From: Davidlohr Bueso <dave@stgolabs.net>
To: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: linux-kernel@vger.kernel.org,
"Andr� Almeida" <andrealmeid@igalia.com>,
"Calvin Owens" <calvin@wbinvd.org>,
"Darren Hart" <dvhart@infradead.org>,
"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 09:37:43 -0700 [thread overview]
Message-ID: <20250623163743.ocimtxqdrwnkffjv@offworld> (raw)
In-Reply-To: <20250623083408.jTiJiC6_@linutronix.de>
On Mon, 23 Jun 2025, Sebastian Andrzej Siewior wrote:
>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: Davidlohr Bueso <dave@stgolabs.net>
prev parent reply other threads:[~2025-06-23 16:37 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 ` [PATCH] " André Almeida
2025-06-23 16:37 ` Davidlohr Bueso [this message]
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