From mboxrd@z Thu Jan 1 00:00:00 1970 From: Oleg Nesterov Subject: Re: ptrace.2: PTRACE_KILL needs a stopped process too Date: Wed, 9 May 2012 22:12:19 +0200 Message-ID: <20120509201219.GA32051@redhat.com> References: <20091216004533.22261.qmail@kosh.dhis.org> <20120422200459.GA7519@redhat.com> <201205091109.35637.vapier@gentoo.org> <4FAAC706.6000808@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <4FAAC706.6000808-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> Sender: linux-man-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Pedro Alves Cc: Mike Frysinger , "Michael Kerrisk (man-pages)" , pacman-ptgZXYu0fikgsBAKwltoeQ@public.gmane.org, linux-man , lkml , Denys Vlasenko , Tejun Heo , Jan Kratochvil List-Id: linux-man@vger.kernel.org On 05/09, Pedro Alves wrote: > > On 05/09/2012 04:09 PM, Mike Frysinger wrote: > > > probably not that big of a deal, but the reason i like using > > ptrace(PTRACE_KILL) over a raw kill() is that you are less likely to kill the > > wrong process by accident. maybe not that big of a deal in practice though. > > > And you can do tgkill instead. It was specifically invented to handle the > reuse case. tgkill() can kill the wrong process/thread too, although it lessens the risk. But I don't really understand the problem. The traced thread can't go away until the tracer does wait/detach, and thus its pid can't be reused? May be, "by accident" above means something else, not pid reuse... Oleg. -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html