From: Borislav Petkov <[email protected]>
Derek noticed that a critical MCE gets reported with the wrong error message:
[Hardware Error]: CPU 34: Machine Check Exception: 5 Bank 9: f200003f000100b0
[Hardware Error]: RIP !INEXACT! 10:<ffffffff812e14c1> {intel_idle+0xb1/0x170}
[Hardware Error]: TSC 49587b8e321cb
[Hardware Error]: PROCESSOR 0:306e4 TIME 1431561296 SOCKET 1 APIC 29
[Hardware Error]: Some CPUs didn't answer in synchronization
[Hardware Error]: Machine check: Invalid
^^^^^^^
due to the fact that mce_no_way_out() iterates over all MCA banks
and possibly overwrites the @msg argument which is used in the panic
printing later.
Change behavior to take the message of only and the (last) critical MCE
it detects.
Reported-by: Derek <[email protected]>
Signed-off-by: Borislav Petkov <[email protected]>
Cc: Tony Luck <[email protected]>
Cc: <[email protected]>
---
arch/x86/kernel/cpu/mcheck/mce.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
index 521e5016aca6..4d450ac74e3d 100644
--- a/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/arch/x86/kernel/cpu/mcheck/mce.c
@@ -708,6 +708,7 @@ static int mce_no_way_out(struct mce *m, char **msg,
unsigned long *validp,
struct pt_regs *regs)
{
int i, ret = 0;
+ char *tmp;
for (i = 0; i < mca_cfg.banks; i++) {
m->status = mce_rdmsrl(MSR_IA32_MCx_STATUS(i));
@@ -716,9 +717,11 @@ static int mce_no_way_out(struct mce *m, char **msg,
unsigned long *validp,
if (quirk_no_way_out)
quirk_no_way_out(i, m, regs);
}
- if (mce_severity(m, mca_cfg.tolerant, msg, true) >=
- MCE_PANIC_SEVERITY)
+
+ if (mce_severity(m, mca_cfg.tolerant, &tmp, true) >=
MCE_PANIC_SEVERITY) {
+ *msg = tmp;
ret = 1;
+ }
}
return ret;
}
--
2.3.5
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