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fix: crash: IP: __bitmap_intersects+0x48/0x73 

-tip testing found this crash:

> [   35.258515] calling  acpi_cpufreq_init+0x0/0x127 @ 1
> [   35.264127] BUG: unable to handle kernel NULL pointer dereference at (null)
> [   35.267554] IP: [<ffffffff80478092>] __bitmap_intersects+0x48/0x73
> [   35.267554] PGD 0
> [   35.267554] Oops: 0000 [#1] SMP DEBUG_PAGEALLOC

arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c is still broken: there's no
allocation of the variable mask, so we pass in an uninitialized cmd.mask
field to drv_read(), which then passes it to the scheduler which then
crashes ...

Switch it over to the much simpler constant-cpumask-pointers approach.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
wifi-calibration
Ingo Molnar 2009-01-15 15:46:08 +01:00
parent 7285908185
commit bfa318ad52
1 changed files with 4 additions and 7 deletions
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11
arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c
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@ -145,7 +145,7 @@ typedef union {
struct drv_cmd {
unsigned int type;
cpumask_var_t mask;
const struct cpumask *mask;
drv_addr_union addr;
u32 val;
};
@ -231,6 +231,7 @@ static u32 get_cur_val(const struct cpumask *mask)
return 0;
}
cmd.mask = mask;
drv_read(&cmd);
dprintk("get_cur_val = %u\n", cmd.val);
@ -397,9 +398,6 @@ static int acpi_cpufreq_target(struct cpufreq_policy *policy,
return -ENODEV;
}
if (unlikely(!alloc_cpumask_var(&cmd.mask, GFP_KERNEL)))
return -ENOMEM;
perf = data->acpi_data;
result = cpufreq_frequency_table_target(policy,
data->freq_table,
@ -444,9 +442,9 @@ static int acpi_cpufreq_target(struct cpufreq_policy *policy,
/* cpufreq holds the hotplug lock, so we are safe from here on */
if (policy->shared_type != CPUFREQ_SHARED_TYPE_ANY)
cpumask_and(cmd.mask, cpu_online_mask, policy->cpus);
cmd.mask = policy->cpus;
else
cpumask_copy(cmd.mask, cpumask_of(policy->cpu));
cmd.mask = cpumask_of(policy->cpu);
freqs.old = perf->states[perf->state].core_frequency * 1000;
freqs.new = data->freq_table[next_state].frequency;
@ -473,7 +471,6 @@ static int acpi_cpufreq_target(struct cpufreq_policy *policy,
perf->state = next_perf_state;
out:
free_cpumask_var(cmd.mask);
return result;
}