On Tue, 2013-06-25 at 13:21 -0400, Steven Rostedt wrote: > On Tue, 2013-06-25 at 12:55 -0400, Dave Jones wrote: > > > While I've been spinning wheels trying to reproduce that softlockup bug, > > On another machine I've been refining my list-walk debug patch. > > I added an ugly "ok, the ringbuffer is playing games with lower two bits" > > special case. > > > > But what the hell is going on here ? > > > > next->prev should be prev (ffff88023c6cdd18), but was 00ffff88023c6cdd. > > (next=ffff880243288001).
Ah you didn't handle the bit set case. I just noticed "00" in 00ffff88023c6cdd. To test this, you really need to do a "next & ~3", to clear the pointer. Perhaps its best to have just a "raw_list_for_each" that doesn't do any check, and have the ring buffer use that instead. The rb_head_page_deactivate() is usually followed by an integrity check anyway. -- Steve -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
