The patch below does not apply to the 5.15-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@xxxxxxxxxxxxxxx>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y git checkout FETCH_HEAD git cherry-pick -x 782e53d0c14420858dbf0f8f797973c150d3b6d7 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable@xxxxxxxxxxxxxxx>' --in-reply-to '2023062317-gradient-unopened-2f06@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 782e53d0c14420858dbf0f8f797973c150d3b6d7 Mon Sep 17 00:00:00 2001 From: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxx> Date: Mon, 12 Jun 2023 11:14:56 +0900 Subject: [PATCH] nilfs2: prevent general protection fault in nilfs_clear_dirty_page() In a syzbot stress test that deliberately causes file system errors on nilfs2 with a corrupted disk image, it has been reported that nilfs_clear_dirty_page() called from nilfs_clear_dirty_pages() can cause a general protection fault. In nilfs_clear_dirty_pages(), when looking up dirty pages from the page cache and calling nilfs_clear_dirty_page() for each dirty page/folio retrieved, the back reference from the argument page to "mapping" may have been changed to NULL (and possibly others). It is necessary to check this after locking the page/folio. So, fix this issue by not calling nilfs_clear_dirty_page() on a page/folio after locking it in nilfs_clear_dirty_pages() if the back reference "mapping" from the page/folio is different from the "mapping" that held the page/folio just before. Link: https://lkml.kernel.org/r/20230612021456.3682-1-konishi.ryusuke@xxxxxxxxx Signed-off-by: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxx> Reported-by: syzbot+53369d11851d8f26735c@xxxxxxxxxxxxxxxxxxxxxxxxx Closes: https://lkml.kernel.org/r/000000000000da4f6b05eb9bf593@xxxxxxxxxx Tested-by: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> diff --git a/fs/nilfs2/page.c b/fs/nilfs2/page.c index 5cf30827f244..b4e54d079b7d 100644 --- a/fs/nilfs2/page.c +++ b/fs/nilfs2/page.c @@ -370,7 +370,15 @@ void nilfs_clear_dirty_pages(struct address_space *mapping, bool silent) struct folio *folio = fbatch.folios[i]; folio_lock(folio); - nilfs_clear_dirty_page(&folio->page, silent); + + /* + * This folio may have been removed from the address + * space by truncation or invalidation when the lock + * was acquired. Skip processing in that case. + */ + if (likely(folio->mapping == mapping)) + nilfs_clear_dirty_page(&folio->page, silent); + folio_unlock(folio); } folio_batch_release(&fbatch);
