* [RESEND PATCH] jbd2:remove unnecessary finish_wait call in jbd2_journal_wait_updates
@ 2026-08-03 12:35 shuo chen
2026-08-03 13:47 ` Jan Kara
2026-08-17 3:40 ` kernel test robot
0 siblings, 2 replies; 4+ messages in thread
From: shuo chen @ 2026-08-03 12:35 UTC (permalink / raw)
To: tytso, jack; +Cc: linux-ext4
merge transaction and atomic_read(&transaction->t_updates) check.
remove redundant finish_wait call.
Signed-off-by: shuo chen <1289151713@qq.com>
---
fs/jbd2/transaction.c | 7 ++-----
1 file changed, 2 insertions(+), 5 deletions(-)
diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c
index 5cc7d097b2ac..0f193d02a054 100644
--- a/fs/jbd2/transaction.c
+++ b/fs/jbd2/transaction.c
@@ -831,15 +831,12 @@ void jbd2_journal_wait_updates(journal_t *journal)
*/
transaction_t *transaction = journal->j_running_transaction;
- if (!transaction)
+ if (!transaction || !atomic_read(&transaction->t_updates))
break;
prepare_to_wait(&journal->j_wait_updates, &wait,
TASK_UNINTERRUPTIBLE);
- if (!atomic_read(&transaction->t_updates)) {
- finish_wait(&journal->j_wait_updates, &wait);
- break;
- }
+
write_unlock(&journal->j_state_lock);
schedule();
finish_wait(&journal->j_wait_updates, &wait);
--
2.47.3
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [RESEND PATCH] jbd2:remove unnecessary finish_wait call in jbd2_journal_wait_updates
2026-08-03 12:35 [RESEND PATCH] jbd2:remove unnecessary finish_wait call in jbd2_journal_wait_updates shuo chen
@ 2026-08-03 13:47 ` Jan Kara
2026-08-04 9:31 ` shuo chen
2026-08-17 3:40 ` kernel test robot
1 sibling, 1 reply; 4+ messages in thread
From: Jan Kara @ 2026-08-03 13:47 UTC (permalink / raw)
To: shuo chen; +Cc: tytso, jack, linux-ext4
On Mon 03-08-26 20:35:39, shuo chen wrote:
> merge transaction and atomic_read(&transaction->t_updates) check.
> remove redundant finish_wait call.
>
> Signed-off-by: shuo chen <1289151713@qq.com>
The changelog should mention what is the motivation of the patch. Simple
cleanup?
> ---
> fs/jbd2/transaction.c | 7 ++-----
> 1 file changed, 2 insertions(+), 5 deletions(-)
>
> diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c
> index 5cc7d097b2ac..0f193d02a054 100644
> --- a/fs/jbd2/transaction.c
> +++ b/fs/jbd2/transaction.c
> @@ -831,15 +831,12 @@ void jbd2_journal_wait_updates(journal_t *journal)
> */
> transaction_t *transaction = journal->j_running_transaction;
>
> - if (!transaction)
> + if (!transaction || !atomic_read(&transaction->t_updates))
> break;
>
> prepare_to_wait(&journal->j_wait_updates, &wait,
> TASK_UNINTERRUPTIBLE);
> - if (!atomic_read(&transaction->t_updates)) {
> - finish_wait(&journal->j_wait_updates, &wait);
> - break;
> - }
> +
This introduces a race with stop_this_handle() possibly causing a lost
wakeup (I can see Sashiko noticed as well).
Honza
--
Jan Kara <jack@suse.com>
SUSE Labs, CR
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [RESEND PATCH] jbd2:remove unnecessary finish_wait call in jbd2_journal_wait_updates
2026-08-03 13:47 ` Jan Kara
@ 2026-08-04 9:31 ` shuo chen
0 siblings, 0 replies; 4+ messages in thread
From: shuo chen @ 2026-08-04 9:31 UTC (permalink / raw)
To: Jan Kara; +Cc: linux-ext4
On Mon, Aug 03, 2026 at 03:47:18PM +0200, Jan Kara wrote:
> On Mon 03-08-26 20:35:39, shuo chen wrote:
> > merge transaction and atomic_read(&transaction->t_updates) check.
> > remove redundant finish_wait call.
> >
> > Signed-off-by: shuo chen <1289151713@qq.com>
>
> The changelog should mention what is the motivation of the patch. Simple
> cleanup?
>
> > ---
> > fs/jbd2/transaction.c | 7 ++-----
> > 1 file changed, 2 insertions(+), 5 deletions(-)
> >
> > diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c
> > index 5cc7d097b2ac..0f193d02a054 100644
> > --- a/fs/jbd2/transaction.c
> > +++ b/fs/jbd2/transaction.c
> > @@ -831,15 +831,12 @@ void jbd2_journal_wait_updates(journal_t *journal)
> > */
> > transaction_t *transaction = journal->j_running_transaction;
> >
> > - if (!transaction)
> > + if (!transaction || !atomic_read(&transaction->t_updates))
> > break;
> >
> > prepare_to_wait(&journal->j_wait_updates, &wait,
> > TASK_UNINTERRUPTIBLE);
> > - if (!atomic_read(&transaction->t_updates)) {
> > - finish_wait(&journal->j_wait_updates, &wait);
> > - break;
> > - }
> > +
>
> This introduces a race with stop_this_handle() possibly causing a lost
> wakeup (I can see Sashiko noticed as well).
Thank you for the review.
After reconsideration, I realized this patch actually causes a lost wakeup
in some scenarios, so it should be withdrawn.
I will withdraw this patch. Sorry for the noise,and thank you for your time.
>
> Honza
> --
> Jan Kara <jack@suse.com>
> SUSE Labs, CR
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [RESEND PATCH] jbd2:remove unnecessary finish_wait call in jbd2_journal_wait_updates
2026-08-03 12:35 [RESEND PATCH] jbd2:remove unnecessary finish_wait call in jbd2_journal_wait_updates shuo chen
2026-08-03 13:47 ` Jan Kara
@ 2026-08-17 3:40 ` kernel test robot
1 sibling, 0 replies; 4+ messages in thread
From: kernel test robot @ 2026-08-17 3:40 UTC (permalink / raw)
To: shuo chen; +Cc: oe-lkp, lkp, linux-ext4, tytso, jack, yi1.lai
Hello,
kernel test robot noticed "INFO:task_blocked_for_more_than#seconds" on:
commit: 2a8eec86fbe20e3599766fd1c3d97949e577dd83 ("[RESEND PATCH] jbd2:remove unnecessary finish_wait call in jbd2_journal_wait_updates")
url: https://github.com/intel-lab-lkp/linux/commits/shuo-chen/jbd2-remove-unnecessary-finish_wait-call-in-jbd2_journal_wait_updates/20260806-124301
base: https://git.kernel.org/cgit/linux/kernel/git/vfs/vfs.git vfs.all patch
link: https://lore.kernel.org/all/tencent_AA7E2FDA8D68E1E3430F219A8C3DAB442508@qq.com/
patch subject: [RESEND PATCH] jbd2:remove unnecessary finish_wait call in jbd2_journal_wait_updates
in testcase: stress-ng
version: stress-ng-x86_64-f179fd9c6-1_20260812
with following parameters:
nr_threads: 100%
disk: 1SSD
testtime: 60s
fs: ext4
test: chown
cpufreq_governor: performance
config: x86_64-rhel-9.4
compiler: gcc-14
test machine: 224 threads 2 sockets Intel(R) Xeon(R) (Sapphire Rapids) with 128G memory
If you fix the issue in a separate patch/commit (i.e. not just a new version of the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <yi1.lai@intel.com>
| Closes: https://lore.kernel.org/oe-lkp/202608170527.19fb56ff-lkp@intel.com
kern :err : [ 991.254044] [ T1509] INFO: task jbd2/sdb3-8:12832 blocked for more than 491 seconds.
kern :err : [ 991.262978] [ T1509] Tainted: G S 7.2.0-rc5+ #1
kern :err : [ 991.270278] [ T1509] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
kern :info : [ 991.279925] [ T1509] task:jbd2/sdb3-8 state:D stack:0 pid:12832 tgid:12832 ppid:2 task_flags:0x240040 flags:0x00080000
kern :info : [ 991.293161] [ T1509] Call Trace:
kern :info : [ 991.296770] [ T1509] <TASK>
kern :info : [ 991.299998] [ T1509] __schedule (sched/core.c:5510 sched/core.c:7234)
kern :info : [ 991.304788] [ T1509] schedule (sched/core.c:7311 sched/core.c:7326)
kern :info : [ 991.309189] [ T1509] jbd2_journal_wait_updates (jbd2/transaction.c:841) jbd2
kern :info : [ 991.315913] [ T1509] ? __pfx_autoremove_wake_function (sched/wait_bit.c:161)
kern :info : [ 991.322656] [ T1509] jbd2_journal_commit_transaction (jbd2/commit.c:482) jbd2
kern :info : [ 991.330273] [ T1509] ? raw_spin_rq_lock_nested (sched/core.c:667)
kern :info : [ 991.336306] [ T1509] ? finish_task_switch+0xc7/0x3f0
kern :info : [ 991.342642] [ T1509] ? __try_to_del_timer_sync (time/timer.c:1467)
kern :info : [ 991.348674] [ T1509] kjournald2 (jbd2/journal.c:199) jbd2
kern :info : [ 991.354057] [ T1509] ? __pfx_autoremove_wake_function (sched/wait_bit.c:161)
kern :info : [ 991.360786] [ T1509] ? __pfx_kjournald2 (jbd2/journal.c:893) jbd2
kern :info : [ 991.366824] [ T1509] kthread (kthread.c:436)
kern :info : [ 991.371220] [ T1509] ? __pfx_kthread (kthread.c:948)
kern :info : [ 991.376297] [ T1509] ret_from_fork (x86/kernel/process.c:158)
kern :info : [ 991.381361] [ T1509] ? __pfx_kthread (kthread.c:948)
kern :info : [ 991.386433] [ T1509] ret_from_fork_asm (x86/entry/entry_64.S:245)
kern :info : [ 991.391693] [ T1509] </TASK>
kern :err : [ 991.395061] [ T1509] INFO: task stress-ng-chown:16436 blocked for more than 491 seconds.
kern :err : [ 991.404133] [ T1509] Tainted: G S 7.2.0-rc5+ #1
kern :err : [ 991.411439] [ T1509] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
kern :info : [ 991.421059] [ T1509] task:stress-ng-chown state:D stack:0 pid:16436 tgid:16436 ppid:16132 task_flags:0x400040 flags:0x00080002
kern :info : [ 991.434286] [ T1509] Call Trace:
kern :info : [ 991.437906] [ T1509] <TASK>
kern :info : [ 991.441137] [ T1509] __schedule (sched/core.c:5510 sched/core.c:7234)
kern :info : [ 991.445922] [ T1509] schedule (sched/core.c:7311 sched/core.c:7326)
kern :info : [ 991.450307] [ T1509] wait_transaction_locked (jbd2.mod.c:?) jbd2
kern :info : [ 991.456838] [ T1509] ? __pfx_autoremove_wake_function (sched/wait_bit.c:161)
kern :info : [ 991.463570] [ T1509] add_transaction_credits (jbd2.mod.c:?) jbd2
kern :info : [ 991.470288] [ T1509] ? wake_up_q (sched/core.c:4547 sched/core.c:1173)
kern :info : [ 991.474954] [ T1509] start_this_handle (jbd2/transaction.c:403) jbd2
kern :info : [ 991.481011] [ T1509] ? kmem_cache_alloc_noprof (slub.c:4594 (discriminator 3) slub.c:4917 (discriminator 3) slub.c:4931 (discriminator 3))
kern :info : [ 991.487246] [ T1509] ? jbd2__journal_start (jbd2/transaction.c:457 (discriminator 2) jbd2/transaction.c:485 (discriminator 2)) jbd2
kern :info : [ 991.493688] [ T1509] jbd2__journal_start (jbd2/transaction.c:502) jbd2
kern :info : [ 991.499924] [ T1509] ext4_dirty_inode (ext4/ext4_jbd2.h:242 ext4/inode.c:6674) ext4
kern :info : [ 991.505839] [ T1509] __mark_inode_dirty (fs-writeback.c:2729)
kern :info : [ 991.511289] [ T1509] ext4_setattr (linux/fs.h:2207 ext4/inode.c:6181) ext4
kern :info : [ 991.516964] [ T1509] notify_change (attr.c:556)
kern :info : [ 991.522317] [ T1509] ? chown_common (open.c:825)
kern :info : [ 991.527693] [ T1509] chown_common (open.c:825)
kern :info : [ 991.532861] [ T1509] ? up_write (locking/rwsem.c:1420 locking/rwsem.c:1688)
kern :info : [ 991.537610] [ T1509] vfs_fchown (open.c:890 open.c:882)
kern :info : [ 991.542295] [ T1509] __x64_sys_fchown (open.c:902 open.c:907 open.c:905 open.c:905)
kern :info : [ 991.547590] [ T1509] do_syscall_64 (x86/entry/syscall_64.c:63 x86/entry/syscall_64.c:94)
kern :info : [ 991.552692] [ T1509] ? __x64_sys_fchown (open.c:902 open.c:907 open.c:905 open.c:905)
kern :info : [ 991.558159] [ T1509] ? do_syscall_64 (linux/irq-entry-common.h:210 linux/irq-entry-common.h:230 linux/entry-common.h:318 x86/entry/syscall_64.c:100)
kern :info : [ 991.563523] [ T1509] ? __x64_sys_lchown (open.c:878 open.c:876 open.c:876)
kern :info : [ 991.568989] [ T1509] ? do_syscall_64 (linux/irq-entry-common.h:210 linux/irq-entry-common.h:230 linux/entry-common.h:318 x86/entry/syscall_64.c:100)
kern :info : [ 991.574349] [ T1509] ? do_syscall_64 (linux/irq-entry-common.h:210 linux/irq-entry-common.h:230 linux/entry-common.h:318 x86/entry/syscall_64.c:100)
kern :info : [ 991.579732] [ T1509] ? do_syscall_64 (linux/randomize_kstack.h:57 x86/entry/syscall_64.c:92)
kern :info : [ 991.584966] [ T1509] entry_SYSCALL_64_after_hwframe (x86/entry/entry_64.S:121)
kern :info : [ 991.591591] [ T1509] RIP: 0033:0x7f0b50646e17
kern :info : [ 991.596546] [ T1509] RSP: 002b:00007ffea1566b48 EFLAGS: 00000213 ORIG_RAX: 000000000000005d
kern :info : [ 991.605988] [ T1509] RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 00007f0b50646e17
kern :info : [ 991.614943] [ T1509] RDX: 00000000ffffffff RSI: 00000000ffffffff RDI: 0000000000000005
kern :info : [ 991.623876] [ T1509] RBP: 00007f0b4fcb99c8 R08: 0000000000000000 R09: 0000000000000000
kern :info : [ 991.632818] [ T1509] R10: 0000000000000000 R11: 0000000000000213 R12: 00007ffea1566b70
kern :info : [ 991.641767] [ T1509] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000017
kern :info : [ 991.650731] [ T1509] </TASK>
kern :err : [ 991.654143] [ T1509] INFO: task stress-ng-chown:16453 blocked for more than 491 seconds.
kern :err : [ 991.663280] [ T1509] Tainted: G S 7.2.0-rc5+ #1
kern :err : [ 991.670694] [ T1509] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
kern :info : [ 991.680398] [ T1509] task:stress-ng-chown state:D stack:0 pid:16453 tgid:16453 ppid:16132 task_flags:0x400040 flags:0x00080002
kern :info : [ 991.693833] [ T1509] Call Trace:
kern :info : [ 991.697539] [ T1509] <TASK>
kern :info : [ 991.700842] [ T1509] __schedule (sched/core.c:5510 sched/core.c:7234)
kern :info : [ 991.705722] [ T1509] schedule (sched/core.c:7311 sched/core.c:7326)
kern :info : [ 991.710195] [ T1509] jbd2_log_wait_commit (jbd2/journal.c:681 (discriminator 7)) jbd2
kern :info : [ 991.716623] [ T1509] ? __pfx_autoremove_wake_function (sched/wait_bit.c:161)
kern :info : [ 991.723421] [ T1509] ext4_sync_file (ext4/fsync.c:114 ext4/fsync.c:162) ext4
kern :info : [ 991.729378] [ T1509] do_fsync (sync.c:186 sync.c:200 sync.c:211)
kern :info : [ 991.733854] [ T1509] __x64_sys_fsync (sync.c:216 sync.c:214 sync.c:214)
kern :info : [ 991.739008] [ T1509] do_syscall_64 (x86/entry/syscall_64.c:63 x86/entry/syscall_64.c:94)
kern :info : [ 991.744074] [ T1509] ? __x64_sys_lchown (open.c:878 open.c:876 open.c:876)
kern :info : [ 991.749490] [ T1509] ? do_syscall_64 (linux/irq-entry-common.h:210 linux/irq-entry-common.h:230 linux/entry-common.h:318 x86/entry/syscall_64.c:100)
kern :info : [ 991.754832] [ T1509] ? do_syscall_64 (linux/randomize_kstack.h:57 x86/entry/syscall_64.c:92)
kern :info : [ 991.760066] [ T1509] entry_SYSCALL_64_after_hwframe (x86/entry/entry_64.S:121)
kern :info : [ 991.766655] [ T1509] RIP: 0033:0x7f0b505d6687
kern :info : [ 991.771614] [ T1509] RSP: 002b:00007ffea1566b00 EFLAGS: 00000202 ORIG_RAX: 000000000000004a
kern :info : [ 991.781039] [ T1509] RAX: ffffffffffffffda RBX: 00007f0b4fd31b00 RCX: 00007f0b505d6687
kern :info : [ 991.789965] [ T1509] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000005
kern :info : [ 991.798875] [ T1509] RBP: 00007f0b4fcc9268 R08: 0000000000000000 R09: 0000000000000000
kern :info : [ 991.807820] [ T1509] R10: 0000000000000000 R11: 0000000000000202 R12: 00007ffea1566b70
kern :info : [ 991.816762] [ T1509] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
kern :info : [ 991.825727] [ T1509] </TASK>
kern :info : [ 2465.958258] [ T1509] Future hung task reports are suppressed, see sysctl kernel.hung_task_warnings
The kernel config and materials to reproduce are available at:
https://download.01.org/0day-ci/archive/20260817/202608170527.19fb56ff-lkp@intel.com
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2026-08-17 3:40 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2026-08-03 12:35 [RESEND PATCH] jbd2:remove unnecessary finish_wait call in jbd2_journal_wait_updates shuo chen
2026-08-03 13:47 ` Jan Kara
2026-08-04 9:31 ` shuo chen
2026-08-17 3:40 ` kernel test robot
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