From: yangerkun yangerkun@huawei.com

hulk inclusion category: bugfix bugzilla: 172146 CVE: NA ---------------------------

'commit c92dc856848f ("ext4: defer saving error info from atomic context")' and '2d01ddc86606 ("ext4: save error info to sb through journal if available")' add s_error_work to fix checksum error problem. But the error path in ext4_fill_super can lead the follow BUG_ON.

Our testcase got follow BUG: [32031.759805] ------------[ cut here ]------------ [32031.759807] kernel BUG at fs/jbd2/transaction.c:373! [32031.760075] invalid opcode: 0000 [#1] SMP PTI [32031.760336] CPU: 5 PID: 1029268 Comm: kworker/5:1 Kdump: loaded Tainted: G OE --------- - - 4.18.0 ... [32031.766665] jbd2__journal_start+0xf1/0x1f0 [jbd2] [32031.766934] jbd2_journal_start+0x19/0x20 [jbd2] [32031.767218] flush_stashed_error_work+0x30/0x90 [ext4] [32031.767487] process_one_work+0x195/0x390 [32031.767747] worker_thread+0x30/0x390 [32031.768007] ? process_one_work+0x390/0x390 [32031.768265] kthread+0x10d/0x130 [32031.768521] ? kthread_flush_work_fn+0x10/0x10 [32031.768778] ret_from_fork+0x35/0x40

static int start_this_handle(...) BUG_ON(journal->j_flags & JBD2_UNMOUNT); <---- Trigger this

For this case, flush_stashed_error_work will try to access journal with parallel ext4_fill_super try to destroy journal. We need make sure there is no work before me destroy journal. Fix it by flush error work before we destroy journal.

Fixes: c92dc856848f ("ext4: defer saving error info from atomic context") Fixes: 2d01ddc86606 ("ext4: save error info to sb through journal if available") Signed-off-by: yangerkun yangerkun@huawei.com Reviewed-by: Zhang Yi yi.zhang@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- fs/ext4/super.c | 1 + 1 file changed, 1 insertion(+)

diff --git a/fs/ext4/super.c b/fs/ext4/super.c index d793e597c0623..280e991e61f47 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -4832,6 +4832,7 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) sbi->s_ea_block_cache = NULL; } if (sbi->s_journal) { + flush_work(&sbi->s_error_work); jbd2_journal_destroy(sbi->s_journal); sbi->s_journal = NULL; }