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From: Krister Johansen <kjlx@templeofstupid.com>
To: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: "Namhyung Kim" <namhyung@kernel.org>,
	"Masami Hiramatsu" <mhiramat@kernel.org>,
	"Frédéric Weisbecker" <fweisbec@gmail.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 perf/core] perf script: fix a use after free crash.
Date: Fri, 20 Jan 2017 17:48:50 -0800	[thread overview]
Message-ID: <20170121014850.GA2598@templeofstupid.com> (raw)
In-Reply-To: <20170106062331.GB2707@templeofstupid.com>

Hey Arnaldo,

On Thu, Jan 05, 2017 at 10:23:31PM -0800, Krister Johansen wrote:
> If dso__load_kcore frees all of the existing maps, but one has already
> been attached to a callchain cursor node, then we can get a SIGSEGV in
> any function that happens to try to use this invalid cursor.  Use the
> existing map refcount mechanism to forestall cleanup of a map until the
> cursor iterates past the node.

It's been a couple of weeks since I sent you the v3 of this patch.  Last
time I fiddled with it, I was able to reproduce your 'perf top' core,
and was able to verify that the latest patch I sent out could survive
running 'perf top' through the course of a full kernel build.

Is there anything else I can do to help with this one?

Thanks,

-K

  reply	other threads:[~2017-01-21  1:48 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-10-02  3:13 [PATCH perf/core] perf script: fix a use after free crash Krister Johansen
2016-10-05 11:45 ` callchain map refcounting fixes was " Arnaldo Carvalho de Melo
2016-10-06  0:29   ` Masami Hiramatsu
2016-10-06  6:12   ` Krister Johansen
2016-10-07  2:22   ` Namhyung Kim
2016-10-09  6:13     ` Krister Johansen
2016-10-11  9:28       ` Krister Johansen
2016-10-11  9:28     ` [PATCH v2 " Krister Johansen
2016-10-26  0:20       ` Krister Johansen
2016-10-26 13:44         ` Arnaldo Carvalho de Melo
2016-11-11  0:40           ` Krister Johansen
2016-11-22 19:01             ` Arnaldo Carvalho de Melo
2016-12-02  7:12               ` Krister Johansen
2016-12-29  1:39               ` Krister Johansen
2017-01-02 15:15                 ` Arnaldo Carvalho de Melo
2017-01-02 17:35                   ` Arnaldo Carvalho de Melo
2017-01-02 17:36                     ` Arnaldo Carvalho de Melo
2017-01-02 19:39                       ` Arnaldo Carvalho de Melo
2017-01-03  0:30                         ` Arnaldo Carvalho de Melo
2017-01-04  8:37                           ` Krister Johansen
2017-01-06  6:22                             ` Krister Johansen
2017-01-06  6:23                           ` [PATCH v3 " Krister Johansen
2017-01-21  1:48                             ` Krister Johansen [this message]
2017-02-01 14:39                             ` [tip:perf/core] perf callchain: Reference count maps tip-bot for Krister Johansen
2017-02-03 19:47                             ` [tip:perf/urgent] " tip-bot for Krister Johansen

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