From: Borislav Petkov <[email protected]> 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 <[email protected]> Cc: Sebastian Andrzej Siewior <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Yazen Ghannam <[email protected]> Fixes: 4d7b02d58c40 ("x86/mcheck: Split threshold_cpu_callback into two callbacks") --- arch/x86/kernel/cpu/mcheck/mce_amd.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/cpu/mcheck/mce_amd.c b/arch/x86/kernel/cpu/mcheck/mce_amd.c index 5c181610af58..bffc4253008b 100644 --- a/arch/x86/kernel/cpu/mcheck/mce_amd.c +++ b/arch/x86/kernel/cpu/mcheck/mce_amd.c @@ -1160,6 +1160,9 @@ 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); @@ -1168,8 +1171,6 @@ static __init int threshold_init_device(void) return err; } - thresholding_en = true; - return 0; } /* -- 2.10.0
