On Tue, 2013-03-19 at 11:14 +0100, Peter Zijlstra wrote: > On Mon, 2013-03-18 at 12:22 -0700, Tejun Heo wrote: > > try_to_wake_up_local() should only be invoked to wake up another task > > in the same runqueue and BUG_ON()s are used to enforce the rule. > > Missing try_to_wake_up_local() can stall workqueue execution but such > > stalls are likely to be finite either by another work item being > > queued or the one blocked getting unblocked. There's no reason to > > trigger BUG while holding rq lock crashing the whole system. > > > > Convert BUG_ON()s in try_to_wake_up_local() to WARN_ON_ONCE()s. > > Doesn't really matter either way, the printk()s triggered by either > will very likely kill the system anyhow ;-)
Only if something blocks on the console lock, and it tries to wake it up. But even then, it has to be a reverse rq locking order, or wakeup on the same rq that its running on (which is very unlikely). I admit that it doesn't "solve" the bug. But at least there's a chance to investigate what happened when the bug does occur. Right now we have only one conclusion when the bug triggers, and that's a hard lockup. -- Steve -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
