From: Peter Zijlstra <peterz@infradead.org>
To: Waiman Long <longman@redhat.com>
Cc: "Ingo Molnar" <mingo@redhat.com>,
"Juri Lelli" <juri.lelli@redhat.com>,
"Vincent Guittot" <vincent.guittot@linaro.org>,
"Dietmar Eggemann" <dietmar.eggemann@arm.com>,
"Steven Rostedt" <rostedt@goodmis.org>,
"Ben Segall" <bsegall@google.com>, "Mel Gorman" <mgorman@suse.de>,
"Daniel Bristot de Oliveira" <bristot@redhat.com>,
"Phil Auld" <pauld@redhat.com>,
"Wenjie Li" <wenjieli@qti.qualcomm.com>,
"David Wang 王标" <wangbiao3@xiaomi.com>,
linux-kernel@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH-tip v2] sched: Fix use-after-free bug in dup_user_cpus_ptr()
Date: Thu, 22 Dec 2022 20:34:15 +0100 [thread overview]
Message-ID: <Y6SxNwUn7/4/8IQa@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20221205164832.2151247-1-longman@redhat.com>
On Mon, Dec 05, 2022 at 11:48:32AM -0500, Waiman Long wrote:
> Since commit 07ec77a1d4e8 ("sched: Allow task CPU affinity to be
> restricted on asymmetric systems"), the setting and clearing of
> user_cpus_ptr are done under pi_lock for arm64 architecture. However,
> dup_user_cpus_ptr() accesses user_cpus_ptr without any lock
> protection. When racing with the clearing of user_cpus_ptr in
> __set_cpus_allowed_ptr_locked(), it can lead to user-after-free and
> double-free in arm64 kernel.
How? the task cannot be in migrate_enable() and fork() at the same time,
no?
next prev parent reply other threads:[~2022-12-22 19:35 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-12-05 16:48 Waiman Long
2022-12-22 19:34 ` Peter Zijlstra [this message]
2022-12-22 20:16 ` Waiman Long
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