From 36eef400c2d571d05b6e41a9a61f874d4a7b82c5 Mon Sep 17 00:00:00 2001 From: Sebastian Andrzej Siewior Date: Tue, 28 May 2024 16:13:41 +0200 Subject: [PATCH] memcg: remove the lockdep assert from __mod_objcg_mlstate() The assert was introduced in the commit cited below as an insurance that the semantic is the same after the local_irq_save() has been removed and the function has been made static. The original requirement to disable interrupt was due the modification of per-CPU counters which require interrupts to be disabled because the counter update operation is not atomic and some of the counters are updated from interrupt context. All callers of __mod_objcg_mlstate() acquire a lock (memcg_stock.stock_lock) which disables interrupts on !PREEMPT_RT and the lockdep assert is satisfied. On PREEMPT_RT the interrupts are not disabled and the assert triggers. The safety of the counter update is already ensured by VM_WARN_ON_IRQS_ENABLED() which is part of __mod_memcg_lruvec_state() and does not require yet another check. Remove the lockdep assert from __mod_objcg_mlstate(). Link: https://lkml.kernel.org/r/20240528141341.rz_rytN_@linutronix.de Fixes: 91882c1617c1 ("memcg: simple cleanup of stats update functions") Signed-off-by: Sebastian Andrzej Siewior Acked-by: Vlastimil Babka Acked-by: Shakeel Butt Acked-by: Michal Hocko Reviewed-by: Vlastimil Babka Cc: Johannes Weiner Cc: Muchun Song Cc: Roman Gushchin Cc: Thomas Gleixner Signed-off-by: Andrew Morton --- mm/memcontrol.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 7fad15b2290c..36793e509f47 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -3147,8 +3147,6 @@ static inline void __mod_objcg_mlstate(struct obj_cgroup *objcg, struct mem_cgroup *memcg; struct lruvec *lruvec; - lockdep_assert_irqs_disabled(); - rcu_read_lock(); memcg = obj_cgroup_memcg(objcg); lruvec = mem_cgroup_lruvec(memcg, pgdat);