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] ,
missed here :(
Signed-off-by: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
---
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)
