From: Ryusuke Konishi Date: Thu, 17 Oct 2024 19:33:10 +0000 (+0900) Subject: nilfs2: fix kernel bug due to missing clearing of checked flag X-Git-Url: http://git.hungrycats.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=aa0cee46c5d3fd9a39575a4c8a4f65f25f095b89;p=linux nilfs2: fix kernel bug due to missing clearing of checked flag commit 41e192ad2779cae0102879612dfe46726e4396aa upstream. 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 Reported-by: syzbot+d6ca2daf692c7a82f959@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=d6ca2daf692c7a82f959 Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman --- diff --git a/fs/nilfs2/page.c b/fs/nilfs2/page.c index 98be72e93b40..7adf74b52550 100644 --- a/fs/nilfs2/page.c +++ b/fs/nilfs2/page.c @@ -404,6 +404,7 @@ void nilfs_clear_dirty_page(struct page *page, bool silent) ClearPageUptodate(page); ClearPageMappedToDisk(page); + ClearPageChecked(page); if (page_has_buffers(page)) { struct buffer_head *bh, *head;