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In-Reply-To: <516dc726dc6311d8bb9f1a90258190f628a3b636.1640036051.git.andreyknvl@google.com>
From:   Alexander Potapenko <glider@google.com>
Date:   Tue, 21 Dec 2021 12:50:17 +0100
Message-ID: <CAG_fn=UJErkCbrF5f6RW8RbvKLV3k6Gxb-ZrjPMMbS5MvNtN0Q@mail.gmail.com>
Subject: Re: [PATCH mm v4 26/39] kasan, vmalloc: unpoison VM_ALLOC pages after mapping
To:     andrey.konovalov@linux.dev
Cc:     Marco Elver <elver@google.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Andrey Konovalov <andreyknvl@gmail.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        Andrey Ryabinin <ryabinin.a.a@gmail.com>,
        kasan-dev <kasan-dev@googlegroups.com>,
        Linux Memory Management List <linux-mm@kvack.org>,
        Vincenzo Frascino <vincenzo.frascino@arm.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        Peter Collingbourne <pcc@google.com>,
        Evgenii Stepanov <eugenis@google.com>,
        LKML <linux-kernel@vger.kernel.org>,
        Andrey Konovalov <andreyknvl@google.com>
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On Mon, Dec 20, 2021 at 11:02 PM <andrey.konovalov@linux.dev> wrote:
>
> From: Andrey Konovalov <andreyknvl@google.com>
>
> Make KASAN unpoison vmalloc mappings after they have been mapped in
> when it's possible: for vmalloc() (indentified via VM_ALLOC) and
> vm_map_ram().
>
> The reasons for this are:
>
> - For vmalloc() and vm_map_ram(): pages don't get unpoisoned in case
>   mapping them fails.
> - For vmalloc(): HW_TAGS KASAN needs pages to be mapped to set tags via
>   kasan_unpoison_vmalloc().
>
> As a part of these changes, the return value of __vmalloc_node_range()
> is changed to area->addr. This is a non-functional change, as
> __vmalloc_area_node() returns area->addr anyway.
>
> Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>