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Commit 907f7f2c authored by Mathieu Desnoyers's avatar Mathieu Desnoyers Committed by Greg Kroah-Hartman
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sched/membarrier: fix missing local execution of ipi_sync_rq_state() 



commit ce29ddc47b91f97e7f69a0fb7cbb5845f52a9825 upstream.

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: 227a4aad ("sched/membarrier: Fix p->mm->membarrier_state racy load")
Reported-by: default avatarNadav Amit <nadav.amit@gmail.com>
Signed-off-by: default avatarMathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Cc: stable@vger.kernel.org # 5.4.x+
Link: https://lore.kernel.org/r/74F1E842-4A84-47BF-B6C2-5407DFDD4A4A@gmail.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 2306580a

kernel/sched/membarrier.c

+1 −3
Original line number Diff line number Diff line
@@ -265,9 +265,7 @@ 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();