From: "Christoph Lameter (Ampere)" <cl@gentwo.org>
To: Vlad Dumitrescu <vdumitrescu@nvidia.com>
Cc: Dennis Zhou <dennis@kernel.org>, Tejun Heo <tj@kernel.org>,
Baoquan He <bhe@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] percpu: fix race on alloc failed warning limit
Date: Tue, 2 Sep 2025 10:39:54 -0700 (PDT) [thread overview]
Message-ID: <061405e5-8670-2873-9b6f-0f152863adfc@gentwo.org> (raw)
In-Reply-To: <ab22061a-a62f-4429-945b-744e5cc4ba35@nvidia.com>
On Fri, 22 Aug 2025, Vlad Dumitrescu wrote:
> + if (do_warn && atomic_read(&warn_limit) > 0) {
> + int remaining = atomic_dec_return(&warn_limit);
The code creates a race condition since another atomic_dec_return() can
happen on another cpu between these two lines. warn_limit can go negative.
Use a single atomic operation instead?
next prev parent reply other threads:[~2025-09-02 17:39 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-08-22 22:55 Vlad Dumitrescu
2025-08-24 3:07 ` Baoquan He
2025-09-02 17:39 ` Christoph Lameter (Ampere) [this message]
2025-09-02 21:06 ` Vlad Dumitrescu
2025-09-02 21:41 ` Christoph Lameter (Ampere)
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