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Commit bd9e0b74 authored by Shaohua Li's avatar Shaohua Li Committed by Linus Torvalds
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[PATCH] x86: cpu_init(): avoid GFP_KERNEL allocation while atomic 



The patch fixes two issues:

1.  cpu_init is called with interrupt disabled.  Allocating gdt table
   there isn't good at runtime.

2. gdt table page cause memory leak in CPU hotplug case.

Signed-off-by: default avatarShaohua Li <shaohua.li@intel.com>
Cc: Ashok Raj <ashok.raj@intel.com>
Cc: Zachary Amsden <zach@vmware.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 28eba5bf

arch/i386/kernel/cpu/common.c

+7 −1
Original line number Diff line number Diff line
@@ -613,6 +613,12 @@ void __cpuinit cpu_init(void) 
		set_in_cr4(X86_CR4_TSD);

	}



	/* The CPU hotplug case */

	if (cpu_gdt_descr->address) {

		gdt = (struct desc_struct *)cpu_gdt_descr->address;

		memset(gdt, 0, PAGE_SIZE);

		goto old_gdt;

	}

	/*

	 * This is a horrible hack to allocate the GDT.  The problem

	 * is that cpu_init() is called really early for the boot CPU
@@ -631,7 +637,7 @@ void __cpuinit cpu_init(void) 
				local_irq_enable();

		}

	}



old_gdt:

	/*

	 * Initialize the per-CPU GDT with the boot GDT,

	 * and set up the GDT descriptor:

arch/i386/kernel/smpboot.c

+13 −0
Original line number Diff line number Diff line
@@ -1056,6 +1056,7 @@ static int __cpuinit __smp_prepare_cpu(int cpu) 
	struct warm_boot_cpu_info info;

	struct work_struct task;

	int	apicid, ret;

	struct Xgt_desc_struct *cpu_gdt_descr = &per_cpu(cpu_gdt_descr, cpu);



	apicid = x86_cpu_to_apicid[cpu];

	if (apicid == BAD_APICID) {
@@ -1063,6 +1064,18 @@ static int __cpuinit __smp_prepare_cpu(int cpu) 
		goto exit;

	}



	/*

	 * the CPU isn't initialized at boot time, allocate gdt table here.

	 * cpu_init will initialize it

	 */

	if (!cpu_gdt_descr->address) {

		cpu_gdt_descr->address = get_zeroed_page(GFP_KERNEL);

		if (!cpu_gdt_descr->address)

			printk(KERN_CRIT "CPU%d failed to allocate GDT\n", cpu);

			ret = -ENOMEM;

			goto exit;

	}



	info.complete = &done;

	info.apicid = apicid;

	info.cpu = cpu;