Re: kernel/trace/ftrace.c:6651:40: sparse: sparse: incorrect type in assignment (different address spaces)

[Steven Rostedt]

Can you send this as a proper patch to linux-trace-kernel@xxxxxxxxxxxxxxx

Thanks,

-- Steve


On Fri, 11 Sep 2026 11:14:00 +0800
Leon Hwang <leon.hwang@xxxxxxxxx> wrote:

> >From 03079b720a8cba88b3da579acfbcf88d983a838d Mon Sep 17 00:00:00 2001  
> From: Leon Hwang <leon.hwang@xxxxxxxxx>
> Date: Fri, 11 Sep 2026 10:43:13 +0800
> Subject: [PATCH] ftrace: Use rcu_assign_pointer() for tmp_ops filter hash
> 
> tmp_ops.func_hash->filter_hash is annotated __rcu, but
> update_ftrace_direct_mod() assigns hash to it directly. Sparse reports an
> address-space mismatch.
> 
> Use rcu_assign_pointer() for the assignment.
> 
> Fixes: 50b35c9e50a8 ("ftrace: Use hash argument for tmp_ops in
> update_ftrace_direct_mod")
> Reported-by: kernel test robot <lkp@xxxxxxxxx>
> Closes:
> https://lore.kernel.org/oe-kbuild-all/202609110704.Q3M5vCDV-lkp@xxxxxxxxx/
> Signed-off-by: Leon Hwang <leon.hwang@xxxxxxxxx>
> ---
>  kernel/trace/ftrace.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
> index 53d5db60bfa5..673a54fdf392 100644
> --- a/kernel/trace/ftrace.c
> +++ b/kernel/trace/ftrace.c
> @@ -6675,7 +6675,7 @@ int update_ftrace_direct_mod(struct ftrace_ops
> *ops, struct ftrace_hash *hash, b
> 
>         /* Enable the tmp_ops to have the same functions as the hash
> object. */
>         ftrace_ops_init(&tmp_ops);
> -       tmp_ops.func_hash->filter_hash = hash;
> +       rcu_assign_pointer(tmp_ops.func_hash->filter_hash, hash);
> 
>         err = register_ftrace_function_nolock(&tmp_ops);
>         if (err)
> --
> 2.55.0