Re: [PATCH v3 3/3] kasan: arm64: Fix pcpu_page_first_chunk crash with KASAN_VMALLOC

[Kefeng Wang]

On 2021/8/9 19:21, Marco Elver wrote:
> On Mon, 9 Aug 2021 at 13:10, Kefeng Wang <wangkefeng.wang@xxxxxxxxxx> wrote:
> > On 2021/8/9 17:37, 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.
> > Should add Acked-by: Marco Elver <elver@xxxxxxxxxx> [for KASAN parts] ,
> My Ack is still valid, thanks for noting.
Thanks,  Marco ;)