On 08/04, Peter Zijlstra wrote:
>
> while (1) {
> - prepare_to_wait(&group->notification_waitq, &wait,
> TASK_INTERRUPTIBLE);
> -
> mutex_lock(&group->notification_mutex);
So yes, even these 2 lines look obviously buggy. Even if
fsnotify_add_notify_event()->wake_up(&group->notification_waitq) uses
TASK_NORMAL, so at least this can't miss an event.
It is too later for me, but I am wondering if we can do another thing.
Something like
int state;
prepare_to_wait(wait, TASK_INTERRUPTIBLE);
PUSH(&wait, state);
mutex_lock();
mutex_unlock();
POP(&wait, state);
and, ignoring all races, lack of barriers, etc
#define PUSH(w, s) s = current->state; current->state = RUNNING;
#define POP(w, s) current->state = WOKEN(w) ? RUNNING : s;
Probably not... just curious.
Oleg.
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