Date: Sat, 7 Jul 2018 19:54:59 -0700 From: Pete Wright <pete@nomadlogic.org> To: Hans Petter Selasky <hps@selasky.org>, Johannes Lundberg <johalun0@gmail.com>, Konstantin Belousov <kostikbel@gmail.com> Cc: Niclas Zeising <zeising+freebsd@daemonic.se>, Warner Losh <imp@bsdimp.com>, jhb@freebsd.org, ohartmann@walstatt.org, freebsd-current <freebsd-current@freebsd.org> Subject: Re: atomic changes break drm-next-kmod? Message-ID: <e852dc68-f3d5-cca8-fb40-20d6af5f4798@nomadlogic.org> In-Reply-To: <1cd8c3c6-5d85-fbf3-cc06-1df8282216a1@selasky.org> References: <4c5411dd-9f6b-7245-6ade-e11040f74687@FreeBSD.org> <24f5d737-a205-6fcc-0a33-a84601d2ff7a@nomadlogic.org> <c459a76c-21a2-2510-54b1-d7edee6eaa1e@FreeBSD.org> <eb84c2ed-1cd8-794f-9d5e-9454edeba4e4@nomadlogic.org> <29ce4eab-6667-d2ca-b5d8-3deeef28f142@selasky.org> <df73594c-785a-663d-6c76-bf95466a7aa3@selasky.org> <20180705193646.GM5562@kib.kiev.ua> <5dc2a315-4b71-9ff0-0a37-576649e9144b@FreeBSD.org> <CANCZdfqGyANQ5uUz_Ebc3i5HDLvkWocDs=J2p5xuj=1OttGWYQ@mail.gmail.com> <4797c607-c261-77f7-eccf-45056bf56694@daemonic.se> <20180706084729.GN5562@kib.kiev.ua> <CAECmPwtBJEp_4fFLr1KZhKu2ZJfSGANBD21C0OXUZ=-qfomNBQ@mail.gmail.com> <1cd8c3c6-5d85-fbf3-cc06-1df8282216a1@selasky.org>
next in thread | previous in thread | raw e-mail | index | archive | help
On 07/06/2018 03:15, Hans Petter Selasky wrote: > On 07/06/18 11:14, Johannes Lundberg wrote: >> On Fri, Jul 6, 2018 at 9:49 AM Konstantin Belousov <kostikbel@gmail.com> >> wrote: >> >>> On Fri, Jul 06, 2018 at 09:52:24AM +0200, Niclas Zeising wrote: >>>> On 07/06/18 00:02, Warner Losh wrote: >>>>> >>>>> >>>>> On Thu, Jul 5, 2018 at 1:44 PM, John Baldwin <jhb@freebsd.org >>>>> <mailto:jhb@freebsd.org>> wrote: >>>>> >>>>> On 7/5/18 12:36 PM, Konstantin Belousov wrote: >>>>> > On Thu, Jul 05, 2018 at 09:12:24PM +0200, Hans Petter Selasky >>> wrote: >>>>> >> On 07/05/18 20:59, Hans Petter Selasky wrote: >>>>> >>> On 07/05/18 19:48, Pete Wright wrote: >>>>> >>>> >>>>> >>>> >>>>> >>>> On 07/05/2018 10:10, John Baldwin wrote: >>>>> >>>>> On 7/3/18 5:10 PM, Pete Wright wrote: >>>>> >>>>>> >>>>> >>>>>> On 07/03/2018 15:56, John Baldwin wrote: >>>>> >>>>>>> On 7/3/18 3:34 PM, Pete Wright wrote: >>>>> >>>>>>>> On 07/03/2018 15:29, John Baldwin wrote: >>>>> >>>>>>>>> That seems like kgdb is looking at the wrong CPU. >>>>> Can >>>>> you use >>>>> >>>>>>>>> 'info threads' and look for threads not stopped in >>>>> 'sched_switch' >>>>> >>>>>>>>> and get their backtraces? You could also just do >>> 'thread >>>>> apply >>>>> >>>>>>>>> all bt' and put that file at a URL if that is >>>>> easiest. >>>>> >>>>>>>>> >>>>> >>>>>>>> sure thing John - here's a gist of "thread apply >>>>> all bt" >>>>> >>>>>>>> >>>>> >>>>>>>> >>>>> https://gist.github.com/gem-pete/d8d7ab220dc8781f0827f965f09d43ed >>>>> <https://gist.github.com/gem-pete/d8d7ab220dc8781f0827f965f09d43ed >>>> >>>>> >>>>>>> That doesn't look right at all. Are you sure the >>>>> kernel >>>>> matches the >>>>> >>>>>>> vmcore? Also, which kgdb version are you using? >>>>> >>>>>>> >>>>> >>>>>> yea i agree that doesn't look right at all. here is my >>> setup: >>>>> >>>>>> >>>>> >>>>>> $ which kgdb >>>>> >>>>>> /usr/bin/kgdb >>>>> >>>>>> $ kgdb >>>>> >>>>>> GNU gdb 6.1.1 [FreeBSD] >>>>> >>>>>> $ ls -lh /var/crash/vmcore.1 >>>>> >>>>>> -rw------- 1 root wheel 1.6G Jul 3 15:03 >>>>> /var/crash/vmcore.1 >>>>> >>>>>> $ ls -l /usr/lib/debug/boot/kernel/kernel.debug >>>>> >>>>>> -r-xr-xr-x 1 root wheel 87840496 Jul 3 13:54 >>>>> >>>>>> /usr/lib/debug/boot/kernel/kernel.debug >>>>> >>>>>> >>>>> >>>>>> and i invoke kgdb like so: >>>>> >>>>>> $ sudo kgdb /usr/lib/debug/boot/kernel/kernel.debug >>>>> /var/crash/vmcore.1 >>>>> >>>>>> >>>>> >>>>>> here's a gist of my full gdb session: >>>>> >>>>>> http://termbin.com/krsn >>>>> >>>>>> >>>>> >>>>>> dunno - maybe i have a bad core dump? regardless, more >>> than >>>>> happy to >>>>> >>>>>> help so let me know if i should try anything else or >>> patches >>>>> etc.. >>>>> >>>>> Can you try installing gdb from ports and using >>>>> /usr/local/bin/kgdb? >>>>> >>>>> >>>>> >>>> >>>>> >>>> that seems to have done the trick, at least the output >>>>> looks >>> more >>>>> >>>> encouraging. >>>>> >>>> >>>>> >>>> --- trap 0, rip = 0, rsp = 0, rbp = 0 --- >>>>> >>>> KDB: enter: panic >>>>> >>>> >>>>> >>>> __curthread () at ./machine/pcpu.h:231 >>>>> >>>> 231 __asm("movq %%gs:%1,%0" : "=r" (td) >>>>> >>>> >>>>> >>>> >>>>> >>>> here's my full kgdb session: >>>>> >>>> http://termbin.com/qa4f >>>>> >>>> >>>>> >>>> i don't see any threads not in "sched_switch" though :( >>>>> >>> >>>>> >>> Hi, >>>>> >>> >>>>> >>> The problem may be that the patch to enable atomic inlining >>> of all >>>>> >>> macros forgot to set the SMP keyword which means SMP is not >>>>> defined at >>>>> >>> all for KLD's so all non-kernel atomic usage is with >>>>> MPLOCKED >>>>> empty! >>>>> > Problem is that out-of-tree modules build does not have >>>>> opt*.h >>> files >>>>> > from the kernel. UP config is a valid one, flipping some >>> option's >>>>> > default value does not solve the problem. >>>>> >>>>> Yes, but using the lock prefix in a generic module is ok (it >>>>> will >>> still >>>>> work, just not quite as fast) whereas the lack of lock is >>>>> fatal on >>>>> SMP. I would amend Hans' patch slightly to honor the opt_* >>>>> setting >>>>> for KLD_TIED (but that is only true if KLD_TIED means "built as >>> part of >>>>> a kernel build, so has valid opt_foo.h headers" and not >>>>> 'a standalone module where someone put MODULES_TIED=1 on the >>> command >>>>> line >>>>> to make'). >>>>> >>>>> >>>>> I agree with this default. It's sensible to default to (a) the most >>>>> popular thing and (b) thing that always works, especially when (a) >>>>> and >>>>> (b) are identical. >>>>> >>>>> Don't make me start the "Do we really need an SMP option, why not >>>>> make >>>>> it always on" thread :) The number of relevant uniprocessor x86 boxes >>>>> that benefit from omitting SMP is so small as to be irrelevant, IMHO. >>> A >>>>> MP kernel runs just fine on them... >>>>> >>>>> Warner >>>> >>>> Where are we on this? >>>> It is important to get it fixed, it's already been 4 days, which >>>> means 4 >>>> days of all modern FreeBSD desktop systems being broken, and possibly >>>> other systems with kernel modules from ports as well. >>>> >>>> >>>> Another question, how hard would it be to expose how the kernel was >>>> built to modules built from ports, so that they can figure out stuff >>>> like SMP and others, that might affect the module build? >>> Point the KERNBUILDDIR variable to the directory of the kernel build. >>> This is the directory where *.o and opt*.h are located. Then >>> everything >>> would just work. >>> >> >> Is the solution that we require everyone to build a kernel before >> they can >> build the standalone modules or am I missing something here? >> > > Hi, > > Here is a temporary fix: > https://svnweb.freebsd.org/changeset/base/336025 > > Like Konstantin says this issue needs to be revisited. > this patch has been stable for me for a couple days now after rebuilding drm-next under the new kernel containing this update. we may want to kick-off an update of the drm-next pkg if that hasn't happened already. the old package caused periodic kernel-panics on my end. cheers, -pete -- Pete Wright pete@nomadlogic.org @nomadlogicLA
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?e852dc68-f3d5-cca8-fb40-20d6af5f4798>