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Date:   Tue, 2 Nov 2021 15:39:16 +0100
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Subject: Re: [PATCH v2] mm, slub: emit the "free" trace report before freeing
 memory in kmem_cache_free()
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To:     Tang Yizhou <tangyizhou@huawei.com>,
        Yunfeng Ye <yeyunfeng@huawei.com>, cl@linux.com,
        penberg@kernel.org, rientjes@google.com, iamjoonsoo.kim@lge.com,
        Andrew Morton <akpm@linux-foundation.org>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org
Cc:     jhubbard@nvidia.com, songmuchun@bytedance.com, willy@infradead.org,
        wuxu.wu@huawei.com, Hewenliang <hewenliang4@huawei.com>
References: <a6824ebe-a0ad-fedb-ada3-c362f9c8f363@huawei.com>
 <ee45ee4c-0993-e752-f4fc-fed519b67525@huawei.com>
From:   Vlastimil Babka <vbabka@suse.cz>
In-Reply-To: <ee45ee4c-0993-e752-f4fc-fed519b67525@huawei.com>
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On 11/2/21 14:53, Tang Yizhou wrote:
> On 2021/11/2 19:43, Yunfeng Ye wrote:
>> --- a/mm/slub.c
>> +++ b/mm/slub.c
>> @@ -3526,8 +3526,8 @@ void kmem_cache_free(struct kmem_cache *s, void *x)
>>  	s = cache_from_obj(s, x);
>>  	if (!s)
>>  		return;
>> -	slab_free(s, virt_to_head_page(x), x, NULL, 1, _RET_IP_);
>>  	trace_kmem_cache_free(_RET_IP_, x, s->name);
>> +	slab_free(s, virt_to_head_page(x), x, NULL, 1, _RET_IP_);
>>  }
> 
> It seems that kmem_cache_free() in mm/slab.c has the same problem.
> We can fix it. Thanks.

Doh, true. Should go best before the local_irq_save() there.
And also kmem_cache_free() in mm/slob.c.

Interestingly kfree() is already OK in all 3 implementations.

>>  EXPORT_SYMBOL(kmem_cache_free);
>> 
>