From: Oleg Nesterov <oleg@redhat.com>
To: Prashant Bhole <bhole_prashant_q7@lab.ntt.co.jp>
Cc: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] perf/core: fix use-after-free in uprobe_perf_close
Date: Mon, 9 Apr 2018 14:25:53 +0200 [thread overview]
Message-ID: <20180409122553.GA24920@redhat.com> (raw)
In-Reply-To: <20180409100346.6416-1-bhole_prashant_q7@lab.ntt.co.jp>
On 04/09, Prashant Bhole wrote:
>
> It occurs because task_struct is freed before perf_event which refers
> to the task and task flags are checked while teardown of the event.
> perf_event_alloc() assigns task_struct to hw.target of perf_event,
> but there is no reference counting for it.
>
> As a fix we get_task_struct() in perf_event_alloc() at above mentioned
> assignment and put_task_struct() in _free_event().
>
> Signed-off-by: Prashant Bhole <bhole_prashant_q7@lab.ntt.co.jp>
Agreed, lets make a simple fix for the start. I'd suggest cc:stable,
afaics this fixes the commit 63b6da39bb38e8f1a1ef3180d32a39d6
("perf: Fix perf_event_exit_task() race").
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
next prev parent reply other threads:[~2018-04-09 12:25 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-09 10:03 [PATCH] perf/core: fix use-after-free in uprobe_perf_close Prashant Bhole
2018-04-09 11:48 ` Peter Zijlstra
2018-04-09 12:25 ` Oleg Nesterov [this message]
2018-04-09 17:10 ` [tip:perf/urgent] perf/core: Fix use-after-free in uprobe_perf_close() tip-bot for Prashant Bhole
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