Comment # 3 on bug 110142 from Michel Dänzer

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=c713a461459202504050305242cd854bad57837c
seems the most likely candidate, it's the only significant change to
gmc_v9_0_late_init between 4.20 and 5.0.

I guess the problem is actually in gmc_v9_0_allocate_vm_inv_eng though. Peter,
what does

 scripts/faddr2line drivers/gpu/drm/amd/amdgpu/amdgpu.ko
gmc_v9_0_late_init+0x114/0x500

say in the kernel build tree (in the state after building the binaries which
generated the attached dmesg output)?