Messages in this thread Patch in this message |  | | From | Borislav Petkov <> | Subject | [PATCH 2/2] x86/microcode: Do not exit early from __reload_late() | Date | Sat, 21 Apr 2018 10:19:30 +0200 |
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From: Borislav Petkov <bp@suse.de>
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 <vitezslav@samel.cz> Tested-by: Vitezslav Samel <vitezslav@samel.cz> Tested-by: Ashok Raj <ashok.raj@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Cc: <stable@vger.kernel.org> Fixes: bb8c13d61a62 ("x86/microcode: Fix CPU synchronization routine") Link: http://lkml.kernel.org/r/20180418081140.GA2439@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
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