@@ -69,11 +69,11 @@ static DEFINE_PER_CPU(struct cpu_flags, cpu_flags);
static void init_cpu_flags(void *dummy)
{
int cpu = smp_processor_id();
- struct cpu_flags *flags = &per_cpu(cpu_flags, cpu);
+ struct cpu_flags flags;
struct cpuinfo_x86 *c = &cpu_data(cpu);
unsigned int eax, ebx, ecx, edx;
- memcpy(flags->val, c->x86_capability, NCAPINTS * sizeof(u32));
+ memcpy(&flags, c->x86_capability, sizeof(flags));
/*
* Clear feature bits masked using cpuid masking/faulting.
@@ -81,26 +81,27 @@ static void init_cpu_flags(void *dummy)
if (c->cpuid_level >= 0x00000001) {
__do_cpuid_fault(0x00000001, 0, &eax, &ebx, &ecx, &edx);
- flags->val[4] &= ecx;
- flags->val[0] &= edx;
+ flags.val[4] &= ecx;
+ flags.val[0] &= edx;
}
if (c->cpuid_level >= 0x00000007) {
__do_cpuid_fault(0x00000007, 0, &eax, &ebx, &ecx, &edx);
- flags->val[9] &= ebx;
+ flags.val[9] &= ebx;
}
if ((c->extended_cpuid_level & 0xffff0000) == 0x80000000 &&
c->extended_cpuid_level >= 0x80000001) {
__do_cpuid_fault(0x80000001, 0, &eax, &ebx, &ecx, &edx);
- flags->val[6] &= ecx;
- flags->val[1] &= edx;
+ flags.val[6] &= ecx;
+ flags.val[1] &= edx;
}
if (c->cpuid_level >= 0x0000000d) {
__do_cpuid_fault(0x0000000d, 1, &eax, &ebx, &ecx, &edx);
- flags->val[10] &= eax;
+ flags.val[10] &= eax;
}
+ memcpy(&per_cpu(cpu_flags, cpu), &flags, sizeof(flags));
}
static int show_cpuinfo(struct seq_file *m, void *v)
If several threads read /proc/cpuinfo some can see in 'flags' values from c->x86_capability, before __do_cpuid_fault() called and masks applied. Fix this by forming 'flags' on stack first and copy them in per_cpu(cpu_flags, cpu) as a last step. https://jira.sw.ru/browse/PSBM-121823 Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> --- arch/x86/kernel/cpu/proc.c | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-)