| 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 |
| @@ -400,6 +400,7 @@ 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) { |
| _ |
