The patch titled Subject: nilfs2: prevent general protection fault in nilfs_clear_dirty_page() has been added to the -mm mm-hotfixes-unstable branch. Its filename is nilfs2-prevent-general-protection-fault-in-nilfs_clear_dirty_page.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: prevent general protection fault in nilfs_clear_dirty_page() Date: Mon, 12 Jun 2023 11:14:56 +0900
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@gmail.com Signed-off-by: Ryusuke Konishi konishi.ryusuke@gmail.com Reported-by: syzbot+53369d11851d8f26735c@syzkaller.appspotmail.com Closes: https://lkml.kernel.org/r/000000000000da4f6b05eb9bf593@google.com Tested-by: Ryusuke Konishi konishi.ryusuke@gmail.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---
fs/nilfs2/page.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-)
--- a/fs/nilfs2/page.c~nilfs2-prevent-general-protection-fault-in-nilfs_clear_dirty_page +++ a/fs/nilfs2/page.c @@ -370,7 +370,15 @@ void nilfs_clear_dirty_pages(struct addr 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); _
Patches currently in -mm which might be from konishi.ryusuke@gmail.com are
nilfs2-fix-buffer-corruption-due-to-concurrent-device-reads.patch nilfs2-prevent-general-protection-fault-in-nilfs_clear_dirty_page.patch