| From d65dfc81bb3894fdb68cbc74bbf5fb48d2354071 Mon Sep 17 00:00:00 2001 |
| From: Yazen Ghannam <yazen.ghannam@amd.com> |
| Date: Mon, 6 Nov 2017 18:46:32 +0100 |
| Subject: x86/MCE/AMD: Always give panic severity for UC errors in kernel context |
| |
| From: Yazen Ghannam <yazen.ghannam@amd.com> |
| |
| commit d65dfc81bb3894fdb68cbc74bbf5fb48d2354071 upstream. |
| |
| The AMD severity grading function was introduced in kernel 4.1. The |
| current logic can possibly give MCE_AR_SEVERITY for uncorrectable |
| errors in kernel context. The system may then get stuck in a loop as |
| memory_failure() will try to handle the bad kernel memory and find it |
| busy. |
| |
| Return MCE_PANIC_SEVERITY for all UC errors IN_KERNEL context on AMD |
| systems. |
| |
| After: |
| |
| b2f9d678e28c ("x86/mce: Check for faults tagged in EXTABLE_CLASS_FAULT exception table entries") |
| |
| was accepted in v4.6, this issue was masked because of the tail-end attempt |
| at kernel mode recovery in the #MC handler. |
| |
| However, uncorrectable errors IN_KERNEL context should always be considered |
| unrecoverable and cause a panic. |
| |
| Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com> |
| Signed-off-by: Borislav Petkov <bp@suse.de> |
| Cc: Linus Torvalds <torvalds@linux-foundation.org> |
| Cc: Peter Zijlstra <peterz@infradead.org> |
| Cc: Thomas Gleixner <tglx@linutronix.de> |
| Cc: Tony Luck <tony.luck@intel.com> |
| Cc: linux-edac <linux-edac@vger.kernel.org> |
| Fixes: bf80bbd7dcf5 (x86/mce: Add an AMD severities-grading function) |
| Link: http://lkml.kernel.org/r/20171106174633.13576-1-bp@alien8.de |
| Signed-off-by: Ingo Molnar <mingo@kernel.org> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| arch/x86/kernel/cpu/mcheck/mce-severity.c | 7 +++---- |
| 1 file changed, 3 insertions(+), 4 deletions(-) |
| |
| --- a/arch/x86/kernel/cpu/mcheck/mce-severity.c |
| +++ b/arch/x86/kernel/cpu/mcheck/mce-severity.c |
| @@ -245,6 +245,9 @@ static int mce_severity_amd(struct mce * |
| |
| if (m->status & MCI_STATUS_UC) { |
| |
| + if (ctx == IN_KERNEL) |
| + return MCE_PANIC_SEVERITY; |
| + |
| /* |
| * On older systems where overflow_recov flag is not present, we |
| * should simply panic if an error overflow occurs. If |
| @@ -255,10 +258,6 @@ static int mce_severity_amd(struct mce * |
| if (mce_flags.smca) |
| return mce_severity_amd_smca(m, ctx); |
| |
| - /* software can try to contain */ |
| - if (!(m->mcgstatus & MCG_STATUS_RIPV) && (ctx == IN_KERNEL)) |
| - return MCE_PANIC_SEVERITY; |
| - |
| /* kill current process */ |
| return MCE_AR_SEVERITY; |
| } else { |
