Messages in this thread | | | Date | Tue, 28 Jul 2009 14:49:59 +1000 | From | Paul Mackerras <> | Subject | NMI between switch_mm and switch_to |
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Ben H. suggested there might be a problem if we get a PMU interrupt and try to do a stack trace of userspace in the interval between when we call switch_mm() from sched.c:context_switch() and when we call switch_to(). If we get an NMI in that interval and do a stack trace of userspace, we'll see the registers of the old task but when we peek at user addresses we'll see the memory image for the new task, so the stack trace we get will be completely bogus.
Is this in fact also a problem on x86, or is there some subtle reason why it can't happen there?
Paul.
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