Re: [PATCH v4 3/3] kasan: arm64: Fix pcpu_page_first_chunk crash with KASAN_VMALLOC

[Catalin Marinas]

On Fri, Sep 10, 2021 at 01:33:54PM +0800, Kefeng Wang wrote:
> With KASAN_VMALLOC and NEED_PER_CPU_PAGE_FIRST_CHUNK, it crashs,
> 
> Unable to handle kernel paging request at virtual address ffff7000028f2000
> ...
> swapper pgtable: 64k pages, 48-bit VAs, pgdp=0000000042440000
> [ffff7000028f2000] pgd=000000063e7c0003, p4d=000000063e7c0003, pud=000000063e7c0003, pmd=000000063e7b0003, pte=0000000000000000
> Internal error: Oops: 96000007 [#1] PREEMPT SMP
> Modules linked in:
> CPU: 0 PID: 0 Comm: swapper Not tainted 5.13.0-rc4-00003-gc6e6e28f3f30-dirty #62
> Hardware name: linux,dummy-virt (DT)
> pstate: 200000c5 (nzCv daIF -PAN -UAO -TCO BTYPE=--)
> pc : kasan_check_range+0x90/0x1a0
> lr : memcpy+0x88/0xf4
> sp : ffff80001378fe20
> ...
> Call trace:
>  kasan_check_range+0x90/0x1a0
>  pcpu_page_first_chunk+0x3f0/0x568
>  setup_per_cpu_areas+0xb8/0x184
>  start_kernel+0x8c/0x328
> 
> The vm area used in vm_area_register_early() has no kasan shadow memory,
> Let's add a new kasan_populate_early_vm_area_shadow() function to populate
> the vm area shadow memory to fix the issue.
> 
> Acked-by: Marco Elver <elver@xxxxxxxxxx> (for KASAN parts)
> Acked-by: Andrey Konovalov <andreyknvl@xxxxxxxxx> (for KASAN parts)
> Signed-off-by: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>

It looks like I only acked patch 2 previously, so here it is:

Acked-by: Catalin Marinas <catalin.marinas@xxxxxxx>