Messages in this thread | | | Date | Thu, 21 Feb 2013 09:53:48 -0800 | Subject | Re: [PATCH] nohz: Make tick_nohz_irq_exit() irq safe | From | Linus Torvalds <> |
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On Wed, Feb 20, 2013 at 1:00 PM, Thomas Gleixner <tglx@linutronix.de> wrote: > */ > void irq_exit(void) > { > +#ifndef __ARCH_IRQ_EXIT_IRQS_DISABLED > + unsigned long flags; > + > + local_irq_save(flags); > +#else > + BUG_ON(!irqs_disabled(); > +#endif
Guys, STOP DOING THIS!
Adding BUG_ON()'s just makes things much much much worse. There is *never* a reason to add a BUG_ON(). And doing it in an interrupt path is totally unacceptable. BUG_ON() makes it almost impossible to debug something, because you just killed the machine. So using BUG_ON() for "please notice this" is stupid as hell, because the most common end result is: "Oh, the machine just hung with no messages".
Make it WARN_ON_ONCE() if you absolutely have to let people know, but for something like this, why would you do even that?
Linus
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