On Sat, Dec 15, 2007 at 02:04:49PM +0800, Herbert Xu wrote: > On Fri, Dec 14, 2007 at 11:52:18PM -0600, Matt Mackall wrote: > > > > No. The code as written above should reduce to: > > > > if (val == NULL) > > return -EFAULT; > > > > If I hadn't wanted to return -EFAULT in this case, I would have just > > written: > > > > WARN_ON(val == NULL); > > Well the only reason I introduced > > if (WARN_ON) > > is so that what would otherwise be a BUG_ON condition would have > a chance to get written to disk when invoked from an IRQ handler. > > > I don't want code that was running safely (ie returning -EFAULT) to > > start crashing the system just because I've, say, disabled printk. > > That's creating an obnoxious heisenbug. > > I'm disappointed that it has been used in ways that it shouldn't > have been. > > I suppose we'll have to either introduce a new primitive or just > go back to using BUG_ON.
Seems we haven't yet reached concensus on what an appropriate use for BUG_ON is. There's a fairly large camp who think that there are basically no good reasons to outright crash a machine and that WARN_ON should replace BUG_ON everywhere. I tend to agree with this position, except when it comes to handling filesystems, where panic is often (but not always) the right thing to do. -- Mathematics is the supreme nostalgia of our time. -- 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/
