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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Wed, 28 Oct 2020 18:15:32 +0100
Subject: [PATCH] mm/memcontrol: Disable preemption in
__mod_memcg_lruvec_state()
The callers expect disabled preemption/interrupts while invoking
__mod_memcg_lruvec_state(). This works mainline because a lock of
somekind is acquired.
Use preempt_disable_rt() where per-CPU variables are accessed and a
stable pointer is expected. This is also done in __mod_zone_page_state()
for the same reason.
Cc: stable-rt@vger.kernel.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
mm/memcontrol.c | 2 ++
1 file changed, 2 insertions(+)
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -809,6 +809,7 @@ void __mod_memcg_lruvec_state(struct lru
pn = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
memcg = pn->memcg;
+ preempt_disable_rt();
/* Update memcg */
__mod_memcg_state(memcg, idx, val);
@@ -828,6 +829,7 @@ void __mod_memcg_lruvec_state(struct lru
x = 0;
}
__this_cpu_write(pn->lruvec_stat_cpu->count[idx], x);
+ preempt_enable_rt();
}
/**
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