From: Borislav Petkov Date: Sat, 21 Apr 2018 08:19:30 +0000 (+0200) Subject: x86/microcode: Do not exit early from __reload_late() X-Git-Tag: v4.14.39~4 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=922e5129eb011ebbc62c416bc1c423a20ae359d7;p=platform%2Fkernel%2Flinux-exynos.git 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 Signed-off-by: Borislav Petkov Signed-off-by: Thomas Gleixner Tested-by: Vitezslav Samel Tested-by: Ashok Raj 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 --- diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c index 021c904..c8e0cda 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; } /*