The following commit has been merged into the sched/urgent branch of tip: Commit-ID: fba111913e51a934eaad85734254eab801343836 Gitweb: https://git.kernel.org/tip/fba111913e51a934eaad85734254eab801343836 Author: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx> AuthorDate: Wed, 17 Feb 2021 11:56:51 -05:00 Committer: Peter Zijlstra <peterz@xxxxxxxxxxxxx> CommitterDate: Mon, 01 Mar 2021 11:02:15 +01:00 sched/membarrier: fix missing local execution of ipi_sync_rq_state() The function sync_runqueues_membarrier_state() should copy the membarrier state from the @mm received as parameter to each runqueue currently running tasks using that mm. However, the use of smp_call_function_many() skips the current runqueue, which is unintended. Replace by a call to on_each_cpu_mask(). Fixes: 227a4aadc75b ("sched/membarrier: Fix p->mm->membarrier_state racy load") Reported-by: Nadav Amit <nadav.amit@xxxxxxxxx> Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx> Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Cc: stable@xxxxxxxxxxxxxxx # 5.4.x+ Link: https://lore.kernel.org/r/74F1E842-4A84-47BF-B6C2-5407DFDD4A4A@xxxxxxxxx --- kernel/sched/membarrier.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/kernel/sched/membarrier.c b/kernel/sched/membarrier.c index acdae62..b5add64 100644 --- a/kernel/sched/membarrier.c +++ b/kernel/sched/membarrier.c @@ -471,9 +471,7 @@ static int sync_runqueues_membarrier_state(struct mm_struct *mm) } rcu_read_unlock(); - preempt_disable(); - smp_call_function_many(tmpmask, ipi_sync_rq_state, mm, 1); - preempt_enable(); + on_each_cpu_mask(tmpmask, ipi_sync_rq_state, mm, true); free_cpumask_var(tmpmask); cpus_read_unlock();
