From: Matt Fleming <matt@readmodwrite.com>
To: Tejun Heo <tj@kernel.org>
Cc: David Vernet <void@manifault.com>,
Andrea Righi <arighi@nvidia.com>,
Changwoo Min <changwoo@igalia.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Suren Baghdasaryan <surenb@google.com>,
Peter Zijlstra <peterz@infradead.org>,
Edward Adam Davis <eadavis@qq.com>,
Chen Ridong <chenridong@huaweicloud.com>,
Matt Fleming <mfleming@cloudflare.com>,
sched-ext@lists.linux.dev, cgroups@vger.kernel.org,
linux-kernel@vger.kernel.org, stable@vger.kernel.org,
kernel-team@cloudflare.com
Subject: Re: [PATCH cgroup/for-7.2-fixes] cgroup: Create the psimon kthread outside of cgroup_mutex
Date: Sat, 11 Jul 2026 06:54:25 +0100 [thread overview]
Message-ID: <alHaU4MhWzq9kA1i@matt-Precision-5490> (raw)
In-Reply-To: <20260710134945-psimon-fix-tj@kernel.org>
On Fri, Jul 10, 2026 at 01:49:45PM -1000, Tejun Heo wrote:
> Matt, your reordering trades one deadlock for another: CLONE_INTO_CGROUP
> forks grab cgroup_mutex inside the scx_fork_rwsem read section, so an
> enable racing such a clone deadlocks the other way around. The fork has to
> move out of the locked sections instead. Can you verify this fixes the
> deadlock in your setup?
Thanks for fixing this. I'll test this out ASAP and report back.
next prev parent reply other threads:[~2026-07-11 5:54 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-10 10:04 [PATCH] sched_ext: Fix deadlock with PSI trigger creation Matt Fleming
2026-07-10 17:46 ` Andrea Righi
2026-07-10 18:24 ` Andrea Righi
2026-07-10 23:49 ` [PATCH cgroup/for-7.2-fixes] cgroup: Create the psimon kthread outside of cgroup_mutex Tejun Heo
2026-07-11 5:54 ` Matt Fleming [this message]
2026-07-12 17:49 ` Tejun Heo
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