Messages in this thread | | | Date | Mon, 14 Feb 2011 17:33:46 +0100 | From | Tejun Heo <> | Subject | Re: [PATCH 1/1] ptrace: make sure do_wait() won't hang after PTRACE_ATTACH |
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Hello,
On Mon, Feb 14, 2011 at 05:15:15PM +0100, Oleg Nesterov wrote: > > > PTRACE_CONT in this situation would do the same. > > > > This can be fixed by updating strace, right? strace can look at the > > wait(2) exit code and if the tracee stopped for group stop, wait for > > the tracee to be continued instead of issuing PTRACE_SYSCALL. > > Yes, in this particular case strace could be more clever. > > But. The tracee should react to SIGCONT after that, this means we > shouldn't "delay" this stop or force the TASK_TRACED state.
Yeap, which is achievable by treating group stop differently from ptrace traps and make it proceed to TASK_TRACED only if ptrace wants to issue commands. (reiterating just to make sure there's no misunderstanding)
> And note that in this case real_parent == debugger. Another case > is more interesting, and this means we shouldn't delay or hide the > notifications. > > (I just tried to summarize the previous discussion for Denys)
Agreed. We should be notifying both the real parent and ptracer.
Thanks.
-- tejun
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