linux-kernel - Re: [PATCH 1/1] mm/mm_init.c: eliminate a local variable in mem_debugging_and_hardening

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <016273da-8f11-4cfa-a5c0-6e5dd60956be@arm.com>
Date: Tue, 19 Mar 2024 11:53:15 +0530
From: Anshuman Khandual <anshuman.khandual@....com>
To: Mike Rapoport <rppt@...nel.org>, thunder.leizhen@...weicloud.com
Cc: Andrew Morton <akpm@...ux-foundation.org>, linux-mm@...ck.org,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/1] mm/mm_init.c: eliminate a local variable in
 mem_debugging_and_hardening_init()



On 3/18/24 22:03, Mike Rapoport wrote:
> On Mon, Mar 18, 2024 at 09:57:14PM +0800, thunder.leizhen@...weicloud.com wrote:
>> From: Zhen Lei <thunder.leizhen@...wei.com>
>>
>> The local variable 'page_poisoning_requested' is assigned true at only
>> one point. It can be eliminated by moving the code that depends on it
>> to the location where it is assigned true. This also make the moved
>> code to be compiled only if CONFIG_PAGE_POISONING is set.
> 
> I don't see it as much of an improvement and code readability becomes worse
> IMO.

+1 agreed.

>  
>> Signed-off-by: Zhen Lei <thunder.leizhen@...wei.com>
>> ---
>>  mm/mm_init.c | 17 +++++++----------
>>  1 file changed, 7 insertions(+), 10 deletions(-)
>>
>> diff --git a/mm/mm_init.c b/mm/mm_init.c
>> index 549e76af8f82a8e..3eb217130bcb2b5 100644
>> --- a/mm/mm_init.c
>> +++ b/mm/mm_init.c
>> @@ -2614,7 +2614,6 @@ DEFINE_STATIC_KEY_MAYBE(CONFIG_DEBUG_VM, check_pages_enabled);
>>   */
>>  static void __init mem_debugging_and_hardening_init(void)
>>  {
>> -	bool page_poisoning_requested = false;
>>  	bool want_check_pages = false;
>>  
>>  #ifdef CONFIG_PAGE_POISONING
>> @@ -2626,18 +2625,16 @@ static void __init mem_debugging_and_hardening_init(void)
>>  	     (!IS_ENABLED(CONFIG_ARCH_SUPPORTS_DEBUG_PAGEALLOC) &&
>>  	      debug_pagealloc_enabled())) {
>>  		static_branch_enable(&_page_poisoning_enabled);
>> -		page_poisoning_requested = true;
>>  		want_check_pages = true;
>> -	}
>> -#endif
>>  
>> -	if ((_init_on_alloc_enabled_early || _init_on_free_enabled_early) &&
>> -	    page_poisoning_requested) {
>> -		pr_info("mem auto-init: CONFIG_PAGE_POISONING is on, "
>> -			"will take precedence over init_on_alloc and init_on_free\n");
>> -		_init_on_alloc_enabled_early = false;
>> -		_init_on_free_enabled_early = false;
>> +		if (_init_on_alloc_enabled_early || _init_on_free_enabled_early) {
>> +			pr_info("mem auto-init: CONFIG_PAGE_POISONING is on, "
>> +				"will take precedence over init_on_alloc and init_on_free\n");
>> +			_init_on_alloc_enabled_early = false;
>> +			_init_on_free_enabled_early = false;
>> +		}
>>  	}
>> +#endif
>>  
>>  	if (_init_on_alloc_enabled_early) {
>>  		want_check_pages = true;
>> -- 
>> 2.34.1
>>
>