From: "Michal Koutný" <mkoutny@suse.com>
To: Tao Cui <cui.tao@linux.dev>
Cc: longman@redhat.com, chenridong@huaweicloud.com, tj@kernel.org,
hannes@cmpxchg.org, cgroups@vger.kernel.org,
linux-kernel@vger.kernel.org, Tao Cui <cuitao@kylinos.cn>
Subject: Re: [PATCH v2] cgroup/cpuset: Fix update_prstate() always returning 0 on partition errors
Date: Tue, 2 Jun 2026 09:46:46 +0200 [thread overview]
Message-ID: <ah6JpNvdO7vaBmjS@localhost.localdomain> (raw)
In-Reply-To: <20260602045521.2381230-1-cui.tao@linux.dev>
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Hi.
On Tue, Jun 02, 2026 at 12:55:21PM +0800, Tao Cui <cui.tao@linux.dev> wrote:
> update_prstate() stores the error code in cs->prs_err and transitions
> the partition to an invalid state, but always returns 0. The caller
> cpuset_partition_write() uses "return retval ?: nbytes", so the write
> syscall always appears to succeed from userspace even when the partition
> became invalid.
> Return -EINVAL when err is set so userspace can detect
> the failure immediately.
This is quite a visible UAPI change (a write can succeed to invalidate a
partition) and users are meant to watch for cpuset.cpus.partition state
anyway for asynchronous changes.
I'd not change this gratuitously.
Michal
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next prev parent reply other threads:[~2026-06-02 7:46 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-02 4:55 [PATCH v2] cgroup/cpuset: Fix update_prstate() always returning 0 on partition errors Tao Cui
2026-06-02 7:46 ` Michal Koutný [this message]
2026-06-02 8:19 ` Tao Cui
2026-06-02 18:41 ` Waiman Long
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