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bh=MkFYGolSn2w76q7qvE9Vgn56UKUzs1q54gLC/lVyUL0=; b=OHsPb9VFxpcrwzQ/ugk7ZC3FJUsPK8WnkQuZiB11Sbc5a+qCoHckfsyQPkKEbGp4uY 1oXYC16C7h9CmHHD9QI4YhntI0yCzFlbbLXeSIYIcdgSrHjHrXo1bhXBXWVAyk64tkis gcuy1pAcuIGRZ4VHfzB3wgUqW1LpBBIUKNEIJF/4ZA85kFhKVrlnngHNalfHef0hJg2H 6IEyfLaE8Wj4InD5FpdWk5k8f0rb+VAmftwbDAKt0ILqxITBEKLLsar3um+g7JIgKUEi 8AL2FjT4x3OF3x9YwVCQIO04YPV+GyjfarXJZgzqakBFbHM8ovVdOO4jHwZro7XTzCUY LGVw== X-Gm-Message-State: AOAM532I8dz7IenjVlJFHINSuH48SMy/QrzVyCfPs7wNqFFJ/sy5m441 6PiFA9LbnSz1JSONU6IxYuQf/6TcNFCc7P2LZrDOKA== X-Google-Smtp-Source: ABdhPJw2dAx0xwZwf7oFVAglW4Mx/VmIQLu0Vm32HDbc5/1HQi39uzQswpjxiizzKhJAa4SszTrlfB8qBvg9IZhyb4I= X-Received: by 2002:aca:2316:: with SMTP id e22mr9967822oie.172.1628508115719; Mon, 09 Aug 2021 04:21:55 -0700 (PDT) MIME-Version: 1.0 References: <20210809093750.131091-1-wangkefeng.wang@huawei.com> <20210809093750.131091-4-wangkefeng.wang@huawei.com> In-Reply-To: From: Marco Elver Date: Mon, 9 Aug 2021 13:21:44 +0200 Message-ID: Subject: Re: [PATCH v3 3/3] kasan: arm64: Fix pcpu_page_first_chunk crash with KASAN_VMALLOC To: Kefeng Wang Cc: will@kernel.org, catalin.marinas@arm.com, ryabinin.a.a@gmail.com, andreyknvl@gmail.com, dvyukov@google.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, linux-mm@kvack.org Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 9 Aug 2021 at 13:10, Kefeng Wang 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 [for KASAN parts] , My Ack is still valid, thanks for noting. > > Signed-off-by: Kefeng Wang > > --- > > arch/arm64/mm/kasan_init.c | 16 ++++++++++++++++ > > include/linux/kasan.h | 6 ++++++ > > mm/kasan/init.c | 5 +++++ > > mm/vmalloc.c | 1 + > > 4 files changed, 28 insertions(+) > > > > diff --git a/arch/arm64/mm/kasan_init.c b/arch/arm64/mm/kasan_init.c > > index 61b52a92b8b6..5b996ca4d996 100644 > > --- a/arch/arm64/mm/kasan_init.c > > +++ b/arch/arm64/mm/kasan_init.c > > @@ -287,6 +287,22 @@ 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, NUMA_NO_NODE); > > +} > > +#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 1e8fe08725b8..66a7e1ea2561 100644 > > --- a/mm/vmalloc.c > > +++ b/mm/vmalloc.c > > @@ -2253,6 +2253,7 @@ 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)