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x86/mce: Do not overwrite no_way_out if mce_end() fails

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commit 25bc65d8ddfc17cc1d7a45bd48e9bdc0e729ced3 upstream.

Currently, if mce_end() fails, no_way_out - the variable denoting
whether the machine can recover from this MCE - is determined by whether
the worst severity that was found across the MCA banks associated with
the current CPU, is of panic severity.

However, at this point no_way_out could have been already set by
mca_start() after looking at all severities of all CPUs that entered the
MCE handler. If mce_end() fails, check first if no_way_out is already
set and, if so, stick to it, otherwise use the local worst value.

 [ bp: Massage. ]

Signed-off-by: Gabriele Paoloni <gabriele.paoloni@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20201127161819.3106432-2-gabriele.paoloni@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Gabriele Paoloni 2020-11-27 16:18:15 +00:00 committed by Greg Kroah-Hartman
parent 62405223ba
commit f753e1c02a
1 changed files with 4 additions and 2 deletions
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6
arch/x86/kernel/cpu/mce/core.c
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@ -1361,8 +1361,10 @@ void do_machine_check(struct pt_regs *regs, long error_code)
* When there's any problem use only local no_way_out state.
*/
if (!lmce) {
if (mce_end(order) < 0)
no_way_out = worst >= MCE_PANIC_SEVERITY;
if (mce_end(order) < 0) {
if (!no_way_out)
no_way_out = worst >= MCE_PANIC_SEVERITY;
}
} else {
/*
* If there was a fatal machine check we should have