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| author |   Trond Myklebust <Trond.Myklebust@netapp.com> | 2013-01-07 14:30:46 -0500 |
|---|---|---|
| committer | Trond Myklebust <Trond.Myklebust@netapp.com> | 2013-01-08 14:30:43 -0500 |
| commit | 87ed50036b866db2ec2ba16b2a7aec4a2b0b7c39 (patch) | |
| tree | 8bd92625c340176d92ab0b77c0617bffd20a97eb /net/sunrpc/xprt.c | |
| parent | Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs (diff) | |
| download | linux-dev-87ed50036b866db2ec2ba16b2a7aec4a2b0b7c39.tar.xz linux-dev-87ed50036b866db2ec2ba16b2a7aec4a2b0b7c39.zip | |
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/sunrpc/xprt.c')
| -rw-r--r-- | net/sunrpc/xprt.c | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c index bd462a532acf..33811db8788a 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) |