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authorTrond Myklebust <Trond.Myklebust@netapp.com>2013-01-07 14:30:46 -0500
committerTrond Myklebust <Trond.Myklebust@netapp.com>2013-01-08 14:30:43 -0500
commit87ed50036b866db2ec2ba16b2a7aec4a2b0b7c39 (patch)
tree8bd92625c340176d92ab0b77c0617bffd20a97eb /net
parentd287b8750e47c1702dab0e37ac11012bb751ece0 (diff)
SUNRPC: Ensure we release the socket write lock if the rpc_task exits early
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 <chris.perl@gmail.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> Cc: stable@vger.kernel.org [>= 3.1]
Diffstat (limited to 'net')
-rw-r--r--net/sunrpc/sched.c3
-rw-r--r--net/sunrpc/xprt.c12
2 files changed, 11 insertions, 4 deletions
diff --git a/net/sunrpc/sched.c b/net/sunrpc/sched.c
index b4133bd1391..bfa31714581 100644
--- a/net/sunrpc/sched.c
+++ b/net/sunrpc/sched.c
@@ -972,8 +972,7 @@ 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 bd462a532ac..33811db8788 100644
--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -1136,10 +1136,18 @@ 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)