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authorTony Luck <tony.luck@intel.com>2019-01-31 16:33:41 -0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-02-12 19:45:01 +0100
commitc2e3f4e632991fa8b6e8f00aae6ae0cb635bd67b (patch)
treed254e74e97081f43f2d9bc2f9ba2ff75c1be58ca
parent296c2f019a4bf230b4bc5f21bf0fbdc76584c102 (diff)
downloadlinux-linaro-stable-c2e3f4e632991fa8b6e8f00aae6ae0cb635bd67b.tar.gz
x86/MCE: Initialize mce.bank in the case of a fatal error in mce_no_way_out()
commit d28af26faa0b1daf3c692603d46bc4687c16f19e upstream. Internal injection testing crashed with a console log that said: mce: [Hardware Error]: CPU 7: Machine Check Exception: f Bank 0: bd80000000100134 This caused a lot of head scratching because the MCACOD (bits 15:0) of that status is a signature from an L1 data cache error. But Linux says that it found it in "Bank 0", which on this model CPU only reports L1 instruction cache errors. The answer was that Linux doesn't initialize "m->bank" in the case that it finds a fatal error in the mce_no_way_out() pre-scan of banks. If this was a local machine check, then this partially initialized struct mce is being passed to mce_panic(). Fix is simple: just initialize m->bank in the case of a fatal error. Fixes: 40c36e2741d7 ("x86/mce: Fix incorrect "Machine check from unknown source" message") Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vishal Verma <vishal.l.verma@intel.com> Cc: x86-ml <x86@kernel.org> Cc: stable@vger.kernel.org # v4.18 Note pre-v5.0 arch/x86/kernel/cpu/mce/core.c was called arch/x86/kernel/cpu/mcheck/mce.c Link: https://lkml.kernel.org/r/20190201003341.10638-1-tony.luck@intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--arch/x86/kernel/cpu/mcheck/mce.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
index 7e6163c9d434..25310d2b8609 100644
--- a/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/arch/x86/kernel/cpu/mcheck/mce.c
@@ -751,6 +751,7 @@ static int mce_no_way_out(struct mce *m, char **msg, unsigned long *validp,
quirk_no_way_out(i, m, regs);
if (mce_severity(m, mca_cfg.tolerant, &tmp, true) >= MCE_PANIC_SEVERITY) {
+ m->bank = i;
mce_read_aux(m, i);
*msg = tmp;
return 1;