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authorYazen Ghannam <yazen.ghannam@amd.com>2017-11-06 18:46:32 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-11-21 09:23:30 +0100
commit54a5155afa84d39d4fa92b775213f46f334625b9 (patch)
treeb9403c1a85e70b1d3e4f83639880f0f5da6f9ad9 /arch
parentf6643fc829e03dae653106c981c7edfa4a356162 (diff)
x86/MCE/AMD: Always give panic severity for UC errors in kernel context
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>
Diffstat (limited to 'arch')
-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 631356c8cca4..f46071cb2c90 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 {