From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CB2DFEEC0; Sun, 28 Jun 2026 01:36:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782610614; cv=none; b=HoI3ApRRe6HScxckgQmNbNRdSH1w5i/D8PX+U5HimLC2jrAdmEJs6UJxd/dOp/ibfqL9QxZ6GjEoH65hVXoMQD5nhQ2kw5GnFCsBpwWoZX+SjfFrK6JZavpENK+2pLEFA08thNdXqKKGxQqmEQbOiS+jx47GPSiCPqDsChtOmZw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782610614; c=relaxed/simple; bh=qcyT18ycfgs67qeBeGLSw680gcNmqxnv+2QGvTVVH64=; h=Date:To:From:Subject:Message-Id; b=iDWIeIecvhRpNHr6pAuNPqPjWNtqt/2eJSlBOYGTXOjMiyM6ggXDfeB8krHGItSWQtWAidsmUZpMIEc9dQtY3revyParJr+u0hUjxudHaTRNQVAWkPT4AMci3dxCykBI/A5fw77z6cHHs0mukXMumq5b6hLahMX2gP5qzDOmmiM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=ubSpsty6; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="ubSpsty6" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3EBDE1F000E9; Sun, 28 Jun 2026 01:36:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1782610612; bh=4ayx45IuqpUBVfUPNG6TijbKmA66iUihHOUZXkkdfuE=; h=Date:To:From:Subject; b=ubSpsty6vaTEh9LRYanM1L+PH9qAIcXBto8YuabribI0/FkkqGCmZLKCTO4Ga5vc1 yut3JUzuBDd0b9CdpghlmQnKtILhkq7qh9NQl/1obqOPvOafWqdpSEA1wcZXxgaZ1Z QDHeUTz4yDNOr8GhDYT2Aixg9xzYQ9EYSjlmPxB0= Date: Sat, 27 Jun 2026 18:36:51 -0700 To: mm-commits@vger.kernel.org,stable@vger.kernel.org,hughd@google.com,baolin.wang@linux.alibaba.com,alhouseenyousef@gmail.com,akpm@linux-foundation.org From: Andrew Morton Subject: + tmpfs-zero-unused-folio-tail-for-long-symlinks.patch added to mm-new branch Message-Id: <20260628013652.3EBDE1F000E9@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: tmpfs: zero unused folio tail for long symlinks has been added to the -mm mm-new branch. Its filename is tmpfs-zero-unused-folio-tail-for-long-symlinks.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/tmpfs-zero-unused-folio-tail-for-long-symlinks.patch This patch will later appear in the mm-new branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Note, mm-new is a provisional staging ground for work-in-progress patches, and acceptance into mm-new is a notification for others take notice and to finish up reviews. Please do not hesitate to respond to review feedback and post updated versions to replace or incrementally fixup patches in mm-new. The mm-new branch of mm.git is not included in linux-next If a few days of testing in mm-new is successful, the patch will me moved into mm.git's mm-unstable branch, which is included in linux-next Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via various branches at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there most days ------------------------------------------------------ From: Yousef Alhouseen Subject: tmpfs: zero unused folio tail for long symlinks Date: Sun, 28 Jun 2026 02:43:14 +0200 shmem_symlink() marks the entire folio uptodate after copying only the NUL-terminated link target. The remainder of the freshly allocated folio is left uninitialized. Reclaim may pass the whole folio to a swap compressor. KMSAN observed sw842_compress() computing a checksum over the uninitialized tail. If the folio is written to a swap device, those bytes can also leave the kernel. Zero the remainder of the folio before marking it uptodate and dirty. Link: https://lore.kernel.org/20260628004314.27370-1-alhouseenyousef@gmail.com Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reported-by: syzbot+bf5586280a66e9ccdfa9@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=bf5586280a66e9ccdfa9 Signed-off-by: Yousef Alhouseen Cc: Baolin Wang Cc: Hugh Dickins Cc: Signed-off-by: Andrew Morton --- mm/shmem.c | 1 + 1 file changed, 1 insertion(+) --- a/mm/shmem.c~tmpfs-zero-unused-folio-tail-for-long-symlinks +++ a/mm/shmem.c @@ -4057,6 +4057,7 @@ static int shmem_symlink(struct mnt_idma goto out_remove_offset; inode->i_op = &shmem_symlink_inode_operations; memcpy(folio_address(folio), symname, len); + folio_zero_range(folio, len, folio_size(folio) - len); folio_mark_uptodate(folio); folio_mark_dirty(folio); folio_unlock(folio); _ Patches currently in -mm which might be from alhouseenyousef@gmail.com are tmpfs-zero-unused-folio-tail-for-long-symlinks.patch