Date: Thu, 17 Jun 2010 17:20:32 -0300
From: Arnaldo Carvalho de Melo <acme@redhat.com>
To: Ian Munsie <imunsie@au1.ibm.com>
Cc: linux-kernel@vger.kernel.org, Peter Zijlstra <a.p.zijlstra@chello.nl>,
       Paul Mackerras <paulus@samba.org>, Ingo Molnar <mingo@elte.hu>,
       Frederic Weisbecker <fweisbec@gmail.com>,
       Tom Zanussi <tzanussi@gmail.com>
Subject: Re: [PATCH] perf: prevent kill(0, SIGTERM);
Message-ID: <20100617202032.GC1626@ghostprotocols.net>
References: <1276072680-17378-1-git-send-email-imunsie@au1.ibm.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <1276072680-17378-1-git-send-email-imunsie@au1.ibm.com>
User-Agent: Mutt/1.5.20 (2009-08-17)
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1181
Lines: 35

Em Wed, Jun 09, 2010 at 06:38:00PM +1000, Ian Munsie escreveu:
> At exit, perf record will kill the process it was profiling by sending a
> SIGTERM to child_pid (if it had been initialised), but in certain
> situations child_pid may be 0 and perf would mistakenly kill more
> processes than intended.
> 
> child_pid is set to the return of fork() to either 0 or the pid of the
> child. Ordinarily this would not present an issue as the child calls
> execvp to spawn the process to be profilled and would therefore never
> run it's sig_atexit and never attempt to kill pid 0.

before:

[root@emilia mingo]# perf record bla
bla: No such file or directory
Terminated

after:

[root@emilia mingo]# perf record bla
bla: No such file or directory
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.006 MB perf.data (~259 samples) ]
[root@emilia mingo]#

Got it, queuing it in perf/urgent,

Thanks!

- Arnaldo
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/