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| author | Borislav Petkov <bp@suse.de> | 2018-04-21 10:19:30 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2018-04-24 09:48:22 +0200 |
| commit | 09e182d17e8891dd73baba961a0f5a82e9274c97 (patch) | |
| tree | 731cf6211c5938540c74d3703cfd4fe320314db8 /arch | |
| parent | 84749d83758af6576552046b215b9b7f37f9556b (diff) | |
| download | linux-0-day-09e182d17e8891dd73baba961a0f5a82e9274c97.tar.gz linux-0-day-09e182d17e8891dd73baba961a0f5a82e9274c97.tar.xz | |
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
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kernel/cpu/microcode/core.c | 6 |
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 10c4fc2c91f8e..77e2013015288 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; } /* |