Tetsuo Handa wrote: > and clarify in your patch that there is no possibility > of waiting for direct/indirect memory allocation inside free_pgtables(), > in addition to fixing the bug above.
Oops, this part was wrong, for __oom_reap_task_mm() will give up after waiting for one second because down_read_trylock(&mm->mmap_sem) continues failing due to down_write(&mm->mmap_sem) by exit_mmap(). # This is after all moving the location of "give up by timeout", isn't it? ;-) Thus, clarify in your patch that there is no possibility of waiting for direct/indirect memory allocation outside down_write()/up_write() (e.g. i_mmap_lock_write() inside unmap_vmas(&tlb, vma, 0, -1) just before down_write()).
