[lkml]   [2016]   [Nov]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
Patch in this message
Subject[PATCH] x86/MCE/AMD: Fix thinko about thresholding_en
From: Borislav Petkov <>

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

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: Sebastian Andrzej Siewior <>
Cc: Thomas Gleixner <>
Cc: Yazen Ghannam <>
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;
 \ /
  Last update: 2016-11-19 11:35    [W:0.069 / U:0.416 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site