This commit addresses a NULL dereference issue in the
amdgpu_atif_handler function.
The issue arises when event->device_class is NULL and is passed to the
DRM_DEBUG_DRIVER macro, which attempts to print the NULL string with the
%s format specifier. This constitutes undefined behavior.
To resolve this, a conditional check is added to ensure that
event->device_class is not NULL before it is passed to the
DRM_DEBUG_DRIVER macro. If it is NULL, the string "NULL" is printed
instead, thereby preventing the NULL dereference.
Fixes the below:
In function ‘amdgpu_atif_handler’,
inlined from ‘amdgpu_acpi_event’ at
drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c:1215:9:
./include/drm/drm_print.h:536:49: warning: ‘%s’ directive argument is null
[-Wformat-overflow=]
536 | #define __drm_dbg(cat, fmt, ...) ___drm_dbg(NULL, cat,
fmt, ##__VA_ARGS__)
|
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
./include/drm/drm_print.h:582:9: note: in expansion of macro ‘__drm_dbg’
582 | __drm_dbg(DRM_UT_DRIVER, fmt, ##__VA_ARGS__)
| ^~~~~~~~~
drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c:452:9: note: in expansion of macro
‘DRM_DEBUG_DRIVER’
452 | DRM_DEBUG_DRIVER("event, device_class = %s, type = %#x\n",
| ^~~~~~~~~~~~~~~~
drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c: In function ‘amdgpu_acpi_event’:
drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c:452:49: note: format string is defined
here
452 | DRM_DEBUG_DRIVER("event, device_class = %s, type = %#x\n",
|
Cc: Alex Deucher <[email protected]>
Cc: Christian König <[email protected]>
Signed-off-by: Srinivasan Shanmugam <[email protected]>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c
b/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c
index f85ace0384d2..27131ff30579 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c
@@ -450,7 +450,7 @@ static int amdgpu_atif_handler(struct amdgpu_device *adev,
int count;
DRM_DEBUG_DRIVER("event, device_class = %s, type = %#x\n",
- event->device_class, event->type);
+ event->device_class ? event->device_class : "NULL",
event->type);
if (strcmp(event->device_class, ACPI_VIDEO_CLASS) != 0)
return NOTIFY_DONE;
--
2.34.1
