From: "André Almeida" <andrealmeid@igalia.com>
To: Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
linux-kernel@vger.kernel.org
Cc: Calvin Owens <calvin@wbinvd.org>,
Darren Hart <dvhart@infradead.org>,
Davidlohr Bueso <dave@stgolabs.net>,
Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH] futex: Initialize futex_phash_new during fork().
Date: Mon, 23 Jun 2025 13:27:22 -0300 [thread overview]
Message-ID: <ca0dab04-7ccc-43e6-b5f3-7a739c867bc0@igalia.com> (raw)
In-Reply-To: <20250623083408.jTiJiC6_@linutronix.de>
Em 23/06/2025 05:34, Sebastian Andrzej Siewior escreveu:
> During a hash resize operation the new private hash is stored in
> mm_struct::futex_phash_new if the current hash can not be immediately
> replaced.
>
> The new hash must not be copied during fork() into the new task. Doing
> so will lead to a double-free of the memory by the two tasks.
>
> Initialize the mm_struct::futex_phash_new during fork().
>
> Reported-by: Calvin Owens <calvin@wbinvd.org>
> Closes: https://lore.kernel.org/all/aFBQ8CBKmRzEqIfS@mozart.vkv.me/
> Tested-by: Calvin Owens <calvin@wbinvd.org>
> Fixes: bd54df5ea7cad ("futex: Allow to resize the private local hash")
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: André Almeida <andrealmeid@igalia.com>
next prev parent reply other threads:[~2025-06-23 16:27 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-06-23 8:34 Sebastian Andrzej Siewior
2025-06-23 13:04 ` [tip: locking/urgent] " tip-bot2 for Sebastian Andrzej Siewior
2025-06-23 16:27 ` André Almeida [this message]
2025-06-23 16:37 ` [PATCH] " Davidlohr Bueso
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