The following commit has been merged into the x86/urgent branch of tip:

Commit-ID: 25bc65d8ddfc17cc1d7a45bd48e9bdc0e729ced3 Gitweb: https://git.kernel.org/tip/25bc65d8ddfc17cc1d7a45bd48e9bdc0e729ced3 Author: Gabriele Paoloni gabriele.paoloni@intel.com AuthorDate: Fri, 27 Nov 2020 16:18:15 Committer: Borislav Petkov bp@suse.de CommitterDate: Fri, 27 Nov 2020 17:38:36 +01:00

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

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.co... --- arch/x86/kernel/cpu/mce/core.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c index 4102b86..32b7099 100644 --- a/arch/x86/kernel/cpu/mce/core.c +++ b/arch/x86/kernel/cpu/mce/core.c @@ -1384,8 +1384,10 @@ noinstr void do_machine_check(struct pt_regs *regs) * 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