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Diffstat (limited to 'arch/x86/kernel/cpu/perf_event.c')
-rw-r--r--arch/x86/kernel/cpu/perf_event.c12
1 files changed, 8 insertions, 4 deletions
diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index 3658de47900f..9469dfa55607 100644
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -2179,21 +2179,25 @@ static unsigned long get_segment_base(unsigned int segment)
int idx = segment >> 3;
if ((segment & SEGMENT_TI_MASK) == SEGMENT_LDT) {
+ struct ldt_struct *ldt;
+
if (idx > LDT_ENTRIES)
return 0;
- if (idx > current->active_mm->context.size)
+ /* IRQs are off, so this synchronizes with smp_store_release */
+ ldt = lockless_dereference(current->active_mm->context.ldt);
+ if (!ldt || idx > ldt->size)
return 0;
- desc = current->active_mm->context.ldt;
+ desc = &ldt->entries[idx];
} else {
if (idx > GDT_ENTRIES)
return 0;
- desc = raw_cpu_ptr(gdt_page.gdt);
+ desc = raw_cpu_ptr(gdt_page.gdt) + idx;
}
- return get_desc_base(desc + idx);
+ return get_desc_base(desc);
}
#ifdef CONFIG_COMPAT