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

[Luís Mendes]

Hi,

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
https://pastebin.com/pcuUWXbj

I've bisected and traced the problem to this commit:
e93b2da9799e5cb97760969f3e1f02a5bdac29fe is the first bad commit
commit e93b2da9799e5cb97760969f3e1f02a5bdac29fe
Author: Christian König <christian.koenig at amd.com>
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 at amd.com>
    Reviewed-by: Dave Airlie <airlied at redhat.com>
    Reviewed-by: Madhav Chauhan <madhav.chauhan at amd.com>
    Tested-by: Huang Rui <ray.huang at 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:
https://bin.privacytools.io/?a88ae63fb95fa1c1#EtrC4qxGWjmgy5C3dBzXFGqjxc7znTKULtz4cxoYFxW5

Best regards,
Luís Mendes
Aparapi developer
PhD Student & Researcher