* Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote: > > Looks like this is in DRM code: > > > > BUG: at include/linux/slub_def.h:88 kmalloc_index() > > I'm going to change that "BUG:" to "WARNING:". > > I know some people disagreed with it (ie Ingo), but I think that's > total and utter bullshit. > > It's a warning. Right now that "BUG:" message makes people all scared > about something that is not fatal at all, just a note that something > hasn't been converted, but is expected to work absolutely fine. > > Calling it a bug is idiotic. i very much agree that this kmalloc_index() one shouldnt be called a "BUG: ", but if you look at the majority of WARN_ON() instances they are checks for clear, serious kernel bugs. Very often we use WARN_ON() not to signal that it's just a harmless warning, but because we do not want to bring the system down via a BUG_ON(). The API is misnamed for sure, but still, the purpose and current practice is clear: to signal kernel bugs. To quantify this a bit more objectively i just did a "grep WARN_ON kernel/*.c" and randomly picked 10 out of the 113 WARN_ON()'s: kernel/cpu.c: WARN_ON(1); kernel/exit.c: WARN_ON(atomic_read(&tsk->fs_excl)); kernel/fork.c: WARN_ON(!(tsk->exit_state & (EXIT_DEAD | EXIT_ZOMBIE))); kernel/futex.c: WARN_ON(!pi_state); kernel/hrtimer.c: WARN_ON_ONCE(timer->cb_mode == HRTIMER_CB_IRQSAFE_NO_SOFTIRQ); kernel/lockdep.c: WARN_ON(1); kernel/mutex-debug.c: DEBUG_LOCKS_WARN_ON(list_empty(&waiter->list)); kernel/rtmutex.c: WARN_ON(rt_mutex_is_locked(lock)); kernel/sched.c: if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0))) kernel/softirq.c: WARN_ON_ONCE(in_irq()); and reviewed each instance, each and every one of these warnings is a serious kernel bug that i would not 'warn' about, but what i'd like to see reported ASAP. [ In fact i added 5 of these WARN_ON()s :-/ ] But maybe that's just me? now regarding the naming of this API, i'd very much agree to do this rename: WARN_ON => BUG_ON BUG_ON => CRASH_ON and make WARN_ON() print a "WARNING: ". and i signalled this in the original discussion too a few months ago when i opposed the watering-down of the WARN_ON printk. OTOH i dont feel that strongly about all this :-) Ingo _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
