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 87DAD3B9930; Tue, 21 Jul 2026 21:50:00 +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=1784670601; cv=none; b=BMfGZnAo56yFb1oPjY/JgelUGZuzgzthYpn7ZW4POz2MHVlv3bSsDpHBGIvpmbdtkv8j9bH26f29QIJXE8S5cGQZrp0vodQXIJNBu5ccl9kEeT8UIMuJq7C08kKNP47rqOdMcotsALjgcQ3ZwF1HsoAbWpf+oZ4F12nRmzZpBkk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784670601; c=relaxed/simple; bh=zHajqg1gMPYlpKnAIuuHSIRHtjLsW6wzhwmTrhr8wto=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=CRLACSUSXsRLzIhVYy0aav8TOut1/mXrrnw/yaH+FOVk8V3vdwOYetJasgvy2It4ANu8AqYjSbls/GQ4nKIl0LyNsAUye0cKnGnDzhmt+PGtVC7nhm1hfkZREckcgx1xD2tLRIbujgbMN4nfUblI3O63RwkVDyhos24so1B2Tu8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Pxq9700/; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="Pxq9700/" Received: by smtp.kernel.org (Postfix) with ESMTPSA id EFE891F000E9; Tue, 21 Jul 2026 21:49:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784670600; bh=ZW+Tj22bpLhRDFVUrowL8mqQhdOwBpOiYpGOu5vaSlw=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Pxq9700/Ov2BHp84zxbwAjSWTxw4d1Fy5IotOy+m9AhvuuTUrJ74VWhEgk4SgL6/+ tV+KCLpEjNU1eWPVBJ6HRzfyRV0embHbLB/oV0CTwKSUz0uVNBGWoGtth7IZoY/iEf /2qd3PFxCAPhqoyD6Hqnvj2tqz+uvPIxREy59pBE= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, David Howells , "Paulo Alcantara (Red Hat)" , Shyam Prasad N , linux-cifs@vger.kernel.org, linux-fsdevel@vger.kernel.org, Steve French , Sasha Levin Subject: [PATCH 6.1 0995/1067] cifs: Fix reacquisition of volume cookie on still-live connection Date: Tue, 21 Jul 2026 17:26:36 +0200 Message-ID: <20260721152446.818937021@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260721152424.521567757@linuxfoundation.org> References: <20260721152424.521567757@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: linux-cifs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: David Howells [ Upstream commit dad80c6bff770d25f67ec25fe011730e4a463008 ] During mount, cifs_mount_get_tcon() gets a tcon resource connection record and then attaches an fscache volume cookie to it. However, it does this irrespective of whether or not the tcon returned from cifs_get_tcon() is a new record or one that's already in use. This leads to a warning about a volume cookie collision and a leaked volume cookie because tcon->fscache gets reset. Fix this be adding a mutex and a "we've already tried this" flag and only doing it once for the lifetime of the tcon. [!] Note: Looking at cifs_mount_get_tcon(), a more general solution may actually be required. Reacquiring the volume cookie isn't the only thing that function does: it also partially reinitialises the tcon record without any locking - which may cause live filesystem ops already using the tcon through a previous mount to malfunction. This can be reproduced simply by something like: mount //example.com/test /xfstest.test -o user=shares,pass=xxx,fsc mount //example.com/test /mnt -o user=shares,pass=xxx,fsc Fixes: 70431bfd825d ("cifs: Support fscache indexing rewrite") Signed-off-by: David Howells Acked-by: Paulo Alcantara (Red Hat) cc: Shyam Prasad N cc: linux-cifs@vger.kernel.org cc: linux-fsdevel@vger.kernel.org Signed-off-by: Steve French Stable-dep-of: ec457f9afe5a ("smb: client: resolve SWN tcon from live registrations") Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- fs/smb/client/cifsglob.h | 2 ++ fs/smb/client/fscache.c | 13 +++++++++++++ fs/smb/client/misc.c | 3 +++ 3 files changed, 18 insertions(+) --- a/fs/smb/client/cifsglob.h +++ b/fs/smb/client/cifsglob.h @@ -1205,7 +1205,9 @@ struct cifs_tcon { __u32 max_bytes_copy; #ifdef CONFIG_CIFS_FSCACHE u64 resource_id; /* server resource id */ + bool fscache_acquired; /* T if we've tried acquiring a cookie */ struct fscache_volume *fscache; /* cookie for share */ + struct mutex fscache_lock; /* Prevent regetting a cookie */ #endif struct list_head pending_opens; /* list of incomplete opens */ struct cached_fids *cfids; --- a/fs/smb/client/fscache.c +++ b/fs/smb/client/fscache.c @@ -43,12 +43,23 @@ int cifs_fscache_get_super_cookie(struct char *key; int ret = -ENOMEM; + if (tcon->fscache_acquired) + return 0; + + mutex_lock(&tcon->fscache_lock); + if (tcon->fscache_acquired) { + mutex_unlock(&tcon->fscache_lock); + return 0; + } + tcon->fscache_acquired = true; + tcon->fscache = NULL; switch (sa->sa_family) { case AF_INET: case AF_INET6: break; default: + mutex_unlock(&tcon->fscache_lock); cifs_dbg(VFS, "Unknown network family '%d'\n", sa->sa_family); return -EINVAL; } @@ -57,6 +68,7 @@ int cifs_fscache_get_super_cookie(struct sharename = extract_sharename(tcon->tree_name); if (IS_ERR(sharename)) { + mutex_unlock(&tcon->fscache_lock); cifs_dbg(FYI, "%s: couldn't extract sharename\n", __func__); return PTR_ERR(sharename); } @@ -90,6 +102,7 @@ out_2: kfree(key); out: kfree(sharename); + mutex_unlock(&tcon->fscache_lock); return ret; } --- a/fs/smb/client/misc.c +++ b/fs/smb/client/misc.c @@ -139,6 +139,9 @@ tconInfoAlloc(void) spin_lock_init(&ret_buf->stat_lock); atomic_set(&ret_buf->num_local_opens, 0); atomic_set(&ret_buf->num_remote_opens, 0); +#ifdef CONFIG_CIFS_FSCACHE + mutex_init(&ret_buf->fscache_lock); +#endif return ret_buf; }