From: Sebastian Andrzej Siewior 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 --- mm/memcontrol.c | 2 ++ 1 file changed, 2 insertions(+) --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -805,6 +805,7 @@ 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); @@ -824,6 +825,7 @@ void __mod_memcg_lruvec_state(struct lru x = 0; } __this_cpu_write(pn->lruvec_stat_cpu->count[idx], x); + preempt_enable_rt(); } /**