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>

1 files changed, 4 insertions, 2 deletions

diff --git a/net/sunrpc/backchannel_rqst.c b/net/sunrpc/backchannel_rqst.c
index 890a29912d5a..e860d4f7ed2a 100644
--- 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;