From 76d8cc3c8f45cc597726616f11db4180f7e21ce0 Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Tue, 4 May 2021 18:37:51 -0700 Subject: mm: restore node stat checking in /proc/sys/vm/stat_refresh In v4.7 commit 52b6f46bc163 ("mm: /proc/sys/vm/stat_refresh to force vmstat update") introduced vmstat_refresh(), with its vmstat underflow checking; then in v4.8 commit 75ef71840539 ("mm, vmstat: add infrastructure for per-node vmstats") split NR_VM_NODE_STAT_ITEMS out of NR_VM_ZONE_STAT_ITEMS without updating vmstat_refresh(): so it has been missing out much of the vmstat underflow checking ever since. Reinstate it. Thanks to Roman Gushchin for tangentially pointing this out. Link: https://lkml.kernel.org/r/alpine.LSU.2.11.2102251502240.13363@eggly.anvils Signed-off-by: Hugh Dickins Cc: Roman Gushchin Cc: Johannes Weiner Cc: Michal Hocko Cc: Vlastimil Babka Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/vmstat.c | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'mm/vmstat.c') diff --git a/mm/vmstat.c b/mm/vmstat.c index 49a8456ec079..14d0ba4fd46b 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -1875,6 +1875,14 @@ int vmstat_refresh(struct ctl_table *table, int write, } } #endif + for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++) { + val = atomic_long_read(&vm_node_stat[i]); + if (val < 0) { + pr_warn("%s: %s %ld\n", + __func__, node_stat_name(i), val); + err = -EINVAL; + } + } if (err) return err; if (write) -- cgit v1.2.3