[PATCH 5/6] x86-mce: check if no_way_out applies before deciding not to clear MCE banks.

From: Havard Skinnemoen
Date: Wed Jul 09 2014 - 13:10:17 EST


From: Ewout van Bekkum <ewout@xxxxxxxxxx>

The machine check handler, do_machine_check(), has a sanity check before
clearing the MCE banks in case the system has no_way_out and has to
crash. However, this sanity check does not take into account the
configured MCE tolerant level as the system may still keep running. The
sanity check was updated to check if the system has no_way_out and that
no_way_out is relevant (tolerant level is less than 3).

Signed-off-by: Ewout van Bekkum <ewout@xxxxxxxxxx>
Signed-off-by: Havard Skinnemoen <hskinnemoen@xxxxxxxxxx>
---
arch/x86/kernel/cpu/mcheck/mce.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
index 64270d7..1587b18 100644
--- a/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/arch/x86/kernel/cpu/mcheck/mce.c
@@ -1153,7 +1153,7 @@ void do_machine_check(struct pt_regs *regs, long error_code)
/* mce_clear_state will clear *final, save locally for use later */
m = *final;

- if (!no_way_out)
+ if (!(no_way_out && cfg->tolerant < 3))
mce_clear_state(toclear);

/*
--
2.0.0.526.g5318336

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