From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 5DFCD35A95D; Fri, 9 Jan 2026 12:09:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767960573; cv=none; b=kGcCgb/hksg1zmsyIc7PwHEAOpyHd4ud1GaYNZIvjc/NixXtDQpfqKrPNje0P1ZvN1EDvYtklsnxpACrhVZx1F9UxD+4gdXnHxMctWx1j7VLlnYZWX4hnTUTM2NDDewuFt6tGUi0daq82j78TX+AqqHM+MJdIXp3wkwsTmodtM0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767960573; c=relaxed/simple; bh=iQXku+aYhhz5DiDjUO+hJFzTtM9bINVRvcHJ5Pk4p34=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=dS2+MkEc91p/dCRMY0KfHdzOuRlNNx6exGGc2DaiUpuuAHP2YaSFOLycTd8GLkKxBes2lqBcdkPXUjuMcAOteqrm8GjoV2XNI2rgoDYcldwnkxPLFHoGTej4+jtoq/YhzKYqW9DRjvcJKJ4fWUU8QHDjW4UAoHmcO9u6qLDmfTY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=gGidwzfl; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="gGidwzfl" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DC5E3C16AAE; Fri, 9 Jan 2026 12:09:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1767960573; bh=iQXku+aYhhz5DiDjUO+hJFzTtM9bINVRvcHJ5Pk4p34=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=gGidwzflY3PC5a8oVW5JfYuqUUqg8y7ziDgTkZ8Qw3tJOHVGF1bfyVbbWocJVd2OK uicGsNbr3DFXcIeAVEiuQEexTu90Nwq9u9ybU9BQNI5GowvWl4qMWeok54nPbFo7So hQ79WP5GRJ6pYUOCV0O+AQwG1cTH4Py/SIj7k2SI= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+632cf32276a9a564188d@syzkaller.appspotmail.com, Chao Yu , Deepanshu Kartikey , Jaegeuk Kim Subject: [PATCH 6.6 451/737] f2fs: invalidate dentry cache on failed whiteout creation Date: Fri, 9 Jan 2026 12:39:50 +0100 Message-ID: <20260109112150.960867916@linuxfoundation.org> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260109112133.973195406@linuxfoundation.org> References: <20260109112133.973195406@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Deepanshu Kartikey commit d33f89b34aa313f50f9a512d58dd288999f246b0 upstream. F2FS can mount filesystems with corrupted directory depth values that get runtime-clamped to MAX_DIR_HASH_DEPTH. When RENAME_WHITEOUT operations are performed on such directories, f2fs_rename performs directory modifications (updating target entry and deleting source entry) before attempting to add the whiteout entry via f2fs_add_link. If f2fs_add_link fails due to the corrupted directory structure, the function returns an error to VFS, but the partial directory modifications have already been committed to disk. VFS assumes the entire rename operation failed and does not update the dentry cache, leaving stale mappings. In the error path, VFS does not call d_move() to update the dentry cache. This results in new_dentry still pointing to the old inode (new_inode) which has already had its i_nlink decremented to zero. The stale cache causes subsequent operations to incorrectly reference the freed inode. This causes subsequent operations to use cached dentry information that no longer matches the on-disk state. When a second rename targets the same entry, VFS attempts to decrement i_nlink on the stale inode, which may already have i_nlink=0, triggering a WARNING in drop_nlink(). Example sequence: 1. First rename (RENAME_WHITEOUT): file2 → file1 - f2fs updates file1 entry on disk (points to inode 8) - f2fs deletes file2 entry on disk - f2fs_add_link(whiteout) fails (corrupted directory) - Returns error to VFS - VFS does not call d_move() due to error - VFS cache still has: file1 → inode 7 (stale!) - inode 7 has i_nlink=0 (already decremented) 2. Second rename: file3 → file1 - VFS uses stale cache: file1 → inode 7 - Tries to drop_nlink on inode 7 (i_nlink already 0) - WARNING in drop_nlink() Fix this by explicitly invalidating old_dentry and new_dentry when f2fs_add_link fails during whiteout creation. This forces VFS to refresh from disk on subsequent operations, ensuring cache consistency even when the rename partially succeeds. Reproducer: 1. Mount F2FS image with corrupted i_current_depth 2. renameat2(file2, file1, RENAME_WHITEOUT) 3. renameat2(file3, file1, 0) 4. System triggers WARNING in drop_nlink() Fixes: 7e01e7ad746b ("f2fs: support RENAME_WHITEOUT") Reported-by: syzbot+632cf32276a9a564188d@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=632cf32276a9a564188d Suggested-by: Chao Yu Link: https://lore.kernel.org/all/20251022233349.102728-1-kartikey406@gmail.com/ [v1] Cc: stable@vger.kernel.org Signed-off-by: Deepanshu Kartikey Reviewed-by: Chao Yu Signed-off-by: Jaegeuk Kim Signed-off-by: Greg Kroah-Hartman --- fs/f2fs/namei.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) --- a/fs/f2fs/namei.c +++ b/fs/f2fs/namei.c @@ -1044,9 +1044,11 @@ static int f2fs_rename(struct mnt_idmap if (whiteout) { set_inode_flag(whiteout, FI_INC_LINK); err = f2fs_add_link(old_dentry, whiteout); - if (err) + if (err) { + d_invalidate(old_dentry); + d_invalidate(new_dentry); goto put_out_dir; - + } spin_lock(&whiteout->i_lock); whiteout->i_state &= ~I_LINKABLE; spin_unlock(&whiteout->i_lock);