RE: [linux-next:master 2241/2462] include/linux/compiler_types.h:542:45: error: call to '__compiletime_assert_413' declared with attribute error: clamp() low limit source_min greater than high limit source_max

[David Laight <David.Laight@ACULAB.COM>]

>    drivers/gpu/drm/i915/display/intel_backlight.c: In function 'scale':

I think this has been reported before.

The 'problem' is in drivers/gpu/drm/i915/display/intel_backlight.c
The compiler is inlining functions enough to detect a call to clamp()
with min > max.
The error isn't obvious and even the full compiler output doesn't say where
'scale' is being inlined from so it is hard to see why there is a problem.

I'm not in a position to rerun the failing build.
Probably needs rerunning with the lines commented out one by one to see which
is responsible.

	David

> -----Original Message-----
> From: kernel test robot <lkp@intel.com>
> Sent: 10 December 2024 01:07
> To: David Laight <David.Laight@ACULAB.COM>
> Cc: oe-kbuild-all@lists.linux.dev; Andrew Morton <akpm@linux-foundation.org>; Linux Memory Management
> List <linux-mm@kvack.org>
> Subject: [linux-next:master 2241/2462] include/linux/compiler_types.h:542:45: error: call to
> '__compiletime_assert_413' declared with attribute error: clamp() low limit source_min greater than
> high limit source_max
> 
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
> head:   d1486dca38afd08ca279ae94eb3a397f10737824
> commit: 58febb0202b31e9e8d55a603a70f7f131455ef2f [2241/2462] minmax.h: use BUILD_BUG_ON_MSG() for the
> lo < hi test in clamp()
> config: parisc-allmodconfig (https://download.01.org/0day-ci/archive/20241210/202412100848.HfPEKlvV-
> lkp@intel.com/config)
> compiler: hppa-linux-gcc (GCC) 14.2.0
> reproduce (this is a W=1 build): (https://download.01.org/0day-
> ci/archive/20241210/202412100848.HfPEKlvV-lkp@intel.com/reproduce)
> 
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <lkp@intel.com>
> | Closes: https://lore.kernel.org/oe-kbuild-all/202412100848.HfPEKlvV-lkp@intel.com/
> 
> All errors (new ones prefixed by >>):
> 
>    In file included from <command-line>:
>    drivers/gpu/drm/i915/display/intel_backlight.c: In function 'scale':
> >> include/linux/compiler_types.h:542:45: error: call to '__compiletime_assert_413' declared with
> attribute error: clamp() low limit source_min greater than high limit source_max
>      542 |         _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
>          |                                             ^
>    include/linux/compiler_types.h:523:25: note: in definition of macro '__compiletime_assert'
>      523 |                         prefix ## suffix();                             \
>          |                         ^~~~~~
>    include/linux/compiler_types.h:542:9: note: in expansion of macro '_compiletime_assert'
>      542 |         _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
>          |         ^~~~~~~~~~~~~~~~~~~
>    include/linux/build_bug.h:39:37: note: in expansion of macro 'compiletime_assert'
>       39 | #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
>          |                                     ^~~~~~~~~~~~~~~~~~
>    include/linux/minmax.h:109:9: note: in expansion of macro 'BUILD_BUG_ON_MSG'
>      109 |         BUILD_BUG_ON_MSG(statically_true(ulo > uhi),                            \
>          |         ^~~~~~~~~~~~~~~~
>    include/linux/minmax.h:116:9: note: in expansion of macro '__clamp_once'
>      116 |         __clamp_once(val, lo, hi, __UNIQUE_ID(v_), __UNIQUE_ID(l_), __UNIQUE_ID(h_))
>          |         ^~~~~~~~~~~~
>    include/linux/minmax.h:192:28: note: in expansion of macro '__careful_clamp'
>      192 | #define clamp(val, lo, hi) __careful_clamp(val, lo, hi)
>          |                            ^~~~~~~~~~~~~~~
>    drivers/gpu/drm/i915/display/intel_backlight.c:47:22: note: in expansion of macro 'clamp'
>       47 |         source_val = clamp(source_val, source_min, source_max);
>          |                      ^~~~~
> 
> 
> vim +/__compiletime_assert_413 +542 include/linux/compiler_types.h
> 
> eb5c2d4b45e3d2 Will Deacon 2020-07-21  528
> eb5c2d4b45e3d2 Will Deacon 2020-07-21  529  #define _compiletime_assert(condition, msg, prefix,
> suffix) \
> eb5c2d4b45e3d2 Will Deacon 2020-07-21  530  	__compiletime_assert(condition, msg, prefix, suffix)
> eb5c2d4b45e3d2 Will Deacon 2020-07-21  531
> eb5c2d4b45e3d2 Will Deacon 2020-07-21  532  /**
> eb5c2d4b45e3d2 Will Deacon 2020-07-21  533   * compiletime_assert - break build and emit msg if
> condition is false
> eb5c2d4b45e3d2 Will Deacon 2020-07-21  534   * @condition: a compile-time constant condition to check
> eb5c2d4b45e3d2 Will Deacon 2020-07-21  535   * @msg:       a message to emit if condition is false
> eb5c2d4b45e3d2 Will Deacon 2020-07-21  536   *
> eb5c2d4b45e3d2 Will Deacon 2020-07-21  537   * In tradition of POSIX assert, this macro will break the
> build if the
> eb5c2d4b45e3d2 Will Deacon 2020-07-21  538   * supplied condition is *false*, emitting the supplied
> error message if the
> eb5c2d4b45e3d2 Will Deacon 2020-07-21  539   * compiler has support to do so.
> eb5c2d4b45e3d2 Will Deacon 2020-07-21  540   */
> eb5c2d4b45e3d2 Will Deacon 2020-07-21  541  #define compiletime_assert(condition, msg) \
> eb5c2d4b45e3d2 Will Deacon 2020-07-21 @542  	_compiletime_assert(condition, msg,
> __compiletime_assert_, __COUNTER__)
> eb5c2d4b45e3d2 Will Deacon 2020-07-21  543
> 
> :::::: The code at line 542 was first introduced by commit
> :::::: eb5c2d4b45e3d2d5d052ea6b8f1463976b1020d5 compiler.h: Move compiletime_assert() macros into
> compiler_types.h
> 
> :::::: TO: Will Deacon <will@kernel.org>
> :::::: CC: Will Deacon <will@kernel.org>
> 
> --
> 0-DAY CI Kernel Test Service
> https://github.com/intel/lkp-tests/wiki

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