FAILED: patch "[PATCH] sched/smt: Fix unbalance sched_smt_present dec/inc" failed to apply to 5.10-stable tree
Subsystems (2)
[email protected]
maintainerThe 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 <[email protected]>.
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 '<[email protected]>' --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 <[email protected]>
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.
kernel/sched/core.c +1 -0
@@ -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);