From 76d8cc3c8f45cc597726616f11db4180f7e21ce0 Mon Sep 17 00:00:00 2001
From: Hugh Dickins <hughd@google.com>
Date: Tue, 4 May 2021 18:37:51 -0700
Subject: [PATCH] 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 <guro@fb.com> for tangentially pointing this out.
Link: https://lkml.kernel.org/r/alpine.LSU.2.11.2102251502240.13363@eggly.anvils
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
mm/vmstat.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 49a8456ec079b..14d0ba4fd46bf 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)
--
GitLab