From: Oleg Nesterov <oleg@redhat.com>
To: Roland McGrath <roland@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org
Subject: Re: [PATCH] ptrace: copy_process() should disable stepping
Date: Mon, 9 Nov 2009 17:24:08 +0100 [thread overview]
Message-ID: <20091109162408.GA5160@redhat.com> (raw)
In-Reply-To: <20091109041546.925461E@magilla.sf.frob.com>
On 11/08, Roland McGrath wrote:
>
> That is inappropriate use of arch details in generic code. It might
> happen to be harmless fritter in practice on the arch's we have but it
> is certainly not the correct way to go about things. You should just
> call user_disable_single_step() unconditionally. Even on an arch with
> no such machinery at all that should be defined safely as a no-op (see
> linux/ptrace.h). If there is some reason not to do that, please
> explain it.
Yes, we have arch_has_single_step.
I added test_tsk_thread_flag(TIF_SINGLESTEP) check for 2 reasons: to
optimize out user_disable_single_step() in the likely case, and because
I wasn't sure it is safe to call user_disable_single_step() unconditionally.
OK, will resend, thanks.
Oleg.
next prev parent reply other threads:[~2009-11-09 16:29 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-11-06 21:16 [PATCH] ptrace: copy_thread() should clear TIF_SINGLESTEP and X86_EFLAGS_TF Oleg Nesterov
2009-11-06 21:25 ` Roland McGrath
2009-11-06 21:50 ` Oleg Nesterov
2009-11-06 22:10 ` Roland McGrath
2009-11-07 21:55 ` [PATCH] ptrace: copy_process() should disable stepping Oleg Nesterov
2009-11-09 4:15 ` Roland McGrath
2009-11-09 16:24 ` Oleg Nesterov [this message]
2009-11-09 23:53 ` [PATCH v2] " Oleg Nesterov
2009-11-10 20:39 ` Roland McGrath
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