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Message-Id: <20240702081128.4008011-1-yangyingliang@huaweicloud.com>
Date: Tue, 2 Jul 2024 16:11:28 +0800
From: Yang Yingliang <yangyingliang@...weicloud.com>
To: linux-kernel@...r.kernel.org
Cc: mingo@...hat.com,
peterz@...radead.org,
juri.lelli@...hat.com,
vincent.guittot@...aro.org,
dietmar.eggemann@....com,
rostedt@...dmis.org,
bsegall@...gle.com,
mgorman@...e.de,
bristot@...hat.com,
vschneid@...hat.com,
tglx@...utronix.de,
yu.c.chen@...el.com,
tim.c.chen@...ux.intel.com,
yangyingliang@...wei.com,
liwei391@...wei.com
Subject: [PATCH resend] sched/smt: fix unbalance sched_smt_present dec/inc
From: Yang Yingliang <yangyingliang@...wei.com>
I got the following warn report while doing stress test:
jump label: negative count!
WARNING: CPU: 3 PID: 38 at kernel/jump_label.c:263 static_key_slow_try_dec+0x9d/0xb0
Call Trace:
<TASK>
__static_key_slow_dec_cpuslocked+0x16/0x70
sched_cpu_deactivate+0x26e/0x2a0
cpuhp_invoke_callback+0x3ad/0x10d0
cpuhp_thread_fun+0x3f5/0x680
smpboot_thread_fn+0x56d/0x8d0
kthread+0x309/0x400
ret_from_fork+0x41/0x70
ret_from_fork_asm+0x1b/0x30
</TASK>
Because when cpuset_cpu_inactive() fails in sched_cpu_deactivate(),
the cpu offline failed, but sched_smt_present is decremented before
calling sched_cpu_deactivate(), it leads to unbalanced dec/inc, so
fix it by incrementing sched_smt_present in the error path.
Fixes: c5511d03ec09 ("sched/smt: Make sched_smt_present track topology")
Reviewed-by: Chen Yu <yu.c.chen@...el.com>
Reviewed-by: Tim Chen <tim.c.chen@...ux.intel.com>
Signed-off-by: Yang Yingliang <yangyingliang@...wei.com>
---
kernel/sched/core.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index bcf2c4cc0522..5ab6717b57e0 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -9756,6 +9756,10 @@ int sched_cpu_deactivate(unsigned int cpu)
sched_update_numa(cpu, false);
ret = cpuset_cpu_inactive(cpu);
if (ret) {
+#ifdef CONFIG_SCHED_SMT
+ if (cpumask_weight(cpu_smt_mask(cpu)) == 2)
+ static_branch_inc_cpuslocked(&sched_smt_present);
+#endif
balance_push_set(cpu, false);
set_cpu_active(cpu, true);
sched_update_numa(cpu, true);
--
2.25.1
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