683bd827b056c2b6b2ee808387b