Re: [PATCH 4/5] freezer: clear fake signal on exit from__refrigerator

From: Oleg Nesterov
Date: Sat Feb 23 2013 - 14:43:11 EST


On 02/20, Mandeep Singh Baines wrote:
>
> I think we need something like this in order to be able to fix
> wait_event_freezable and friends. Here is one idea:
>
> #define __wait_event_freezable(wq, condition, ret) \
> do { \
> DEFINE_WAIT(__wait); \
> \
> for (;;) { \
> prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE); \
> if (condition) \
> break; \
> if (!signal_pending(current)) { \
> freezable_schedule();

...

> If you cleaned up the fake signal in __refrigerator()

Perhaps. Or we can add recalc_sigpending into wait_freezable().
But note that

if (!signal_pending(current))
freezable_schedule();

is not actually right, wait_event_freezable() should be interruptible,
but not by freezer.

And let me repeat, as for coredump this can only solve the problems in
wait_for_dump_handler(). As for other users, I simply do not see any
valid user today, so perhaps wait_event_freezable() should die... Or
I missed something.

I'll try to make the coredumping fixes tomorrow, then we discuss this
again.

Oleg.

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