From: "santosh.shilimkar@xxxxxxxxxx" <santosh.shilimkar@xxxxxxxxxx> 3.12-stable review patch. If anyone has any objections, please let me know. =============== commit e47db94e10447fc467777a40302f2b393e9af2fa upstream. Two different threads with different rds sockets may be in rds_recv_rcvbuf_delta() via receive path. If their ports both map to the same word in the congestion map, then using non-atomic ops to update it could cause the map to be incorrect. Lets use atomics to avoid such an issue. Full credit to Wengang <wen.gang.wang@xxxxxxxxxx> for finding the issue, analysing it and also pointing out to offending code with spin lock based fix. Reviewed-by: Leon Romanovsky <leon@xxxxxxx> Signed-off-by: Wengang Wang <wen.gang.wang@xxxxxxxxxx> Signed-off-by: Santosh Shilimkar <santosh.shilimkar@xxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Cc: Julia Lawall <julia.lawall@xxxxxxx> Signed-off-by: Jiri Slaby <jslaby@xxxxxxx> --- net/rds/cong.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/net/rds/cong.c b/net/rds/cong.c index e5b65acd650b..cec4c4e6d905 100644 --- a/net/rds/cong.c +++ b/net/rds/cong.c @@ -285,7 +285,7 @@ void rds_cong_set_bit(struct rds_cong_map *map, __be16 port) i = be16_to_cpu(port) / RDS_CONG_MAP_PAGE_BITS; off = be16_to_cpu(port) % RDS_CONG_MAP_PAGE_BITS; - __set_bit_le(off, (void *)map->m_page_addrs[i]); + set_bit_le(off, (void *)map->m_page_addrs[i]); } void rds_cong_clear_bit(struct rds_cong_map *map, __be16 port) @@ -299,7 +299,7 @@ void rds_cong_clear_bit(struct rds_cong_map *map, __be16 port) i = be16_to_cpu(port) / RDS_CONG_MAP_PAGE_BITS; off = be16_to_cpu(port) % RDS_CONG_MAP_PAGE_BITS; - __clear_bit_le(off, (void *)map->m_page_addrs[i]); + clear_bit_le(off, (void *)map->m_page_addrs[i]); } static int rds_cong_test_bit(struct rds_cong_map *map, __be16 port) -- 2.12.2