From: Ye Bin yebin10@huawei.com

mainline inclusion from mainline-v6.7-rc6 commit 6c02757c936063f0631b4e43fe156f8c8f1f351f category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I8RRXU?from=project-issue CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...

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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@huawei.com Reviewed-by: Jan Kara jack@suse.cz Link: https://lore.kernel.org/r/20231211112544.3879780-1-yebin10@huawei.com Signed-off-by: Theodore Ts'o tytso@mit.edu Signed-off-by: Zizhi Wo wozizhi@huawei.com --- fs/jbd2/commit.c | 1 + 1 file changed, 1 insertion(+)

diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c index 8c13c0a030a4..99562835be45 100644 --- a/fs/jbd2/commit.c +++ b/fs/jbd2/commit.c @@ -274,6 +274,7 @@ static int journal_finish_inode_data_buffers(journal_t *journal, dirty_end); if (!ret) ret = err; + cond_resched(); spin_lock(&journal->j_list_lock); jinode->i_flags &= ~JI_COMMIT_RUNNING; smp_mb();