Messages in this thread | | | Date | Thu, 19 Nov 2015 19:47:09 +0100 | From | Oleg Nesterov <> | Subject | [PATCH 0/2] (Was: ptrace() hangs on attempt to seize/attach stopped & frozen task) |
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On 11/09, Andrey Ryabinin wrote: > > So, the ptrace() hangs if we try to attach to stopped task from freezing cgroup.
OK, lets make it killable at least, TASK_KILLABLE looks better in any case.
I am starting to think again that we should remove JOBCTL_TRAPPING, but this needs a bit more discussion and probably testing.
Anyway I agree with Tejun, the freezer doesn't look nice too.
Hmm. I need to re-check but it seems we have another problem... ptrace_stop() does task_participate_group_stop() and this (in particular) clears JOBCTL_STOP_PENDING. This is only correct if the task is still traced, but this is not necessarily true and we can in fact clear JOBCTL_STOP_PENDING set by __ptrace_unlink() called by the exiting tracer.
Oleg.
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