[PATCH] drm/amd/dc/dce120: Fix audio register mapping, stop triggering KASAN

Lyude Paul lyude at redhat.com
Mon Nov 14 22:20:45 UTC 2022


There's been a very long running bug that seems to have been neglected for
a while, where amdgpu consistently triggers a KASAN error at start:

  BUG: KASAN: global-out-of-bounds in read_indirect_azalia_reg+0x1d4/0x2a0 [amdgpu]
  Read of size 4 at addr ffffffffc2274b28 by task modprobe/1889

After digging through amd's rather creative method for accessing registers,
I eventually discovered the problem likely has to do with the fact that on
my dce120 GPU there are supposedly 7 sets of audio registers. But we only
define a register mapping for 6 sets.

So, fix this and fix the KASAN warning finally.

Signed-off-by: Lyude Paul <lyude at redhat.com>
Cc: stable at vger.kernel.org
---
Sending this one separately from the rest of my fixes since:

* It's definitely completely unrelated to the Gitlab 2171 issue
* I'm not sure if this is the correct fix since it's in DC

 drivers/gpu/drm/amd/display/dc/dce120/dce120_resource.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/display/dc/dce120/dce120_resource.c b/drivers/gpu/drm/amd/display/dc/dce120/dce120_resource.c
index 1b70b78e2fa15..af631085e88c5 100644
--- a/drivers/gpu/drm/amd/display/dc/dce120/dce120_resource.c
+++ b/drivers/gpu/drm/amd/display/dc/dce120/dce120_resource.c
@@ -359,7 +359,8 @@ static const struct dce_audio_registers audio_regs[] = {
 	audio_regs(2),
 	audio_regs(3),
 	audio_regs(4),
-	audio_regs(5)
+	audio_regs(5),
+	audio_regs(6),
 };
 
 #define DCE120_AUD_COMMON_MASK_SH_LIST(mask_sh)\
-- 
2.37.3



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