From: Borislav Petkov Date: Sat, 19 Nov 2016 10:34:02 +0000 (+0100) Subject: x86/MCE/AMD: Fix thinko about thresholding_en X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=254fe9c7a4187ebf5ce23e0ca0e9ba98b1dbef18;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git x86/MCE/AMD: Fix thinko about thresholding_en So adding thresholding_en et al was a good thing for removing the per-CPU thresholding callback, i.e., threshold_cpu_callback. But, in order for it to work and especially that test in mce_threshold_create_device() so that all thresholding banks get properly created and not the whole thing to fail with a NULL ptr dereference at mce_cpu_pre_down() when we offline the CPUs, we need to set the thresholding_en flag *before* we start creating the devices. Yap, it failed because thresholding_en wasn't set at the time we were creating the banks so we didn't create any and then at mce_cpu_pre_down() -> mce_threshold_remove_device() time, we would blow up. And the fix is actually easy: we have thresholding on the system when we have managed to set the thresholding vector to amd_threshold_interrupt() earlier in mce_amd_feature_init() while we were picking apart the thresholding banks and what is set and what not. So let's do that. Signed-off-by: Borislav Petkov Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Sebastian Andrzej Siewior Cc: Thomas Gleixner Cc: Yazen Ghannam Fixes: 4d7b02d58c40 ("x86/mcheck: Split threshold_cpu_callback into two callbacks") Link: http://lkml.kernel.org/r/20161119103402.5227-1-bp@alien8.de Signed-off-by: Ingo Molnar --- diff --git a/arch/x86/kernel/cpu/mcheck/mce_amd.c b/arch/x86/kernel/cpu/mcheck/mce_amd.c index c33a3ee2e383..4e82e5324063 100644 --- a/arch/x86/kernel/cpu/mcheck/mce_amd.c +++ b/arch/x86/kernel/cpu/mcheck/mce_amd.c @@ -1134,6 +1134,9 @@ static __init int threshold_init_device(void) { unsigned lcpu = 0; + if (mce_threshold_vector == amd_threshold_interrupt) + thresholding_en = true; + /* to hit CPUs online before the notifier is up */ for_each_online_cpu(lcpu) { int err = mce_threshold_create_device(lcpu); @@ -1142,8 +1145,6 @@ static __init int threshold_init_device(void) return err; } - thresholding_en = true; - return 0; } /*