diff options
| author | Baptiste Lepers <baptiste.lepers@gmail.com> | 2021-05-01 14:10:51 +1000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-05-19 10:29:44 +0200 |
| commit | a521954cc34f2df86d2e0fa8a553b25dff6736a4 (patch) | |
| tree | 64cc9095d3299ece8ca1d4b6228df546edc3ca08 | |
| parent | 8e27c4731aecfff34c5d33781fb59d7a2a86ef6c (diff) | |
sunrpc: Fix misplaced barrier in call_decode
[ Upstream commit f8f7e0fb22b2e75be55f2f0c13e229e75b0eac07 ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | net/sunrpc/clnt.c | 11 |
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); |