2020-02-07 22:29:36

by Qian Cai

[permalink] [raw]
Subject: [PATCH -next] mm/frontswap: mark various intentional data races

There are a few information counters that are intentionally not
protected against increment races, so just annotate them using the
data_race() macro.

BUG: KCSAN: data-race in __frontswap_store / __frontswap_store

write to 0xffffffff8b7174d8 of 8 bytes by task 6396 on cpu 103:
__frontswap_store+0x2d0/0x344
inc_frontswap_failed_stores at mm/frontswap.c:70
(inlined by) __frontswap_store at mm/frontswap.c:280
swap_writepage+0x83/0xf0
pageout+0x33e/0xae0
shrink_page_list+0x1f57/0x2870
shrink_inactive_list+0x316/0x880
shrink_lruvec+0x8dc/0x1380
shrink_node+0x317/0xd80
do_try_to_free_pages+0x1f7/0xa10
try_to_free_pages+0x26c/0x5e0
__alloc_pages_slowpath+0x458/0x1290
__alloc_pages_nodemask+0x3bb/0x450
alloc_pages_vma+0x8a/0x2c0
do_anonymous_page+0x170/0x700
__handle_mm_fault+0xc9f/0xd00
handle_mm_fault+0xfc/0x2f0
do_page_fault+0x263/0x6f9
page_fault+0x34/0x40

read to 0xffffffff8b7174d8 of 8 bytes by task 6405 on cpu 47:
__frontswap_store+0x2b9/0x344
inc_frontswap_failed_stores at mm/frontswap.c:70
(inlined by) __frontswap_store at mm/frontswap.c:280
swap_writepage+0x83/0xf0
pageout+0x33e/0xae0
shrink_page_list+0x1f57/0x2870
shrink_inactive_list+0x316/0x880
shrink_lruvec+0x8dc/0x1380
shrink_node+0x317/0xd80
do_try_to_free_pages+0x1f7/0xa10
try_to_free_pages+0x26c/0x5e0
__alloc_pages_slowpath+0x458/0x1290
__alloc_pages_nodemask+0x3bb/0x450
alloc_pages_vma+0x8a/0x2c0
do_anonymous_page+0x170/0x700
__handle_mm_fault+0xc9f/0xd00
handle_mm_fault+0xfc/0x2f0
do_page_fault+0x263/0x6f9
page_fault+0x34/0x40

Signed-off-by: Qian Cai <[email protected]>
---
mm/frontswap.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/mm/frontswap.c b/mm/frontswap.c
index 60bb20e8a951..b8c14f298332 100644
--- a/mm/frontswap.c
+++ b/mm/frontswap.c
@@ -61,16 +61,16 @@
static u64 frontswap_invalidates;

static inline void inc_frontswap_loads(void) {
- frontswap_loads++;
+ data_race(frontswap_loads++);
}
static inline void inc_frontswap_succ_stores(void) {
- frontswap_succ_stores++;
+ data_race(frontswap_succ_stores++);
}
static inline void inc_frontswap_failed_stores(void) {
- frontswap_failed_stores++;
+ data_race(frontswap_failed_stores++);
}
static inline void inc_frontswap_invalidates(void) {
- frontswap_invalidates++;
+ data_race(frontswap_invalidates++);
}
#else
static inline void inc_frontswap_loads(void) { }
--
1.8.3.1