6.6-stable review patch. If anyone has any objections, please let me know.
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From: Yang Yingliang yangyingliang@huawei.com
commit e22f910a26cc2a3ac9c66b8e935ef2a7dd881117 upstream.
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.... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- kernel/sched/core.c | 1 + 1 file changed, 1 insertion(+)
--- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -9760,6 +9760,7 @@ int sched_cpu_deactivate(unsigned int cp 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);