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authorBaptiste Lepers <baptiste.lepers@gmail.com>2021-05-01 14:10:51 +1000
committerTrond Myklebust <trond.myklebust@hammerspace.com>2021-05-01 19:42:14 -0400
commitf8f7e0fb22b2e75be55f2f0c13e229e75b0eac07 (patch)
treee0c29141e3a872cc35cdb8d12f7381476aea3e70 /net/sunrpc/clnt.c
parentd9092b4bb2109502eb8972021a3f74febc931a63 (diff)
sunrpc: Fix misplaced barrier in call_decode
Fix a misplaced barrier in call_decode. The struct rpc_rqst is modified as follows by xprt_complete_rqst: req->rq_private_buf.len = copied; /* Ensure all writes are done before we update */ /* req->rq_reply_bytes_recvd */ smp_wmb(); req->rq_reply_bytes_recvd = copied; And currently read as follows by call_decode: smp_rmb(); // misplaced if (!req->rq_reply_bytes_recvd) goto out; req->rq_rcv_buf.len = req->rq_private_buf.len; This patch places the smp_rmb after the if to ensure that rq_reply_bytes_recvd and rq_private_buf.len are read in order. Fixes: 9ba828861c56a ("SUNRPC: Don't try to parse incomplete RPC messages") Signed-off-by: Baptiste Lepers <baptiste.lepers@gmail.com> Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Diffstat (limited to 'net/sunrpc/clnt.c')
-rw-r--r--net/sunrpc/clnt.c11
1 files changed, 5 insertions, 6 deletions
diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index c2a01125be1a..f555d335e910 100644
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -2457,12 +2457,6 @@ call_decode(struct rpc_task *task)
}
/*
- * Ensure that we see all writes made by xprt_complete_rqst()
- * before it changed req->rq_reply_bytes_recvd.
- */
- smp_rmb();
-
- /*
* Did we ever call xprt_complete_rqst()? If not, we should assume
* the message is incomplete.
*/
@@ -2470,6 +2464,11 @@ call_decode(struct rpc_task *task)
if (!req->rq_reply_bytes_recvd)
goto out;
+ /* Ensure that we see all writes made by xprt_complete_rqst()
+ * before it changed req->rq_reply_bytes_recvd.
+ */
+ smp_rmb();
+
req->rq_rcv_buf.len = req->rq_private_buf.len;
trace_rpc_xdr_recvfrom(task, &req->rq_rcv_buf);