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authorBorislav Petkov <bp@suse.de>2018-04-21 10:19:30 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-05-01 12:58:26 -0700
commit922e5129eb011ebbc62c416bc1c423a20ae359d7 (patch)
parent7c6bcaac737fa72dd8aef00cb38b9c96b9b04cd8 (diff)
x86/microcode: Do not exit early from __reload_late()
commit 09e182d17e8891dd73baba961a0f5a82e9274c97 upstream. 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 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1 files changed, 2 insertions, 4 deletions
diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c
index 021c90464cc2..c8e0cda0f272 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)
+ /* 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;