On Thu, Jul 24, 2014 at 11:18:16AM -0700, Linus Torvalds wrote: > On Thu, Jul 24, 2014 at 5:58 AM, Peter Zijlstra <pet...@infradead.org> wrote: > > > > So going by the nifty picture rostedt made: > > > > [ 61.454336] CPU0 CPU1 > > [ 61.454336] ---- ---- > > [ 61.454336] lock(&(&p->alloc_lock)->rlock); > > [ 61.454336] local_irq_disable(); > > [ 61.454336] lock(tasklist_lock); > > [ 61.454336] > > lock(&(&p->alloc_lock)->rlock); > > [ 61.454336] <Interrupt> > > [ 61.454336] lock(tasklist_lock); > > So this *should* be fine. It always has been in the past, and it was > certainly the *intention* that it should continue to work with > qrwlock, even in the presense of pending writers on other cpu's. > > The qrwlock rules are that a read-lock in an interrupt is still going > to be unfair and succeed if there are other readers.
Ah, indeed. Should have checked :/ > So it sounds to me like the new lockdep rules in tip/master are too > strict and are throwing a false positive. Right. Waiman can you have a look? -- 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/
