diff options
Diffstat (limited to 'arch/x86/include/asm/mmu_context.h')
| -rw-r--r-- | arch/x86/include/asm/mmu_context.h | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/arch/x86/include/asm/mmu_context.h b/arch/x86/include/asm/mmu_context.h index 8dac45a2c7fc..19091ebb8633 100644 --- a/arch/x86/include/asm/mmu_context.h +++ b/arch/x86/include/asm/mmu_context.h @@ -88,7 +88,13 @@ static inline void switch_ldt(struct mm_struct *prev, struct mm_struct *next) #ifdef CONFIG_ADDRESS_MASKING static inline unsigned long mm_lam_cr3_mask(struct mm_struct *mm) { - return mm->context.lam_cr3_mask; + /* + * When switch_mm_irqs_off() is called for a kthread, it may race with + * LAM enablement. switch_mm_irqs_off() uses the LAM mask to do two + * things: populate CR3 and populate 'cpu_tlbstate.lam'. Make sure it + * reads a single value for both. + */ + return READ_ONCE(mm->context.lam_cr3_mask); } static inline void dup_lam(struct mm_struct *oldmm, struct mm_struct *mm) |