Re: Linux 3.11-rc4

From: Oleg Nesterov
Date: Mon Aug 05 2013 - 14:51:56 EST


On 08/04, Felipe Contreras wrote:
>
> I found a regression while running all v3.11-rcX kernels; Starcract II
> through wine crashes. The culprit is fab840f (ptrace: PTRACE_DETACH
> should do flush_ptrace_hw_breakpoint(child)), I revert that commit and
> there's no crash.

Heh. I pulled wine-git.

set_thread_context() does a lot of PTRACE_POKEUSER requests and then
it calls resume_after_ptrace() which simply does PTRACE_DETACH.

I'll recheck tomorrow, but it really looks as if it _wants_ to leak
the debug registers after detach. And more, it does PTRACE_ATTACH
only to set these regs.

And this is exactly what fab840f tries to prevent.

Oleg.

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