On Thu, 2017-12-21 at 10:02 -0700, Jens Axboe wrote: > On 12/21/17 9:42 AM, Bruno Wolff III wrote: > > > > On Thu, Dec 21, 2017 at 23:48:19 +0800, > > weiping zhang <zwp10...@gmail.com> wrote: > > > > > > > > > > > output you want. I never saw it for any kernels I compiled > > > > myself. Only when I test kernels built by Fedora do I see it. > > > > see it every boot ? > > > > I don't look every boot. The warning gets scrolled of the screen. > > Once I see the CPU hang warnings I know the boot is failing. I > > don't always look at journalctl later to see what's there. > > I'm going to revert a0747a859ef6 for now, since we're now 8 days into > this and no progress has been made on fixing it.
I think this is correct. If you build the kernel with CONFIG_DEBUG_FS=N, you're definitely going to get the same hang (because the debugfs_ functions fail with -ENODEV and the bdi will never get registered). This alone leads me to suspect the commit is bogus because it's a randconfig/test accident waiting to happen. We should still root cause the debugfs failure in this case, but I really think debugfs files should be treated as optional, so a failure in setting them up should translate to some sort of warning not a failure to set up the bdi. James
