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

JIRA: https://issues.redhat.com/browse/RHEL-117597

commit 4c113a5
Author: Yazen Ghannam <yazen.ghannam@amd.com>
Date:   Tue Jun 24 14:15:56 2025 +0000

    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

Signed-off-by: Steve Best <sbest@redhat.com>

Author: sfbest

arch/x86/kernel/cpu/mce/core.c

@@ -2756,15 +2756,9 @@ 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;