Re: [PATCH RFC v2 07/13] sysctl, net: update register_net_sysctl{_sz}() callers with template arguments

[Mauricio Faria de Oliveira <mfo@igalia.com>]

On 2026-08-18 23:48, sashiko-bot@kernel.org wrote:
> Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:
> - [Low] Syntax error and implicit function declaration when CONFIG_SYSCTL is disabled due to macro collision.
> - [Low] The `__UNIQUE_ID` macro is used without arguments in `__MODULE_SYSCTL_TABLE_NAME`, preventing it from generating a unique identifier.

Both fixed previously.

> --
> 
> --- Patch [7]: [PATCH RFC v2 07/13] sysctl, net: update register_net_sysctl{_sz}() callers with template arguments ---
> commit 35e3405d9382d3cfe84c302ce928023b61da151b
> Author: Mauricio Faria de Oliveira <mfo@igalia.com>
> 
> sysctl, net: update register_net_sysctl{_sz}() callers with template arguments
> 
> Update most callers with dynamic table/path to use template arguments.
> 
>> diff --git a/net/core/neighbour.c b/net/core/neighbour.c
>> index 1349c0eedb642..bdd67dd879d24 100644
>> --- a/net/core/neighbour.c
>> +++ b/net/core/neighbour.c
>> @@ -12,6 +12,7 @@
>>   */
>> 
>>  #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
>> +#define SYSCTL_MODULE_ALIASES_UNIQUE_ID
> 
> [Severity: Low]
> When SYSCTL_MODULE_ALIASES_UNIQUE_ID is defined here, the macro
> __MODULE_SYSCTL_TABLE_NAME(table) in include/linux/sysctl.h expands to
> __mod_device_table(sysctl, __UNIQUE_ID).
> 
> Since __UNIQUE_ID is a function-like macro requiring a prefix argument, does
> omitting the parentheses prevent it from being expanded by the preprocessor?
> Could this create identical literal symbol names for all instances in a module
> and defeat the uniqueness mechanism?
> 
>> 
>>  #include <linux/slab.h>
>>  #include <linux/types.h>
> [ ... ]
>> @@ -3910,11 +3911,15 @@ int neigh_sysctl_register(struct net_device *dev, struct neigh_parms *p,
>>  	      BUG();
>>  	}
>> 
>> -	snprintf(neigh_path, sizeof(neigh_path), "net/%s/neigh/%s",
>> -		p_name, dev_name_source);
>> +#define path_template "net/%s/neigh/%s"
>> +	snprintf(neigh_path, sizeof(neigh_path), path_template,
>> +		 p_name, dev_name_source);
>>  	t->sysctl_header = register_net_sysctl_sz(neigh_parms_net(p),
>>  						  neigh_path, t->neigh_vars,
>> -						  neigh_vars_size);
>> +						  neigh_vars_size,
>> +						  neigh_sysctl_template.neigh_vars,
>> +						  path_template);
> 
> [Severity: Low]
> Does this call to register_net_sysctl_sz() cause a build failure when
> CONFIG_SYSCTL is disabled?
> 
> It looks like register_net_sysctl_sz is globally defined as a macro, which
> unconditionally expands over the static inline fallback definition in
> include/net/net_namespace.h, producing invalid C syntax. Additionally, would
> this macro expand to __register_net_sysctl_sz(), which lacks a stub in the
> !CONFIG_SYSCTL path, causing implicit function declaration errors?
> 
>> +#undef path_template
>>  	if (!t->sysctl_header)
>>  		goto free;

-- 
Mauricio