From 368dfe10dabe89d0494012624845a1714390bd32 Mon Sep 17 00:00:00 2001 From: Mark Salter Date: Fri, 24 Mar 2017 09:53:56 -0400 Subject: [PATCH] arm64: fix NULL dereference in have_cpu_die() Commit c020d9654c3e ("arm64: smp: Add function to determine if cpus are stuck in the kernel") added a helper function to determine if die() is supported in cpu_ops. This function assumes a cpu will have a valid cpu_ops entry, but that may not be the case for cpu0 is spin-table or parking protocol is used to boot secondary cpus. In that case, there is a NULL dereference if have_cpu_die() is called by cpu0. So add a check for a valid cpu_ops before dereferencing it. Fixes: c020d9654c3e ("arm64: smp: Add function to determine if cpus are stuck in the kernel") Signed-off-by: Mark Salter Signed-off-by: Will Deacon --- arch/arm64/kernel/smp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c index ef1caae02110e..9b1036570586f 100644 --- a/arch/arm64/kernel/smp.c +++ b/arch/arm64/kernel/smp.c @@ -944,7 +944,7 @@ static bool have_cpu_die(void) #ifdef CONFIG_HOTPLUG_CPU int any_cpu = raw_smp_processor_id(); - if (cpu_ops[any_cpu]->cpu_die) + if (cpu_ops[any_cpu] && cpu_ops[any_cpu]->cpu_die) return true; #endif return false; -- 2.39.5