The patch titled Subject: nilfs2: fix kernel bug due to missing clearing of checked flag has been added to the -mm mm-hotfixes-unstable branch. Its filename is nilfs2-fix-kernel-bug-due-to-missing-clearing-of-checked-flag.patch

This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches...

This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------ From: Ryusuke Konishi konishi.ryusuke@gmail.com Subject: nilfs2: fix kernel bug due to missing clearing of checked flag Date: Fri, 18 Oct 2024 04:33:10 +0900

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(+)

--- a/fs/nilfs2/page.c~nilfs2-fix-kernel-bug-due-to-missing-clearing-of-checked-flag +++ a/fs/nilfs2/page.c @@ -401,6 +401,7 @@ void nilfs_clear_folio_dirty(struct foli

folio_clear_uptodate(folio); folio_clear_mappedtodisk(folio); + folio_clear_checked(folio);

head = folio_buffers(folio); if (head) { _

Patches currently in -mm which might be from konishi.ryusuke@gmail.com are

nilfs2-fix-kernel-bug-due-to-missing-clearing-of-buffer-delay-flag.patch nilfs2-fix-kernel-bug-due-to-missing-clearing-of-checked-flag.patch