diff options
| author | Trond Myklebust <Trond.Myklebust@netapp.com> | 2013-01-07 14:30:46 -0500 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2013-02-06 04:33:27 +0000 |
| commit | 88d6d79b6a8f4469311a0b55098c98ea15ccbc94 (patch) | |
| tree | b59cd497e642d428610029a1ae55a8ff4aed66a5 /net/sunrpc | |
| parent | 96908901a62457cdb9272d6658cd9903ac824115 (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: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'net/sunrpc')
| -rw-r--r-- | net/sunrpc/sched.c | 3 | ||||
| -rw-r--r-- | net/sunrpc/xprt.c | 12 |
2 files changed, 11 insertions, 4 deletions
diff --git a/net/sunrpc/sched.c b/net/sunrpc/sched.c index 56c3f855f4e..18c5a502221 100644 --- a/net/sunrpc/sched.c +++ b/net/sunrpc/sched.c @@ -918,8 +918,7 @@ 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 ffba2076c42..6c912088e67 100644 --- a/net/sunrpc/xprt.c +++ b/net/sunrpc/xprt.c @@ -1132,10 +1132,18 @@ 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; rpc_count_iostats(task); |