On Thu, Dec 17, 2015 at 3:06 PM, Peter Zijlstra <pet...@infradead.org> wrote:
> On Thu, Dec 10, 2015 at 08:57:40PM +0100, Peter Zijlstra wrote:
>> I'm not sure I can explain your problem with this, but I figure its
>> worth a try.
>
> Did it make a difference?
>
> Also, does the syzkaller thing do cpu-hotplug during its runs?
See my email on Dec 15.
I have CONFIG_HOTPLUG enabled, but I don't do actual hotplug (well,
actually I don't know how to do hotplug, but I still think I am not
doing it).
>> ---
>> kernel/events/core.c | 15 +++++----------
>> 1 file changed, 5 insertions(+), 10 deletions(-)
>>
>> diff --git a/kernel/events/core.c b/kernel/events/core.c
>> index c3d61b92d805..d5293325d8c5 100644
>> --- a/kernel/events/core.c
>> +++ b/kernel/events/core.c
>> @@ -3136,15 +3136,16 @@ static int event_enable_on_exec(struct perf_event
>> *event,
>> * Enable all of a task's events that have been marked enable-on-exec.
>> * This expects task == current.
>> */
>> -static void perf_event_enable_on_exec(struct perf_event_context *ctx)
>> +static void perf_event_enable_on_exec(int ctxn)
>> {
>> - struct perf_event_context *clone_ctx = NULL;
>> + struct perf_event_context *ctx, *clone_ctx = NULL;
>> struct perf_event *event;
>> unsigned long flags;
>> int enabled = 0;
>> int ret;
>>
>> local_irq_save(flags);
>> + ctx = current->perf_event_ctxp[ctxn];
>> if (!ctx || !ctx->nr_events)
>> goto out;
>>
>> @@ -3187,17 +3188,11 @@ static void perf_event_enable_on_exec(struct
>> perf_event_context *ctx)
>>
>> void perf_event_exec(void)
>> {
>> - struct perf_event_context *ctx;
>> int ctxn;
>>
>> rcu_read_lock();
>> - for_each_task_context_nr(ctxn) {
>> - ctx = current->perf_event_ctxp[ctxn];
>> - if (!ctx)
>> - continue;
>> -
>> - perf_event_enable_on_exec(ctx);
>> - }
>> + for_each_task_context_nr(ctxn)
>> + perf_event_enable_on_exec(ctxn);
>> rcu_read_unlock();
>> }
>>
--
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