linux-hardening - Re: [PATCH] rcuscale: using kmalloc

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Message-ID: <576c236f-3c12-42d9-b2cc-7367339fb37e@nfschina.com>
Date: Tue, 22 Apr 2025 09:37:39 +0800
From: Su Hui <suhui@...china.com>
To: paulmck@...nel.org
Cc: dave@...olabs.net, josh@...htriplett.org, frederic@...nel.org,
 neeraj.upadhyay@...nel.org, joel@...lfernandes.org, boqun.feng@...il.com,
 urezki@...il.com, rostedt@...dmis.org, mathieu.desnoyers@...icios.com,
 jiangshanlai@...il.com, qiang.zhang1211@...il.com,
 linux-kernel@...r.kernel.org, rcu@...r.kernel.org,
 kernel-janitors@...r.kernel.org, linux-hardening@...r.kernel.org
Subject: Re: [PATCH] rcuscale: using kmalloc_array() to relpace kmalloc()

On 2025/4/21 21:49, Paul E. McKenney wrote:
> On Mon, Apr 21, 2025 at 02:15:09PM +0800, Su Hui wrote:
>> It's safer to using kmalloc_array() because it can prevent overflow
>> problem.
>>
>> Signed-off-by: Su Hui <suhui@...china.com>
> Thank you!
>
> But isn't kcalloc just a wrapper around kmalloc_array() anyway?
Yes, and kcalloc() add the _GFP_ZERO flag. I can send a v2 patch with 
kcalloc().
Thanks for your suggestion.

Su Hui

>> ---
>>   kernel/rcu/rcuscale.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/kernel/rcu/rcuscale.c b/kernel/rcu/rcuscale.c
>> index 0f3059b1b80d..cbe2195f08d6 100644
>> --- a/kernel/rcu/rcuscale.c
>> +++ b/kernel/rcu/rcuscale.c
>> @@ -762,7 +762,7 @@ kfree_scale_thread(void *arg)
>>   		}
>>   
>>   		for (i = 0; i < kfree_alloc_num; i++) {
>> -			alloc_ptr = kmalloc(kfree_mult * sizeof(struct kfree_obj), GFP_KERNEL);
>> +			alloc_ptr = kmalloc_array(kfree_mult, sizeof(struct kfree_obj), GFP_KERNEL);
>>   			if (!alloc_ptr)
>>   				return -ENOMEM;
>>   
>> -- 
>> 2.30.2
>>
>>