This is a note to let you know that I've just added the patch titled
sched/membarrier: fix missing local execution of ipi_sync_rq_state()
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
sched-membarrier-fix-missing-local-execution-of-ipi_sync_rq_state.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From ce29ddc47b91f97e7f69a0fb7cbb5845f52a9825 Mon Sep 17 00:00:00 2001
From: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx>
Date: Wed, 17 Feb 2021 11:56:51 -0500
Subject: sched/membarrier: fix missing local execution of ipi_sync_rq_state()
From: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx>
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: 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>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx # 5.4.x+
Link: https://lore.kernel.org/r/74F1E842-4A84-47BF-B6C2-5407DFDD4A4A@xxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/sched/membarrier.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
--- a/kernel/sched/membarrier.c
+++ b/kernel/sched/membarrier.c
@@ -265,9 +265,7 @@ static int sync_runqueues_membarrier_sta
}
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();
Patches currently in stable-queue which might be from mathieu.desnoyers@xxxxxxxxxxxx are
queue-5.4/sched-membarrier-fix-missing-local-execution-of-ipi_sync_rq_state.patch
