Re: coverity-sunrpc-xprt-task-null-check.patch added to -mm tree

From: Alexey Dobriyan
Date: Sat Jul 02 2005 - 06:55:33 EST


On Friday 01 July 2005 10:15, akpm@xxxxxxxx wrote:
> --- devel/net/sunrpc/xprt.c~coverity-sunrpc-xprt-task-null-check
> +++ devel-akpm/net/sunrpc/xprt.c
> @@ -140,7 +140,10 @@ xprt_from_sock(struct sock *sk)
> static int
> __xprt_lock_write(struct rpc_xprt *xprt, struct rpc_task *task)
> {
> - struct rpc_rqst *req = task->tk_rqstp;
> + struct rpc_rqst *req = NULL;
> +
> + if (task)
> + req = task->tk_rqstp;

2 callers of __xprt_lock_write():
----------------------------------------------------------------------------
static inline int xprt_lock_write(struct rpc_xprt *xprt, struct rpc_task *task)
{
int retval;

spin_lock_bh(&xprt->sock_lock);
===> retval = __xprt_lock_write(xprt, task); <===
spin_unlock_bh(&xprt->sock_lock);
return retval;
}
----+-----------------------------------------------------------------------
|1 caller for xprt_lock_write():
|
|void xprt_connect(struct rpc_task *task)
|{
|===> struct rpc_xprt *xprt = task->tk_xprt; <===
|
| dprintk("RPC: %4d xprt_connect xprt %p %s connected\n", task->tk_pid,
| xprt, (xprt_connected(xprt) ? "is" : "is not"));
|
| if (xprt->shutdown) {
| task->tk_status = -EIO;
| return;
| }
| if (!xprt->addr.sin_port) {
| task->tk_status = -EIO;
| return;
| }
| if (!xprt_lock_write(xprt, task))
|
|task was already dereferenced.
----+-----------------------------------------------------------------------
int xprt_prepare_transmit(struct rpc_task *task)
{
===> struct rpc_rqst *req = task->tk_rqstp; <===
struct rpc_xprt *xprt = req->rq_xprt;
int err = 0;

dprintk("RPC: %4d xprt_prepare_transmit\n", task->tk_pid);

if (xprt->shutdown)
return -EIO;

spin_lock_bh(&xprt->sock_lock);
if (req->rq_received && !req->rq_bytes_sent) {
err = req->rq_received;
goto out_unlock;
}
if (!__xprt_lock_write(xprt, task)) {

task was already dereferenced.
----------------------------------------------------------------------------
-
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