Hello,
On Sun, Jun 14, 2020 at 5:39 AM Daniël Sonck <[email protected]> wrote:
>
> Hello,
>
> I found on the archive that this bug I encountered also happened to
> others. I too have a very similar stacktrace. The issue I'm
> experiencing is:
>
> Whenever I fully boot my cluster, in some time, the host crashes with
> the __cgroup_bpf_run_filter_skb NULL pointer dereference. This has
> been sporadic enough before not to cause real issues. However, as of
> lately, the bug is triggered much more frequently. I've changed my
> server hardware so I could capture serial output in order to get the
> trace. This trace looked very similar as reported by Lu Fengqi. As it
> currently stands, I cannot run the cluster as it's almost instantly
> crashing the host.
This has been reported for multiple times. Are you able to test the
attached patch? And let me know if everything goes fine with it.
I suspect we may still leak some cgroup refcnt even with the patch,
but it might be much harder to trigger with this patch applied.
Thanks.
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index 6c9c6ac83936..c01245a19ea2 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -6438,9 +6438,6 @@ void cgroup_sk_alloc_disable(void)
void cgroup_sk_alloc(struct sock_cgroup_data *skcd)
{
- if (cgroup_sk_alloc_disabled)
- return;
-
/* Socket clone path */
if (skcd->val) {
/*
@@ -6453,6 +6450,9 @@ void cgroup_sk_alloc(struct sock_cgroup_data *skcd)
return;
}
+ if (cgroup_sk_alloc_disabled)
+ return;
+
/* Don't associate the sock with unrelated interrupted task's cgroup. */
if (in_interrupt())
return;
