Re: [PATCH 1/1] lib/alloc_tag: do not register sysctl interface when CONFIG_SYSCTL=n

[Vlastimil Babka <vbabka@suse.cz>]

On 6/2/24 1:38 AM, Suren Baghdasaryan wrote:
> Memory allocation profiling is trying to register sysctl interface even
> when CONFIG_SYSCTL=n, resulting in proc_do_static_key() being undefined.
> Prevent that by skipping sysctl registration for such configurations.
> 
> Fixes: 22d407b164ff ("lib: add allocation tagging support for memory allocation profiling")
> Reported-by: kernel test robot <lkp@intel.com>
> Closes: https://lore.kernel.org/oe-kbuild-all/202405280616.wcOGWJEj-lkp@intel.com/
> Signed-off-by: Suren Baghdasaryan <surenb@google.com>
> Cc: Kent Overstreet <kent.overstreet@linux.dev>

Acked-by: Vlastimil Babka <vbabka@suse.cz>

> ---
>  lib/alloc_tag.c | 16 +++++++++++++---
>  1 file changed, 13 insertions(+), 3 deletions(-)
> 
> diff --git a/lib/alloc_tag.c b/lib/alloc_tag.c
> index 11ed973ac359..c347b8b72d78 100644
> --- a/lib/alloc_tag.c
> +++ b/lib/alloc_tag.c
> @@ -227,6 +227,7 @@ struct page_ext_operations page_alloc_tagging_ops = {
>  };
>  EXPORT_SYMBOL(page_alloc_tagging_ops);
>  
> +#ifdef CONFIG_SYSCTL
>  static struct ctl_table memory_allocation_profiling_sysctls[] = {
>  	{
>  		.procname	= "mem_profiling",
> @@ -241,6 +242,17 @@ static struct ctl_table memory_allocation_profiling_sysctls[] = {
>  	{ }
>  };
>  
> +static void __init sysctl_init(void)
> +{
> +	if (!mem_profiling_support)
> +		memory_allocation_profiling_sysctls[0].mode = 0444;
> +
> +	register_sysctl_init("vm", memory_allocation_profiling_sysctls);
> +}
> +#else /* CONFIG_SYSCTL */
> +static inline void sysctl_init(void) {}
> +#endif /* CONFIG_SYSCTL */
> +
>  static int __init alloc_tag_init(void)
>  {
>  	const struct codetag_type_desc desc = {
> @@ -253,9 +265,7 @@ static int __init alloc_tag_init(void)
>  	if (IS_ERR(alloc_tag_cttype))
>  		return PTR_ERR(alloc_tag_cttype);
>  
> -	if (!mem_profiling_support)
> -		memory_allocation_profiling_sysctls[0].mode = 0444;
> -	register_sysctl_init("vm", memory_allocation_profiling_sysctls);
> +	sysctl_init();
>  	procfs_init();
>  
>  	return 0;
> 
> base-commit: 065d3634d60843b8e338d405b844cc7f2e5e1c66