On Tue, 9 Dec 2025 23:58:10 +0800
kernel test robot <[email protected]> wrote:

> tree:   https://gitlab.freedesktop.org/drm/misc/kernel.git drm-misc-next
> head:   0823bd894278e4c0f1acb8f3a8a3c67745e6d1f6
> commit: 99bda20d6d4cac30ed6d357658d8bc328c3b27d9 [4/11] drm/gem: Introduce 
> drm_gem_get_unmapped_area() fop
> config: arm-randconfig-003-20251209 
> (https://download.01.org/0day-ci/archive/20251209/[email protected]/config)
> compiler: clang version 22.0.0git (https://github.com/llvm/llvm-project 
> 6ec8c4351cfc1d0627d1633b02ea787bd29c77d8)
> reproduce (this is a W=1 build): 
> (https://download.01.org/0day-ci/archive/20251209/[email protected]/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 <[email protected]>
> | Closes: 
> https://lore.kernel.org/oe-kbuild-all/[email protected]/
> 
> All errors (new ones prefixed by >>):
> 
> >> drivers/gpu/drm/drm_gem.c:1261:10: error: call to undeclared function 
> >> 'mm_get_unmapped_area'; ISO C99 and later do not support implicit function 
> >> declarations [-Wimplicit-function-declaration]  
>     1261 |                 return mm_get_unmapped_area(current->mm, filp, 
> uaddr, len, 0,
>          |                        ^
>    drivers/gpu/drm/drm_gem.c:1261:10: note: did you mean 
> '__get_unmapped_area'?
>    include/linux/mm.h:3441:1: note: '__get_unmapped_area' declared here
>     3441 | __get_unmapped_area(struct file *file, unsigned long addr, 
> unsigned long len,
>          | ^
>    1 error generated.
> 
> 
> vim +/mm_get_unmapped_area +1261 drivers/gpu/drm/drm_gem.c
> 
>   1229        
>   1230        /**
>   1231         * drm_gem_get_unmapped_area - get memory mapping region 
> routine for GEM objects
>   1232         * @filp: DRM file pointer
>   1233         * @uaddr: User address hint
>   1234         * @len: Mapping length
>   1235         * @pgoff: Offset (in pages)
>   1236         * @flags: Mapping flags
>   1237         *
>   1238         * If a driver supports GEM object mapping, before ending up in 
> drm_gem_mmap(),
>   1239         * mmap calls on the DRM file descriptor will first try to find 
> a free linear
>   1240         * address space large enough for a mapping. Since GEM objects 
> are backed by
>   1241         * shmem buffers, this should preferably be handled by the 
> shmem virtual memory
>   1242         * filesystem which can appropriately align addresses to huge 
> page sizes when
>   1243         * needed.
>   1244         *
>   1245         * Look up the GEM object based on the offset passed in 
> (vma->vm_pgoff will
>   1246         * contain the fake offset we created) and call 
> shmem_get_unmapped_area() with
>   1247         * the right file pointer.
>   1248         *
>   1249         * If a GEM object is not available at the given offset or if 
> the caller is not
>   1250         * granted access to it, fall back to mm_get_unmapped_area().
>   1251         */
>   1252        unsigned long drm_gem_get_unmapped_area(struct file *filp, 
> unsigned long uaddr,
>   1253                                                unsigned long len, 
> unsigned long pgoff,
>   1254                                                unsigned long flags)
>   1255        {
>   1256                struct drm_gem_object *obj;
>   1257                unsigned long ret;
>   1258        
>   1259                obj = drm_gem_object_lookup_at_offset(filp, pgoff, len 
> >> PAGE_SHIFT);
>   1260                if (IS_ERR(obj) || !obj->filp || 
> !obj->filp->f_op->get_unmapped_area)
> > 1261                        return mm_get_unmapped_area(current->mm, filp, 
> > uaddr, len, 0,  
>   1262                                                    flags);

Hm, smells like a build without CONFIG_MMU=n. I guess we need some
#ifdef CONFIG_MMU around drm_gem_get_unmapped_area() definitions.

>   1263        
>   1264                ret = obj->filp->f_op->get_unmapped_area(obj->filp, 
> uaddr, len, 0,
>   1265                                                         flags);
>   1266        
>   1267                drm_gem_object_put(obj);
>   1268        
>   1269                return ret;
>   1270        }
>   1271        EXPORT_SYMBOL_GPL(drm_gem_get_unmapped_area);
>   1272        
> 

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