SUNRPC: Fix potential memory scribble in xprt_free_bc_request()

The call to xprt_free_allocation() will call list_del() on
req->rq_bc_pa_list, which is not attached to a list.
This patch moves the list_del() out of xprt_free_allocation()
and into those callers that need it.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

diff --git a/net/sunrpc/backchannel_rqst.c b/net/sunrpc/backchannel_rqst.c
index 890a29912d5ab3f39d156891d4844ede04d367e8..e860d4f7ed2accd100c9ae9f715018daaae469a1 100644 (file)
--- a/net/sunrpc/backchannel_rqst.c
+++ b/net/sunrpc/backchannel_rqst.c
@@ -64,7 +64,6 @@ static void xprt_free_allocation(struct rpc_rqst *req)
        free_page((unsigned long)xbufp->head[0].iov_base);
        xbufp = &req->rq_snd_buf;
        free_page((unsigned long)xbufp->head[0].iov_base);
-       list_del(&req->rq_bc_pa_list);
        kfree(req);
 }
 
@@ -168,8 +167,10 @@ out_free:
        /*
         * Memory allocation failed, free the temporary list
         */
-       list_for_each_entry_safe(req, tmp, &tmp_list, rq_bc_pa_list)
+       list_for_each_entry_safe(req, tmp, &tmp_list, rq_bc_pa_list) {
+               list_del(&req->rq_bc_pa_list);
                xprt_free_allocation(req);
+       }
 
        dprintk("RPC:       setup backchannel transport failed\n");
        return -ENOMEM;
@@ -198,6 +199,7 @@ void xprt_destroy_backchannel(struct rpc_xprt *xprt, unsigned int max_reqs)
        xprt_dec_alloc_count(xprt, max_reqs);
        list_for_each_entry_safe(req, tmp, &xprt->bc_pa_list, rq_bc_pa_list) {
                dprintk("RPC:        req=%p\n", req);
+               list_del(&req->rq_bc_pa_list);
                xprt_free_allocation(req);
                if (--max_reqs == 0)
                        break;