From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794450738; b=E/0v0vajX+M6BpnueeK+wypTGhyWnsaJ6abNmxBakycc2ZJfPrPU8DNMe1+0CB5B7pfN 8fJlg4hs+PqfGd7NYkOLCV3qmjVpRwAe8Tc6gdsJV4kKW1hiMM9y22PCQQAKxCGwoE0JU LU+EkoyLrChYDzZFfVDQs4Iizd3DHqToIzkdLFDJDtrE+3vrdC1tVZtMiYsyuUkmLNTep 06aWtTZLSYZLsvi3H7YrjuUUzpZZ3ZfgA1wdpcBPJ3/mau30OSBC5dcM1xu+c2rsXdWwl 0+FC3z1axlXjQw4BViiox7UuTxCSGpP3DyxyoV5/cbuXtjb+Bu0Emyw00kNt0XkRt6Q== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794450738; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=ObXXE3SuFk7hda+oDvW2wcngecvTocyXpSxN2HoTRbA=; b=i+7pxmmotFuNOLFZY1bXGrklFqpOF9MIZlINVa5vS86kw11Se/pzHQ0jI+RNIxu7I6P/ SMq+435on0t/U/+4Q6YQ9GK9LTX5fVhkVRdyuDfLvFC4lv4KeutxbB8nSL6T16G/ZKXQn cA0piStVdLVVxcJR/MZmc0AIKTad/4ChmA21eJCqWW94zS31seoYDIOAm4ve+Owve9mwa WIbhIApOkbxWsdjcJzWbOEMERP6Vjs8KvdAoLYnWjO2m525/b5MoNImH9ca2QRvALZEzy VjxtIJFe2tlGQW8HJoY7Bj9/f5Q2Tu8ogQMtZ5pOrJs8LrkXKvsQCbcpWQaVglMvKFA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=UPk+EYYl; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 91732606A324 for ; Thu, 12 Nov 2026 02:32:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=UPk+EYYl Received: by smtp.kernel.org (Postfix) with ESMTPSA id BE3711F00A06; Thu, 12 Nov 2026 02:32:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794450738; bh=ObXXE3SuFk7hda+oDvW2wcngecvTocyXpSxN2HoTRbA=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=UPk+EYYlwQFL3Ts5XEXU0BrRb1rQR/Jweca22GpmTaLpZuynte3ZEo9cEDmzlYJL0 pJ5dVjdLWeeaStOPOBa1D0V/cVsT8GqPgs0WHdGFob+wmIHFKgmxR1JdOKzYM4tYbn fOByNhHh3htVrQIuy0JD/9BzcQGEQli9fQQL7zXcqEgdh1f3bwO0duWvLua+OKhr3m CW6Wv2xbjx9AwKvZqmTol1j2JwIzrWeEg2aJBXXP7aJUOopzjX7MhxdKZ7puhUvLDK Y4HfZzf8t5UbkIYmS5cxiRtOxIS7HPgmpD183WsX+Iz3eIuGPdxmZyDY4/X7/Wicr9 lKF0taI6TYfjQ== From: Sasha Levin To: stable@vger.kernel.org Cc: Amir Goldstein , "Christian Brauner (Amutable)" , Edvard Conrad , Sasha Levin Subject: [PATCH 6.1.y] ovl: inherit FMODE_NONOTIFY when opening directory realfiles Date: Wed, 11 Nov 2026 21:32:16 -0500 Message-ID: <20261112023145.1391367-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20261109201908-failed-6.1-323899b4ed23@kernel.org> References: <20261109201908-failed-6.1-323899b4ed23@kernel.org> X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Amir Goldstein [ Upstream commit 323899b4ed233d5b6e2fc160c16fbf39cf0317da ] When fanotify hands a listener an fd for a permission event on an overlay directory, ovl_dir_open_realfile() opens the real directory via dentry_open(), not backing_file_open(), so the lower open could still raise FS_OPEN_PERM and deadlock a listener that also marks the backing filesystem. Export dentry_open_nonotify() and call it from ovl_path_open_realfile() when the overlay user file must not generate events. Ordinary ovl_path_open() callers are unchanged. Reported-by: Christian Brauner (Amutable) Closes: https://lore.kernel.org/all/20261030-welpen-anbinden-nullen-b2432cee1d10@brauner/ Fixes: 130fdbc3d1f99 ("ovl: pass correct flags for opening real directory") Cc: stable@vger.kernel.org Tested-by: Edvard Conrad Link: https://lore.kernel.org/ltp/P5Iny41--F-9@tuta.io/ Signed-off-by: Amir Goldstein [ sashal: passed __FMODE_NONOTIFY through ovl_path_open() flags instead of using dentry_open_nonotify() ] Signed-off-by: Sasha Levin --- fs/overlayfs/readdir.c | 10 +++++++++- fs/overlayfs/util.c | 2 +- 2 files changed, 10 insertions(+), 2 deletions(-) diff --git a/fs/overlayfs/readdir.c b/fs/overlayfs/readdir.c index cd7a81b6da8be..ff3d30a9b3344 100644 --- a/fs/overlayfs/readdir.c +++ b/fs/overlayfs/readdir.c @@ -850,9 +850,17 @@ static struct file *ovl_dir_open_realfile(const struct file *file, { struct file *res; const struct cred *old_cred; + int flags = O_RDONLY | (file->f_flags & O_LARGEFILE); + + /* + * Inherit FMODE_NONOTIFY from a fanotify permission fd so a listener + * that also watches the real filesystem does not deadlock. + */ + if (file->f_mode & FMODE_NONOTIFY) + flags |= __FMODE_NONOTIFY; old_cred = ovl_override_creds(file_inode(file)->i_sb); - res = ovl_path_open(realpath, O_RDONLY | (file->f_flags & O_LARGEFILE)); + res = ovl_path_open(realpath, flags); revert_creds(old_cred); return res; diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c index 6922d8d705cb3..08ec15773121e 100644 --- a/fs/overlayfs/util.c +++ b/fs/overlayfs/util.c @@ -519,7 +519,7 @@ struct file *ovl_path_open(const struct path *path, int flags) struct user_namespace *real_mnt_userns = mnt_user_ns(path->mnt); int err, acc_mode; - if (flags & ~(O_ACCMODE | O_LARGEFILE)) + if (flags & ~(O_ACCMODE | O_LARGEFILE | __FMODE_NONOTIFY)) BUG(); switch (flags & O_ACCMODE) { -- 2.53.0