atomic changes break drm-next-kmod?

[Konstantin Belousov]

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
> >>>>> 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.

The build invocation for such modules needs to provide KERNBUILDDIR
variable pointing to the kernel build directory, where all opt*.h files
are located.

> > 
> > /*
> >   * For userland, always use lock prefixes so that the binaries will run
> >   * on both SMP and !SMP systems.
> >   */
> > #if defined(SMP) || !defined(_KERNEL)
> > #define MPLOCKED        "lock ; "
> > #else
> > #define MPLOCKED
> > #endif
> > 
> > Can you try to recompile the LinuxKPI /sys/modules/linuxkpi with 
> > DEBUG_FLAGS="-DSMP" ?
> > 
> > and similarly the drm-next package?
> > 
> 
> Also please find attached a patch for amd64.
> 
> --HPS
> 

> Index: sys/amd64/include/atomic.h
> ===================================================================
> --- sys/amd64/include/atomic.h	(revision 335974)
> +++ sys/amd64/include/atomic.h	(working copy)
> @@ -132,7 +132,7 @@
>   * For userland, always use lock prefixes so that the binaries will run
>   * on both SMP and !SMP systems.
>   */
> -#if defined(SMP) || !defined(_KERNEL)
> +#if defined(SMP) || !defined(_KERNEL) || defined(KLD_MODULE)
>  #define	MPLOCKED	"lock ; "
>  #else
>  #define	MPLOCKED
> @@ -354,7 +354,7 @@
>   */
>  #define	OFFSETOF_MONITORBUF	0x100
>  
> -#if defined(SMP)
> +#if defined(SMP) || defined(KLD_MODULE)
>  static __inline void
>  __storeload_barrier(void)
>  {

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