From: Sebastian Andrzej Siewior Date: Wed, 28 Oct 2020 18:15:32 +0100 Subject: [PATCH 332/351] mm/memcontrol: Disable preemption in __mod_memcg_lruvec_state() Origin: https://git.kernel.org/cgit/linux/kernel/git/rt/linux-stable-rt.git/commit?id=c8d747a7c7dd6b59f68b8466893b0c18d1fa2074 [ Upstream commit 74858f0d38a8d3c069a0745ff53ae084c8e7cabb ] 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 Signed-off-by: Tom Zanussi Conflicts: mm/memcontrol.c --- include/linux/memcontrol.h | 2 ++ 1 file changed, 2 insertions(+) diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index cc6b6532eb56..dbb2c4e27277 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -665,6 +665,7 @@ static inline void __mod_lruvec_state(struct lruvec *lruvec, pn = container_of(lruvec, struct mem_cgroup_per_node, lruvec); + preempt_disable_rt(); /* Update memcg */ __mod_memcg_state(pn->memcg, idx, val); @@ -675,6 +676,7 @@ static inline void __mod_lruvec_state(struct lruvec *lruvec, x = 0; } __this_cpu_write(pn->lruvec_stat_cpu->count[idx], x); + preempt_enable_rt(); } static inline void mod_lruvec_state(struct lruvec *lruvec,