On Fri 30-09-16 14:47:41, Oleg Nesterov wrote:
> On 09/30, Andrey Ryabinin wrote:
> >
> > @@ -423,7 +424,9 @@ static int coredump_wait(int exit_code, struct 
> > core_state *core_state)
> >     if (core_waiters > 0) {
> >             struct core_thread *ptr;
> >  
> > +           freezer_do_not_count();
> >             wait_for_completion(&core_state->startup);
> > +           freezer_count();
> 
> Agreed... we could probably even do
> 
>       --- x/fs/coredump.c
>       +++ x/fs/coredump.c
>       @@ -423,7 +423,13 @@ static int coredump_wait(int exit_code, 
>               if (core_waiters > 0) {
>                       struct core_thread *ptr;
>        
>       -               wait_for_completion(&core_state->startup);
>       +               if 
> (wait_for_completion_interruptible(&core_state->startup)) {
>       +                       /* see the comment in dump_interrupted() */
>       +                       down_write(&mm->mmap_sem);
>       +                       coredump_finish(mm, false);
>       +                       up_write(&mm->mmap_sem);
>       +                       return -EINTR;
>       +               }
>                       /*
>                        * Wait for all the threads to become inactive, so that
>                        * all the thread context (extended register state, like

This looks like a very good idea to me. We really want to make the whole
coredump_wait killable. I guess this should help us to remove the
hackish sig->flags & SIGNAL_GROUP_COREDUMP check from
__task_will_free_mem. Or are there any other problems that would make
oom victims in the middle of coredump problematic?
-- 
Michal Hocko
SUSE Labs

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