When the kernel panics early for some unrelated reason there would be eventually an early exception inside panic because clear_local_APIC tried to disable the not yet mapped APIC. Check for that explicitely.
Signed-off-by: Andi Kleen <[EMAIL PROTECTED]> --- arch/x86/kernel/apic_32.c | 11 ++++++++--- arch/x86/kernel/apic_64.c | 9 +++++++-- 2 files changed, 15 insertions(+), 5 deletions(-) Index: linux/arch/x86/kernel/apic_32.c =================================================================== --- linux.orig/arch/x86/kernel/apic_32.c +++ linux/arch/x86/kernel/apic_32.c @@ -99,6 +99,8 @@ static DEFINE_PER_CPU(struct clock_event /* Local APIC was disabled by the BIOS and enabled by the kernel */ static int enabled_via_apicbase; +static unsigned long apic_phys; + /* * Get the LAPIC version */ @@ -616,9 +618,14 @@ int setup_profiling_timer(unsigned int m */ void clear_local_APIC(void) { - int maxlvt = lapic_get_maxlvt(); + int maxlvt; u32 v; + /* APIC hasn't been mapped yet */ + if (!apic_phys) + return; + + maxlvt = lapic_get_maxlvt(); /* * Masking an LVT entry can trigger a local APIC error * if the vector is zero. Mask LVTERR first to prevent this. @@ -1105,8 +1112,6 @@ no_apic: */ void __init init_apic_mappings(void) { - unsigned long apic_phys; - /* * If no local APIC can be found then set up a fake all * zeroes page to simulate the local APIC and another Index: linux/arch/x86/kernel/apic_64.c =================================================================== --- linux.orig/arch/x86/kernel/apic_64.c +++ linux/arch/x86/kernel/apic_64.c @@ -81,6 +81,8 @@ static struct clock_event_device lapic_c }; static DEFINE_PER_CPU(struct clock_event_device, lapic_events); +static unsigned long apic_phys; + /* * Get the LAPIC version */ @@ -516,6 +518,11 @@ void clear_local_APIC(void) int maxlvt = lapic_get_maxlvt(); u32 v; + /* APIC hasn't been mapped yet */ + if (!apic_phys) + return; + + maxlvt = lapic_get_maxlvt(); /* * Masking an LVT entry can trigger a local APIC error * if the vector is zero. Mask LVTERR first to prevent this. @@ -850,8 +857,6 @@ static int __init detect_init_APIC(void) */ void __init init_apic_mappings(void) { - unsigned long apic_phys; - /* * If no local APIC can be found then set up a fake all * zeroes page to simulate the local APIC and another -- 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/