RE: [PATCH v2 2/3] kfence: maximize allocation wait timeout duration

[David Laight]

From: Kefeng Wang
> Sent: 16 September 2021 02:21
> 
> We found kfence_test will fails  on ARM64 with this patch with/without
> CONFIG_DETECT_HUNG_TASK,
> 
> Any thought ?
> 
...
> >>       /* Enable static key, and await allocation to happen. */
> >>       static_branch_enable(&kfence_allocation_key);
> >>   -    wait_event_timeout(allocation_wait, atomic_read(&kfence_allocation_gate), HZ);
> >> +    if (sysctl_hung_task_timeout_secs) {
> >> +        /*
> >> +         * During low activity with no allocations we might wait a
> >> +         * while; let's avoid the hung task warning.
> >> +         */
> >> +        wait_event_timeout(allocation_wait, atomic_read(&kfence_allocation_gate),
> >> +                   sysctl_hung_task_timeout_secs * HZ / 2);
> >> +    } else {
> >> +        wait_event(allocation_wait, atomic_read(&kfence_allocation_gate));
> >> +    }
> >>         /* Disable static key and reset timer. */
> >>       static_branch_disable(&kfence_allocation_key);

It has replaced a wait_event_timeout() with a wait_event().

That probably isn't intended.
Although I'd expect their to be some test for the wait being
signalled or timing out.

	David

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