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authorChuck Lever <chuck.lever@oracle.com>2018-12-07 11:11:44 -0500
committerAnna Schumaker <Anna.Schumaker@Netapp.com>2019-01-02 12:05:19 -0500
commit07e10308ee5da8e6132e0b737ece1c99dd651fb6 (patch)
tree1b5af1aca24cfbb01ea6d2f9b74f3f9d30a370a3
parent9aeaf8cfcb71f3663737bc21b93da7e1b8845c0d (diff)
downloadlinux-07e10308ee5da8e6132e0b737ece1c99dd651fb6.tar.bz2
xprtrdma: Prevent leak of rpcrdma_rep objects
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 <chuck.lever@oracle.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
-rw-r--r--include/trace/events/rpcrdma.h28
-rw-r--r--net/sunrpc/xprtrdma/rpc_rdma.c4
2 files changed, 32 insertions, 0 deletions
diff --git a/include/trace/events/rpcrdma.h b/include/trace/events/rpcrdma.h
index ce528d5942c5..399b1aedc927 100644
--- a/include/trace/events/rpcrdma.h
+++ b/include/trace/events/rpcrdma.h
@@ -1065,6 +1065,34 @@ 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 062aee97b070..d18614e02b4e 100644
--- a/net/sunrpc/xprtrdma/rpc_rdma.c
+++ b/net/sunrpc/xprtrdma/rpc_rdma.c
@@ -1350,6 +1350,10 @@ void rpcrdma_reply_handler(struct rpcrdma_rep *rep)
}
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);