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authorThomas Gleixner <tglx@linutronix.de>2016-07-12 21:59:23 +0200
committerIngo Molnar <mingo@kernel.org>2016-07-13 09:29:39 +0200
commita7c734140aa36413944eef0f8c660e0e2256357d (patch)
tree4042fca5f5e1c17f1f4e04aa12b21d1bdd177788 /kernel/cpu.c
parent0ea5ad869c85ac604f3e022bf2c5bef54838433b (diff)
downloadlinux-a7c734140aa36413944eef0f8c660e0e2256357d.tar.bz2
cpu/hotplug: Keep enough storage space if SMP=n to avoid array out of bounds scribble
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 <xiaolong.ye@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Adam Borowski <kilobyte@angband.pl> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Anna-Maria Gleixner <anna-maria@linutronix.de> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Borislav Petkov <bp@suse.de> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Kan Liang <kan.liang@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Stephane Eranian <eranian@google.com> Cc: Vince Weaver <vincent.weaver@maine.edu> Cc: lkp@01.org Cc: stable@vger.kernel.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 <mingo@kernel.org>
Diffstat (limited to 'kernel/cpu.c')
-rw-r--r--kernel/cpu.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/kernel/cpu.c b/kernel/cpu.c
index d948e44c471e..7b61887f7ccd 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -1201,6 +1201,8 @@ static struct cpuhp_step cpuhp_bp_states[] = {
.teardown = takedown_cpu,
.cant_stop = true,
},
+#else
+ [CPUHP_BRINGUP_CPU] = { },
#endif
};