From e5f509bf8e83b274b464ea02d79a1bdc648ea3ba Mon Sep 17 00:00:00 2001 From: Suresh Siddha Date: Wed, 31 Mar 2010 18:04:47 -0700 Subject: [PATCH] x86: Fix double enable_IR_x2apic() call on SMP kernel on !SMP boards commit 472a474c6630efd195d3738339fd1bdc8aa3b1aa upstream. Jan Grossmann reported kernel boot panic while booting SMP kernel on his system with a single core cpu. SMP kernels call enable_IR_x2apic() from native_smp_prepare_cpus() and on platforms where the kernel doesn't find SMP configuration we ended up again calling enable_IR_x2apic() from the APIC_init_uniprocessor() call in the smp_sanity_check(). Thus leading to kernel panic. Don't call enable_IR_x2apic() and default_setup_apic_routing() from APIC_init_uniprocessor() in CONFIG_SMP case. NOTE: this kind of non-idempotent and assymetric initialization sequence is rather fragile and unclean, we'll clean that up in v2.6.35. This is the minimal fix for v2.6.34. Reported-by: Jan.Grossmann@kielnet.net Signed-off-by: Suresh Siddha Cc: Cc: Cc: Cc: Cc: LKML-Reference: <1270083887.7835.78.camel@sbs-t61.sc.intel.com> Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/apic/apic.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c index dfca210f6a10..d4df51725290 100644 --- a/arch/x86/kernel/apic/apic.c +++ b/arch/x86/kernel/apic/apic.c @@ -1640,8 +1640,10 @@ int __init APIC_init_uniprocessor(void) } #endif +#ifndef CONFIG_SMP enable_IR_x2apic(); default_setup_apic_routing(); +#endif verify_local_APIC(); connect_bsp_APIC(); -- 2.39.5