The -next commit "mm: vmscan: simplify lruvec_lru_size()" [1] introduced an undefined behavior as zone_idx could equal to MAX_NR_ZONES, and then zid is then out of range. [ 5399.483257] LTP: starting mtest01w (mtest01 -p80 -w) [ 5400.245051] ================================================================================ [ 5400.255784] UBSAN: Undefined behaviour in ./include/linux/memcontrol.h:536:26 [ 5400.265235] index 5 is out of range for type 'long unsigned int [5][5]' [ 5400.273925] CPU: 28 PID: 455 Comm: kswapd7 Tainted: G W 5.4.0-rc6-next-20191108 #3 [ 5400.285461] Hardware name: HPE ProLiant DL385 Gen10/ProLiant DL385 Gen10, BIOS A40 07/10/2019 [ 5400.295784] Call Trace: [ 5400.299483] dump_stack+0x7a/0xaa [ 5400.304052] ubsan_epilogue+0x9/0x26 [ 5400.309180] __ubsan_handle_out_of_bounds.cold.13+0x2b/0x36 [ 5400.316192] inactive_list_is_low+0x8bb/0x9f0 [ 5400.321952] balance_pgdat+0x252/0x7d0 [ 5400.327006] kswapd+0x251/0x590 [ 5400.331725] ? finish_wait+0x90/0x90 [ 5400.336574] kthread+0x12a/0x140 [ 5400.341102] ? balance_pgdat+0x7d0/0x7d0 [ 5400.346330] ? kthread_create_worker_on_cpu+0x70/0x70 [ 5400.352810] ret_from_fork+0x27/0x50 [1] https://lore.kernel.org/linux-mm/20191022144803.302233-2-hannes@xxxxxxxxxxx/ Signed-off-by: Qian Cai <cai@xxxxxx> --- mm/vmscan.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index d97985262dda..9485b80d6b5b 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -317,7 +317,7 @@ unsigned long lruvec_lru_size(struct lruvec *lruvec, enum lru_list lru, int zone unsigned long size = 0; int zid; - for (zid = 0; zid <= zone_idx; zid++) { + for (zid = 0; zid < zone_idx; zid++) { struct zone *zone = &lruvec_pgdat(lruvec)->node_zones[zid]; if (!managed_zone(zone)) -- 2.21.0 (Apple Git-122.2)
