[Lima] [bug report] new kvmalloc() WARN() triggered by DRM ioctls tracking

[Boris Brezillon]

Hi Steve,

On Thu, 16 Dec 2021 14:02:25 +0000
Steven Price <steven.price at arm.com> wrote:

> + Boris
> 
> On 16/12/2021 12:08, Dan Carpenter wrote:
> > Hi DRM Devs,
> > 
> > In commit 7661809d493b ("mm: don't allow oversized kvmalloc() calls")
> > from July, Linus added a WARN_ONCE() for "crazy" allocations over 2GB.
> > I have a static checker warning for this and most of the warnings are
> > from DRM ioctls.
> > 
> > drivers/gpu/drm/lima/lima_drv.c:124 lima_ioctl_gem_submit() warn: uncapped user size for kvmalloc() will WARN
> > drivers/gpu/drm/radeon/radeon_cs.c:291 radeon_cs_parser_init() warn: uncapped user size for kvmalloc() will WARN
> > drivers/gpu/drm/v3d/v3d_gem.c:311 v3d_lookup_bos() warn: uncapped user size for kvmalloc() will WARN
> > drivers/gpu/drm/v3d/v3d_gem.c:319 v3d_lookup_bos() warn: uncapped user size for kvmalloc() will WARN
> > drivers/gpu/drm/v3d/v3d_gem.c:601 v3d_get_multisync_post_deps() warn: uncapped user size for kvmalloc() will WARN
> > drivers/gpu/drm/etnaviv/etnaviv_gem_submit.c:476 etnaviv_ioctl_gem_submit() warn: uncapped user size for kvmalloc() will WARN
> > drivers/gpu/drm/etnaviv/etnaviv_gem_submit.c:477 etnaviv_ioctl_gem_submit() warn: uncapped user size for kvmalloc() will WARN
> > drivers/gpu/drm/etnaviv/etnaviv_gem_submit.c:478 etnaviv_ioctl_gem_submit() warn: uncapped user size for kvmalloc() will WARN
> > drivers/gpu/drm/etnaviv/etnaviv_gem_submit.c:479 etnaviv_ioctl_gem_submit() warn: uncapped user size for kvmalloc() will WARN
> > drivers/gpu/drm/virtio/virtgpu_ioctl.c:186 virtio_gpu_execbuffer_ioctl() warn: uncapped user size for kvmalloc() will WARN
> > drivers/gpu/drm/panfrost/panfrost_drv.c:198 panfrost_copy_in_sync() warn: uncapped user size for kvmalloc() will WARN  
> 
> I believe this one in Panfrost would be fixed by Boris's series
> reworking the submit ioctl[1].
> 
> Boris: are you planning on submitting that series soon - or is it worth
> cherry picking the rework in patch 5 to fix this issue?

Don't know when I'll get back to it, so I'd recommend cherry-picking
what you need.

Regards,

Boris