The following commit has been merged into the sched/core branch of tip:
Commit-ID: e22f910a26cc2a3ac9c66b8e935ef2a7dd881117
Gitweb: https://git.kernel.org/tip/e22f910a26cc2a3ac9c66b8e935ef2a7dd881117
Author: Yang Yingliang <yangyingliang@xxxxxxxxxx>
AuthorDate: Wed, 03 Jul 2024 11:16:08 +08:00
Committer: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
CommitterDate: Mon, 29 Jul 2024 12:22:32 +02:00
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@xxxxxxxxxx
Signed-off-by: Yang Yingliang <yangyingliang@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Reviewed-by: Chen Yu <yu.c.chen@xxxxxxxxx>
Reviewed-by: Tim Chen <tim.c.chen@xxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20240703031610.587047-3-yangyingliang@xxxxxxxxxxxxxxx
---
kernel/sched/core.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index acc04ed..949473e 100644
--- 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);
|