Re: [PATCH] ptrace: add ability to get clear_tid_address

From: Cyrill Gorcunov
Date: Wed Feb 08 2012 - 14:20:52 EST


On Wed, Feb 08, 2012 at 08:02:50PM +0100, Oleg Nesterov wrote:
> > Right, as I said. :-) I saw that a watchpoint trap isn't reported either
> > for the CLONE_CHILD_SETTID case (that is, within clone, when the kernel
> > writes the tid to the memory address passed in to the clone syscall).
>
> Yes. But in this case the new thread has no bps even if it is auto-
> attached.
>
> IOW, I think that hw bp can detect the write from the kernel space,
> but I didn't check.

yes, that's how kgdb work (if only I'm not missing something obvious)

Cyrill
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