From 27524f65621f490184f2ace44cd8e5f3685af4a3 Mon Sep 17 00:00:00 2001 From: Ryusuke Konishi Date: Wed, 16 Oct 2024 06:32:07 +0900 Subject: [PATCH] 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 Link: https://lore.kernel.org/r/20241015213300.7114-1-konishi.ryusuke@gmail.com Fixes: 8c26c4e2694a ("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 Signed-off-by: Greg Kroah-Hartman --- fs/nilfs2/page.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/fs/nilfs2/page.c b/fs/nilfs2/page.c index 7d31833e68d1..19bc8eea2b35 100644 --- a/fs/nilfs2/page.c +++ b/fs/nilfs2/page.c @@ -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); @@ -409,7 +410,8 @@ 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 {