Hi,
Executing generic/001 test on XFS on a machine running next-20240201 kernel
causes the following hung task to occur,
INFO: task umount:6305 blocked for more than 122 seconds.
Not tainted 6.8.0-rc2-next-20240202 #17
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:umount state:D stack:13008 pid:6305 tgid:6305 ppid:6301 flags:0x00004000
Call Trace:
<TASK>
__schedule+0x2f6/0xa20
schedule+0x36/0xb0
schedule_timeout+0x20b/0x280
? srso_return_thunk+0x5/0x5f
? irq_work_queue+0x40/0x60
? srso_return_thunk+0x5/0x5f
? __wake_up_klogd.part.0+0x5a/0x80
wait_for_completion+0x8a/0x140
__flush_workqueue+0x11a/0x3b0
xfs_inodegc_flush+0x24/0xf0
xfs_unmountfs+0x14/0x180
xfs_fs_put_super+0x3d/0x90
generic_shutdown_super+0x7c/0x160
kill_block_super+0x1b/0x40
xfs_kill_sb+0x12/0x30
deactivate_locked_super+0x35/0x90
deactivate_super+0x42/0x50
cleanup_mnt+0x109/0x170
__cleanup_mnt+0x12/0x20
task_work_run+0x60/0x90
syscall_exit_to_user_mode+0x146/0x150
do_syscall_64+0x5d/0x110
entry_SYSCALL_64_after_hwframe+0x6c/0x74
RIP: 0033:0x7f13c103b38b
RSP: 002b:00007fff161aeff8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007f13c116d204 RCX: 00007f13c103b38b
RDX: ffffffffffffff78 RSI: 0000000000000000 RDI: 000055964eda0030
RBP: 000055964ed99310 R08: 0000000000000000 R09: 00007fff161adda0
R10: 00007f13c1159379 R11: 0000000000000246 R12: 000055964eda0030
R13: 0000000000000000 R14: 000055964ed99408 R15: 000055964ed99520
Git bisect revealed the following as the bad commit,
dd6c3c5441263723305a9c52c5ccc899a4653000 is the first bad commit
commit dd6c3c5441263723305a9c52c5ccc899a4653000
Author: Tejun Heo <tj@xxxxxxxxxx>
Date: Mon Jan 29 08:11:24 2024 -1000
workqueue: Move pwq_dec_nr_in_flight() to the end of work item handling
The planned shared nr_active handling for unbound workqueues will make
pwq_dec_nr_active() sometimes drop the pool lock temporarily to acquire
other pool locks, which is necessary as retirement of an nr_active count
from one pool may need kick off an inactive work item in another pool.
This patch moves pwq_dec_nr_in_flight() call in try_to_grab_pending() to the
end of work item handling so that work item state changes stay atomic.
process_one_work() which is the other user of pwq_dec_nr_in_flight() already
calls it at the end of work item handling. Comments are added to both call
sites and pwq_dec_nr_in_flight().
This shouldn't cause any behavior changes.
Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
Reviewed-by: Lai Jiangshan <jiangshanlai@xxxxxxxxx>
kernel/workqueue.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)
Here is the full git bisect log,
# bad: [076d56d74f17e625b3d63cf4743b3d7d02180379] Add linux-next specific files for 20240202
# good: [881f78f472556ed05588172d5b5676b48dc48240] xfs: remove conditional building of rt geometry validator functions
git bisect start 'HEAD' '881f78f47255' 'fs/'
# good: [50673a33b8dc743777e79d7206acdc8d64452498] Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma.git
git bisect good 50673a33b8dc743777e79d7206acdc8d64452498
# good: [717a7216eaa84233dc70498db3e92989153fa444] Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/ulfh/mmc.git
git bisect good 717a7216eaa84233dc70498db3e92989153fa444
# bad: [e6ead6ea890b2c2df0faf62ca2da15392cdc4165] Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/westeri/thunderbolt.git
git bisect bad e6ead6ea890b2c2df0faf62ca2da15392cdc4165
# good: [be364bf6099dc52d26ce25e2996fa2a04502a890] Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git
git bisect good be364bf6099dc52d26ce25e2996fa2a04502a890
# good: [b043e7f00dfd9def840c03a8eb1cb56b0def4db9] Merge branch 'next' of https://github.com/kvm-x86/linux.git
git bisect good b043e7f00dfd9def840c03a8eb1cb56b0def4db9
# bad: [6806f880feafd5a565f00714f2f6254e7c80e961] Merge branch 'driver-core-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core.git
git bisect bad 6806f880feafd5a565f00714f2f6254e7c80e961
# bad: [6e50cdc4feb87e269649adb2c7498ce98fcf458c] Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq.git
git bisect bad 6e50cdc4feb87e269649adb2c7498ce98fcf458c
# good: [c5404d4e6df6faba1007544b5f4e62c7c14416dd] workqueue: Make wq_adjust_max_active() round-robin pwqs while activating
git bisect good c5404d4e6df6faba1007544b5f4e62c7c14416dd
# bad: [15930da42f8981dc42c19038042947b475b19f47] workqueue: Don't call cpumask_test_cpu() with -1 CPU in wq_update_node_max_active()
git bisect bad 15930da42f8981dc42c19038042947b475b19f47
# bad: [91ccc6e7233bb10a9c176aa4cc70d6f432a441a5] workqueue: Introduce struct wq_node_nr_active
git bisect bad 91ccc6e7233bb10a9c176aa4cc70d6f432a441a5
# bad: [dd6c3c5441263723305a9c52c5ccc899a4653000] workqueue: Move pwq_dec_nr_in_flight() to the end of work item handling
git bisect bad dd6c3c5441263723305a9c52c5ccc899a4653000
# good: [9f66cff212bb3c1cd25996aaa0dfd0c9e9d8baab] workqueue: RCU protect wq->dfl_pwq and implement accessors for it
git bisect good 9f66cff212bb3c1cd25996aaa0dfd0c9e9d8baab
# first bad commit: [dd6c3c5441263723305a9c52c5ccc899a4653000] workqueue: Move pwq_dec_nr_in_flight() to the end of work item handling
--
Chandan
