From da63865a01c6384d459464e5165d95d4f04878d8 Mon Sep 17 00:00:00 2001 From: Boris Ostrovsky Date: Tue, 27 Jan 2015 21:21:09 -0500 Subject: [PATCH] x86, microcode: Return error from driver init code when loader is disabled Commits 65cef1311d5d ("x86, microcode: Add a disable chicken bit") and a18a0f6850d4 ("x86, microcode: Don't initialize microcode code on paravirt") allow microcode driver skip initialization when microcode loading is not permitted. However, they don't prevent the driver from being loaded since the init code returns 0. If at some point later the driver gets unloaded this will result in an oops while trying to deregister the (never registered) device. To avoid this, make init code return an error on paravirt or when microcode loading is disabled. The driver will then never be loaded. Signed-off-by: Boris Ostrovsky Link: http://lkml.kernel.org/r/1422411669-25147-1-git-send-email-boris.ostrovsky@oracle.com Reported-by: James Digwall Cc: stable@vger.kernel.org # 3.18 Signed-off-by: Borislav Petkov --- arch/x86/kernel/cpu/microcode/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c index 15c29096136b..36a83617eb21 100644 --- a/arch/x86/kernel/cpu/microcode/core.c +++ b/arch/x86/kernel/cpu/microcode/core.c @@ -552,7 +552,7 @@ static int __init microcode_init(void) int error; if (paravirt_enabled() || dis_ucode_ldr) - return 0; + return -EINVAL; if (c->x86_vendor == X86_VENDOR_INTEL) microcode_ops = init_intel_microcode(); -- 2.39.5