Created attachment 145698 [details]
dmesg log with kernel 5.4-rc2 that shows the null pointer dereference

While running the Vulkan CTS, I encountered the following:

Running the cases dEQP-VK.memory.allocation.* will trigger a kernel NULL
pointer dereference in amdgpu on 5.4-rc2, see the attached dmesg log. After
this happens, the GPU can hang too, but doesn't always hang.

Hardware:
AMD Radeon RX 5700XT (reference card, made by Sapphire)
Dell U2718Q (two of them: one through HDMI, other through DisplayPort)
AMD Ryzen 7 3700X
MSI B450i

Software:
Fedora Workstation 31 x86_64
LLVM 9
Mesa master (what will be 19.3)