[PATCH] lsm: use unrcu_pointer() for current->cred in security_init()

[Xiujianfeng]

Hi Paul,

On 11/19/2025 8:28 AM, Paul Moore wrote:
> We need to directly allocate the cred's LSM state for the initial task
> when we initialize the LSM framework.  Unfortunately, this results in a
> RCU related type mismatch, use the unrcu_pointer() macro to handle this
> a bit more elegantly.
> 
> The explicit type casting still remains as we need to work around the
> constification of current->cred in this particular case.
> 
> Signed-off-by: Paul Moore <paul at paul-moore.com>
> ---
>   security/lsm_init.c | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/security/lsm_init.c b/security/lsm_init.c
> index 6bb67d41ce52..4dec9199e4c2 100644
> --- a/security/lsm_init.c
> +++ b/security/lsm_init.c
> @@ -467,7 +467,8 @@ int __init security_init(void)
>   						    blob_sizes.lbs_inode, 0,
>   						    SLAB_PANIC, NULL);
>   
> -	if (lsm_cred_alloc((struct cred __rcu *)current->cred, GFP_KERNEL))
> +	if (lsm_cred_alloc(unrcu_pointer((struct cred __rcu *)current->cred),
> +			   GFP_KERNEL))

Since the casting from const to non-const is inevitable, why not
directly cast it to (struct cred *)?

>   		panic("early LSM cred alloc failed\n");
>   	if (lsm_task_alloc(current))
>   		panic("early LSM task alloc failed\n");