I can't answer authoritatively, but
On 06/06, zhong jiang wrote:
>
> Hi
>
> when I review the code, I find the following scenario will lead to a race ,
> but I am not sure whether the real issue will hit or not.
>
> cpu1 cpu2
> exit_mmap
> mmu_notifier_unregister
> __mmu_notifier_release srcu_read_lock
> srcu_read_lock
> mm->ops->release(mn, mm) mm->ops->release(mn,mm)
> srcu_read_unlock
> srcu_read_unlock
>
>
> obviously, the specified mm will call identical release function when
> the related condition satisfy. is it right?
I think you are right, this is possible, perhaps the comments should mention
this explicitly.
See the changelog in d34883d4e35c0a994e91dd847a82b4c9e0c31d83 "mm: mmu_notifier:
re-fix freed page still mapped in secondary MMU":
"multiple ->release() callouts", we needn't care it too much ...
Oleg.
