From a5eb57fdd1584aa672a87579590dc3ef6f6ed0c8 Mon Sep 17 00:00:00 2001 From: Chuck Lever Date: Mon, 9 Dec 2019 17:57:55 +0800 Subject: [PATCH] xprtrdma: Prevent leak of rpcrdma_rep objects [ Upstream commit 07e10308ee5da8e6132e0b737ece1c99dd651fb6 ] If a reply has been processed but the RPC is later retransmitted anyway, the req->rl_reply field still contains the only pointer to the old rpcrdma rep. When the next reply comes in, the reply handler will stomp on the rl_reply field, leaking the old rep. A trace event is added to capture such leaks. This problem seems to be worsened by the restructuring of the RPC Call path in v4.20. Fully addressing this issue will require at least a re-architecture of the disconnect logic, which is not appropriate during -rc. Signed-off-by: Chuck Lever Signed-off-by: Anna Schumaker Signed-off-by: Sasha Levin Signed-off-by: Yang Yingliang --- include/trace/events/rpcrdma.h | 28 ++++++++++++++++++++++++++++ net/sunrpc/xprtrdma/rpc_rdma.c | 4 ++++ 2 files changed, 32 insertions(+) diff --git a/include/trace/events/rpcrdma.h b/include/trace/events/rpcrdma.h index b27f5aad0a09..b4306cf8f3c2 100644 --- a/include/trace/events/rpcrdma.h +++ b/include/trace/events/rpcrdma.h @@ -917,6 +917,34 @@ TRACE_EVENT(xprtrdma_cb_setup, DEFINE_CB_EVENT(xprtrdma_cb_call); DEFINE_CB_EVENT(xprtrdma_cb_reply); +TRACE_EVENT(xprtrdma_leaked_rep, + TP_PROTO( + const struct rpc_rqst *rqst, + const struct rpcrdma_rep *rep + ), + + TP_ARGS(rqst, rep), + + TP_STRUCT__entry( + __field(unsigned int, task_id) + __field(unsigned int, client_id) + __field(u32, xid) + __field(const void *, rep) + ), + + TP_fast_assign( + __entry->task_id = rqst->rq_task->tk_pid; + __entry->client_id = rqst->rq_task->tk_client->cl_clid; + __entry->xid = be32_to_cpu(rqst->rq_xid); + __entry->rep = rep; + ), + + TP_printk("task:%u@%u xid=0x%08x rep=%p", + __entry->task_id, __entry->client_id, __entry->xid, + __entry->rep + ) +); + /** ** Server-side RPC/RDMA events **/ diff --git a/net/sunrpc/xprtrdma/rpc_rdma.c b/net/sunrpc/xprtrdma/rpc_rdma.c index c8ae983c6cc0..f2eaf264726b 100644 --- a/net/sunrpc/xprtrdma/rpc_rdma.c +++ b/net/sunrpc/xprtrdma/rpc_rdma.c @@ -1360,6 +1360,10 @@ void rpcrdma_reply_handler(struct rpcrdma_rep *rep) spin_unlock(&xprt->recv_lock); req = rpcr_to_rdmar(rqst); + if (req->rl_reply) { + trace_xprtrdma_leaked_rep(rqst, req->rl_reply); + rpcrdma_recv_buffer_put(req->rl_reply); + } req->rl_reply = rep; rep->rr_rqst = rqst; clear_bit(RPCRDMA_REQ_F_PENDING, &req->rl_flags); -- GitLab