Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 4.8 058/138] x86/smpboot: Init apic mapping before usage | Date | Wed, 9 Nov 2016 11:45:41 +0100 |
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4.8-stable review patch. If anyone has any objections, please let me know.
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From: Thomas Gleixner <tglx@linutronix.de>
commit 1e90a13d0c3dc94512af1ccb2b6563e8297838fa upstream.
The recent changes, which forced the registration of the boot cpu on UP systems, which do not have ACPI tables, have been fixed for systems w/o local APIC, but left a wreckage for systems which have neither ACPI nor mptables, but the CPU has an APIC, e.g. virtualbox.
The boot process crashes in prefill_possible_map() as it wants to register the boot cpu, which needs to access the local apic, but the local APIC is not yet mapped.
There is no reason why init_apic_mapping() can't be invoked before prefill_possible_map(). So instead of playing another silly early mapping game, as the ACPI/mptables code does, we just move init_apic_mapping() before the call to prefill_possible_map().
In hindsight, I should have noticed that combination earlier.
Sorry for the churn (also in stable)!
Fixes: ff8560512b8d ("x86/boot/smp: Don't try to poke disabled/non-existent APIC") Reported-and-debugged-by: Michal Necasek <michal.necasek@oracle.com> Reported-and-tested-by: Wolfgang Bauer <wbauer@tmo.at> Cc: prarit@redhat.com Cc: ville.syrjala@linux.intel.com Cc: michael.thayer@oracle.com Cc: knut.osmundsen@oracle.com Cc: frank.mehnert@oracle.com Cc: Borislav Petkov <bp@alien8.de> Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1610282114380.5053@nanos Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- arch/x86/kernel/setup.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
--- a/arch/x86/kernel/setup.c +++ b/arch/x86/kernel/setup.c @@ -1222,11 +1222,16 @@ void __init setup_arch(char **cmdline_p) if (smp_found_config) get_smp_config(); + /* + * Systems w/o ACPI and mptables might not have it mapped the local + * APIC yet, but prefill_possible_map() might need to access it. + */ + init_apic_mappings(); + prefill_possible_map(); init_cpu_to_node(); - init_apic_mappings(); io_apic_init_mappings(); kvm_guest_init();
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