On Wed, 02 Jun 2021, Peter Zijlstra wrote:
Remove broken task->state references and let wake_up_process() DTRT.The anti-pattern in these patches breaks the ordering of ->state vs COND as described in the comment near set_current_state() and can lead to missed wakeups: (OoO load, observes RUNNING)<-. for (;;) { | t->state = UNINTERRUPTIBLE; | smp_mb(); ,-----> ,' (OoO load, observed !COND) | | | | COND = 1; | `- if (t->state != RUNNING) | wake_up_process(t); // not done if (COND) ---------' break; schedule(); // forever waiting } t->state = TASK_RUNNING; Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org>
Reviewed-by: Davidlohr Bueso <dbu...@suse.de> _______________________________________________ Kgdb-bugreport mailing list Kgdb-bugreport@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kgdb-bugreport
