From a90110c61073eab95d1986322693c2b9a8a6a5f6 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Sun, 21 Mar 2010 21:51:51 +0100 Subject: [PATCH] x86 / perf: Fix suspend to RAM on HP nx6325 Commit 3f6da3905398826d85731247e7fbcf53400c18bd (perf: Rework and fix the arch CPU-hotplug hooks) broke suspend to RAM on my HP nx6325 (and most likely on other AMD-based boxes too) by allowing amd_pmu_cpu_offline() to be executed for CPUs that are going offline as part of the suspend process. The problem is that cpuhw->amd_nb may be NULL already, so the function should make sure it's not NULL before accessing the object pointed to by it. Signed-off-by: Rafael J. Wysocki Signed-off-by: Linus Torvalds --- arch/x86/kernel/cpu/perf_event_amd.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/cpu/perf_event_amd.c b/arch/x86/kernel/cpu/perf_event_amd.c index 573458f1caf2..b87e0b6970cb 100644 --- a/arch/x86/kernel/cpu/perf_event_amd.c +++ b/arch/x86/kernel/cpu/perf_event_amd.c @@ -348,10 +348,12 @@ static void amd_pmu_cpu_offline(int cpu) raw_spin_lock(&amd_nb_lock); - if (--cpuhw->amd_nb->refcnt == 0) - kfree(cpuhw->amd_nb); + if (cpuhw->amd_nb) { + if (--cpuhw->amd_nb->refcnt == 0) + kfree(cpuhw->amd_nb); - cpuhw->amd_nb = NULL; + cpuhw->amd_nb = NULL; + } raw_spin_unlock(&amd_nb_lock); } -- 2.20.1