Vitezslav reported a case where the
"Timeout during microcode update!"
panic would hit. After a deeper look, it turned out that his .config had
CONFIG_HOTPLUG_CPU disabled which practically made save_mc_for_early() a
no-op.
When that happened, the discovered microcode patch wasn't saved into our
cache and the late loading path wouldn't find any.
This, then, lead to early exit from __reload_late() and thus CPUs
waiting until the timeout is reached, leading to the panic.
In hindsight, I should've made that function not return before the
post-synchronization. Oh well, I know better now...
Reported-by: Vitezslav Samel <vitezs...@samel.cz>
Signed-off-by: Borislav Petkov <b...@suse.de>
Cc: Ashok Raj <ashok....@intel.com>
Cc: <sta...@vger.kernel.org>
Fixes: bb8c13d61a62 ("x86/microcode: Fix CPU synchronization routine")
Link: http://lkml.kernel.org/r/20180418081140.ga2...@pc11.op.pod.cz
---
arch/x86/kernel/cpu/microcode/core.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/arch/x86/kernel/cpu/microcode/core.c
b/arch/x86/kernel/cpu/microcode/core.c
index 10c4fc2c91f8..77e201301528 100644
--- a/arch/x86/kernel/cpu/microcode/core.c
+++ b/arch/x86/kernel/cpu/microcode/core.c
@@ -564,14 +564,12 @@ static int __reload_late(void *info)
apply_microcode_local(&err);
spin_unlock(&update_lock);
+ /* siblings return UCODE_OK because their engine got updated already */
if (err > UCODE_NFOUND) {
pr_warn("Error reloading microcode on CPU %d\n", cpu);
- return -1;
- /* siblings return UCODE_OK because their engine got updated already */
+ ret = -1;
} else if (err == UCODE_UPDATED || err == UCODE_OK) {
ret = 1;
- } else {
- return ret;
}
/*
--
2.13.0
SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284
(AG Nürnberg)
--
