[LU-4794] MDS threads all stuck in jbd2_journal_start

• Status: Resolved
• Project: Lustre
• Affects Version/s: Lustre 2.1.6
• Type: Bug
• Priority: Minor
• Reporter: Patrick Valentin (Inactive)
• Assignee: Zhenyu Xu
• Resolution: Cannot Reproduce
• Severity: 3

Description

This seems to be a duplicate of LU-1276, which was closed with "Cannot Reproduce", and in which I initially added the following note.

One of the Bull customers (TGCC) had the same deadlock as described in LU-1276 twice during the past six months: one thread is stuck in jbd2_journal_commit_transaction() and many other thread are stuck in jbd2_journal_start().

PID: 29225 TASK: ffff88107c3bb040 CPU: 15 COMMAND: "jbd2/dm-2-8"
 #0 [ffff88107a343c60] schedule at ffffffff81485765
 0000001 [ffff88107a343d28] jbd2_journal_commit_transaction at ffffffffa006a94f [jbd2]
 0000002 [ffff88107a343e68] kjournald2 at ffffffffa0070c08 [jbd2]
 0000003 [ffff88107a343ee8] kthread at ffffffff8107b5f6
 0000004 [ffff88107a343f48] kernel_thread at ffffffff8100412a

and most of the threads:

PID: 15585 TASK: ffff88063062a790 CPU: 0 COMMAND: "mdt_503"
PID: 15586 TASK: ffff88063062a040 CPU: 23 COMMAND: "mdt_504"
PID: 15587 TASK: ffff88020f3ad7d0 CPU: 30 COMMAND: "mdt_505"
PID: 29286 TASK: ffff88087505e790 CPU: 25 COMMAND: "mdt_01"
...
#0 [ffff881949c078f0] schedule at ffffffff81485765
0000001 [ffff881949c079b8] start_this_handle at ffffffffa006908a [jbd2]
0000002 [ffff881949c07a78] jbd2_journal_start at ffffffffa0069500 [jbd2]
0000003 [ffff881949c07ac8] ldiskfs_journal_start_sb at ffffffffa0451ca8 [ldiskfs]
0000004 [ffff881949c07ad8] osd_trans_start at ffffffffa0d4a324 [osd_ldiskfs]
0000005 [ffff881949c07b18] mdd_trans_start at ffffffffa0c4c4e3 [mdd]
0000006 [ffff881949c07b38] mdd_unlink at ffffffffa0c401eb [mdd]
0000007 [ffff881949c07bf8] cml_unlink at ffffffffa0d82e07 [cmm]
0000008 [ffff881949c07c38] mdt_reint_unlink at ffffffffa0cba0f4 [mdt]
0000009 [ffff881949c07cb8] mdt_reint_rec at ffffffffa0cb7cb1 [mdt]
0000010 [ffff881949c07cd8] mdt_reint_internal at ffffffffa0caeed4 [mdt]
0000011 [ffff881949c07d28] mdt_reint at ffffffffa0caf2b4 [mdt]
0000012 [ffff881949c07d48] mdt_handle_common at ffffffffa0ca3762 [mdt]
0000013 [ffff881949c07d98] mdt_regular_handle at ffffffffa0ca4655 [mdt]
0000014 [ffff881949c07da8] ptlrpc_main at ffffffffa071f4f6 [ptlrpc]
0000015 [ffff881949c07f48] kernel_thread at ffffffff8100412a

They are running lustre 2.1.6 which contains http://review.whamcloud.com/4743 from LU-1648.

I attach two files containing the dmseg and the crash back trace of all threads.

Issue Links

• is duplicated by: LU-5052 threads stuck in jbd2_journal_start
• is related to: LU-1648 MDS Crash

Comments

[Peter Jones]

Bobijam

Could you please advise?

Thanks

Peter

[Zhenyu Xu]

Relates to LU-1648.

Thread 27469 stack trace from bt-all.merged.txt

PID: 27469  TASK: ffff88199d25a080  CPU: 12  COMMAND: "ldlm_cn_88"
 #0 [ffff881c4f78b490] schedule at ffffffff81485765
 #1 [ffff881c4f78b558] start_this_handle at ffffffffa006908a [jbd2]
 #2 [ffff881c4f78b618] jbd2_journal_restart at ffffffffa00693d1 [jbd2]
 #3 [ffff881c4f78b668] ldiskfs_truncate_restart_trans at ffffffffa042791a [ldiskfs]
 #4 [ffff881c4f78b698] ldiskfs_clear_blocks at ffffffffa042cc3d [ldiskfs]
 #5 [ffff881c4f78b6f8] ldiskfs_free_data at ffffffffa042ce24 [ldiskfs]
 #6 [ffff881c4f78b758] ldiskfs_free_branches at ffffffffa042d063 [ldiskfs]
 #7 [ffff881c4f78b7b8] ldiskfs_free_branches at ffffffffa042cf56 [ldiskfs]
 #8 [ffff881c4f78b818] ldiskfs_truncate at ffffffffa042d659 [ldiskfs]
 #9 [ffff881c4f78b938] ldiskfs_delete_inode at ffffffffa042e9d0 [ldiskfs]
#10 [ffff881c4f78b958] generic_delete_inode at ffffffff8117f0de
#11 [ffff881c4f78b988] generic_drop_inode at ffffffff8117f235
#12 [ffff881c4f78b9a8] iput at ffffffff8117df52
#13 [ffff881c4f78b9c8] mds_obd_destroy at ffffffffa0bf717d [mds]
#14 [ffff881c4f78bb08] llog_lvfs_destroy at ffffffffa05705cd [obdclass]
#15 [ffff881c4f78bbd8] llog_cancel_rec at ffffffffa0566424 [obdclass]
#16 [ffff881c4f78bc08] llog_cat_cancel_records at ffffffffa056a3a1 [obdclass]
#17 [ffff881c4f78bc68] llog_origin_handle_cancel at ffffffffa072923b [ptlrpc]
#18 [ffff881c4f78bd68] ldlm_cancel_handler at ffffffffa06ee8ff [ptlrpc]
#19 [ffff881c4f78bda8] ptlrpc_main at ffffffffa071f4f6 [ptlrpc]
#20 [ffff881c4f78bf48] kernel_thread at ffffffff8100412a

the transaction credit is not enough, and the thread restart the transaction while holding log_handle::lgh_lock

[Zhenyu Xu]

the competing deadlock thread 15514

PID: 15514  TASK: ffff88199fe40850  CPU: 16  COMMAND: "mdt_432"
 #0 [ffff881cc6f1b548] schedule at ffffffff81485765
 #1 [ffff881cc6f1b610] rwsem_down_failed_common at ffffffff81487d65
 #2 [ffff881cc6f1b670] rwsem_down_read_failed at ffffffff81487f16
 #3 [ffff881cc6f1b6b0] call_rwsem_down_read_failed at ffffffff81262b24
 #4 [ffff881cc6f1b718] llog_cat_current_log.clone.0 at ffffffffa056ada5 [obdclass]
 #5 [ffff881cc6f1b7b8] llog_cat_add_rec at ffffffffa056baca [obdclass]
 #6 [ffff881cc6f1b808] llog_obd_origin_add at ffffffffa0571627 [obdclass]
 #7 [ffff881cc6f1b838] llog_add at ffffffffa0571801 [obdclass]
 #8 [ffff881cc6f1b888] lov_llog_origin_add at ffffffffa09f70fc [lov]
 #9 [ffff881cc6f1b908] llog_add at ffffffffa0571801 [obdclass]
#10 [ffff881cc6f1b958] mds_llog_origin_add at ffffffffa0bf8d53 [mds]
#11 [ffff881cc6f1b9a8] llog_add at ffffffffa0571801 [obdclass]
#12 [ffff881cc6f1b9f8] mds_llog_add_unlink at ffffffffa0bf93ca [mds]
#13 [ffff881cc6f1ba48] mds_log_op_unlink at ffffffffa0bf9a08 [mds]
#14 [ffff881cc6f1baa8] mdd_unlink_log at ffffffffa0c2df31 [mdd]
#15 [ffff881cc6f1bac8] mdd_object_kill at ffffffffa0c2526b [mdd]
#16 [ffff881cc6f1baf8] mdd_finish_unlink at ffffffffa0c3b13e [mdd]
#17 [ffff881cc6f1bb38] mdd_unlink at ffffffffa0c40696 [mdd]
#18 [ffff881cc6f1bbf8] cml_unlink at ffffffffa0d82e07 [cmm]
#19 [ffff881cc6f1bc38] mdt_reint_unlink at ffffffffa0cba0f4 [mdt]
#20 [ffff881cc6f1bcb8] mdt_reint_rec at ffffffffa0cb7cb1 [mdt]
#21 [ffff881cc6f1bcd8] mdt_reint_internal at ffffffffa0caeed4 [mdt]
#22 [ffff881cc6f1bd28] mdt_reint at ffffffffa0caf2b4 [mdt]
#23 [ffff881cc6f1bd48] mdt_handle_common at ffffffffa0ca3762 [mdt]
#24 [ffff881cc6f1bd98] mdt_regular_handle at ffffffffa0ca4655 [mdt]
#25 [ffff881cc6f1bda8] ptlrpc_main at ffffffffa071f4f6 [ptlrpc]
#26 [ffff881cc6f1bf48] kernel_thread at ffffffff8100412a

[Zhenyu Xu]

patch tracking at http://review.whamcloud.com/10076 (b2_1 needs it, b2_4 does not)