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SUNRPC: remove printk when back channel request not found

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If the client interface is down, or there is a network partition between
the client and server that prevents the callback request to reach the
client, TCP on the server will keep re-transmitting the callback for about
~9 minutes before giving up and closing the connection.

If the connection between the client and the server is re-established
before the connection is closed and after the callback timed out (9 secs)
then the re-transmitted callback request will arrive at the client. When
the server receives the reply of the callback, receive_cb_reply prints the
"Got unrecognized reply..." message in the system log since the callback
request was already removed from the server xprt's recv_queue.

Even though this scenario has no effect on the server operation, a
malfunctioning or malicious client can fill up the server's system log.

Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
This commit is contained in:
Dai Ngo 2023-12-15 13:47:15 -08:00 committed by Chuck Lever
parent d3dba53410
commit 05a4b58301
1 changed files with 2 additions and 12 deletions
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14
net/sunrpc/svcsock.c
View file

@ -1049,18 +1049,14 @@ static int receive_cb_reply(struct svc_sock *svsk, struct svc_rqst *rqstp)
struct rpc_rqst *req = NULL;
struct kvec *src, *dst;
__be32 *p = (__be32 *)rqstp->rq_arg.head[0].iov_base;
__be32 xid;
__be32 calldir;
xid = *p++;
calldir = *p;
__be32 xid = *p;
if (!bc_xprt)
return -EAGAIN;
spin_lock(&bc_xprt->queue_lock);
req = xprt_lookup_rqst(bc_xprt, xid);
if (!req)
goto unlock_notfound;
goto unlock_eagain;
memcpy(&req->rq_private_buf, &req->rq_rcv_buf, sizeof(struct xdr_buf));
/*
@ -1077,12 +1073,6 @@ static int receive_cb_reply(struct svc_sock *svsk, struct svc_rqst *rqstp)
rqstp->rq_arg.len = 0;
spin_unlock(&bc_xprt->queue_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(&bc_xprt->queue_lock);
return -EAGAIN;