From patchwork Wed Jan 23 04:42:58 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Herton Ronaldo Krzesinski X-Patchwork-Id: 214755 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from chlorine.canonical.com (chlorine.canonical.com [91.189.94.204]) by ozlabs.org (Postfix) with ESMTP id 826C02C0084 for ; Wed, 23 Jan 2013 15:43:31 +1100 (EST) Received: from localhost ([127.0.0.1] helo=chlorine.canonical.com) by chlorine.canonical.com with esmtp (Exim 4.71) (envelope-from ) id 1TxsBD-0005pF-CV; Wed, 23 Jan 2013 04:43:19 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by chlorine.canonical.com with esmtp (Exim 4.71) (envelope-from ) id 1TxsAy-0005f2-1K for kernel-team@lists.ubuntu.com; Wed, 23 Jan 2013 04:43:04 +0000 Received: from 189.58.23.113.dynamic.adsl.gvt.net.br ([189.58.23.113] helo=canonical.com) by youngberry.canonical.com with esmtpsa (TLS1.0:DHE_RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1TxsAv-0007XZ-TV; Wed, 23 Jan 2013 04:43:02 +0000 From: Herton Ronaldo Krzesinski To: Trond Myklebust Subject: [ 3.5.y.z extended stable ] Patch "SUNRPC: Ensure we release the socket write lock if the" has been added to staging queue Date: Wed, 23 Jan 2013 02:42:58 -0200 Message-Id: <1358916178-23094-1-git-send-email-herton.krzesinski@canonical.com> X-Mailer: git-send-email 1.7.9.5 X-Extended-Stable: 3.5 Cc: Chris Perl , kernel-team@lists.ubuntu.com X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.13 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: kernel-team-bounces@lists.ubuntu.com Errors-To: kernel-team-bounces@lists.ubuntu.com This is a note to let you know that I have just added a patch titled SUNRPC: Ensure we release the socket write lock if the to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree which can be found at: http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.5.y.z tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Herton ------ From 54b1298470d6b4f2cf4de4a0bf1a7e9ae91e3299 Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Mon, 7 Jan 2013 14:30:46 -0500 Subject: [PATCH] SUNRPC: Ensure we release the socket write lock if the rpc_task exits early commit 87ed50036b866db2ec2ba16b2a7aec4a2b0b7c39 upstream. If the rpc_task exits while holding the socket write lock before it has allocated an rpc slot, then the usual mechanism for releasing the write lock in xprt_release() is defeated. The problem occurs if the call to xprt_lock_write() initially fails, so that the rpc_task is put on the xprt->sending wait queue. If the task exits after being assigned the lock by __xprt_lock_write_func, but before it has retried the call to xprt_lock_and_alloc_slot(), then it calls xprt_release() while holding the write lock, but will immediately exit due to the test for task->tk_rqstp != NULL. Reported-by: Chris Perl Signed-off-by: Trond Myklebust Signed-off-by: Herton Ronaldo Krzesinski --- net/sunrpc/sched.c | 3 +-- net/sunrpc/xprt.c | 12 ++++++++++-- 2 files changed, 11 insertions(+), 4 deletions(-) -- 1.7.9.5 diff --git a/net/sunrpc/sched.c b/net/sunrpc/sched.c index fe2cf2f..85b9235 100644 --- a/net/sunrpc/sched.c +++ b/net/sunrpc/sched.c @@ -953,8 +953,7 @@ static void rpc_async_release(struct work_struct *work) static void rpc_release_resources_task(struct rpc_task *task) { - if (task->tk_rqstp) - xprt_release(task); + xprt_release(task); if (task->tk_msg.rpc_cred) { put_rpccred(task->tk_msg.rpc_cred); task->tk_msg.rpc_cred = NULL; diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c index 2d5b811..6329ff3 100644 --- a/net/sunrpc/xprt.c +++ b/net/sunrpc/xprt.c @@ -1139,10 +1139,18 @@ static void xprt_request_init(struct rpc_task *task, struct rpc_xprt *xprt) void xprt_release(struct rpc_task *task) { struct rpc_xprt *xprt; - struct rpc_rqst *req; + struct rpc_rqst *req = task->tk_rqstp; - if (!(req = task->tk_rqstp)) + if (req == NULL) { + if (task->tk_client) { + rcu_read_lock(); + xprt = rcu_dereference(task->tk_client->cl_xprt); + if (xprt->snd_task == task) + xprt_release_write(xprt, task); + rcu_read_unlock(); + } return; + } xprt = req->rq_xprt; if (task->tk_ops->rpc_count_stats != NULL)