linux-kernel - [PATCH] perf: Prevent divide by zero exception in kernel/events/core.c

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Message-ID: <5242D207.10306@t-online.de>
Date:	Wed, 25 Sep 2013 14:07:35 +0200
From:	Knut Petersen <Knut_Petersen@...nline.de>
To:	Linus Torvalds <torvalds@...ux-foundation.org>
CC:	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Paul Mackerras <paulus@...ba.org>,
	Ingo Molnar <mingo@...hat.com>,
	Arnaldo Carvalho de Melo <acme@...stprotocols.net>,
	linux-kernel <linux-kernel@...r.kernel.org>
Subject: [PATCH] perf: Prevent divide by zero exception in kernel/events/core.c

Any value written to /proc/sys/kernel/perf_event_max_sample_rate
is accepted and used as a divisor in perf_proc_update_handler().

Obviously that is wrong. 0 will cause a divide by 0 exception,
and negative values are unreasonable.

The attached patch enforces a lower limit of 1.

cu,
  Knut

View attachment "0001-Enforce-1-as-lower-limit-for-perf_event_max_sample_r.patch" of type "text/x-patch" (1123 bytes)