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Diffstat (limited to 'arch/x86/include/asm/mmu_context.h')
-rw-r--r--arch/x86/include/asm/mmu_context.h11
1 files changed, 10 insertions, 1 deletions
diff --git a/arch/x86/include/asm/mmu_context.h b/arch/x86/include/asm/mmu_context.h
index be91d5736e08..40269a2bf6f9 100644
--- a/arch/x86/include/asm/mmu_context.h
+++ b/arch/x86/include/asm/mmu_context.h
@@ -52,7 +52,16 @@ static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
/* Stop flush ipis for the previous mm */
cpumask_clear_cpu(cpu, mm_cpumask(prev));
- /* Load the LDT, if the LDT is different: */
+ /*
+ * Load the LDT, if the LDT is different.
+ *
+ * It's possible leave_mm(prev) has been called. If so,
+ * then prev->context.ldt could be out of sync with the
+ * LDT descriptor or the LDT register. This can only happen
+ * if prev->context.ldt is non-null, since we never free
+ * an LDT. But LDTs can't be shared across mms, so
+ * prev->context.ldt won't be equal to next->context.ldt.
+ */
if (unlikely(prev->context.ldt != next->context.ldt))
load_LDT_nolock(&next->context);
}
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