* [PATCH] net/smc: loop in smc_listen
@ 2021-11-20 7:54 Daxing Guo
2021-11-22 3:19 ` Tony Lu
` (2 more replies)
0 siblings, 3 replies; 6+ messages in thread
From: Daxing Guo @ 2021-11-20 7:54 UTC (permalink / raw)
To: netdev; +Cc: chenzhe, linux-s390, greg, Guo DaXing
From: Guo DaXing <guodaxing@huawei.com>
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.
Signed-off-by: Guo DaXing <guodaxing@huawei.com>
---
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
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH] net/smc: loop in smc_listen
2021-11-20 7:54 Daxing Guo
@ 2021-11-22 3:19 ` Tony Lu
2021-11-22 7:28 ` Karsten Graul
2021-11-22 8:37 ` Tony Lu
2 siblings, 0 replies; 6+ messages in thread
From: Tony Lu @ 2021-11-22 3:19 UTC (permalink / raw)
To: Daxing Guo; +Cc: netdev, chenzhe, linux-s390, greg
On Sat, Nov 20, 2021 at 03:54:51PM +0800, Daxing Guo wrote:
> From: Guo DaXing <guodaxing@huawei.com>
>
> 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
>
> Signed-off-by: Guo DaXing <guodaxing@huawei.com>
> ---
> 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
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] net/smc: loop in smc_listen
2021-11-20 7:54 Daxing Guo
2021-11-22 3:19 ` Tony Lu
@ 2021-11-22 7:28 ` Karsten Graul
2021-11-22 8:37 ` Tony Lu
2 siblings, 0 replies; 6+ messages in thread
From: Karsten Graul @ 2021-11-22 7:28 UTC (permalink / raw)
To: Daxing Guo, netdev; +Cc: chenzhe, linux-s390, greg
On 20/11/2021 08:54, Daxing Guo wrote:
> From: Guo DaXing <guodaxing@huawei.com>
>
> 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.
>
> Signed-off-by: Guo DaXing <guodaxing@huawei.com>
> ---
Thanks for your patch, I will pick it up and submit it to the net tree.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] net/smc: loop in smc_listen
2021-11-20 7:54 Daxing Guo
2021-11-22 3:19 ` Tony Lu
2021-11-22 7:28 ` Karsten Graul
@ 2021-11-22 8:37 ` Tony Lu
2 siblings, 0 replies; 6+ messages in thread
From: Tony Lu @ 2021-11-22 8:37 UTC (permalink / raw)
To: Daxing Guo; +Cc: netdev, chenzhe, linux-s390, greg
On Sat, Nov 20, 2021 at 03:54:51PM +0800, Daxing Guo wrote:
> From: Guo DaXing <guodaxing@huawei.com>
>
> 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.
>
> Signed-off-by: Guo DaXing <guodaxing@huawei.com>
It works in my testing environment, thanks.
Acked-by: Tony Lu <tonylu@linux.alibaba.com>
^ permalink raw reply [flat|nested] 6+ messages in thread
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2021-11-19 7:09 ` [PATCH] net/smc: loop in smc_listen greg
2021-11-19 9:22 ` 答复: " guodaxing
2021-11-20 7:54 Daxing Guo
2021-11-22 3:19 ` Tony Lu
2021-11-22 7:28 ` Karsten Graul
2021-11-22 8:37 ` Tony Lu
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