[PATCH 0/1] (Was: ptrace: clean transitions between TASK_STOPPEDand TRACED)

From: Oleg Nesterov
Date: Thu Feb 03 2011 - 15:49:54 EST


On 01/28, Tejun Heo wrote:
>
> Currently, if the task is STOPPED on ptrace attach, it's left alone
> and the state is silently changed to TRACED on the next ptrace call.

In particular, this means that it is very hard to attach correctly.
Any ptrace request needs STOPPED/TRACED tracee, but apart from wait()
there is no simple way to verify this and many applications (imho
rightly) assume that wait() after PTRACE_ATTACH should work.

While this patch should fix this old known problem, it needs more
discussion.

Tejun, Roland, perhaps it makes sense to fix this partcular problem
first? Personally I do not know, but as Jan reports this is really
annoying for gdb at least.

Oleg.

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