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cpumask: fix CONFIG_CPUMASK_OFFSTACK=y cpu hotunplug crash

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Impact: Fix cpu offline when CONFIG_MAXSMP=y

Changeset bc9b83dd1f "cpumask: convert
c1e_mask in arch/x86/kernel/process.c to cpumask_var_t" contained a
bug: c1e_mask is manipulated even if C1E isn't detected (and hence
not allocated).

This is simply fixed by checking for NULL (which gcc optimizes out
anyway of CONFIG_CPUMASK_OFFSTACK=n, since it knows ce1_mask can never
be NULL).

In addition, fix a leak where select_idle_routine re-allocates
(and re-clears) c1e_mask on every cpu init.

Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Mike Travis <travis@sgi.com>
LKML-Reference: <200903171450.34549.rusty@rustcorp.com.au>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Rusty Russell 2009-03-17 14:50:34 +10:30 committed by Ingo Molnar
parent 082edb7bf4
commit 30e1e6d1af
3 changed files with 13 additions and 3 deletions
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1
arch/x86/include/asm/processor.h
View File

@ -733,6 +733,7 @@ static inline void __sti_mwait(unsigned long eax, unsigned long ecx)
extern void mwait_idle_with_hints(unsigned long eax, unsigned long ecx);
extern void select_idle_routine(const struct cpuinfo_x86 *c);
extern void init_c1e_mask(void);
extern unsigned long boot_option_idle_override;
extern unsigned long idle_halt;

1
arch/x86/kernel/cpu/common.c
View File

@ -812,6 +812,7 @@ static void vgetcpu_set_mode(void)
void __init identify_boot_cpu(void)
{
identify_cpu(&boot_cpu_data);
init_c1e_mask();
#ifdef CONFIG_X86_32
sysenter_setup();
enable_sep_cpu();

14
arch/x86/kernel/process.c
View File

@ -479,7 +479,8 @@ static int c1e_detected;
void c1e_remove_cpu(int cpu)
{
cpumask_clear_cpu(cpu, c1e_mask);
if (c1e_mask != NULL)
cpumask_clear_cpu(cpu, c1e_mask);
}
/*
@ -556,13 +557,20 @@ void __cpuinit select_idle_routine(const struct cpuinfo_x86 *c)
pm_idle = mwait_idle;
} else if (check_c1e_idle(c)) {
printk(KERN_INFO "using C1E aware idle routine\n");
alloc_cpumask_var(&c1e_mask, GFP_KERNEL);
cpumask_clear(c1e_mask);
pm_idle = c1e_idle;
} else
pm_idle = default_idle;
}
void __init init_c1e_mask(void)
{
/* If we're using c1e_idle, we need to allocate c1e_mask. */
if (pm_idle == c1e_idle) {
alloc_cpumask_var(&c1e_mask, GFP_KERNEL);
cpumask_clear(c1e_mask);
}
}
static int __init idle_setup(char *str)
{
if (!str)