Messages in this thread | | | Date | Tue, 31 May 2016 15:18:17 +0100 | From | Russell King - ARM Linux <> | Subject | Re: Possible race between PTRACE_SETVFPREGS and PTRACE_CONT on ARM? |
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On Tue, May 31, 2016 at 02:52:52PM +0100, Will Deacon wrote: > The only thing I'm uncertain of is whether or not PTRACE_SEIZE/PTRACE_LISTEN > allow switching to the child (but even then, how is the parent doing > to issue such a request?).
I can't see how that would be possible - the parent needs to finish the vfp_set() call before it can issue any others - and there can only be one tracer. IOW, if we're in vfp_set(), the thread must have attached to the child, at which point PTRACE_SEIZE will be rejected.
PTRACE_LISTEN also requires the child to be in STOP state as well, and again, can only be issued from the current tracer.
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