From 8d42629be0cb6c58a5c77cd02e47974c0e724e63 Mon Sep 17 00:00:00 2001 From: Chuck Lever Date: Fri, 28 Oct 2016 22:22:33 -0400 Subject: [PATCH] svcrdma: backchannel cannot share a page for send and rcv buffers The underlying transport releases the page pointed to by rq_buffer during xprt_rdma_bc_send_request. When the backchannel reply arrives, rq_rbuffer then points to freed memory. Fixes: 68778945e46f ('SUNRPC: Separate buffer pointers for RPC ...') Signed-off-by: Chuck Lever Cc: Jeff Layton Signed-off-by: J. Bruce Fields --- net/sunrpc/xprtrdma/svc_rdma_backchannel.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/net/sunrpc/xprtrdma/svc_rdma_backchannel.c b/net/sunrpc/xprtrdma/svc_rdma_backchannel.c index fc4535ead7c2..20027f8de129 100644 --- a/net/sunrpc/xprtrdma/svc_rdma_backchannel.c +++ b/net/sunrpc/xprtrdma/svc_rdma_backchannel.c @@ -177,19 +177,26 @@ xprt_rdma_bc_allocate(struct rpc_task *task) return -EINVAL; } + /* svc_rdma_sendto releases this page */ page = alloc_page(RPCRDMA_DEF_GFP); if (!page) return -ENOMEM; - rqst->rq_buffer = page_address(page); - rqst->rq_rbuffer = (char *)rqst->rq_buffer + rqst->rq_callsize; + + rqst->rq_rbuffer = kmalloc(rqst->rq_rcvsize, RPCRDMA_DEF_GFP); + if (!rqst->rq_rbuffer) { + put_page(page); + return -ENOMEM; + } return 0; } static void xprt_rdma_bc_free(struct rpc_task *task) { - /* No-op: ctxt and page have already been freed. */ + struct rpc_rqst *rqst = task->tk_rqstp; + + kfree(rqst->rq_rbuffer); } static int -- 2.20.1