sched/smt: Fix unbalance sched_smt_present dec/inc

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")
Cc: stable@kernel.org
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Chen Yu <yu.c.chen@intel.com>
Reviewed-by: Tim Chen <tim.c.chen@linux.intel.com>
Link: https://lore.kernel.org/r/20240703031610.587047-3-yangyingliang@huaweicloud.com

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index acc04ed9dbc222e347d5e08e6d455c2de2046374..949473e414f976cf848b67fa90050c4b87ecb405 100644 (file)
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -8009,6 +8009,7 @@ int sched_cpu_deactivate(unsigned int cpu)
        sched_update_numa(cpu, false);
        ret = cpuset_cpu_inactive(cpu);
        if (ret) {
+               sched_smt_present_inc(cpu);
                balance_push_set(cpu, false);
                set_cpu_active(cpu, true);
                sched_update_numa(cpu, true);