From 093a1468b6edb0e568be7311b8d2228d205702db Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Wed, 12 Nov 2014 18:04:04 -0500 Subject: [PATCH] SUNRPC: Fix locking around callback channel reply receive Both xprt_lookup_rqst() and xprt_complete_rqst() require that you take the transport lock in order to avoid races with xprt_transmit(). Signed-off-by: Trond Myklebust Cc: stable@vger.kernel.org Reviewed-by: Jeff Layton Signed-off-by: J. Bruce Fields --- net/sunrpc/svcsock.c | 27 ++++++++++++++++----------- 1 file changed, 16 insertions(+), 11 deletions(-) diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c index 3f959c681885..f9c052d508f0 100644 --- a/net/sunrpc/svcsock.c +++ b/net/sunrpc/svcsock.c @@ -1019,17 +1019,12 @@ static int receive_cb_reply(struct svc_sock *svsk, struct svc_rqst *rqstp) xid = *p++; calldir = *p; - if (bc_xprt) - req = xprt_lookup_rqst(bc_xprt, xid); - - if (!req) { - printk(KERN_NOTICE - "%s: Got unrecognized reply: " - "calldir 0x%x xpt_bc_xprt %p xid %08x\n", - __func__, ntohl(calldir), - bc_xprt, ntohl(xid)); + if (!bc_xprt) return -EAGAIN; - } + spin_lock_bh(&bc_xprt->transport_lock); + req = xprt_lookup_rqst(bc_xprt, xid); + if (!req) + goto unlock_notfound; memcpy(&req->rq_private_buf, &req->rq_rcv_buf, sizeof(struct xdr_buf)); /* @@ -1040,11 +1035,21 @@ static int receive_cb_reply(struct svc_sock *svsk, struct svc_rqst *rqstp) dst = &req->rq_private_buf.head[0]; src = &rqstp->rq_arg.head[0]; if (dst->iov_len < src->iov_len) - return -EAGAIN; /* whatever; just giving up. */ + goto unlock_eagain; /* whatever; just giving up. */ memcpy(dst->iov_base, src->iov_base, src->iov_len); xprt_complete_rqst(req->rq_task, rqstp->rq_arg.len); rqstp->rq_arg.len = 0; + spin_unlock_bh(&bc_xprt->transport_lock); return 0; +unlock_notfound: + printk(KERN_NOTICE + "%s: Got unrecognized reply: " + "calldir 0x%x xpt_bc_xprt %p xid %08x\n", + __func__, ntohl(calldir), + bc_xprt, ntohl(xid)); +unlock_eagain: + spin_unlock_bh(&bc_xprt->transport_lock); + return -EAGAIN; } static int copy_pages_to_kvecs(struct kvec *vec, struct page **pages, int len)