linux-kernel - Re: [PATCH iwlwifi-next v4] wifi: iwlwifi: fix uninitialized pointers with free attribute

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Message-ID: <3ef371f6-c296-44d8-87d7-477d6a97dabb@kernel.org>
Date: Sat, 22 Nov 2025 15:20:02 +0100
From: Krzysztof Kozlowski <krzk@...nel.org>
To: Ally Heev <allyheev@...il.com>,
 Miri Korenblit <miriam.rachel.korenblit@...el.com>
Cc: Johannes Berg <johannes@...solutions.net>,
 linux-wireless@...r.kernel.org, linux-kernel@...r.kernel.org,
 Dan Carpenter <dan.carpenter@...aro.org>
Subject: Re: [PATCH iwlwifi-next v4] wifi: iwlwifi: fix uninitialized pointers
 with free attribute

On 21/11/2025 15:25, Ally Heev wrote:
> Uninitialized pointers with `__free` attribute can cause undefined
> behavior as the memory assigned randomly to the pointer is freed
> automatically when the pointer goes out of scope.
> 
> It is better to initialize and assign pointers with `__free` attribute
> in one statement to ensure proper scope-based cleanup
> 
> Reported-by: Dan Carpenter <dan.carpenter@...aro.org>
> Closes: https://lore.kernel.org/all/aPiG_F5EBQUjZqsl@stanley.mountain/
> Signed-off-by: Ally Heev <allyheev@...il.com>
> ---
> Changes in v4:
> - moved pointers declaration to where the allocation is
> - Link to v3: https://lore.kernel.org/r/20251111-aheev-uninitialized-free-attr-wireless-v3-1-26e889d0e7ee@gmail.com
> 
> Changes in v3:
> - fixed commit message to include iwlwifi
> - reverted unused variable removal. To be done in a different patch
> - Link to v2: https://lore.kernel.org/r/20251107-aheev-uninitialized-free-attr-wireless-v2-1-674fc3e5c78e@gmail.com
> 
> Changes in v2:
> - fixed style issues
> - ignore v1 of this patch
> - Link to v1: https://lore.kernel.org/r/20251105-aheev-uninitialized-free-attr-wireless-v1-1-6c850a4a952a@gmail.com
> ---
>  drivers/net/wireless/intel/iwlwifi/fw/uefi.c | 2 +-
>  drivers/net/wireless/intel/iwlwifi/mld/d3.c  | 6 +++---
>  2 files changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/net/wireless/intel/iwlwifi/fw/uefi.c b/drivers/net/wireless/intel/iwlwifi/fw/uefi.c
> index 4ae4d215e633e0d51194d818d479349e7c502201..2fe5f744a81cf42e768cc409f1af8823e204946f 100644
> --- a/drivers/net/wireless/intel/iwlwifi/fw/uefi.c
> +++ b/drivers/net/wireless/intel/iwlwifi/fw/uefi.c
> @@ -818,9 +818,9 @@ int iwl_uefi_get_dsbr(struct iwl_fw_runtime *fwrt, u32 *value)
>  
>  int iwl_uefi_get_phy_filters(struct iwl_fw_runtime *fwrt)
>  {
> -	struct uefi_cnv_wpfc_data *data __free(kfree);
>  	struct iwl_phy_specific_cfg *filters = &fwrt->phy_filters;
>  
> +	struct uefi_cnv_wpfc_data *data __free(kfree) = NULL;
>  	data = iwl_uefi_get_verified_variable(fwrt->trans, IWL_UEFI_WPFC_NAME,

This should be one line. Please do not split declaration from
constructors. If maintainers do not like that syntax, then they should
not allow to use cleanup.h in their subsystem.

> Best regards,


Best regards,
Krzysztof