Hi Sasha

About 6 hours ago, I posted an adjusted patch to the list (and to Greg) that allows for backporting of this patch to 6.6-stable and earlier.

The patch is titled "[PATCH 4.19 5.4 5.10 5.15 6.1 6.6] nilfs2: fix kernel bug due to missing clearing of checked flag".

(or https://lkml.kernel.org/r/20241105235654.15044-1-konishi.ryusuke@gmail.com )

Normally, Greg would pick up the adjusted patch and apply it, and it would be backported without any problems, but if the backport of the adjusted patch I requested has been rejected, I would like to ask for your confirmation.

If it is a misunderstanding, I will wait for Greg's work, but is the process different from usual?

Thank you in advance.

Ryusuke Konishi

On Wed, Nov 6, 2024 at 11:09 AM Sasha Levin sashal@kernel.org wrote:

The patch below does not apply to the v6.6-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

Thanks, Sasha

------------------ original commit in Linus's tree ------------------

From 41e192ad2779cae0102879612dfe46726e4396aa Mon Sep 17 00:00:00 2001 From: Ryusuke Konishi konishi.ryusuke@gmail.com Date: Fri, 18 Oct 2024 04:33:10 +0900 Subject: [PATCH] nilfs2: fix kernel bug due to missing clearing of checked flag

Syzbot reported that in directory operations after nilfs2 detects filesystem corruption and degrades to read-only, __block_write_begin_int(), which is called to prepare block writes, may fail the BUG_ON check for accesses exceeding the folio/page size, triggering a kernel bug.

This was found to be because the "checked" flag of a page/folio was not cleared when it was discarded by nilfs2's own routine, which causes the sanity check of directory entries to be skipped when the directory page/folio is reloaded. So, fix that.

This was necessary when the use of nilfs2's own page discard routine was applied to more than just metadata files.

Link: https://lkml.kernel.org/r/20241017193359.5051-1-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") Signed-off-by: Ryusuke Konishi konishi.ryusuke@gmail.com Reported-by: syzbot+d6ca2daf692c7a82f959@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=d6ca2daf692c7a82f959 Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org

---

fs/nilfs2/page.c | 1 + 1 file changed, 1 insertion(+)

diff --git a/fs/nilfs2/page.c b/fs/nilfs2/page.c index 5436eb0424bd1..10def4b559956 100644 --- a/fs/nilfs2/page.c +++ b/fs/nilfs2/page.c @@ -401,6 +401,7 @@ void nilfs_clear_folio_dirty(struct folio *folio)

    folio_clear_uptodate(folio);
    folio_clear_mappedtodisk(folio);

•   folio_clear_checked(folio);
  
    head = folio_buffers(folio);
    if (head) {
  

-- 2.43.0