From: Mark Salter Date: Fri, 24 Mar 2017 13:53:56 +0000 (-0400) Subject: arm64: fix NULL dereference in have_cpu_die() X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=335d2c2d192266358c5dfa64953a4c162f46e464;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git arm64: fix NULL dereference in have_cpu_die() Commit 5c492c3f5255 ("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: 5c492c3f5255 ("arm64: smp: Add function to determine if cpus are stuck in the kernel") Signed-off-by: Mark Salter Signed-off-by: Will Deacon --- diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c index ef1caae02110..9b1036570586 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;