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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 19:47:26 +0100
commit5b27e3bc5a2bdf58ff0aedacd194c3ed86821f07 (patch)
treef3c5ca2d0ddf23271111e642f0098a38304fd5fe
parent4e6bfd756f8e855a74d50d4d8a0125b7fa077566 (diff)
downloadlinux-linaro-stable-5b27e3bc5a2bdf58ff0aedacd194c3ed86821f07.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 cdbedeb3f3db..f9e7096b1804 100644
--- a/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/arch/x86/kernel/cpu/mcheck/mce.c
@@ -783,6 +783,7 @@ 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;