From 09e182d17e8891dd73baba961a0f5a82e9274c97 Mon Sep 17 00:00:00 2001 | |
From: Borislav Petkov <bp@suse.de> | |
Date: Sat, 21 Apr 2018 10:19:30 +0200 | |
Subject: x86/microcode: Do not exit early from __reload_late() | |
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 the | |
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, that function should have been written so it does not return | |
before the post-synchronization. Oh well, I know better now... | |
Fixes: bb8c13d61a62 ("x86/microcode: Fix CPU synchronization routine") | |
Reported-by: Vitezslav Samel <vitezslav@samel.cz> | |
Signed-off-by: Borislav Petkov <bp@suse.de> | |
Signed-off-by: Thomas Gleixner <tglx@linutronix.de> | |
Tested-by: Vitezslav Samel <vitezslav@samel.cz> | |
Tested-by: Ashok Raj <ashok.raj@intel.com> | |
Cc: stable@vger.kernel.org | |
Link: http://lkml.kernel.org/r/20180418081140.GA2439@pc11.op.pod.cz | |
Link: https://lkml.kernel.org/r/20180421081930.15741-2-bp@alien8.de | |
--- | |
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 10c4fc2..77e2013 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; | |
} | |
/* | |
-- | |
cgit v1.1 | |