Commit 0207df4f authored by Andrey Ryabinin's avatar Andrey Ryabinin Committed by Linus Torvalds
Browse files

kernel/memremap, kasan: make ZONE_DEVICE with work with KASAN

KASAN learns about hotadded memory via the memory hotplug notifier.
devm_memremap_pages() intentionally skips calling memory hotplug
notifiers.  So KASAN doesn't know anything about new memory added by
devm_memremap_pages().  This causes a crash when KASAN tries to access
non-existent shadow memory:

 BUG: unable to handle kernel paging request at ffffed0078000000
 RIP: 0010:check_memory_region+0x82/0x1e0
 Call Trace:
  memcpy+0x1f/0x50
  pmem_do_bvec+0x163/0x720
  pmem_make_request+0x305/0xac0
  generic_make_request+0x54f/0xcf0
  submit_bio+0x9c/0x370
  submit_bh_wbc+0x4c7/0x700
  block_read_full_page+0x5ef/0x870
  do_read_cache_page+0x2b8/0xb30
  read_dev_sector+0xbd/0x3f0
  read_lba.isra.0+0x277/0x670
  efi_partition+0x41a/0x18f0
  check_partition+0x30d/0x5e9
  rescan_partitions+0x18c/0x840
  __blkdev_get+0x859/0x1060
  blkdev_get+0x23f/0x810
  __device_add_disk+0x9c8/0xde0
  pmem_attach_disk+0x9a8/0xf50
  nvdimm_bus_probe+0xf3/0x3c0
  driver_probe_device+0x493/0xbd0
  bus_for_each_drv+0x118/0x1b0
  __device_attach+0x1cd/0x2b0
  bus_probe_device+0x1ac/0x260
  device_add+0x90d/0x1380
  nd_async_device_register+0xe/0x50
  async_run_entry_fn+0xc3/0x5d0
  process_one_work+0xa0a/0x1810
  worker_thread+0x87/0xe80
  kthread+0x2d7/0x390
  ret_from_fork+0x3a/0x50

Add kasan_add_zero_shadow()/kasan_remove_zero_shadow() - post mm_init()
interface to map/unmap kasan_zero_page at requested virtual addresses.
And use it to add/remove the shadow memory for hotplugged/unplugged
device memory.

Link: http://lkml.kernel.org/r/20180629164932.740-1-aryabinin@virtuozzo.com
Fixes: 41e94a85

 ("add devm_memremap_pages")
Signed-off-by: default avatarAndrey Ryabinin <aryabinin@virtuozzo.com>
Reported-by: default avatarDave Chinner <david@fromorbit.com>
Reviewed-by: default avatarDan Williams <dan.j.williams@intel.com>
Tested-by: default avatarDan Williams <dan.j.williams@intel.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Alexander Potapenko <glider@google.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 50f8b92f
......@@ -20,7 +20,7 @@ extern pmd_t kasan_zero_pmd[PTRS_PER_PMD];
extern pud_t kasan_zero_pud[PTRS_PER_PUD];
extern p4d_t kasan_zero_p4d[MAX_PTRS_PER_P4D];
void kasan_populate_zero_shadow(const void *shadow_start,
int kasan_populate_zero_shadow(const void *shadow_start,
const void *shadow_end);
static inline void *kasan_mem_to_shadow(const void *addr)
......@@ -71,6 +71,9 @@ struct kasan_cache {
int kasan_module_alloc(void *addr, size_t size);
void kasan_free_shadow(const struct vm_struct *vm);
int kasan_add_zero_shadow(void *start, unsigned long size);
void kasan_remove_zero_shadow(void *start, unsigned long size);
size_t ksize(const void *);
static inline void kasan_unpoison_slab(const void *ptr) { ksize(ptr); }
size_t kasan_metadata_size(struct kmem_cache *cache);
......@@ -124,6 +127,14 @@ static inline bool kasan_slab_free(struct kmem_cache *s, void *object,
static inline int kasan_module_alloc(void *addr, size_t size) { return 0; }
static inline void kasan_free_shadow(const struct vm_struct *vm) {}
static inline int kasan_add_zero_shadow(void *start, unsigned long size)
{
return 0;
}
static inline void kasan_remove_zero_shadow(void *start,
unsigned long size)
{}
static inline void kasan_unpoison_slab(const void *ptr) { }
static inline size_t kasan_metadata_size(struct kmem_cache *cache) { return 0; }
......
......@@ -5,6 +5,7 @@
#include <linux/types.h>
#include <linux/pfn_t.h>
#include <linux/io.h>
#include <linux/kasan.h>
#include <linux/mm.h>
#include <linux/memory_hotplug.h>
#include <linux/swap.h>
......@@ -137,6 +138,7 @@ static void devm_memremap_pages_release(void *data)
mem_hotplug_begin();
arch_remove_memory(align_start, align_size, pgmap->altmap_valid ?
&pgmap->altmap : NULL);
kasan_remove_zero_shadow(__va(align_start), align_size);
mem_hotplug_done();
untrack_pfn(NULL, PHYS_PFN(align_start), align_size);
......@@ -239,6 +241,12 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap)
goto err_pfn_remap;
mem_hotplug_begin();
error = kasan_add_zero_shadow(__va(align_start), align_size);
if (error) {
mem_hotplug_done();
goto err_kasan;
}
error = arch_add_memory(nid, align_start, align_size, altmap, false);
if (!error)
move_pfn_range_to_zone(&NODE_DATA(nid)->node_zones[ZONE_DEVICE],
......@@ -267,6 +275,8 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap)
return __va(res->start);
err_add_memory:
kasan_remove_zero_shadow(__va(align_start), align_size);
err_kasan:
untrack_pfn(NULL, PHYS_PFN(align_start), align_size);
err_pfn_remap:
err_radix:
......
......@@ -17,10 +17,13 @@
#include <linux/memblock.h>
#include <linux/mm.h>
#include <linux/pfn.h>
#include <linux/slab.h>
#include <asm/page.h>
#include <asm/pgalloc.h>
#include "kasan.h"
/*
* This page serves two purposes:
* - It used as early shadow memory. The entire shadow region populated
......@@ -32,22 +35,59 @@ unsigned char kasan_zero_page[PAGE_SIZE] __page_aligned_bss;
#if CONFIG_PGTABLE_LEVELS > 4
p4d_t kasan_zero_p4d[MAX_PTRS_PER_P4D] __page_aligned_bss;
static inline bool kasan_p4d_table(pgd_t pgd)
{
return pgd_page(pgd) == virt_to_page(lm_alias(kasan_zero_p4d));
}
#else
static inline bool kasan_p4d_table(pgd_t pgd)
{
return 0;
}
#endif
#if CONFIG_PGTABLE_LEVELS > 3
pud_t kasan_zero_pud[PTRS_PER_PUD] __page_aligned_bss;
static inline bool kasan_pud_table(p4d_t p4d)
{
return p4d_page(p4d) == virt_to_page(lm_alias(kasan_zero_pud));
}
#else
static inline bool kasan_pud_table(p4d_t p4d)
{
return 0;
}
#endif
#if CONFIG_PGTABLE_LEVELS > 2
pmd_t kasan_zero_pmd[PTRS_PER_PMD] __page_aligned_bss;
static inline bool kasan_pmd_table(pud_t pud)
{
return pud_page(pud) == virt_to_page(lm_alias(kasan_zero_pmd));
}
#else
static inline bool kasan_pmd_table(pud_t pud)
{
return 0;
}
#endif
pte_t kasan_zero_pte[PTRS_PER_PTE] __page_aligned_bss;
static inline bool kasan_pte_table(pmd_t pmd)
{
return pmd_page(pmd) == virt_to_page(lm_alias(kasan_zero_pte));
}
static inline bool kasan_zero_page_entry(pte_t pte)
{
return pte_page(pte) == virt_to_page(lm_alias(kasan_zero_page));
}
static __init void *early_alloc(size_t size, int node)
{
return memblock_virt_alloc_try_nid(size, size, __pa(MAX_DMA_ADDRESS),
BOOTMEM_ALLOC_ACCESSIBLE, node);
}
static void __init zero_pte_populate(pmd_t *pmd, unsigned long addr,
static void __ref zero_pte_populate(pmd_t *pmd, unsigned long addr,
unsigned long end)
{
pte_t *pte = pte_offset_kernel(pmd, addr);
......@@ -63,7 +103,7 @@ static void __init zero_pte_populate(pmd_t *pmd, unsigned long addr,
}
}
static void __init zero_pmd_populate(pud_t *pud, unsigned long addr,
static int __ref zero_pmd_populate(pud_t *pud, unsigned long addr,
unsigned long end)
{
pmd_t *pmd = pmd_offset(pud, addr);
......@@ -78,14 +118,24 @@ static void __init zero_pmd_populate(pud_t *pud, unsigned long addr,
}
if (pmd_none(*pmd)) {
pmd_populate_kernel(&init_mm, pmd,
early_alloc(PAGE_SIZE, NUMA_NO_NODE));
pte_t *p;
if (slab_is_available())
p = pte_alloc_one_kernel(&init_mm, addr);
else
p = early_alloc(PAGE_SIZE, NUMA_NO_NODE);
if (!p)
return -ENOMEM;
pmd_populate_kernel(&init_mm, pmd, p);
}
zero_pte_populate(pmd, addr, next);
} while (pmd++, addr = next, addr != end);
return 0;
}
static void __init zero_pud_populate(p4d_t *p4d, unsigned long addr,
static int __ref zero_pud_populate(p4d_t *p4d, unsigned long addr,
unsigned long end)
{
pud_t *pud = pud_offset(p4d, addr);
......@@ -103,14 +153,24 @@ static void __init zero_pud_populate(p4d_t *p4d, unsigned long addr,
}
if (pud_none(*pud)) {
pud_populate(&init_mm, pud,
early_alloc(PAGE_SIZE, NUMA_NO_NODE));
pmd_t *p;
if (slab_is_available()) {
p = pmd_alloc(&init_mm, pud, addr);
if (!p)
return -ENOMEM;
} else {
pud_populate(&init_mm, pud,
early_alloc(PAGE_SIZE, NUMA_NO_NODE));
}
}
zero_pmd_populate(pud, addr, next);
} while (pud++, addr = next, addr != end);
return 0;
}
static void __init zero_p4d_populate(pgd_t *pgd, unsigned long addr,
static int __ref zero_p4d_populate(pgd_t *pgd, unsigned long addr,
unsigned long end)
{
p4d_t *p4d = p4d_offset(pgd, addr);
......@@ -132,11 +192,21 @@ static void __init zero_p4d_populate(pgd_t *pgd, unsigned long addr,
}
if (p4d_none(*p4d)) {
p4d_populate(&init_mm, p4d,
early_alloc(PAGE_SIZE, NUMA_NO_NODE));
pud_t *p;
if (slab_is_available()) {
p = pud_alloc(&init_mm, p4d, addr);
if (!p)
return -ENOMEM;
} else {
p4d_populate(&init_mm, p4d,
early_alloc(PAGE_SIZE, NUMA_NO_NODE));
}
}
zero_pud_populate(p4d, addr, next);
} while (p4d++, addr = next, addr != end);
return 0;
}
/**
......@@ -145,7 +215,7 @@ static void __init zero_p4d_populate(pgd_t *pgd, unsigned long addr,
* @shadow_start - start of the memory range to populate
* @shadow_end - end of the memory range to populate
*/
void __init kasan_populate_zero_shadow(const void *shadow_start,
int __ref kasan_populate_zero_shadow(const void *shadow_start,
const void *shadow_end)
{
unsigned long addr = (unsigned long)shadow_start;
......@@ -191,9 +261,229 @@ void __init kasan_populate_zero_shadow(const void *shadow_start,
}
if (pgd_none(*pgd)) {
pgd_populate(&init_mm, pgd,
early_alloc(PAGE_SIZE, NUMA_NO_NODE));
p4d_t *p;
if (slab_is_available()) {
p = p4d_alloc(&init_mm, pgd, addr);
if (!p)
return -ENOMEM;
} else {
pgd_populate(&init_mm, pgd,
early_alloc(PAGE_SIZE, NUMA_NO_NODE));
}
}
zero_p4d_populate(pgd, addr, next);
} while (pgd++, addr = next, addr != end);
return 0;
}
static void kasan_free_pte(pte_t *pte_start, pmd_t *pmd)
{
pte_t *pte;
int i;
for (i = 0; i < PTRS_PER_PTE; i++) {
pte = pte_start + i;
if (!pte_none(*pte))
return;
}
pte_free_kernel(&init_mm, (pte_t *)page_to_virt(pmd_page(*pmd)));
pmd_clear(pmd);
}
static void kasan_free_pmd(pmd_t *pmd_start, pud_t *pud)
{
pmd_t *pmd;
int i;
for (i = 0; i < PTRS_PER_PMD; i++) {
pmd = pmd_start + i;
if (!pmd_none(*pmd))
return;
}
pmd_free(&init_mm, (pmd_t *)page_to_virt(pud_page(*pud)));
pud_clear(pud);
}
static void kasan_free_pud(pud_t *pud_start, p4d_t *p4d)
{
pud_t *pud;
int i;
for (i = 0; i < PTRS_PER_PUD; i++) {
pud = pud_start + i;
if (!pud_none(*pud))
return;
}
pud_free(&init_mm, (pud_t *)page_to_virt(p4d_page(*p4d)));
p4d_clear(p4d);
}
static void kasan_free_p4d(p4d_t *p4d_start, pgd_t *pgd)
{
p4d_t *p4d;
int i;
for (i = 0; i < PTRS_PER_P4D; i++) {
p4d = p4d_start + i;
if (!p4d_none(*p4d))
return;
}
p4d_free(&init_mm, (p4d_t *)page_to_virt(pgd_page(*pgd)));
pgd_clear(pgd);
}
static void kasan_remove_pte_table(pte_t *pte, unsigned long addr,
unsigned long end)
{
unsigned long next;
for (; addr < end; addr = next, pte++) {
next = (addr + PAGE_SIZE) & PAGE_MASK;
if (next > end)
next = end;
if (!pte_present(*pte))
continue;
if (WARN_ON(!kasan_zero_page_entry(*pte)))
continue;
pte_clear(&init_mm, addr, pte);
}
}
static void kasan_remove_pmd_table(pmd_t *pmd, unsigned long addr,
unsigned long end)
{
unsigned long next;
for (; addr < end; addr = next, pmd++) {
pte_t *pte;
next = pmd_addr_end(addr, end);
if (!pmd_present(*pmd))
continue;
if (kasan_pte_table(*pmd)) {
if (IS_ALIGNED(addr, PMD_SIZE) &&
IS_ALIGNED(next, PMD_SIZE))
pmd_clear(pmd);
continue;
}
pte = pte_offset_kernel(pmd, addr);
kasan_remove_pte_table(pte, addr, next);
kasan_free_pte(pte_offset_kernel(pmd, 0), pmd);
}
}
static void kasan_remove_pud_table(pud_t *pud, unsigned long addr,
unsigned long end)
{
unsigned long next;
for (; addr < end; addr = next, pud++) {
pmd_t *pmd, *pmd_base;
next = pud_addr_end(addr, end);
if (!pud_present(*pud))
continue;
if (kasan_pmd_table(*pud)) {
if (IS_ALIGNED(addr, PUD_SIZE) &&
IS_ALIGNED(next, PUD_SIZE))
pud_clear(pud);
continue;
}
pmd = pmd_offset(pud, addr);
pmd_base = pmd_offset(pud, 0);
kasan_remove_pmd_table(pmd, addr, next);
kasan_free_pmd(pmd_base, pud);
}
}
static void kasan_remove_p4d_table(p4d_t *p4d, unsigned long addr,
unsigned long end)
{
unsigned long next;
for (; addr < end; addr = next, p4d++) {
pud_t *pud;
next = p4d_addr_end(addr, end);
if (!p4d_present(*p4d))
continue;
if (kasan_pud_table(*p4d)) {
if (IS_ALIGNED(addr, P4D_SIZE) &&
IS_ALIGNED(next, P4D_SIZE))
p4d_clear(p4d);
continue;
}
pud = pud_offset(p4d, addr);
kasan_remove_pud_table(pud, addr, next);
kasan_free_pud(pud_offset(p4d, 0), p4d);
}
}
void kasan_remove_zero_shadow(void *start, unsigned long size)
{
unsigned long addr, end, next;
pgd_t *pgd;
addr = (unsigned long)kasan_mem_to_shadow(start);
end = addr + (size >> KASAN_SHADOW_SCALE_SHIFT);
if (WARN_ON((unsigned long)start %
(KASAN_SHADOW_SCALE_SIZE * PAGE_SIZE)) ||
WARN_ON(size % (KASAN_SHADOW_SCALE_SIZE * PAGE_SIZE)))
return;
for (; addr < end; addr = next) {
p4d_t *p4d;
next = pgd_addr_end(addr, end);
pgd = pgd_offset_k(addr);
if (!pgd_present(*pgd))
continue;
if (kasan_p4d_table(*pgd)) {
if (IS_ALIGNED(addr, PGDIR_SIZE) &&
IS_ALIGNED(next, PGDIR_SIZE))
pgd_clear(pgd);
continue;
}
p4d = p4d_offset(pgd, addr);
kasan_remove_p4d_table(p4d, addr, next);
kasan_free_p4d(p4d_offset(pgd, 0), pgd);
}
}
int kasan_add_zero_shadow(void *start, unsigned long size)
{
int ret;
void *shadow_start, *shadow_end;
shadow_start = kasan_mem_to_shadow(start);
shadow_end = shadow_start + (size >> KASAN_SHADOW_SCALE_SHIFT);
if (WARN_ON((unsigned long)start %
(KASAN_SHADOW_SCALE_SIZE * PAGE_SIZE)) ||
WARN_ON(size % (KASAN_SHADOW_SCALE_SIZE * PAGE_SIZE)))
return -EINVAL;
ret = kasan_populate_zero_shadow(shadow_start, shadow_end);
if (ret)
kasan_remove_zero_shadow(shadow_start,
size >> KASAN_SHADOW_SCALE_SHIFT);
return ret;
}
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