Re: [PATCH 1/4] vmalloc: add vm_flags argument to internal __vmalloc_node()

From: Andrey Ryabinin <aryabinin@virtuozzo.com>
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
Subject: Re: [PATCH 1/4] vmalloc: add vm_flags argument to internal __vmalloc_node()
Date: Wed, 21 Feb 2018 15:39:26 +0300	[thread overview]
Message-ID: <6e4ab6e1-7ba5-4b18-9399-75eb593050ac@virtuozzo.com> (raw)
In-Reply-To: <20180221122444.GA11791@bombadil.infradead.org>

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;
>  	}
> 