FAILED: patch "[PATCH] sched/smt: Fix unbalance sched_smt_present dec/inc" failed to apply to 5.10-stable tree

FAILED: patch "[PATCH] sched/smt: Fix unbalance sched_smt_present dec/inc" failed to apply to 5.10-stable tree

[gregkh]

The patch below does not apply to the 5.10-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y
git checkout FETCH_HEAD
git cherry-pick -x e22f910a26cc2a3ac9c66b8e935ef2a7dd881117
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2024081238-catalyst-resident-aec1@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^..

Possible dependencies:

e22f910a26cc ("sched/smt: Fix unbalance sched_smt_present dec/inc")
2558aacff858 ("sched/hotplug: Ensure only per-cpu kthreads run during hotplug")
565790d28b1e ("sched: Fix balance_callback()")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From e22f910a26cc2a3ac9c66b8e935ef2a7dd881117 Mon Sep 17 00:00:00 2001
From: Yang Yingliang <yangyingliang@huawei.com>
Date: Wed, 3 Jul 2024 11:16:08 +0800
Subject: [PATCH] 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 acc04ed9dbc2..949473e414f9 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);