Re: preempt bug in set_pmd_pfn?

[Jeremy Fitzhardinge]

Andi Kleen wrote:
> > Won't this leave a stale tlb on the old processor?
> >     
>
> __set_fixmap should be only used in early boot, so it's always
> on CPU 0

vdso32-setup.c:map_compat_vdso() uses it to create the compat vdso 
mapping, which typically happens on the first execve(), and could happen 
if you turn compat vdso off and on during runtime.  (It follows the call 
with flush_tlb_all(), so there's no risk of stray tlb entries in this case.)

But that answers my broader question about how __set_fixmap can get away 
with just flushing on the current cpu; I'll add a preempt disable 
bracket to keep everyone happy.

Any opinions on set_pte_at(&init_mm, ...) without holding any locks?  
All ok?

   J
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/