On 10/04, Michal Hocko wrote:
>
> 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.
Well, it is already killable. And with the change above it can sleep
in down_write(mmap_sem) and we really need this lock to abort, so it
won't necessarily react to SIGKILL faster.
> I guess this should help us to remove the
> hackish sig->flags & SIGNAL_GROUP_COREDUMP check from
> __task_will_free_mem.
Why? This doesn't depend on "killable". __task_will_free_mem() checks
this flag to detect the CLONE_VM processes which won't exit soon because
they participate in the coredumping.
Oleg.
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