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Date:   Thu, 21 Apr 2022 20:30:21 +0100
From:   Matthew Wilcox <willy@infradead.org>
To:     Nico Pache <npache@redhat.com>
Cc:     linux-kernel@vger.kernel.org, linux-mm@kvack.org,
        Andrew Morton <akpm@linux-foundation.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Darren Hart <dvhart@infradead.org>,
        Davidlohr Bueso <dave@stgolabs.net>,
        =?iso-8859-1?Q?Andr=E9?= Almeida <andrealmeid@collabora.com>,
        Arjan van de Ven <arjan@infradead.org>,
        Ulrich Drepper <drepper@redhat.com>
Subject: Re: [RFC 2/3] futex: exit: Print a warning when futex_cleanup fails
Message-ID: <YmGwzRIHFlKZk3Hm@casper.infradead.org>
References: <20220421190533.1601879-1-npache@redhat.com>
 <20220421190533.1601879-3-npache@redhat.com>
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On Thu, Apr 21, 2022 at 03:05:32PM -0400, Nico Pache wrote:
> @@ -1007,13 +1013,15 @@ static inline void exit_pi_state_list(struct task_struct *curr) { }
>  static void futex_cleanup(struct task_struct *tsk)
>  {
>  	if (unlikely(tsk->robust_list)) {
> -		exit_robust_list(tsk);
> +		if (!exit_robust_list(tsk))
> +			pr_info("futex: exit_robust_list failed");

Doesn't this allow a malicious user process to spam the kernel logs
with messages?  There needs to be a ratelimit on this, at least.