Currently, the MCE subsystem sysfs interface will be removed if the
thresholding sysfs interface fails to be created. A common failure is
due to new MCA bank types that are not recognized and don't have a short
name set.

The MCA thresholding feature is optional and should not break the common
MCE sysfs interface. Also, new MCA bank types are occasionally
introduced, and updates will be needed to recognize them. But likewise,
this should not break the common sysfs interface.

Keep the MCE sysfs interface regardless of the status of the
thresholding sysfs interface.

Reviewed-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
Tested-by: Tony Luck <tony.luck@intel.com>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Cc: stable@vger.kernel.org
---

Notes:
    Link:
    https://lore.kernel.org/r/20250415-wip-mca-updates-v3-1-8ffd9eb4aa56@amd.com
    
    v3->v4:
    * No change.
    
    v2->v3:
    * Added tags from Qiuxu and Tony.
    
    v1->v2:
    * New in v2.
    * Included stable tag but there's no specific commit for Fixes.

 arch/x86/kernel/cpu/mce/core.c | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c
index e9b3c5d4a52e..07d61937427f 100644
--- a/arch/x86/kernel/cpu/mce/core.c
+++ b/arch/x86/kernel/cpu/mce/core.c
@@ -2801,15 +2801,9 @@ static int mce_cpu_dead(unsigned int cpu)
 static int mce_cpu_online(unsigned int cpu)
 {
 	struct timer_list *t = this_cpu_ptr(&mce_timer);
-	int ret;
 
 	mce_device_create(cpu);
-
-	ret = mce_threshold_create_device(cpu);
-	if (ret) {
-		mce_device_remove(cpu);
-		return ret;
-	}
+	mce_threshold_create_device(cpu);
 	mce_reenable_cpu();
 	mce_start_timer(t);
 	return 0;

-- 
2.49.0

The following commit has been merged into the ras/urgent branch of tip:

Commit-ID:     4c113a5b28bfd589e2010b5fc8867578b0135ed7
Gitweb:        https://git.kernel.org/tip/4c113a5b28bfd589e2010b5fc8867578b0135ed7
Author:        Yazen Ghannam <yazen.ghannam@amd.com>
AuthorDate:    Tue, 24 Jun 2025 14:15:56 
Committer:     Borislav Petkov (AMD) <bp@alien8.de>
CommitterDate: Thu, 26 Jun 2025 17:28:13 +02:00

x86/mce: Don't remove sysfs if thresholding sysfs init fails

Currently, the MCE subsystem sysfs interface will be removed if the
thresholding sysfs interface fails to be created. A common failure is due to
new MCA bank types that are not recognized and don't have a short name set.

The MCA thresholding feature is optional and should not break the common MCE
sysfs interface. Also, new MCA bank types are occasionally introduced, and
updates will be needed to recognize them. But likewise, this should not break
the common sysfs interface.

Keep the MCE sysfs interface regardless of the status of the thresholding
sysfs interface.

Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Tested-by: Tony Luck <tony.luck@intel.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/20250624-wip-mca-updates-v4-1-236dd74f645f@amd.com
---
 arch/x86/kernel/cpu/mce/core.c | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c
index e9b3c5d..07d6193 100644
--- a/arch/x86/kernel/cpu/mce/core.c
+++ b/arch/x86/kernel/cpu/mce/core.c
@@ -2801,15 +2801,9 @@ static int mce_cpu_dead(unsigned int cpu)
 static int mce_cpu_online(unsigned int cpu)
 {
 	struct timer_list *t = this_cpu_ptr(&mce_timer);
-	int ret;
 
 	mce_device_create(cpu);
-
-	ret = mce_threshold_create_device(cpu);
-	if (ret) {
-		mce_device_remove(cpu);
-		return ret;
-	}
+	mce_threshold_create_device(cpu);
 	mce_reenable_cpu();
 	mce_start_timer(t);
 	return 0;