Merge tag 'powerpc-6.4-5' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc...

Pull powerpc fix from Michael Ellerman:

 - Disable IRQs when switching mm in exit_lazy_flush_tlb() called from
   exit_mmap()

Thanks to Nicholas Piggin and Sachin Sant.

* tag 'powerpc-6.4-5' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/64s/radix: Fix exit lazy tlb mm switch with irqs enabled

diff --git a/arch/powerpc/mm/book3s64/radix_tlb.c b/arch/powerpc/mm/book3s64/radix_tlb.c
index ce804b7..0bd4866 100644 (file)
--- a/arch/powerpc/mm/book3s64/radix_tlb.c
+++ b/arch/powerpc/mm/book3s64/radix_tlb.c
@@ -795,12 +795,20 @@ void exit_lazy_flush_tlb(struct mm_struct *mm, bool always_flush)
                goto out;
 
        if (current->active_mm == mm) {
+               unsigned long flags;
+
                WARN_ON_ONCE(current->mm != NULL);
-               /* Is a kernel thread and is using mm as the lazy tlb */
+               /*
+                * It is a kernel thread and is using mm as the lazy tlb, so
+                * switch it to init_mm. This is not always called from IPI
+                * (e.g., flush_type_needed), so must disable irqs.
+                */
+               local_irq_save(flags);
                mmgrab_lazy_tlb(&init_mm);
                current->active_mm = &init_mm;
                switch_mm_irqs_off(mm, &init_mm, current);
                mmdrop_lazy_tlb(mm);
+               local_irq_restore(flags);
        }
 
        /*