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Thu, 22 Jul 2021 04:01:04 -0700 (PDT) Date: Thu, 22 Jul 2021 13:00:58 +0200 From: Marco Elver To: Kefeng Wang Cc: Catalin Marinas , Will Deacon , Andrey Ryabinin , Andrey Konovalov , Dmitry Vyukov , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, linux-mm@kvack.org Subject: Re: [PATCH v2 3/3] kasan: arm64: Fix pcpu_page_first_chunk crash with KASAN_VMALLOC Message-ID: References: <20210720025105.103680-1-wangkefeng.wang@huawei.com> <20210720025105.103680-4-wangkefeng.wang@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210720025105.103680-4-wangkefeng.wang@huawei.com> User-Agent: Mutt/2.0.5 (2021-01-21) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jul 20, 2021 at 10:51AM +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. > > Signed-off-by: Kefeng Wang Acked-by: Marco Elver for the kasan bits. > --- > arch/arm64/mm/kasan_init.c | 17 +++++++++++++++++ > include/linux/kasan.h | 6 ++++++ > mm/kasan/init.c | 5 +++++ > mm/vmalloc.c | 1 + > 4 files changed, 29 insertions(+) > > diff --git a/arch/arm64/mm/kasan_init.c b/arch/arm64/mm/kasan_init.c > index 61b52a92b8b6..46c1b3722901 100644 > --- a/arch/arm64/mm/kasan_init.c > +++ b/arch/arm64/mm/kasan_init.c > @@ -287,6 +287,23 @@ static void __init kasan_init_depth(void) > init_task.kasan_depth = 0; > } > > +#ifdef CONFIG_KASAN_VMALLOC > +void __init kasan_populate_early_vm_area_shadow(void *start, unsigned long size) > +{ > + unsigned long shadow_start, shadow_end; > + > + if (!is_vmalloc_or_module_addr(start)) > + return; > + > + shadow_start = (unsigned long)kasan_mem_to_shadow(start); > + shadow_start = ALIGN_DOWN(shadow_start, PAGE_SIZE); > + shadow_end = (unsigned long)kasan_mem_to_shadow(start + size); > + shadow_end = ALIGN(shadow_end, PAGE_SIZE); > + kasan_map_populate(shadow_start, shadow_end, > + early_pfn_to_nid(virt_to_pfn(start))); > +} > +#endif > + > void __init kasan_init(void) > { > kasan_init_shadow(); > diff --git a/include/linux/kasan.h b/include/linux/kasan.h > index dd874a1ee862..3f8c26d9ef82 100644 > --- a/include/linux/kasan.h > +++ b/include/linux/kasan.h > @@ -133,6 +133,8 @@ struct kasan_cache { > bool is_kmalloc; > }; > > +void kasan_populate_early_vm_area_shadow(void *start, unsigned long size); > + > slab_flags_t __kasan_never_merge(void); > static __always_inline slab_flags_t kasan_never_merge(void) > { > @@ -303,6 +305,10 @@ void kasan_restore_multi_shot(bool enabled); > > #else /* CONFIG_KASAN */ > > +static inline void kasan_populate_early_vm_area_shadow(void *start, > + unsigned long size) > +{ } > + > static inline slab_flags_t kasan_never_merge(void) > { > return 0; > diff --git a/mm/kasan/init.c b/mm/kasan/init.c > index cc64ed6858c6..d39577d088a1 100644 > --- a/mm/kasan/init.c > +++ b/mm/kasan/init.c > @@ -279,6 +279,11 @@ int __ref kasan_populate_early_shadow(const void *shadow_start, > return 0; > } > > +void __init __weak kasan_populate_early_vm_area_shadow(void *start, > + unsigned long size) > +{ > +} > + > static void kasan_free_pte(pte_t *pte_start, pmd_t *pmd) > { > pte_t *pte; > diff --git a/mm/vmalloc.c b/mm/vmalloc.c > index a98cf97f032f..f19e07314ee5 100644 > --- a/mm/vmalloc.c > +++ b/mm/vmalloc.c > @@ -2249,6 +2249,7 @@ void __init vm_area_register_early(struct vm_struct *vm, size_t align) > vm->addr = (void *)addr; > > vm_area_add_early(vm); > + kasan_populate_early_vm_area_shadow(vm->addr, vm->size); > } > > static void vmap_init_free_space(void) > -- > 2.26.2