Messages in this thread Patch in this message | | | Date | Wed, 26 Aug 2009 16:20:36 +0900 | From | Hidetoshi Seto <> | Subject | [PATCH -tip] x86, mce: CE in last bank prevents panic by unknown MCE |
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[based on tip/x86/mce]
If MCE handler is called but none of mces_seen have machine check event which might signal the MCE (i.e. event higher than MCE_KEEP_SEVERITY), panic with "Machine check from unknown source" will be taken since the MCE is assumed to be signaled from external agent or so.
Usually mces_seen never point MCE_KEEP_SEVERITY event such as CE. But it can happen because initial value of mces_seen is accidentally modified by mce_no_way_out() - in case if mce_no_way_out() run through all banks and the last bank has the CE, mces_seen points the CE and the "panic by unknown" will not be taken.
This patch fix this undesired behavior, and clarify the logic.
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com> Reported-by: Jin Dongming <jin.dongming@np.css.fujitsu.com>
--- arch/x86/kernel/cpu/mcheck/mce.c | 6 +++--- 1 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c index 54bd1b2..7b485e9 100644 --- a/arch/x86/kernel/cpu/mcheck/mce.c +++ b/arch/x86/kernel/cpu/mcheck/mce.c @@ -665,7 +665,7 @@ static void mce_reign(void) * No machine check event found. Must be some external * source or one CPU is hung. Panic. */ - if (!m && tolerant < 3) + if (global_worst <= MCE_KEEP_SEVERITY && tolerant < 3) mce_panic("Machine check from unknown source", NULL, NULL); /* @@ -889,11 +889,11 @@ void do_machine_check(struct pt_regs *regs, long error_code) mce_setup(&m); m.mcgstatus = mce_rdmsrl(MSR_IA32_MCG_STATUS); - no_way_out = mce_no_way_out(&m, &msg); - final = &__get_cpu_var(mces_seen); *final = m; + no_way_out = mce_no_way_out(&m, &msg); + barrier(); /* -- 1.6.4.1
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