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 DC77E47F6A; Mon, 8 Jan 2024 15:09:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="PPj8qEOK" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 34D46C433C8; Mon, 8 Jan 2024 15:09:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1704726581; bh=uGcLwrMBdfuw0f67vfiofXYt1QSaaLYHK/8T8NfqYXA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=PPj8qEOKvKHu+7u5yAtwZ+88m/xX7qbHjiVbAPwQ7zhCDJFNvszY30GFe1Emdpbx0 7Jt71CXWd4ZP+F81RcVjurG0uphpsRJy4p+4x3UhrCvwDS+3WcwBkB8EIFnL3TrDyO hrfQd7E7o7/ewLdGKMiT1q1hr8oFpn+vVESmGI2E= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Shyam Prasad N , Steve French Subject: [PATCH 6.6 013/124] cifs: do not depend on release_iface for maintaining iface_list Date: Mon, 8 Jan 2024 16:07:19 +0100 Message-ID: <20240108150603.585375476@linuxfoundation.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240108150602.976232871@linuxfoundation.org> References: <20240108150602.976232871@linuxfoundation.org> User-Agent: quilt/0.67 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-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Shyam Prasad N commit 09eeb0723f219fbd96d8865bf9b935e03ee2ec22 upstream. parse_server_interfaces should be in complete charge of maintaining the iface_list linked list. Today, iface entries are removed from the list only when the last refcount is dropped. i.e. in release_iface. However, this can result in undercounting of refcount if the server stops advertising interfaces (which Azure SMB server does). This change puts parse_server_interfaces in full charge of maintaining the iface_list. So if an empty list is returned by the server, the entries in the list will immediately be removed. This way, a following call to the same function will not find entries in the list. Fixes: aa45dadd34e4 ("cifs: change iface_list from array to sorted linked list") Cc: stable@vger.kernel.org Signed-off-by: Shyam Prasad N Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman --- fs/smb/client/cifsglob.h | 1 - fs/smb/client/smb2ops.c | 27 +++++++++++++++++---------- 2 files changed, 17 insertions(+), 11 deletions(-) --- a/fs/smb/client/cifsglob.h +++ b/fs/smb/client/cifsglob.h @@ -993,7 +993,6 @@ release_iface(struct kref *ref) struct cifs_server_iface *iface = container_of(ref, struct cifs_server_iface, refcount); - list_del_init(&iface->iface_head); kfree(iface); } --- a/fs/smb/client/smb2ops.c +++ b/fs/smb/client/smb2ops.c @@ -593,16 +593,12 @@ parse_server_interfaces(struct network_i } /* - * Go through iface_list and do kref_put to remove - * any unused ifaces. ifaces in use will be removed - * when the last user calls a kref_put on it + * Go through iface_list and mark them as inactive */ list_for_each_entry_safe(iface, niface, &ses->iface_list, - iface_head) { + iface_head) iface->is_active = 0; - kref_put(&iface->refcount, release_iface); - ses->iface_count--; - } + spin_unlock(&ses->iface_lock); /* @@ -676,10 +672,7 @@ parse_server_interfaces(struct network_i iface_head) { ret = iface_cmp(iface, &tmp_iface); if (!ret) { - /* just get a ref so that it doesn't get picked/freed */ iface->is_active = 1; - kref_get(&iface->refcount); - ses->iface_count++; spin_unlock(&ses->iface_lock); goto next_iface; } else if (ret < 0) { @@ -746,6 +739,20 @@ next_iface: } out: + /* + * Go through the list again and put the inactive entries + */ + spin_lock(&ses->iface_lock); + list_for_each_entry_safe(iface, niface, &ses->iface_list, + iface_head) { + if (!iface->is_active) { + list_del(&iface->iface_head); + kref_put(&iface->refcount, release_iface); + ses->iface_count--; + } + } + spin_unlock(&ses->iface_lock); + return rc; }