| Date | Thu, 22 Apr 2010 12:09:03 -0700 | From | Greg KH <> | Subject | [092/197] x86: Fix double enable_IR_x2apic() call on SMP kernel on !SMP boards |
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2.6.32-stable review patch. If anyone has any objections, please let us know.
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From: Suresh Siddha <suresh.b.siddha@intel.com>
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 <suresh.b.siddha@intel.com> Cc: <jbarnes@virtuousgeek.org> Cc: <david.woodhouse@intel.com> Cc: <weidong.han@intel.com> Cc: <youquan.song@intel.com> Cc: <Jan.Grossmann@kielnet.net> LKML-Reference: <1270083887.7835.78.camel@sbs-t61.sc.intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- arch/x86/kernel/apic/apic.c | 2 ++ 1 file changed, 2 insertions(+)
--- a/arch/x86/kernel/apic/apic.c +++ b/arch/x86/kernel/apic/apic.c @@ -1664,8 +1664,10 @@ int __init APIC_init_uniprocessor(void) } #endif +#ifndef CONFIG_SMP enable_IR_x2apic(); default_setup_apic_routing(); +#endif verify_local_APIC(); connect_bsp_APIC();
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