x86/MCE/AMD: Fix thinko about thresholding_en
Borislav Petkov
maintainerPATCH 1/1 x86/MCE/AMD: Fix thinko about thresholding_en
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.
--- arch/x86/kernel/cpu/mcheck/mce_amd.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
arch/x86/kernel/cpu/mcheck/mce_amd.c +3 -2
@@ -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 ; }/*
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2.10.0
tip-bot for Borislav Petkov
merge botx86/MCE/AMD: Fix thinko about thresholding_en
Commit-ID: 254fe9c7a4187ebf5ce23e0ca0e9ba98b1dbef18 Gitweb: http://git.kernel.org/tip/254fe9c7a4187ebf5ce23e0ca0e9ba98b1dbef18 Author: Borislav Petkov <[email protected]> AuthorDate: Sat, 19 Nov 2016 11:34:02 +0100 Committer: Ingo Molnar <[email protected]> CommitDate: Mon, 21 Nov 2016 11:02:12 +0100
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.
--- arch/x86/kernel/cpu/mcheck/mce_amd.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
arch/x86/kernel/cpu/mcheck/mce_amd.c +3 -2
@@ -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 ; }/*