Re: [PATCH 6.15 000/187] 6.15.8-rc1 review

[Nathan Chancellor <nathan@kernel.org>]

On Tue, Jul 22, 2025 at 11:06:26PM +0530, Naresh Kamboju wrote:
> Regressions while building allyesconfig build for arm64 and x86 with the
> toolchain clang-nightly version 22.0.0.

This is a "regression" in the sense that the warnings are new but it is
from the toolchain side, not the kernel side.

> ## Build log
> mm/ksm.c:3674:11: error: variable 'output' is used uninitialized
> whenever 'if' condition is false [-Werror,-Wsometimes-uninitialized]
>  3674 |         else if (ksm_advisor == KSM_ADVISOR_SCAN_TIME)
>       |                  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Fix pending in Andrew's tree:

https://git.kernel.org/akpm/mm/c/153ad566724fe6f57b14f66e9726d295d22e576d

> drivers/media/platform/samsung/s5p-mfc/s5p_mfc_cmd_v6.c:45:7: error:
> variable 'h2r_args' is uninitialized when passed as a const pointer
> argument here [-Werror,-Wuninitialized-const-pointer]
>    45 |                                         &h2r_args);
>       |                                          ^~~~~~~~
> 
> drivers/media/platform/samsung/s5p-mfc/s5p_mfc_cmd_v6.c:133:7: error:
> variable 'h2r_args' is uninitialized when passed as a const pointer
> argument here [-Werror,-Wuninitialized-const-pointer]
>   133 |                                         &h2r_args);
>       |                                          ^~~~~~~~
> 
> drivers/media/platform/samsung/s5p-mfc/s5p_mfc_cmd_v6.c:148:7: error:
> variable 'h2r_args' is uninitialized when passed as a const pointer
> argument here [-Werror,-Wuninitialized-const-pointer]
>   148 |                                         &h2r_args);
>       |                                          ^~~~~~~~

https://lore.kernel.org/all/20250715-media-s5p-mfc-fix-uninit-const-pointer-v1-1-4d52b58cafe9@kernel.org/

> drivers/net/wireless/mediatek/mt76/mt7996/mcu.c:3365:21: error:
> variable 'hdr' is uninitialized when passed as a const pointer
> argument here [-Werror,-Wuninitialized-const-pointer]
>  3365 |         skb_put_data(skb, &hdr, sizeof(hdr));
>       |                            ^~~
> 
> drivers/net/wireless/mediatek/mt76/mt7996/mcu.c:1875:21: error:
> variable 'hdr' is uninitialized when passed as a const pointer
> argument here [-Werror,-Wuninitialized-const-pointer]
>  1875 |         skb_put_data(skb, &hdr, sizeof(hdr));
>       |                            ^~~

https://lore.kernel.org/all/20250715-mt7996-fix-uninit-const-pointer-v1-1-b5d8d11d7b78@kernel.org/

> drivers/net/wireless/broadcom/brcm80211/brcmsmac/phy/phy_lcn.c:2728:13:
> error: variable 'diq_start' is uninitialized when passed as a const
> pointer argument here [-Werror,-Wuninitialized-const-pointer]
>  2728 |
> &diq_start, 1, 16, 69);
>       |                                                       ^~~~~~~~~

Pending in the wireless tree:

https://git.kernel.org/wireless/wireless-next/c/81284e86bf8849f8e98e8ead3ff5811926b2107f

> drivers/usb/atm/cxacru.c:1104:6: error: variable 'bp' is used
> uninitialized whenever 'if' condition is false
> [-Werror,-Wsometimes-uninitialized]
>  1104 |         if (instance->modem_type->boot_rom_patch) {
>       |             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

I need to send a v2 for this based on Greg's feedback:

https://lore.kernel.org/all/20250716172903.GA4010969@ax162/

> drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c:1066:6: error: variable
> 'crtc_state' is used uninitialized whenever 'if' condition is false
> [-Werror,-Wsometimes-uninitialized]
>  1066 |         if (plane_state->crtc)
>       |             ^~~~~~~~~~~~~~~~~

https://lore.kernel.org/all/20250715-drm-msm-fix-const-uninit-warning-v1-1-d6a366fd9a32@kernel.org/

> drivers/gpu/drm/amd/amdgpu/imu_v12_0.c:374:30: error: variable 'data'
> is uninitialized when used here [-Werror,-Wuninitialized]
>   374 |                         program_imu_rlc_ram(adev, data, (const
> u32)size);
>       |                                                   ^~~~

https://lore.kernel.org/all/20250715-drm-amdgpu-fix-const-uninit-warning-v1-1-9683661f3197@kernel.org/

Alex said he picked it up but I have not seen it appear in his tree yet:

https://lore.kernel.org/all/BL1PR12MB5144E40FC1D87BABD459A0D6F750A@BL1PR12MB5144.namprd12.prod.outlook.com/

Cheers,
Nathan