Messages in this thread | | | Date | Fri, 7 Nov 2003 16:17:29 +0100 (CET) | From | Ingo Molnar <> | Subject | Re: [PATCH] SMP signal latency fix up. |
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On Fri, 7 Nov 2003, Linus Torvalds wrote:
> (It _looks_ obvious enough, but can you check that there are no pointers > that we might be following in the "is it running" checks that could be > stale because we don't hold the runqueue lock any more).
the 'is it running' check is 'task_curr(p)', which in this circumstance is equivalent to the following test:
per_cpu(runqueues, (cpu)).curr == p
where 'cpu' is p->thread_info->cpu. All pointers dereferenced in this test are stable, because 1) send_signal() is always called within the siglock, which serializes with task exit 2) p->thread_info->cpu is always valid for the same reason.
so this seems to be safe to me.
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