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=1794585744; b=VaT2JpnRtzKZXB7UmImkp1eczm4OHYOenrnQ/iup1vMGiDl0ZzUUnOpnZzayP7e/a6F9 RaD9g5d6U1L8UrdDWLUtbExOYDbjS6fxZoKndxr5/H57Dz/F4sKrFu6USzAp71o5Bd8ad QZ/EtqKmgbod255KiBr1vzEl1e41yUk3Z2FueMAdtdPDysoxVJMf+GlgEtlff3qVNMxtE kkVRkkkRk4qZCAtdzCmY8mFlO0JDDL/LKQDkKhy48SmsGexS/GQWIZA5maNGIquS2iD5l df2DsfAQuWTBHilvCr9Pilo6hGtt8YG1ubKOoYwjLy9O+WJbjJcVC1//8GY1gy0HJNg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794585744; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=BGjYAsBtwqrMGVfT+SDQKY0NQCkDTHAE/z67EEE6xBo=; b=JmV1JdZEK/q+nwmRJXVOtgZ41K/CZnMswCz8FAFfo0PZCyyjtVBu4cswo2A1DRpuo5A5 YBt4oOEeSi+/BYjpWeZGIpnPfbER9U3pJZlF2WcaCmnV8t3bls3Bp00c45bcudiiNAkW7 kumHfXR4XkxRYLfD2fxkqLI747FyZU+duDQb1nrwcw+KGQSC5iZ5F2HrImeAYtiiCk3vB scA8N+mWSuIQsFeDvfxq5YdRGkhwFUVAqorkPJS83oceDfZrl07r+1/WhVRPI0IjMnNp4 4uRVVqQaAHlHo4tZ3suHBPTu48TkJivAtX1C9w3QgHBRWeQre+hbnyUyrTqz31RXkSg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=y379xDfA; 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 E0A10606A336; Fri, 13 Nov 2026 16:02:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=y379xDfA Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8B1551F000C4; Fri, 13 Nov 2026 16:02:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794585743; bh=BGjYAsBtwqrMGVfT+SDQKY0NQCkDTHAE/z67EEE6xBo=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=y379xDfAXK5fDSOFkWHIM0BWBrNnYSP0Gxu3kOL32jQPN6XBuCWKPXJ3m9GSjVTjT aIuaGOewaB9uqiMpPdS0NKOTmq7rL4Bm7GE0HSdH/U+syijdEPMOFd6ondNQp9iAKj xecGbm5mZ8x9jEIj0k6w+ybfhHbvic3lAqqC5VYA= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, "Christian Brauner (Amutable)" , Edvard Conrad , Amir Goldstein , Sasha Levin Subject: [PATCH 7.3 341/507] ovl: inherit FMODE_NONOTIFY when opening directory realfiles Date: Fri, 13 Nov 2026 10:50:45 -0500 Message-ID: <20261113153806.954906776@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261113153753.358973689@linuxfoundation.org> References: <20261113153753.358973689@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore 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 7.3-stable review patch. If anyone has any objections, please let me know. ------------------ 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 6b1c14e684a93..d7d9fcc666ab5 100644 --- a/fs/open.c +++ b/fs/open.c @@ -1147,6 +1147,7 @@ struct file *dentry_open_nonotify(const struct path *path, int flags, } return f; } +EXPORT_SYMBOL_GPL(dentry_open_nonotify); /** * kernel_file_open - open a file for kernel internal use diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h index 4faebb4c6825b..b32089a104291 100644 --- a/fs/overlayfs/overlayfs.h +++ b/fs/overlayfs/overlayfs.h @@ -529,7 +529,14 @@ 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 aefa41b163cd8..e23331212a29b 100644 --- a/fs/overlayfs/readdir.c +++ b/fs/overlayfs/readdir.c @@ -973,7 +973,8 @@ 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 47734eeb97b75..04103a6741ba0 100644 --- a/fs/overlayfs/util.c +++ b/fs/overlayfs/util.c @@ -654,7 +654,8 @@ 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); @@ -682,6 +683,14 @@ 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