Regression: bisected: AMDGPU causes Kernel Bad page state OOPS starting with kernels 5.11.x, 5.12.x, 5.13-rc

AMDGPU was working fine on my armhf systems with 5.10.x and previous kernels and a RX550 card. Unfortunately I have only now tested kernels 5.11.x, 5.12.x and 5.13-rc and all are now showing problems like this one:

May 10 20:23:14 picolo kernel: [ 18.967626] BUG: Bad page state in process gnome-shell pfn:78c08

May 10 20:23:14 picolo kernel: [ 18.973750] page:ce2e9717 refcount:2 mapcount:1 mapping:17edced0 index:0x109e9 pfn:0x78c08

May 10 20:23:14 picolo kernel: [ 18.973763] aops:0xc0e12f54 ino:30d

Full Kernel boot log is here DetailedIssue_5.11.17.txt]

I've bisected and traced the problem to this commit:

e93b2da9799e5cb97760969f3e1f02a5bdac29fe is the first bad commit

commit e93b2da9799e5cb97760969f3e1f02a5bdac29fe

Date: Sat Oct 24 13:11:29 2020 +0200

drm/amdgpu: switch to new allocator v2

It should be able to handle all cases here.

v2: fix debugfs as well

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Dave Airlie <airlied@redhat.com>
Reviewed-by: Madhav Chauhan <madhav.chauhan@amd.com>
Tested-by: Huang Rui <ray.huang@amd.com>
Link: https://patchwork.freedesktop.org/patch/397086/?series=83051&rev=1

drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 45 ++++++++++----------------------- 1 file changed, 14 insertions(+), 31 deletions(-)

Detailed bisect log is here: bisect_LM.txt