From: Shakeel Butt <shakeel.butt@linux.dev>
To: Guenter Roeck <linux@roeck-us.net>
Cc: JP Kobryn <inwardvessel@gmail.com>,
tj@kernel.org, klarasmodin@gmail.com, yosryahmed@google.com,
mkoutny@suse.com, hannes@cmpxchg.org, akpm@linux-foundation.org,
linux-mm@kvack.org, cgroups@vger.kernel.org,
kernel-team@meta.com
Subject: Re: [PATCH cgroup/for-6.16] cgroup: avoid per-cpu allocation of size zero rstat cpu locks
Date: Mon, 2 Jun 2025 21:10:33 -0700 [thread overview]
Message-ID: <CAGj-7pV8-S_b7Bw5uhvdjN-uNRL=gsyyQTMf+36TTzhJXpT3CA@mail.gmail.com> (raw)
In-Reply-To: <b9824a99-cca6-43d3-81db-14f4366c5fef@roeck-us.net>
On Mon, Jun 2, 2025 at 8:38 PM Guenter Roeck <linux@roeck-us.net> wrote:
>
> On Wed, May 21, 2025 at 06:32:02PM -0700, JP Kobryn wrote:
> > Subsystem rstat locks are dynamically allocated per-cpu. It was discovered
> > that a panic can occur during this allocation when the lock size is zero.
> > This is the case on non-smp systems, since arch_spinlock_t is defined as an
> > empty struct. Prevent this allocation when !CONFIG_SMP by adding a
> > pre-processor conditional around the affected block.
> >
>
> It may be defined as empty struct, but it is still dereferenced. This patch
> is causing crashes on non-SMP systems such as xtensa, m68k, or with x86
> non-SMP builds.
>
Does this still happen with the following patch?
https://lore.kernel.org/20250528235130.200966-1-inwardvessel@gmail.com/
next prev parent reply other threads:[~2025-06-03 4:11 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-05-22 1:32 JP Kobryn
2025-05-22 1:55 ` Tejun Heo
2025-05-22 13:22 ` Klara Modin
2025-06-03 3:38 ` Guenter Roeck
2025-06-03 4:10 ` Shakeel Butt [this message]
2025-06-03 4:26 ` Guenter Roeck
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