From: Breno Leitao <leitao@debian.org>
To: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Catalin Marinas <catalin.marinas@arm.com>,
puranjay@kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, bpf@vger.kernel.org,
kernel-team@meta.com
Subject: Re: [PATCH] mm/kmemleak: report RCU-tasks quiescent states during the scan
Date: Mon, 10 Aug 2026 03:00:56 -0700 [thread overview]
Message-ID: <anmhBp_hmvSsLqEa@gmail.com> (raw)
In-Reply-To: <amdWVTs0WKOxguxP@gmail.com>
On Mon, Jul 27, 2026 at 06:04:37AM -0700, Breno Leitao wrote:
> I found 3 different cases on Meta fleet, where rcu task stalls show up:
>
> 1) kmemleak -> This patch solves it
> 2) KVM / kcompactd
> * Holdout: kcompactd0 (pid 1216), state:R, nvcsw frozen at
> 716336/716336 across three reports 10 min apart (stuck ≥20 min in
> one compaction pass)
> * This is coming from: migrate_pages ->
> kvm_mmu_notifier_invalidate_range_start ->
> tdp_mmu_next_root -> tdp_mmu_zap_leafs
>
> 3) Nvidia driver
> * stuck in nv_procfs_read_lock_params
I've found an additional one:
4) While shrinking in reclaim:
INFO: rcu_tasks detected stalls on tasks:
0000000088620d09: .. nvcsw: 6735/6735 holdout: 1 idle_cpu: -1/8
task:GlobalCPUThread state:R running task pid:2552016 tgid:2524552
Call Trace:
shrink_lruvec
mem_cgroup_iter
shrink_node
I've proposing promoting cond_resched() to cond_resched_tasks_rcu_qs():
https://lore.kernel.org/all/20260810-rcu_task_shrink_lruvec-v1-1-4d9f7d5251cb@debian.org/
next prev parent reply other threads:[~2026-08-10 10:01 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-20 13:23 [PATCH] mm/kmemleak: report RCU-tasks quiescent states during the scan Breno Leitao
2026-07-20 15:25 ` Paul E. McKenney
2026-07-20 22:39 ` Andrew Morton
2026-07-21 4:21 ` Paul E. McKenney
2026-07-23 13:26 ` Breno Leitao
2026-07-23 15:56 ` Paul E. McKenney
2026-07-24 9:58 ` Breno Leitao
2026-07-24 17:29 ` Paul E. McKenney
2026-07-27 13:04 ` Breno Leitao
2026-07-27 16:02 ` Breno Leitao
2026-07-30 14:06 ` Breno Leitao
2026-07-30 14:57 ` Paul E. McKenney
2026-07-31 18:07 ` Breno Leitao
2026-07-31 18:19 ` Paul E. McKenney
2026-08-10 10:00 ` Breno Leitao [this message]
2026-07-21 0:00 ` SJ Park
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