WARNING in amdgpu_sync_keep_later / dma_fence_is_later should be rate limited

[Rafał Miłecki]

Hi,

backporting commit 187916e6ed9d ("drm/amdgpu: install stub fence into
potential unused fence pointers") to stable kernels resulted in lots
of WARNINGs on some devices. In my case I was getting 3 WARNINGs per
second (~150 lines logged every second). Commit ended up being
reverted for stable but it exposed a potential problem. My messages
log size was reaching gigabytes and was running my /tmp/ out of space.

Could someone take a look at amdgpu_sync_keep_later /
dma_fence_is_later and make sure its logging is rate limited to avoid
such situations in the future, please?

Revert in linux-5.15.x:
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=linux-5.15.y&id=fae2d591f3cb31f722c7f065acf586830eab8c2a

openSUSE bug report:
https://bugzilla.opensuse.org/show_bug.cgi?id=1215523

-- 
Rafał