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authorHuang Ying <ying.huang@intel.com>2018-04-05 16:24:39 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2018-04-05 21:36:26 -0700
commitcb9f753a3731f7fe16447bea45cb6f8e8bb432fb (patch)
treef9c9d1ec34be344b46c0a26675fbc7b8830933b5
parent1c0ff0f1bdeb183608ac9a345996d4d1ebfed632 (diff)
mm: fix races between swapoff and flush dcache
Thanks to commit 4b3ef9daa4fc ("mm/swap: split swap cache into 64MB trunks"), after swapoff the address_space associated with the swap device will be freed. So page_mapping() users which may touch the address_space need some kind of mechanism to prevent the address_space from being freed during accessing. The dcache flushing functions (flush_dcache_page(), etc) in architecture specific code may access the address_space of swap device for anonymous pages in swap cache via page_mapping() function. But in some cases there are no mechanisms to prevent the swap device from being swapoff, for example, CPU1 CPU2 __get_user_pages() swapoff() flush_dcache_page() mapping = page_mapping() ... exit_swap_address_space() ... kvfree(spaces) mapping_mapped(mapping) The address space may be accessed after being freed. But from cachetlb.txt and Russell King, flush_dcache_page() only care about file cache pages, for anonymous pages, flush_anon_page() should be used. The implementation of flush_dcache_page() in all architectures follows this too. They will check whether page_mapping() is NULL and whether mapping_mapped() is true to determine whether to flush the dcache immediately. And they will use interval tree (mapping->i_mmap) to find all user space mappings. While mapping_mapped() and mapping->i_mmap isn't used by anonymous pages in swap cache at all. So, to fix the race between swapoff and flush dcache, __page_mapping() is add to return the address_space for file cache pages and NULL otherwise. All page_mapping() invoking in flush dcache functions are replaced with page_mapping_file(). [akpm@linux-foundation.org: simplify page_mapping_file(), per Mike] Link: http://lkml.kernel.org/r/20180305083634.15174-1-ying.huang@intel.com Signed-off-by: "Huang, Ying" <ying.huang@intel.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Chen Liqin <liqin.linux@gmail.com> Cc: Russell King <linux@armlinux.org.uk> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: "James E.J. Bottomley" <jejb@parisc-linux.org> Cc: Guan Xuetao <gxt@mprc.pku.edu.cn> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Zankel <chris@zankel.net> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Ley Foon Tan <lftan@altera.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Andi Kleen <ak@linux.intel.com> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--arch/arc/mm/cache.c2
-rw-r--r--arch/arm/mm/copypage-v4mc.c2
-rw-r--r--arch/arm/mm/copypage-v6.c2
-rw-r--r--arch/arm/mm/copypage-xscale.c2
-rw-r--r--arch/arm/mm/fault-armv.c2
-rw-r--r--arch/arm/mm/flush.c6
-rw-r--r--arch/mips/mm/cache.c2
-rw-r--r--arch/nios2/mm/cacheflush.c4
-rw-r--r--arch/parisc/kernel/cache.c5
-rw-r--r--arch/sh/mm/cache-sh4.c2
-rw-r--r--arch/sh/mm/cache-sh7705.c2
-rw-r--r--arch/sparc/kernel/smp_64.c8
-rw-r--r--arch/sparc/mm/init_64.c6
-rw-r--r--arch/sparc/mm/tlb.c2
-rw-r--r--arch/unicore32/mm/flush.c2
-rw-r--r--arch/unicore32/mm/mmu.c2
-rw-r--r--arch/xtensa/mm/cache.c2
-rw-r--r--include/linux/mm.h1
-rw-r--r--mm/util.c10
19 files changed, 38 insertions, 26 deletions
diff --git a/arch/arc/mm/cache.c b/arch/arc/mm/cache.c
index 2072f3451e9c..9dbe645ee127 100644
--- a/arch/arc/mm/cache.c
+++ b/arch/arc/mm/cache.c
@@ -833,7 +833,7 @@ void flush_dcache_page(struct page *page)
}
/* don't handle anon pages here */
- mapping = page_mapping(page);
+ mapping = page_mapping_file(page);
if (!mapping)
return;
diff --git a/arch/arm/mm/copypage-v4mc.c b/arch/arm/mm/copypage-v4mc.c
index 1267e64133b9..0224416cba3c 100644
--- a/arch/arm/mm/copypage-v4mc.c
+++ b/arch/arm/mm/copypage-v4mc.c
@@ -70,7 +70,7 @@ void v4_mc_copy_user_highpage(struct page *to, struct page *from,
void *kto = kmap_atomic(to);
if (!test_and_set_bit(PG_dcache_clean, &from->flags))
- __flush_dcache_page(page_mapping(from), from);
+ __flush_dcache_page(page_mapping_file(from), from);
raw_spin_lock(&minicache_lock);
diff --git a/arch/arm/mm/copypage-v6.c b/arch/arm/mm/copypage-v6.c
index 70423345da26..a698e575e321 100644
--- a/arch/arm/mm/copypage-v6.c
+++ b/arch/arm/mm/copypage-v6.c
@@ -76,7 +76,7 @@ static void v6_copy_user_highpage_aliasing(struct page *to,
unsigned long kfrom, kto;
if (!test_and_set_bit(PG_dcache_clean, &from->flags))
- __flush_dcache_page(page_mapping(from), from);
+ __flush_dcache_page(page_mapping_file(from), from);
/* FIXME: not highmem safe */
discard_old_kernel_data(page_address(to));
diff --git a/arch/arm/mm/copypage-xscale.c b/arch/arm/mm/copypage-xscale.c
index 0fb85025344d..97972379f4d6 100644
--- a/arch/arm/mm/copypage-xscale.c
+++ b/arch/arm/mm/copypage-xscale.c
@@ -90,7 +90,7 @@ void xscale_mc_copy_user_highpage(struct page *to, struct page *from,
void *kto = kmap_atomic(to);
if (!test_and_set_bit(PG_dcache_clean, &from->flags))
- __flush_dcache_page(page_mapping(from), from);
+ __flush_dcache_page(page_mapping_file(from), from);
raw_spin_lock(&minicache_lock);
diff --git a/arch/arm/mm/fault-armv.c b/arch/arm/mm/fault-armv.c
index d9e0d00a6699..4d75dae5ac96 100644
--- a/arch/arm/mm/fault-armv.c
+++ b/arch/arm/mm/fault-armv.c
@@ -195,7 +195,7 @@ void update_mmu_cache(struct vm_area_struct *vma, unsigned long addr,
if (page == ZERO_PAGE(0))
return;
- mapping = page_mapping(page);
+ mapping = page_mapping_file(page);
if (!test_and_set_bit(PG_dcache_clean, &page->flags))
__flush_dcache_page(mapping, page);
if (mapping) {
diff --git a/arch/arm/mm/flush.c b/arch/arm/mm/flush.c
index f1e6190aa7ea..58469623b015 100644
--- a/arch/arm/mm/flush.c
+++ b/arch/arm/mm/flush.c
@@ -285,7 +285,7 @@ void __sync_icache_dcache(pte_t pteval)
page = pfn_to_page(pfn);
if (cache_is_vipt_aliasing())
- mapping = page_mapping(page);
+ mapping = page_mapping_file(page);
else
mapping = NULL;
@@ -333,7 +333,7 @@ void flush_dcache_page(struct page *page)
return;
}
- mapping = page_mapping(page);
+ mapping = page_mapping_file(page);
if (!cache_ops_need_broadcast() &&
mapping && !page_mapcount(page))
@@ -363,7 +363,7 @@ void flush_kernel_dcache_page(struct page *page)
if (cache_is_vivt() || cache_is_vipt_aliasing()) {
struct address_space *mapping;
- mapping = page_mapping(page);
+ mapping = page_mapping_file(page);
if (!mapping || mapping_mapped(mapping)) {
void *addr;
diff --git a/arch/mips/mm/cache.c b/arch/mips/mm/cache.c
index 44ac64d51827..0d3c656feba0 100644
--- a/arch/mips/mm/cache.c
+++ b/arch/mips/mm/cache.c
@@ -86,7 +86,7 @@ SYSCALL_DEFINE3(cacheflush, unsigned long, addr, unsigned long, bytes,
void __flush_dcache_page(struct page *page)
{
- struct address_space *mapping = page_mapping(page);
+ struct address_space *mapping = page_mapping_file(page);
unsigned long addr;
if (mapping && !mapping_mapped(mapping)) {
diff --git a/arch/nios2/mm/cacheflush.c b/arch/nios2/mm/cacheflush.c
index 87bf88ed04c6..506f6e1c86d5 100644
--- a/arch/nios2/mm/cacheflush.c
+++ b/arch/nios2/mm/cacheflush.c
@@ -180,7 +180,7 @@ void flush_dcache_page(struct page *page)
if (page == ZERO_PAGE(0))
return;
- mapping = page_mapping(page);
+ mapping = page_mapping_file(page);
/* Flush this page if there are aliases. */
if (mapping && !mapping_mapped(mapping)) {
@@ -215,7 +215,7 @@ void update_mmu_cache(struct vm_area_struct *vma,
if (page == ZERO_PAGE(0))
return;
- mapping = page_mapping(page);
+ mapping = page_mapping_file(page);
if (!test_and_set_bit(PG_dcache_clean, &page->flags))
__flush_dcache_page(mapping, page);
diff --git a/arch/parisc/kernel/cache.c b/arch/parisc/kernel/cache.c
index e3b45546d589..a99da95fc9fd 100644
--- a/arch/parisc/kernel/cache.c
+++ b/arch/parisc/kernel/cache.c
@@ -88,7 +88,8 @@ update_mmu_cache(struct vm_area_struct *vma, unsigned long address, pte_t *ptep)
return;
page = pfn_to_page(pfn);
- if (page_mapping(page) && test_bit(PG_dcache_dirty, &page->flags)) {
+ if (page_mapping_file(page) &&
+ test_bit(PG_dcache_dirty, &page->flags)) {
flush_kernel_dcache_page_addr(pfn_va(pfn));
clear_bit(PG_dcache_dirty, &page->flags);
} else if (parisc_requires_coherency())
@@ -304,7 +305,7 @@ __flush_cache_page(struct vm_area_struct *vma, unsigned long vmaddr,
void flush_dcache_page(struct page *page)
{
- struct address_space *mapping = page_mapping(page);
+ struct address_space *mapping = page_mapping_file(page);
struct vm_area_struct *mpnt;
unsigned long offset;
unsigned long addr, old_addr = 0;
diff --git a/arch/sh/mm/cache-sh4.c b/arch/sh/mm/cache-sh4.c
index 58aaa4f33b81..eee911422cf9 100644
--- a/arch/sh/mm/cache-sh4.c
+++ b/arch/sh/mm/cache-sh4.c
@@ -112,7 +112,7 @@ static void sh4_flush_dcache_page(void *arg)
struct page *page = arg;
unsigned long addr = (unsigned long)page_address(page);
#ifndef CONFIG_SMP
- struct address_space *mapping = page_mapping(page);
+ struct address_space *mapping = page_mapping_file(page);
if (mapping && !mapping_mapped(mapping))
clear_bit(PG_dcache_clean, &page->flags);
diff --git a/arch/sh/mm/cache-sh7705.c b/arch/sh/mm/cache-sh7705.c
index 6cd2aa395817..ed25eba80667 100644
--- a/arch/sh/mm/cache-sh7705.c
+++ b/arch/sh/mm/cache-sh7705.c
@@ -136,7 +136,7 @@ static void __flush_dcache_page(unsigned long phys)
static void sh7705_flush_dcache_page(void *arg)
{
struct page *page = arg;
- struct address_space *mapping = page_mapping(page);
+ struct address_space *mapping = page_mapping_file(page);
if (mapping && !mapping_mapped(mapping))
clear_bit(PG_dcache_clean, &page->flags);
diff --git a/arch/sparc/kernel/smp_64.c b/arch/sparc/kernel/smp_64.c
index c50182cd2f64..d3ea1f3c06a0 100644
--- a/arch/sparc/kernel/smp_64.c
+++ b/arch/sparc/kernel/smp_64.c
@@ -929,9 +929,9 @@ static inline void __local_flush_dcache_page(struct page *page)
#ifdef DCACHE_ALIASING_POSSIBLE
__flush_dcache_page(page_address(page),
((tlb_type == spitfire) &&
- page_mapping(page) != NULL));
+ page_mapping_file(page) != NULL));
#else
- if (page_mapping(page) != NULL &&
+ if (page_mapping_file(page) != NULL &&
tlb_type == spitfire)
__flush_icache_page(__pa(page_address(page)));
#endif
@@ -958,7 +958,7 @@ void smp_flush_dcache_page_impl(struct page *page, int cpu)
if (tlb_type == spitfire) {
data0 = ((u64)&xcall_flush_dcache_page_spitfire);
- if (page_mapping(page) != NULL)
+ if (page_mapping_file(page) != NULL)
data0 |= ((u64)1 << 32);
} else if (tlb_type == cheetah || tlb_type == cheetah_plus) {
#ifdef DCACHE_ALIASING_POSSIBLE
@@ -994,7 +994,7 @@ void flush_dcache_page_all(struct mm_struct *mm, struct page *page)
pg_addr = page_address(page);
if (tlb_type == spitfire) {
data0 = ((u64)&xcall_flush_dcache_page_spitfire);
- if (page_mapping(page) != NULL)
+ if (page_mapping_file(page) != NULL)
data0 |= ((u64)1 << 32);
} else if (tlb_type == cheetah || tlb_type == cheetah_plus) {
#ifdef DCACHE_ALIASING_POSSIBLE
diff --git a/arch/sparc/mm/init_64.c b/arch/sparc/mm/init_64.c
index cb9ebac6663f..8aeb1aabe76e 100644
--- a/arch/sparc/mm/init_64.c
+++ b/arch/sparc/mm/init_64.c
@@ -206,9 +206,9 @@ inline void flush_dcache_page_impl(struct page *page)
#ifdef DCACHE_ALIASING_POSSIBLE
__flush_dcache_page(page_address(page),
((tlb_type == spitfire) &&
- page_mapping(page) != NULL));
+ page_mapping_file(page) != NULL));
#else
- if (page_mapping(page) != NULL &&
+ if (page_mapping_file(page) != NULL &&
tlb_type == spitfire)
__flush_icache_page(__pa(page_address(page)));
#endif
@@ -490,7 +490,7 @@ void flush_dcache_page(struct page *page)
this_cpu = get_cpu();
- mapping = page_mapping(page);
+ mapping = page_mapping_file(page);
if (mapping && !mapping_mapped(mapping)) {
int dirty = test_bit(PG_dcache_dirty, &page->flags);
if (dirty) {
diff --git a/arch/sparc/mm/tlb.c b/arch/sparc/mm/tlb.c
index b5cfab711651..3d72d2deb13b 100644
--- a/arch/sparc/mm/tlb.c
+++ b/arch/sparc/mm/tlb.c
@@ -128,7 +128,7 @@ void tlb_batch_add(struct mm_struct *mm, unsigned long vaddr,
goto no_cache_flush;
/* A real file page? */
- mapping = page_mapping(page);
+ mapping = page_mapping_file(page);
if (!mapping)
goto no_cache_flush;
diff --git a/arch/unicore32/mm/flush.c b/arch/unicore32/mm/flush.c
index 6d4c096ffa2a..74f4d636df2d 100644
--- a/arch/unicore32/mm/flush.c
+++ b/arch/unicore32/mm/flush.c
@@ -83,7 +83,7 @@ void flush_dcache_page(struct page *page)
if (page == ZERO_PAGE(0))
return;
- mapping = page_mapping(page);
+ mapping = page_mapping_file(page);
if (mapping && !mapping_mapped(mapping))
clear_bit(PG_dcache_clean, &page->flags);
diff --git a/arch/unicore32/mm/mmu.c b/arch/unicore32/mm/mmu.c
index 4f5a532bee13..0c94b7b4514d 100644
--- a/arch/unicore32/mm/mmu.c
+++ b/arch/unicore32/mm/mmu.c
@@ -503,7 +503,7 @@ void update_mmu_cache(struct vm_area_struct *vma, unsigned long addr,
if (page == ZERO_PAGE(0))
return;
- mapping = page_mapping(page);
+ mapping = page_mapping_file(page);
if (!test_and_set_bit(PG_dcache_clean, &page->flags))
__flush_dcache_page(mapping, page);
if (mapping)
diff --git a/arch/xtensa/mm/cache.c b/arch/xtensa/mm/cache.c
index 57dc231a0709..9220dcde7520 100644
--- a/arch/xtensa/mm/cache.c
+++ b/arch/xtensa/mm/cache.c
@@ -127,7 +127,7 @@ EXPORT_SYMBOL(copy_user_highpage);
void flush_dcache_page(struct page *page)
{
- struct address_space *mapping = page_mapping(page);
+ struct address_space *mapping = page_mapping_file(page);
/*
* If we have a mapping but the page is not mapped to user-space
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 40fca1b2b6a1..88d82ba29d72 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1155,6 +1155,7 @@ static inline pgoff_t page_index(struct page *page)
bool page_mapped(struct page *page);
struct address_space *page_mapping(struct page *page);
+struct address_space *page_mapping_file(struct page *page);
/*
* Return true only if the page has been allocated with
diff --git a/mm/util.c b/mm/util.c
index c1250501364f..029fc2f3b395 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -515,6 +515,16 @@ struct address_space *page_mapping(struct page *page)
}
EXPORT_SYMBOL(page_mapping);
+/*
+ * For file cache pages, return the address_space, otherwise return NULL
+ */
+struct address_space *page_mapping_file(struct page *page)
+{
+ if (unlikely(PageSwapCache(page)))
+ return NULL;
+ return page_mapping(page);
+}
+
/* Slow path of page_mapcount() for compound pages */
int __page_mapcount(struct page *page)
{