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Subject: Re: [PATCH] kasan: support vmalloc backing of vm_map_ram()
To:     Daniel Axtens <dja@axtens.net>, kasan-dev@googlegroups.com,
        linux-mm@kvack.org, x86@kernel.org, glider@google.com,
        linux-kernel@vger.kernel.org, dvyukov@google.com
Cc:     Qian Cai <cai@lca.pw>
References: <20191129154519.30964-1-dja@axtens.net>
From:   Andrey Ryabinin <aryabinin@virtuozzo.com>
Message-ID: <cac9cbcf-4286-ae34-d150-79ea81a366b0@virtuozzo.com>
Date:   Wed, 4 Dec 2019 23:44:29 +0300
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On 11/29/19 6:45 PM, Daniel Axtens wrote:
> @@ -1826,7 +1842,15 @@ void *vm_map_ram(struct page **pages, unsigned int count, int node, pgprot_t pro
>  
>  		addr = va->va_start;
>  		mem = (void *)addr;
> +
> +		if (kasan_populate_vmalloc_area(size, mem)) {
> +			vm_unmap_ram(mem, count);
> +			return NULL;
> +		}
>  	}
> +
> +	kasan_unpoison_shadow(mem, size);
> +

This probably gonna explode on CONFIG_KASAN=y && CONFIG_KASAN_VMALLOC=n

I've sent alternative patch which fixes vm_map_ram() and also makes the code a bit easier to follow in my opinion.

>  	if (vmap_page_range(addr, addr + size, prot, pages) < 0) {
>  		vm_unmap_ram(mem, count);
>  		return NULL;
>