From: Prarit Bhargava prarit@redhat.com
stable inclusion from stable-5.10.58 commit fbbb209268e5d4fff68c63812e62d7fe45cd0223 bugzilla: 176984 https://gitee.com/openeuler/kernel/issues/I4E2P4
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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[ 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 Signed-off-by: Chen Jun chenjun102@huawei.com Acked-by: Weilong Chen chenweilong@huawei.com Signed-off-by: Chen Jun chenjun102@huawei.com --- 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 4b2575f936d4..cb64e4797d2a 100644 --- a/arch/alpha/kernel/smp.c +++ b/arch/alpha/kernel/smp.c @@ -582,7 +582,7 @@ 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)