Commit 301428ea authored Oct 29, 2019 by Ursula Braun Committed by David S. Miller Oct 29, 2019

net/smc: fix refcounting for non-blocking connect()



If a nonblocking socket is immediately closed after connect(),
the connect worker may not have started. This results in a refcount
problem, since sock_hold() is called from the connect worker.
This patch moves the sock_hold in front of the connect worker
scheduling.

Reported-by:  <syzbot+4c063e6dea39e4b79f29@syzkaller.appspotmail.com>
Fixes: 50717a37 ("net/smc: nonblocking connect rework")
Reviewed-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent ad9bd8da

net/smc/af_smc.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -707,8 +707,6 @@ static int __smc_connect(struct smc_sock *smc)
		int smc_type;
		int rc = 0;

		sock_hold(&smc->sk); /* sock put in passive closing */

		if (smc->use_fallback)
		return smc_connect_fallback(smc, smc->fallback_rsn);

		@@ -853,6 +851,8 @@ static int smc_connect(struct socket sock, struct sockaddr addr,
		rc = kernel_connect(smc->clcsock, addr, alen, flags);
		if (rc && rc != -EINPROGRESS)
		goto out;

		sock_hold(&smc->sk); /* sock put in passive closing */
		if (flags & O_NONBLOCK) {
		if (schedule_work(&smc->connect_work))
		smc->connect_nonblock = 1;

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