| From | Greg Kroah-Hartman <> | Subject | [PATCH 5.4 83/85] alpha: Send stop IPI to send to online CPUs | Date | Tue, 10 Aug 2021 19:30:56 +0200 |
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From: Prarit Bhargava <prarit@redhat.com>
[ Upstream commit caace6ca4e06f09413fb8f8a63319594cfb7d47d ]
This issue was noticed while debugging a shutdown issue where some secondary CPUs are not being shutdown correctly. A fix for that [1] requires that secondary cpus be offlined using the cpu_online_mask so that the stop operation is a no-op if CPU HOTPLUG is disabled. I, like the author in [1] looked at the architectures and found that alpha is one of two architectures that executes smp_send_stop() on all possible CPUs.
On alpha, smp_send_stop() sends an IPI to all possible CPUs but only needs to send them to online CPUs.
Send the stop IPI to only the online CPUs.
[1] https://lkml.org/lkml/2020/1/10/250
Signed-off-by: Prarit Bhargava <prarit@redhat.com> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Signed-off-by: Matt Turner <mattst88@gmail.com> Signed-off-by: Sasha Levin <sashal@kernel.org> --- arch/alpha/kernel/smp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/alpha/kernel/smp.c b/arch/alpha/kernel/smp.c index 5f90df30be20..06fd42417aa9 100644 --- a/arch/alpha/kernel/smp.c +++ b/arch/alpha/kernel/smp.c @@ -585,7 +585,7 @@ void smp_send_stop(void) { cpumask_t to_whom; - cpumask_copy(&to_whom, cpu_possible_mask); + cpumask_copy(&to_whom, cpu_online_mask); cpumask_clear_cpu(smp_processor_id(), &to_whom); #ifdef DEBUG_IPI_MSG if (hard_smp_processor_id() != boot_cpu_id) -- 2.30.2
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