* Re: [PATCH 2/2] vsock: fix possible infinite sleep in vsock_connectible_wait_data()
@ 2022-10-31 8:43 ` Stefano Garzarella
0 siblings, 0 replies; 13+ messages in thread
From: Stefano Garzarella @ 2022-10-31 8:43 UTC (permalink / raw)
To: Dexuan Cui
Cc: wei.liu, linux-hyperv, netdev, haiyangz, linux-kernel,
virtualization, stephen, edumazet, kuba, arseny.krasnov, pabeni,
davem
On Fri, Oct 28, 2022 at 01:56:46PM -0700, Dexuan Cui wrote:
>Currently vsock_connectible_has_data() may miss a wakeup operation
>between vsock_connectible_has_data() == 0 and the prepare_to_wait().
>
>Fix the race by adding the process to the wait qeuue before checking
s/qeuue/queue
>vsock_connectible_has_data().
>
>Fixes: b3f7fd54881b ("af_vsock: separate wait data loop")
>Signed-off-by: Dexuan Cui <decui@microsoft.com>
>---
> net/vmw_vsock/af_vsock.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
>diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
>index d258fd43092e..03a6b5bc6ba7 100644
>--- a/net/vmw_vsock/af_vsock.c
>+++ b/net/vmw_vsock/af_vsock.c
>@@ -1905,8 +1905,11 @@ static int vsock_connectible_wait_data(struct sock *sk,
> err = 0;
> transport = vsk->transport;
>
>- while ((data = vsock_connectible_has_data(vsk)) == 0) {
>+ while (1) {
> prepare_to_wait(sk_sleep(sk), wait, TASK_INTERRUPTIBLE);
>+ data = vsock_connectible_has_data(vsk);
>+ if (data != 0)
>+ break;
>
> if (sk->sk_err != 0 ||
> (sk->sk_shutdown & RCV_SHUTDOWN) ||
>@@ -1937,6 +1940,8 @@ static int vsock_connectible_wait_data(struct sock *sk,
> err = -EAGAIN;
> break;
> }
>+
>+ finish_wait(sk_sleep(sk), wait);
Since we are going to call again prepare_to_wait() on top of the loop,
is finish_wait() call here really needed?
What about following what we do in vsock_accept and vsock_connect?
prepare_to_wait()
while (condition) {
...
prepare_to_wait();
}
finish_wait()
I find it a little more readable, but your solution is fine too.
Thanks,
Stefano
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https://lists.linuxfoundation.org/mailman/listinfo/virtualization
^ permalink raw reply [flat|nested] 13+ messages in thread* RE: [PATCH 2/2] vsock: fix possible infinite sleep in vsock_connectible_wait_data()
2022-10-31 8:43 ` Stefano Garzarella
(?)
@ 2022-11-01 1:58 ` Dexuan Cui
-1 siblings, 0 replies; 13+ messages in thread
From: Dexuan Cui @ 2022-11-01 1:58 UTC (permalink / raw)
To: Stefano Garzarella
Cc: davem@davemloft.net, edumazet@google.com, kuba@kernel.org,
pabeni@redhat.com, arseny.krasnov@kaspersky.com,
netdev@vger.kernel.org, virtualization@lists.linux-foundation.org,
linux-kernel@vger.kernel.org, KY Srinivasan, Haiyang Zhang,
stephen@networkplumber.org, wei.liu@kernel.org,
linux-hyperv@vger.kernel.org
> From: Stefano Garzarella <sgarzare@redhat.com>
> Sent: Monday, October 31, 2022 1:43 AM
> ...
> s/qeuue/queue
Will fix this.
> >@@ -1905,8 +1905,11 @@ static int vsock_connectible_wait_data(struct
> sock *sk,
> > err = 0;
> > transport = vsk->transport;
> >
> >- while ((data = vsock_connectible_has_data(vsk)) == 0) {
> >+ while (1) {
> > prepare_to_wait(sk_sleep(sk), wait, TASK_INTERRUPTIBLE);
> >+ data = vsock_connectible_has_data(vsk);
> >+ if (data != 0)
> >+ break;
> >
> > if (sk->sk_err != 0 ||
> > (sk->sk_shutdown & RCV_SHUTDOWN) ||
> >@@ -1937,6 +1940,8 @@ static int vsock_connectible_wait_data(struct sock
> *sk,
> > err = -EAGAIN;
> > break;
> > }
> >+
> >+ finish_wait(sk_sleep(sk), wait);
>
> Since we are going to call again prepare_to_wait() on top of the loop,
> is finish_wait() call here really needed?
It's not needed. Will remove this and send v2.
> What about following what we do in vsock_accept and vsock_connect?
>
> prepare_to_wait()
>
> while (condition) {
> ...
> prepare_to_wait();
> }
>
> finish_wait()
>
> I find it a little more readable, but your solution is fine too.
>
> Thanks,
> Stefano
I'd like to stay with my version, as it only needs one line of
prepare_to_wait(), and IMO it's more readable if we only exit from
inside the while loop.
^ permalink raw reply [flat|nested] 13+ messages in thread* Re: [PATCH 2/2] vsock: fix possible infinite sleep in vsock_connectible_wait_data()
2022-10-31 8:43 ` Stefano Garzarella
(?)
(?)
@ 2022-11-01 20:21 ` Frederic Dalleau via Virtualization
2022-11-02 9:45 ` Stefano Garzarella
-1 siblings, 1 reply; 13+ messages in thread
From: Frederic Dalleau via Virtualization @ 2022-11-01 20:21 UTC (permalink / raw)
Cc: wei.liu, netdev, haiyangz, linux-hyperv, virtualization, stephen,
edumazet, kuba, arseny.krasnov
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Hi Dexan, Stephano,
This solution has been proposed here,
https://lists.linuxfoundation.org/pipermail/virtualization/2022-August/062656.html
Best regards,
Frédéric
On Mon, Oct 31, 2022 at 9:43 AM Stefano Garzarella <sgarzare@redhat.com>
wrote:
> On Fri, Oct 28, 2022 at 01:56:46PM -0700, Dexuan Cui wrote:
> >Currently vsock_connectible_has_data() may miss a wakeup operation
> >between vsock_connectible_has_data() == 0 and the prepare_to_wait().
> >
> >Fix the race by adding the process to the wait qeuue before checking
>
> s/qeuue/queue
>
> >vsock_connectible_has_data().
> >
> >Fixes: b3f7fd54881b ("af_vsock: separate wait data loop")
> >Signed-off-by: Dexuan Cui <decui@microsoft.com>
> >---
> > net/vmw_vsock/af_vsock.c | 7 ++++++-
> > 1 file changed, 6 insertions(+), 1 deletion(-)
> >
> >diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
> >index d258fd43092e..03a6b5bc6ba7 100644
> >--- a/net/vmw_vsock/af_vsock.c
> >+++ b/net/vmw_vsock/af_vsock.c
> >@@ -1905,8 +1905,11 @@ static int vsock_connectible_wait_data(struct sock
> *sk,
> > err = 0;
> > transport = vsk->transport;
> >
> >- while ((data = vsock_connectible_has_data(vsk)) == 0) {
> >+ while (1) {
> > prepare_to_wait(sk_sleep(sk), wait, TASK_INTERRUPTIBLE);
> >+ data = vsock_connectible_has_data(vsk);
> >+ if (data != 0)
> >+ break;
> >
> > if (sk->sk_err != 0 ||
> > (sk->sk_shutdown & RCV_SHUTDOWN) ||
> >@@ -1937,6 +1940,8 @@ static int vsock_connectible_wait_data(struct sock
> *sk,
> > err = -EAGAIN;
> > break;
> > }
> >+
> >+ finish_wait(sk_sleep(sk), wait);
>
> Since we are going to call again prepare_to_wait() on top of the loop,
> is finish_wait() call here really needed?
>
> What about following what we do in vsock_accept and vsock_connect?
>
> prepare_to_wait()
>
> while (condition) {
> ...
> prepare_to_wait();
> }
>
> finish_wait()
>
> I find it a little more readable, but your solution is fine too.
>
> Thanks,
> Stefano
>
> _______________________________________________
> Virtualization mailing list
> Virtualization@lists.linux-foundation.org
> https://lists.linuxfoundation.org/mailman/listinfo/virtualization
>
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_______________________________________________
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https://lists.linuxfoundation.org/mailman/listinfo/virtualization
^ permalink raw reply [flat|nested] 13+ messages in thread* Re: [PATCH 2/2] vsock: fix possible infinite sleep in vsock_connectible_wait_data()
2022-11-01 20:21 ` Frederic Dalleau via Virtualization
@ 2022-11-02 9:45 ` Stefano Garzarella
0 siblings, 0 replies; 13+ messages in thread
From: Stefano Garzarella @ 2022-11-02 9:45 UTC (permalink / raw)
To: Frederic Dalleau
Cc: wei.liu, netdev, haiyangz, linux-hyperv, virtualization, stephen,
edumazet, kuba, arseny.krasnov, decui
On Tue, Nov 01, 2022 at 09:21:06PM +0100, Frederic Dalleau via Virtualization wrote:
>Hi Dexan, Stephano,
>
>This solution has been proposed here,
>https://lists.linuxfoundation.org/pipermail/virtualization/2022-August/062656.html
Ops, I missed it!
Did you use scripts/get_maintainer.pl?
https://www.kernel.org/doc/html/v4.17/process/submitting-patches.html#select-the-recipients-for-your-patch
Since your patch should be reposted (hasn't been sent to
netdev@vger.kernel.org, missing Fixes tag, etc.) and Dexuan's patch on
the other hand is ready (I just reviewed it), can you test it and
respond with your Tested-by?
I would like to give credit to both, so I asked to add your Reported-by
to the Dexuan's patch.
Thanks,
Stefano
^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [PATCH 2/2] vsock: fix possible infinite sleep in vsock_connectible_wait_data()
@ 2022-11-02 9:45 ` Stefano Garzarella
0 siblings, 0 replies; 13+ messages in thread
From: Stefano Garzarella @ 2022-11-02 9:45 UTC (permalink / raw)
To: Frederic Dalleau
Cc: wei.liu, netdev, haiyangz, decui, linux-hyperv, virtualization,
stephen, edumazet, kuba, arseny.krasnov
On Tue, Nov 01, 2022 at 09:21:06PM +0100, Frederic Dalleau via Virtualization wrote:
>Hi Dexan, Stephano,
>
>This solution has been proposed here,
>https://lists.linuxfoundation.org/pipermail/virtualization/2022-August/062656.html
Ops, I missed it!
Did you use scripts/get_maintainer.pl?
https://www.kernel.org/doc/html/v4.17/process/submitting-patches.html#select-the-recipients-for-your-patch
Since your patch should be reposted (hasn't been sent to
netdev@vger.kernel.org, missing Fixes tag, etc.) and Dexuan's patch on
the other hand is ready (I just reviewed it), can you test it and
respond with your Tested-by?
I would like to give credit to both, so I asked to add your Reported-by
to the Dexuan's patch.
Thanks,
Stefano
_______________________________________________
Virtualization mailing list
Virtualization@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/virtualization
^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [PATCH 2/2] vsock: fix possible infinite sleep in vsock_connectible_wait_data()
2022-11-02 9:45 ` Stefano Garzarella
@ 2022-11-02 17:08 ` Frederic Dalleau via Virtualization
-1 siblings, 0 replies; 13+ messages in thread
From: Frederic Dalleau @ 2022-11-02 17:08 UTC (permalink / raw)
To: Stefano Garzarella
Cc: wei.liu, netdev, haiyangz, linux-hyperv, virtualization, stephen,
edumazet, kuba, arseny.krasnov, decui
> Did you use scripts/get_maintainer.pl?
Not really, I just picked the list that seemed narrow enough for the topic
> respond with your Tested-by?
Done
> I would like to give credit to both, so I asked to add your Reported-by
> to the Dexuan's patch.
Thank you!
Regards,
Frédéric
^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [PATCH 2/2] vsock: fix possible infinite sleep in vsock_connectible_wait_data()
@ 2022-11-02 17:08 ` Frederic Dalleau via Virtualization
0 siblings, 0 replies; 13+ messages in thread
From: Frederic Dalleau via Virtualization @ 2022-11-02 17:08 UTC (permalink / raw)
To: Stefano Garzarella
Cc: wei.liu, netdev, haiyangz, decui, linux-hyperv, virtualization,
stephen, edumazet, kuba, arseny.krasnov
> Did you use scripts/get_maintainer.pl?
Not really, I just picked the list that seemed narrow enough for the topic
> respond with your Tested-by?
Done
> I would like to give credit to both, so I asked to add your Reported-by
> to the Dexuan's patch.
Thank you!
Regards,
Frédéric
_______________________________________________
Virtualization mailing list
Virtualization@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/virtualization
^ permalink raw reply [flat|nested] 13+ messages in thread