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From: Jiri Olsa <jolsa@redhat.com>
To: Janne Huttunen <janne.huttunen@nokia.com>
Cc: linux-kernel@vger.kernel.org,
	"Alexander Shishkin" <alexander.shishkin@linux.intel.com>,
	"Andi Kleen" <ak@linux.intel.com>,
	"Arnaldo Carvalho de Melo" <acme@kernel.org>,
	"Jaroslav Škarvada" <jskarvad@redhat.com>,
	"Namhyung Kim" <namhyung@kernel.org>,
	"Peter Zijlstra" <peterz@infradead.org>
Subject: Re: [PATCH v2] perf script python: Fix dict reference counting
Date: Mon, 9 Jul 2018 16:55:02 +0200	[thread overview]
Message-ID: <20180709145502.GB7917@krava> (raw)
In-Reply-To: <1531133990-17485-1-git-send-email-janne.huttunen@nokia.com>

On Mon, Jul 09, 2018 at 01:59:50PM +0300, Janne Huttunen wrote:
> The dictionaries are attached to the parameter tuple that steals
> the references and takes care of releasing them when appropriate.
> The code should not decrement the reference counts explicitly.
> E.g. if libpython has been built with reference debugging enabled,
> the superfluous DECREFs will trigger this error when running perf
> script:
> 
>   Fatal Python error: Objects/tupleobject.c:238 object at
>   0x7f10f2041b40 has negative ref count -1
>   Aborted (core dumped)
> 
> If the reference debugging is not enabled, the superfluous DECREFs
> might cause the dict objects to be silently released while they are
> still in use. This may trigger various other assertions or just
> cause perf crashes and/or weird and unexpected data changes in the
> stored Python objects.
> 
> Signed-off-by: Janne Huttunen <janne.huttunen@nokia.com>

Acked-by: Jiri Olsa <jolsa@kernel.org>

thanks,
jirka

  reply	other threads:[~2018-07-09 14:55 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-07-06  6:53 [PATCH] perf script python: Fix dict reference counting Janne Huttunen
2018-07-08 11:17 ` Jiri Olsa
2018-07-09  9:25   ` Janne Huttunen
2018-07-09  9:41     ` Jiri Olsa
2018-07-09 10:59       ` [PATCH v2] " Janne Huttunen
2018-07-09 14:55         ` Jiri Olsa [this message]
2018-07-11  8:14         ` Namhyung Kim
2018-07-12 14:04         ` [tip:perf/urgent] " tip-bot for Janne Huttunen

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