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Subject: Re: [PATCH 1/4] vmalloc: add vm_flags argument to internal
 __vmalloc_node()
To:     Matthew Wilcox <willy@infradead.org>,
        Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc:     Dave Hansen <dave.hansen@intel.com>, linux-kernel@vger.kernel.org,
        Christoph Hellwig <hch@infradead.org>, linux-mm@kvack.org,
        Andy Lutomirski <luto@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        kasan-dev@googlegroups.com
References: <151670492223.658225.4605377710524021456.stgit@buzz>
 <20180221122444.GA11791@bombadil.infradead.org>
From:   Andrey Ryabinin <aryabinin@virtuozzo.com>
Message-ID: <6e4ab6e1-7ba5-4b18-9399-75eb593050ac@virtuozzo.com>
Date:   Wed, 21 Feb 2018 15:39:26 +0300
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On 02/21/2018 03:24 PM, Matthew Wilcox wrote:
> On Tue, Jan 23, 2018 at 01:55:22PM +0300, Konstantin Khlebnikov wrote:
>> This allows to set VM_USERMAP in vmalloc_user() and vmalloc_32_user()
>> directly at allocation and avoid find_vm_area() call.
> 
> While reviewing this patch, I came across this infelicity ...
> 
> have I understood correctly?
> 
> diff --git a/mm/kasan/kasan.c b/mm/kasan/kasan.c
> index e13d911251e7..9060f80b4a41 100644
> --- a/mm/kasan/kasan.c
> +++ b/mm/kasan/kasan.c
> @@ -631,11 +631,10 @@ int kasan_module_alloc(void *addr, size_t size)
>  	ret = __vmalloc_node_range(shadow_size, 1, shadow_start,
>  			shadow_start + shadow_size,
>  			GFP_KERNEL | __GFP_ZERO,
> -			PAGE_KERNEL, VM_NO_GUARD, NUMA_NO_NODE,
> +			PAGE_KERNEL, VM_NO_GUARD | VM_KASAN, NUMA_NO_NODE,
>  			__builtin_return_address(0));
>  
>  	if (ret) {
> -		find_vm_area(addr)->flags |= VM_KASAN;

addr != ret
That's different vm areas.

>  		kmemleak_ignore(ret);
>  		return 0;
>  	}
>