This is a note to let you know that I've just added the patch titled
jbd2: fix soft lockup in journal_finish_inode_data_buffers()
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
jbd2-fix-soft-lockup-in-journal_finish_inode_data_bu.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 1b9ccd568848ee62f246107b2f5b269e3d8173a6
Author: Ye Bin <yebin10@xxxxxxxxxx>
Date: Mon Dec 11 19:25:44 2023 +0800
jbd2: fix soft lockup in journal_finish_inode_data_buffers()
[ Upstream commit 6c02757c936063f0631b4e43fe156f8c8f1f351f ]
There's issue when do io test:
WARN: soft lockup - CPU#45 stuck for 11s! [jbd2/dm-2-8:4170]
CPU: 45 PID: 4170 Comm: jbd2/dm-2-8 Kdump: loaded Tainted: G OE
Call trace:
dump_backtrace+0x0/0x1a0
show_stack+0x24/0x30
dump_stack+0xb0/0x100
watchdog_timer_fn+0x254/0x3f8
__hrtimer_run_queues+0x11c/0x380
hrtimer_interrupt+0xfc/0x2f8
arch_timer_handler_phys+0x38/0x58
handle_percpu_devid_irq+0x90/0x248
generic_handle_irq+0x3c/0x58
__handle_domain_irq+0x68/0xc0
gic_handle_irq+0x90/0x320
el1_irq+0xcc/0x180
queued_spin_lock_slowpath+0x1d8/0x320
jbd2_journal_commit_transaction+0x10f4/0x1c78 [jbd2]
kjournald2+0xec/0x2f0 [jbd2]
kthread+0x134/0x138
ret_from_fork+0x10/0x18
Analyzed informations from vmcore as follows:
(1) There are about 5k+ jbd2_inode in 'commit_transaction->t_inode_list';
(2) Now is processing the 855th jbd2_inode;
(3) JBD2 task has TIF_NEED_RESCHED flag;
(4) There's no pags in address_space around the 855th jbd2_inode;
(5) There are some process is doing drop caches;
(6) Mounted with 'nodioread_nolock' option;
(7) 128 CPUs;
According to informations from vmcore we know 'journal->j_list_lock' spin lock
competition is fierce. So journal_finish_inode_data_buffers() maybe process
slowly. Theoretically, there is scheduling point in the filemap_fdatawait_range_keep_errors().
However, if inode's address_space has no pages which taged with PAGECACHE_TAG_WRITEBACK,
will not call cond_resched(). So may lead to soft lockup.
journal_finish_inode_data_buffers
filemap_fdatawait_range_keep_errors
__filemap_fdatawait_range
while (index <= end)
nr_pages = pagevec_lookup_range_tag(&pvec, mapping, &index, end, PAGECACHE_TAG_WRITEBACK);
if (!nr_pages)
break; --> If 'nr_pages' is equal zero will break, then will not call cond_resched()
for (i = 0; i < nr_pages; i++)
wait_on_page_writeback(page);
cond_resched();
To solve above issue, add scheduling point in the journal_finish_inode_data_buffers();
Signed-off-by: Ye Bin <yebin10@xxxxxxxxxx>
Reviewed-by: Jan Kara <jack@xxxxxxx>
Link: https://lore.kernel.org/r/20231211112544.3879780-1-yebin10@xxxxxxxxxx
Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c
index fa24b407a9dc..db137671a41f 100644
--- a/fs/jbd2/commit.c
+++ b/fs/jbd2/commit.c
@@ -300,6 +300,7 @@ static int journal_finish_inode_data_buffers(journal_t *journal,
if (!ret)
ret = err;
}
+ cond_resched();
spin_lock(&journal->j_list_lock);
jinode->i_flags &= ~JI_COMMIT_RUNNING;
smp_mb();
