5.4-stable review patch. If anyone has any objections, please let me know.
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From: JP Kobryn inwardvessel@gmail.com
commit 30ad231a5029bfa16e46ce868497b1a5cdd3c24d upstream.
CMCI banks are not cleared during shutdown on Intel CPUs. As a side effect, when a kexec is performed, CPUs coming back online are unable to rediscover/claim these occupied banks which breaks MCE reporting.
Clear the CPU ownership during shutdown via cmci_clear() so the banks can be reclaimed and MCE reporting will become functional once more.
[ bp: Massage commit message. ]
Reported-by: Aijay Adams aijay@meta.com Signed-off-by: JP Kobryn inwardvessel@gmail.com Signed-off-by: Borislav Petkov (AMD) bp@alien8.de Reviewed-by: Tony Luck tony.luck@intel.com Reviewed-by: Qiuxu Zhuo qiuxu.zhuo@intel.com Cc: stable@kernel.org Link: https://lore.kernel.org/20250627174935.95194-1-inwardvessel@gmail.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/x86/kernel/cpu/mce/intel.c | 1 + 1 file changed, 1 insertion(+)
--- a/arch/x86/kernel/cpu/mce/intel.c +++ b/arch/x86/kernel/cpu/mce/intel.c @@ -516,4 +516,5 @@ void mce_intel_feature_init(struct cpuin void mce_intel_feature_clear(struct cpuinfo_x86 *c) { intel_clear_lmce(); + cmci_clear(); }