if during CPU hotplug master CPU failed to wake up AP
it set percpu x86_cpu_to_apicid to BAD_APICID=0xFFFF for AP.
However following attempt to unplug that CPU will lead to
out of bound write access to __apicid_to_node[] which is
32768 items long on x86_64 kernel.
So drop setting x86_cpu_to_apicid to BAD_APICID in do_boot_cpu()
and allow acpi_processor_remove()->acpi_unmap_lsapic() cleanly
remove CPU.
Signed-off-by: Igor Mammedov <imammedo@xxxxxxxxxx>
---
arch/x86/kernel/smpboot.c | 2 --
1 files changed, 0 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index e7c15d7..44903ad 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -821,8 +821,6 @@ static int do_boot_cpu(int apicid, int cpu, struct task_struct *idle)
udelay(100);
schedule();
}
- } else {
- per_cpu(x86_cpu_to_apicid, cpu) = BAD_APICID;
}
/* mark "stuck" area as not stuck */
--
1.7.1
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