From: Arnd Bergmann <arnd@xxxxxxxx>
gcc-11 warns about what appears to be an out-of-range array access:
In function ‘snb_wm_latency_quirk’,
inlined from ‘ilk_setup_wm_latency’ at drivers/gpu/drm/i915/intel_pm.c:3108:3:
drivers/gpu/drm/i915/intel_pm.c:3057:9: error: ‘intel_print_wm_latency’ reading 16 bytes from a region of size 10 [-Werror=stringop-overread]
3057 | intel_print_wm_latency(dev_priv, "Primary", dev_priv->wm.pri_latency);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/i915/intel_pm.c: In function ‘ilk_setup_wm_latency’:
drivers/gpu/drm/i915/intel_pm.c:3057:9: note: referencing argument 3 of type ‘const u16 *’ {aka ‘const short unsigned int *’}
drivers/gpu/drm/i915/intel_pm.c:2994:13: note: in a call to function ‘intel_print_wm_latency’
2994 | static void intel_print_wm_latency(struct drm_i915_private *dev_priv,
| ^~~~~~~~~~~~~~~~~~~~~~
My guess is that this code is actually safe because the size of the
array depends on the hardware generation, and the function checks for
that, but at the same time I would not expect the compiler to work it
out correctly, and the code seems a little fragile with regards to
future changes. Simply increasing the size of the array should help.
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
---
drivers/gpu/drm/i915/i915_drv.h | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 26d69d06aa6d..3567602e0a35 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1095,11 +1095,11 @@ struct drm_i915_private {
* in 0.5us units for WM1+.
*/
/* primary */
- u16 pri_latency[5];
+ u16 pri_latency[8];
/* sprite */
- u16 spr_latency[5];
+ u16 spr_latency[8];
/* cursor */
- u16 cur_latency[5];
+ u16 cur_latency[8];
/*
* Raw watermark memory latency values
* for SKL for all 8 levels
--
2.29.2
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