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authorTrond Myklebust <Trond.Myklebust@netapp.com>2013-01-07 14:30:46 -0500
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-01-17 08:50:46 -0800
commit11d607dd94b7e1e4190f20581643555e620e3366 (patch)
tree43d6ee6738bb7046f74073d995f0724067a39126 /net/sunrpc/xprt.c
parentd5b319960ab9e0770b6ecae94045b512cd3029b7 (diff)
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 <chris.perl@gmail.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net/sunrpc/xprt.c')
-rw-r--r--net/sunrpc/xprt.c12
1 files changed, 10 insertions, 2 deletions
diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
index 176a24f0153..feea4741edd 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)