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authorYazen Ghannam <yazen.ghannam@amd.com>2017-11-06 20:46:32 +0300
committerIngo Molnar <mingo@kernel.org>2017-11-07 13:07:50 +0300
commitd65dfc81bb3894fdb68cbc74bbf5fb48d2354071 (patch)
tree30d63ef8df0721357608bda244c836368c92d589 /arch/x86
parent92bb6cb1403015b1b9520332c8f2ad983c220f67 (diff)
downloadlinux-d65dfc81bb3894fdb68cbc74bbf5fb48d2354071.tar.xz
x86/MCE/AMD: Always give panic severity for UC errors in kernel context
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: <stable@vger.kernel.org> # 4.9.x 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>
Diffstat (limited to 'arch/x86')
-rw-r--r--arch/x86/kernel/cpu/mcheck/mce-severity.c7
1 files changed, 3 insertions, 4 deletions
diff --git a/arch/x86/kernel/cpu/mcheck/mce-severity.c b/arch/x86/kernel/cpu/mcheck/mce-severity.c
index 87cc9ab7a13c..4b8187639c2d 100644
--- 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 *m, int tolerant, char **msg, bool is_exc
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 *m, int tolerant, char **msg, bool is_exc
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 {