From: "Luis Henriques (SUSE)" luis.henriques@linux.dev

commit 23dfdb56581ad92a9967bcd720c8c23356af74c1 upstream.

The following kernel trace can be triggered with fstest generic/629 when executed against a filesystem with fast-commit feature enabled:

INFO: trying to register non-static key. The code is fine but needs lockdep annotation, or maybe you didn't initialize this object before use? turning off the locking correctness validator. CPU: 0 PID: 866 Comm: mount Not tainted 6.10.0+ #11 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.2-3-gd478f380-prebuilt.qemu.org 04/01/2014 Call Trace: <TASK> dump_stack_lvl+0x66/0x90 register_lock_class+0x759/0x7d0 __lock_acquire+0x85/0x2630 ? __find_get_block+0xb4/0x380 lock_acquire+0xd1/0x2d0 ? __ext4_journal_get_write_access+0xd5/0x160 _raw_spin_lock+0x33/0x40 ? __ext4_journal_get_write_access+0xd5/0x160 __ext4_journal_get_write_access+0xd5/0x160 ext4_reserve_inode_write+0x61/0xb0 __ext4_mark_inode_dirty+0x79/0x270 ? ext4_ext_replay_set_iblocks+0x2f8/0x450 ext4_ext_replay_set_iblocks+0x330/0x450 ext4_fc_replay+0x14c8/0x1540 ? jread+0x88/0x2e0 ? rcu_is_watching+0x11/0x40 do_one_pass+0x447/0xd00 jbd2_journal_recover+0x139/0x1b0 jbd2_journal_load+0x96/0x390 ext4_load_and_init_journal+0x253/0xd40 ext4_fill_super+0x2cc6/0x3180 ...

In the replay path there's an attempt to lock sbi->s_bdev_wb_lock in function ext4_check_bdev_write_error(). Unfortunately, at this point this spinlock has not been initialized yet. Moving it's initialization to an earlier point in __ext4_fill_super() fixes this splat.

Signed-off-by: Luis Henriques (SUSE) luis.henriques@linux.dev Link: https://patch.msgid.link/20240718094356.7863-1-luis.henriques@linux.dev Signed-off-by: Theodore Ts'o tytso@mit.edu Cc: stable@kernel.org Signed-off-by: Bruno VERNAY bruno.vernay@se.com Signed-off-by: Victor Giraud vgiraud.opensource@witekio.com --- fs/ext4/super.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 0b2591c07166..53f1deb049ec 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -5264,6 +5264,8 @@ static int __ext4_fill_super(struct fs_context *fc, struct super_block *sb) INIT_LIST_HEAD(&sbi->s_orphan); /* unlinked but open files */ mutex_init(&sbi->s_orphan_lock);

+ spin_lock_init(&sbi->s_bdev_wb_lock); + ext4_fast_commit_init(sb);

sb->s_root = NULL; @@ -5514,7 +5516,6 @@ static int __ext4_fill_super(struct fs_context *fc, struct super_block *sb) * Save the original bdev mapping's wb_err value which could be * used to detect the metadata async write error. */ - spin_lock_init(&sbi->s_bdev_wb_lock); errseq_check_and_advance(&sb->s_bdev->bd_inode->i_mapping->wb_err, &sbi->s_bdev_wb_err); sb->s_bdev->bd_super = sb;