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 <[email protected]> Reported-by: James Digwall <[email protected]> Cc: [email protected] # 3.18 --- 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 15c2909..36a8361 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(); -- 1.9.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
