[PATCH 0/1][SRU][Jammy] Fix UBSAN warning for amdgpu yellow carp

[You-Sheng Yang]

BugLink: https://bugs.launchpad.net/bugs/1956497

[Impact]

An UBSAN error is dumped once when unpluging a type-c cable (at DP Alt
Mode) from a AMD Yellow Carp equipped platform. No side effects found
so far, and subsequent hotplugs won't have this error again.

drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm.c:6084:84
[ 38.099550] load of value 32 is not a valid value for type '_Bool'
[ 38.099552] CPU: 9 PID: 1451 Comm: Xorg Not tainted
5.15.0-2013-generic #13~20.04.1+pre14+lp1953008.1
[ 38.099554] Hardware name: AMD LilacKD-RMB/LilacKD-RMB, BIOS
RRL0080C 09/15/2021
[ 38.099555] Call Trace:
[ 38.099556] <TASK>
[ 38.099558] dump_stack_lvl+0x4a/0x5f
[ 38.099563] dump_stack+0x10/0x12
[ 38.099564] ubsan_epilogue+0x9/0x45
[ 38.099565] __ubsan_handle_load_invalid_value+0x70/0x80
[ 38.099568] create_stream_for_sink.cold+0x5d/0xbb [amdgpu]
...

[Fix]

Commit 63ad5371cd1e ("drm/amd/display: explicitly set is_dsc_supported
to false before use") in linux-next.

[Test Case]

1. Connect an external monitor via USB Type-C able to target platform
2. After external monitor turned on and screen was extended, unplug
   Type-C cable
3. check if a similar ubsan warning is dumpped to dmesg.

[Where problems could occur]

No. This initialize a variable before being referenced.

[Other Info]

While UBSAN is only turned on on 5.15 and newer, only Jammy is nominated
for this fix.

Mario Limonciello (1):
  drm/amd/display: explicitly set is_dsc_supported to false before use

 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 1 +
 1 file changed, 1 insertion(+)

-- 
2.33.1