From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, kernel test robot , Thomas Gleixner , Adam Borowski , Alexander Shishkin , Anna-Maria Gleixner , Arnaldo Carvalho de Melo , Arnaldo Carvalho de Melo , Borislav Petkov , Jiri Olsa , Kan Liang , Linus Torvalds , Peter Zijlstra , Sebastian Andrzej Siewior , Stephane Eranian , Vince Weaver , lkp@01.org, tipbuild@zytor.com, Ingo Molnar Subject: [PATCH 4.6 85/96] cpu/hotplug: Keep enough storage space if SMP=n to avoid array out of bounds scribble Date: Mon, 8 Aug 2016 21:11:48 +0200 Message-Id: <20160808180247.635413096@linuxfoundation.org> In-Reply-To: <20160808180243.898163389@linuxfoundation.org> References: <20160808180243.898163389@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: 4.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Thomas Gleixner commit a7c734140aa36413944eef0f8c660e0e2256357d upstream. Xiaolong Ye reported lock debug warnings triggered by the following commit: 8de4a0066106 ("perf/x86: Convert the core to the hotplug state machine") The bug is the following: the cpuhp_bp_states[] array is cut short when CONFIG_SMP=n, but the dynamically registered callbacks are stored nevertheless and happily scribble outside of the array bounds... We need to store them in case that the state is unregistered so we can invoke the teardown function. That's independent of CONFIG_SMP. Make sure the array is large enough. Reported-by: kernel test robot Signed-off-by: Thomas Gleixner Cc: Adam Borowski Cc: Alexander Shishkin Cc: Anna-Maria Gleixner Cc: Arnaldo Carvalho de Melo Cc: Arnaldo Carvalho de Melo Cc: Borislav Petkov Cc: Jiri Olsa Cc: Kan Liang Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Sebastian Andrzej Siewior Cc: Stephane Eranian Cc: Vince Weaver Cc: lkp@01.org Cc: tipbuild@zytor.com Fixes: cff7d378d3fd "cpu/hotplug: Convert to a state machine for the control processor" Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1607122144560.4083@nanos Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman --- kernel/cpu.c | 2 ++ 1 file changed, 2 insertions(+) --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -1218,6 +1218,8 @@ static struct cpuhp_step cpuhp_bp_states .teardown = takedown_cpu, .cant_stop = true, }, +#else + [CPUHP_BRINGUP_CPU] = { }, #endif };