Re: [linux-stable-rc:linux-4.19.y 1181/1498] ERROR: "__compiletime_assert_491" [drivers/gpu/drm/i915/i915.ko] undefined!

[Greg Kroah-Hartman]

On Thu, Aug 05, 2021 at 05:11:10PM -0700, Nathan Chancellor wrote:
> On Thu, Aug 05, 2021 at 04:23:40PM -0700, Nick Desaulniers wrote:
> > On Thu, Aug 5, 2021 at 1:24 PM kernel test robot <lkp@xxxxxxxxx> wrote:
> > >
> > > Hi Nick,
> > >
> > > First bad commit (maybe != root cause):
> > >
> > > tree:   https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-4.19.y
> > > head:   7457eed4b647560ae1b1800c295efc5f1db22e4b
> > > commit: 7c29fd831799d09474dfdae556207b7102647a45 [1181/1498] lib/string.c: implement stpcpy
> > > config: x86_64-randconfig-r024-20210805 (attached as .config)
> > > compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 31a71a393f65d9e07b5b0756fef9dd16690950ee)
> > > reproduce (this is a W=1 build):
> > >         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
> > >         chmod +x ~/bin/make.cross
> > >         # https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git/commit/?id=7c29fd831799d09474dfdae556207b7102647a45
> > >         git remote add linux-stable-rc https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git
> > >         git fetch --no-tags linux-stable-rc linux-4.19.y
> > >         git checkout 7c29fd831799d09474dfdae556207b7102647a45
> > >         # save the attached .config to linux build tree
> > >         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=x86_64
> > >
> > > If you fix the issue, kindly add following tag as appropriate
> > > Reported-by: kernel test robot <lkp@xxxxxxxxx>
> > >
> > > All errors (new ones prefixed by >>):
> > >
> > > >> ERROR: "__compiletime_assert_491" [drivers/gpu/drm/i915/i915.ko] undefined!
> > 
> > ^ I'm actively trying to improve these diagnostics in LLVM at the
> > moment. Hopefully that will make this report clearer!
> > https://reviews.llvm.org/D106030
> 
> It does help :)
> 
> drivers/gpu/drm/i915/intel_engine_cs.c:466:2: error: call to '__compiletime_assert_491' declared with attribute error: BUILD_BUG_ON failed: (execlists_num_ports(execlists)) == 0 || (((execlists_num_ports(execlists)) & ((execlists_num_ports(execlists)) - 1)) != 0)
>         BUILD_BUG_ON_NOT_POWER_OF_2(execlists_num_ports(execlists));
>         ^
> include/linux/build_bug.h:21:2: note: expanded from macro 'BUILD_BUG_ON_NOT_POWER_OF_2'
>         BUILD_BUG_ON((n) == 0 || (((n) & ((n) - 1)) != 0))
>         ^
> include/linux/build_bug.h:69:2: note: expanded from macro 'BUILD_BUG_ON'
>         BUILD_BUG_ON_MSG(condition, "BUILD_BUG_ON failed: " #condition)
>         ^
> include/linux/build_bug.h:45:37: note: expanded from macro 'BUILD_BUG_ON_MSG'
> #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
>                                     ^
> note: (skipping 1 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
> include/linux/compiler.h:336:2: note: expanded from macro '_compiletime_assert'
>         __compiletime_assert(condition, msg, prefix, suffix)
>         ^
> include/linux/compiler.h:329:4: note: expanded from macro '__compiletime_assert'
>                         prefix ## suffix();                             \
>                         ^
> <scratch space>:83:1: note: expanded from here
> __compiletime_assert_491
> ^
> 4 warnings and 1 error generated.
> 
> As it turns out, this has come up before and it was fixed by commit
> 410ed5731a65 ("drm/i915: Ensure intel_engine_init_execlist() builds with
> Clang").
> 
> Greg and Sasha, could this be picked up for 4.19?

Now queued up, thanks.

greg k-h