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nilfs2: fix kernel bug due to missing clearing of buffer delay flag 

commit 6ed469df0bfbef3e4b44fca954a781919db9f7ab upstream.

Syzbot reported that after nilfs2 reads a corrupted file system image
and degrades to read-only, the BUG_ON check for the buffer delay flag
in submit_bh_wbc() may fail, causing a kernel bug.

This is because the buffer delay flag is not cleared when clearing the
buffer state flags to discard a page/folio or a buffer head. So, fix
this.

This became necessary when the use of nilfs2's own page clear routine
was expanded.  This state inconsistency does not occur if the buffer
is written normally by log writing.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Link: https://lore.kernel.org/r/20241015213300.7114-1-konishi.ryusuke@gmail.com
Fixes: 8c26c4e269 ("nilfs2: fix issue with flush kernel thread after remount in RO mode because of driver's internal error or metadata corruption")
Reported-by: syzbot+985ada84bf055a575c07@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=985ada84bf055a575c07
Cc: stable@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Ryusuke Konishi 2024-10-16 06:32:07 +09:00 committed by Greg Kroah-Hartman
parent a299d415dd
commit 743c78d455
1 changed files with 4 additions and 2 deletions
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6
fs/nilfs2/page.c
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@ -77,7 +77,8 @@ void nilfs_forget_buffer(struct buffer_head *bh)
const unsigned long clear_bits =
(BIT(BH_Uptodate) | BIT(BH_Dirty) | BIT(BH_Mapped) |
BIT(BH_Async_Write) | BIT(BH_NILFS_Volatile) |
BIT(BH_NILFS_Checked) | BIT(BH_NILFS_Redirected));
BIT(BH_NILFS_Checked) | BIT(BH_NILFS_Redirected) |
BIT(BH_Delay));
lock_buffer(bh);
set_mask_bits(&bh->b_state, clear_bits, 0);
@ -410,7 +411,8 @@ void nilfs_clear_dirty_page(struct page *page, bool silent)
const unsigned long clear_bits =
(BIT(BH_Uptodate) | BIT(BH_Dirty) | BIT(BH_Mapped) |
BIT(BH_Async_Write) | BIT(BH_NILFS_Volatile) |
BIT(BH_NILFS_Checked) | BIT(BH_NILFS_Redirected));
BIT(BH_NILFS_Checked) | BIT(BH_NILFS_Redirected) |
BIT(BH_Delay));
bh = head = page_buffers(page);
do {