Re: [PATCH next] kernel/trace/trace_printk: Use kstrdup() instead of kmalloc() and strcpy()

[Masami Hiramatsu (Google) <mhiramat@kernel.org>]

On Sat,  6 Jun 2026 21:26:28 +0100
david.laight.linux@gmail.com wrote:

> From: David Laight <david.laight.linux@gmail.com>
> 
> Signed-off-by: David Laight <david.laight.linux@gmail.com>
> ---
> This is one of a group of patches that remove potentially unbounded
> strcpy() calls.
> 
> They are mostly replaced by strscpy() or, when strlen() has just been
> called, with memcpy() (usually including the '\0').
> 
> Calls with copy string literals into arrays are left unchanged.
> They are safe and easily detected as such.
> 
> The changes were made by getting the compiler to detect the calls and
> then fixing the code by hand.
> 
> Note that all the changes are only compile tested.
> 
> Some Makefiles were changed to allow files to contain strcpy().
> As well as 'difficult to fix' files, this included 'show' functions
> as they really need to use sysfs_emit() or seq_printf().
> 
> All the patches are being sent individually to avoid very long cc lists.
> Apologies for the terse commit messages and likely unexpected tags.
> (There are about 100 patches in total.)
> 

This looks good to me.

Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>

Thanks,

>  kernel/trace/trace_printk.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/kernel/trace/trace_printk.c b/kernel/trace/trace_printk.c
> index 3ea17af60169..98171a2398e4 100644
> --- a/kernel/trace/trace_printk.c
> +++ b/kernel/trace/trace_printk.c
> @@ -71,10 +71,9 @@ void hold_module_trace_bprintk_format(const char **start, const char **end)
>  		fmt = NULL;
>  		tb_fmt = kmalloc_obj(*tb_fmt);
>  		if (tb_fmt) {
> -			fmt = kmalloc(strlen(*iter) + 1, GFP_KERNEL);
> +			fmt = kstrdup(*iter, GFP_KERNEL);
>  			if (fmt) {
>  				list_add_tail(&tb_fmt->list, &trace_bprintk_fmt_list);
> -				strcpy(fmt, *iter);
>  				tb_fmt->fmt = fmt;
>  			} else
>  				kfree(tb_fmt);
> -- 
> 2.39.5
> 


-- 
Masami Hiramatsu (Google) <mhiramat@kernel.org>