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=1794448810; b=YNw9k3EiSFAvLwLFa6LW6ZMldQIUaGNE/qzT3+kKX42UFEPHQnV1M3HMMNCbBENHgpL8 OBrLpzfYsOkBuh4oy4PKPMwv899TKZD57T2N6nFHpCrjXQRwNv5dR1c9RsWxf4NCELz7G xSrqNszwXSJbJUfsYvh5xNTbVizcd9TXCxhmLY4oDl21m5nU68b95gQygeKn45Z/H2uKH U6XyFXAmFGm9oyMqhs07qu7Lqim1faTNxo1EV5z9MYu8LO+tnmjX7rDE+kbtPQm2v2Yij RW9P93B+XVBUHxbRCw5STLRnXu9nfRrslh0YMHerm9HkgXE95WFXBuqPvrmr1iim1Iw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794448810; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=5Eyu9Xsx70tqsAXJxCLO/4bq/yOmJ1pQyquaw8D0kU4=; b=sBSlu53gRQkWy0bS9PcvaROGjAuEZLKC8OtM21e0LxeAZMUg5tRQux1bDR6ddYbRYPom pA9ID1idXT9avA8RHIUziJUCZEfaW8tGzmQbmN1sXJzKTjfDCP4ZRe2CiRfIej1dAfMbk 1oXOpxjZJTCaVUdisXC/zwtggAmLVjBJL4xZSDWoJSQDagrGx4Ch42DEuYKWhzmT+UOKY QpaziZS8tyay9urGVmEmUPvOwl+nG9ybnSSVkZ+FoQuGALLJT1lU2ypzT9KpcXPvqteHN buqoAL/wCnSMCodoj7XRwID8al6/Bv5UMUkUrQuTMNciN1X8B0WLQWXro0V+bYjbMvQ== 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=YRp0keGO; 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 9514D606A8A4 for ; Thu, 12 Nov 2026 02:00:10 +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=YRp0keGO Received: by smtp.kernel.org (Postfix) with ESMTPSA id DC3401F00A05; Thu, 12 Nov 2026 02:00:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794448810; bh=5Eyu9Xsx70tqsAXJxCLO/4bq/yOmJ1pQyquaw8D0kU4=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=YRp0keGOGDuXNEUx9E30eca7cMXqa4g71nvp36rRL5bYQjTh73n7DeXUDyHI4Y9+o mds9IRqzY29MUYJreDeOnFQgVwwlVhQe84N7mfuH95H+99rqmWf+IMSUtvJkL+DdFd DzkjKtciFuzTykusSpkcRf/gvbRFa/AfJZy/Gp8oJElKhAK++hc3nkIeWRBC3d5b52 HQ1h6t1icHzre22+2mIcXxiwp5EC6JcEn/rp45XVswM1l175ZMmJmDaym0dRM6PN/G /OBv9nKM2DMixaLTeW1mi7I0fj4Cgdc08dPehv6YezQJSHGXpZZT35kedZMPEVCp9F wGQtotbM/L40g== From: Sasha Levin To: stable@vger.kernel.org Cc: Amir Goldstein , "Christian Brauner (Amutable)" , Edvard Conrad , Sasha Levin Subject: [PATCH 6.18.y 2/2] ovl: inherit FMODE_NONOTIFY when opening directory realfiles Date: Wed, 11 Nov 2026 21:00:07 -0500 Message-ID: <20261112015754.1242132-2-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20261112015754.1242132-1-sashal@kernel.org> References: <20261109200528-failed-6.18-323899b4ed23@kernel.org> <20261112015754.1242132-1-sashal@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 Signed-off-by: Sasha Levin --- fs/open.c | 1 + fs/overlayfs/overlayfs.h | 9 ++++++++- fs/overlayfs/readdir.c | 3 ++- fs/overlayfs/util.c | 11 ++++++++++- 4 files changed, 21 insertions(+), 3 deletions(-) diff --git a/fs/open.c b/fs/open.c index 3d64372ecc675..3d5ff8f58d5c9 100644 --- a/fs/open.c +++ b/fs/open.c @@ -1143,6 +1143,7 @@ struct file *dentry_open_nonotify(const struct path *path, int flags, } return f; } +EXPORT_SYMBOL_GPL(dentry_open_nonotify); /** * dentry_create - Create and open a file diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h index 6268db46483e7..7bd69773f33c9 100644 --- a/fs/overlayfs/overlayfs.h +++ b/fs/overlayfs/overlayfs.h @@ -524,7 +524,14 @@ void ovl_dir_modified(struct dentry *dentry, bool impurity); u64 ovl_inode_version_get(struct inode *inode); bool ovl_is_whiteout(struct dentry *dentry); bool ovl_path_is_whiteout(struct ovl_fs *ofs, const struct path *path); -struct file *ovl_path_open(const struct path *path, int flags); +struct file *ovl_path_open_realfile(const struct file *user_file, + const struct path *path, int flags); + +static inline struct file *ovl_path_open(const struct path *path, int flags) +{ + return ovl_path_open_realfile(NULL, path, flags); +} + int ovl_copy_up_start(struct dentry *dentry, int flags); void ovl_copy_up_end(struct dentry *dentry); bool ovl_already_copied_up(struct dentry *dentry, int flags); diff --git a/fs/overlayfs/readdir.c b/fs/overlayfs/readdir.c index 7fa4fecf15360..3c8fe45b06f12 100644 --- a/fs/overlayfs/readdir.c +++ b/fs/overlayfs/readdir.c @@ -960,7 +960,8 @@ static struct file *ovl_dir_open_realfile(const struct file *file, const struct path *realpath) { with_ovl_creds(file_inode(file)->i_sb) - return ovl_path_open(realpath, O_RDONLY | (file->f_flags & O_LARGEFILE)); + return ovl_path_open_realfile(file, realpath, + O_RDONLY | (file->f_flags & O_LARGEFILE)); } /* diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c index 19f4fe7b98f29..f75e8009fb15f 100644 --- a/fs/overlayfs/util.c +++ b/fs/overlayfs/util.c @@ -659,7 +659,8 @@ bool ovl_path_is_whiteout(struct ovl_fs *ofs, const struct path *path) ovl_path_check_xwhiteout_xattr(ofs, path); } -struct file *ovl_path_open(const struct path *path, int flags) +struct file *ovl_path_open_realfile(const struct file *user_file, + const struct path *path, int flags) { struct inode *inode = d_inode(path->dentry); struct mnt_idmap *real_idmap = mnt_idmap(path->mnt); @@ -687,6 +688,14 @@ struct file *ovl_path_open(const struct path *path, int flags) if (inode_owner_or_capable(real_idmap, inode)) flags |= O_NOATIME; + /* + * Directory opens use dentry_open() here, not backing_file_open(). + * Inherit FMODE_NONOTIFY from a fanotify permission fd so a listener + * that also watches the real filesystem does not deadlock. + */ + if (user_file && FMODE_FSNOTIFY_NONE(user_file->f_mode)) + return dentry_open_nonotify(path, flags, current_cred()); + return dentry_open(path, flags, current_cred()); } -- 2.53.0