Re: [PATCH] net/smc: loop in smc_listen
From: Tony Lu <tonylu@linux.alibaba.com>
Date: 2021-11-22 03:19:23
Also in:
linux-s390
On Sat, Nov 20, 2021 at 03:54:51PM +0800, Daxing Guo wrote:
From: Guo DaXing <redacted> The kernel_listen function in smc_listen will fail when all the available ports are occupied. At this point smc->clcsock->sk->sk_data_ready has been changed to smc_clcsock_data_ready. When we call smc_listen again, now both smc->clcsock->sk->sk_data_ready and smc->clcsk_data_ready point to the smc_clcsock_data_ready function. The smc_clcsock_data_ready() function calls lsmc->clcsk_data_ready which now points to itself resulting in an infinite loop. This patch restores smc->clcsock->sk->sk_data_ready with the old value.
Hi Guo, This indeed seems to be an issue. When listen fails, the original clcsock's sk_data_ready overwrites by smc_clcsock_data_ready and can't be recovered. I will also test it in my environment, thanks. Cheers, Tony Lu
quoted hunk ↗ jump to hunk
Signed-off-by: Guo DaXing <redacted> --- net/smc/af_smc.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c index 59284da9116d..078f5edf6d4d 100644 --- a/net/smc/af_smc.c +++ b/net/smc/af_smc.c@@ -2120,8 +2120,10 @@ static int smc_listen(struct socket *sock, int backlog) smc->clcsock->sk->sk_user_data = (void *)((uintptr_t)smc | SK_USER_DATA_NOCOPY); rc = kernel_listen(smc->clcsock, backlog); - if (rc) + if (rc) { + smc->clcsock->sk->sk_data_ready = smc->clcsk_data_ready; goto out; + } sk->sk_max_ack_backlog = backlog; sk->sk_ack_backlog = 0; sk->sk_state = SMC_LISTEN;-- 2.20.1