Re: [patch] x86, ptrace: fix double-free on race

[Ingo Molnar]

* Markus Metzger <markus.t.metzger@xxxxxxxxx> wrote:

> Ptrace_detach() races with __ptrace_unlink() if the traced task is
> reaped while detaching. This might cause a double-free of the BTS
> buffer.
> 
> Change the ptrace_detach() path to only do the memory accounting in
> ptrace_bts_detach() and leave the buffer free to ptrace_bts_untrace()
> which will be called from __ptrace_unlink().
> 
> The fix follows a proposal from Oleg Nesterov.
> 
> Reported-by: Oleg Nesterov <oleg@xxxxxxxxxx>
> Signed-off-by: Markus Metzger <markus.t.metzger@xxxxxxxxx>

Applied to tip:x86/urgent, thanks Markus!

Note, i fixed up the comment style to match the rest of ptrace.c,
see the final commit below.

	Ingo

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