Re: [PATCH] module: fix lost error code from codetag_load_module()

[Hao Ge <hao.ge@linux.dev>]

Hi Petr


On 2026/8/26 17:24, Petr Pavlu wrote:
> On 8/24/26 3:47 AM, Hao Ge wrote:
>> If codetag_load_module() fails, err is never set and load_module()
>> returns 0 after the module has been torn down.
>>
>> Fixes: 044d2aee6c57 ("alloc_tag: handle module codetag load errors as module load failures")
>> Reported-by: Sashiko <sashiko-bot@kernel.org>
>> Cc: stable@vger.kernel.org
>> Signed-off-by: Hao Ge <hao.ge@linux.dev>
>> ---
>>  kernel/module/main.c | 3 ++-
>>  1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/kernel/module/main.c b/kernel/module/main.c
>> index 46dd8d25a605..afb810f0154c 100644
>> --- a/kernel/module/main.c
>> +++ b/kernel/module/main.c
>> @@ -3568,7 +3568,8 @@ static int load_module(struct load_info *info, const char __user *uargs,
>>  			goto sysfs_cleanup;
>>  	}
>>  
>> -	if (codetag_load_module(mod))
>> +	err = codetag_load_module(mod);
>> +	if (err)
>>  		goto sysfs_cleanup;
>>  
>>  	/* Get rid of temporary copy. */
> 
> This looks ok to me but there appears another bug related to this code
> that would be good to fix at the same time. If the module is
> a livepatch, the preceding call to copy_module_elf() allocates
> mod->klp_info. However, if codetag_load_module() fails, the code doesn't
> free it.
> 

Yes, I missed that. Thanks for catching it!
I've folded your suggested fix into v2 (already sent) and tested it.

Thanks
Best Regards
Hao

> I think we want something like this (not tested):
> 
> diff --git a/kernel/module/main.c b/kernel/module/main.c
> index d0e1e0bd2ad0..c1b34dc1e89a 100644
> --- a/kernel/module/main.c
> +++ b/kernel/module/main.c
> @@ -3581,8 +3581,9 @@ static int load_module(struct load_info *info, const char __user *uargs,
>  			goto sysfs_cleanup;
>  	}
>  
> -	if (codetag_load_module(mod))
> -		goto sysfs_cleanup;
> +	err = codetag_load_module(mod);
> +	if (err)
> +		goto livepatch_cleanup;
>  
>  	/* Get rid of temporary copy. */
>  	free_copy(info, flags);
> @@ -3592,6 +3593,9 @@ static int load_module(struct load_info *info, const char __user *uargs,
>  
>  	return do_init_module(mod);
>  
> + livepatch_cleanup:
> +	if (is_livepatch_module(mod))
> +		free_module_elf(mod);
>   sysfs_cleanup:
>  	mod_sysfs_teardown(mod);
>   coming_cleanup:
>