From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 71F023A2E25; Sat, 17 Oct 2026 16:38:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792255104; cv=none; b=RQjoW2D9cLmYx0Z3mv5WMAfa9JoqnZQL7ZvZlg5uk/E9YzQ7AI/TocXP0WA1BRRV94xm64D6AcrLGnNG1T9loQnKhZ3Uhc8rwNdYEHc80pk4RTrMr2wrQfTICcJ5KfS8IbfHBorB847qDdePCwYGqiV8TNwnZ2ZZly9aIoqpEqs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792255104; c=relaxed/simple; bh=wHy1Swfkb0EVN+1DCJbBTdBChEkTLh4PsD7rik8Hdw4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=kxBEDk1QtuRYUamVZmU80hFh6ScnXvlZc5qlqyrZALO7kgmu2YVq7+NUOkwhvYWUmSf2VWNY4VgweQpoURnBUx5LQtn2KdAP4X+Ddv+C+TyEagHvZPibJR+/G80D9qctSpidznRXDZ+laUGNnVaE0c/9eyp4pwEvCIuD5J82yGY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=PCVtMmCV; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="PCVtMmCV" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8E8221F000C4; Sat, 17 Oct 2026 16:38:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1792255103; bh=aI3LoKLJreWqufn6CWV/M1mvMMjPYB7JZU119fEAvVk=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=PCVtMmCVHY/ZO3warcvI1bzDBeLEXkCzTTZQ90c5vn+7j1Ykngt/r7zW7KrXItHgJ XcUnqTTvOVI+WI5DTNzOziG+mtcRB7DruLVIMn6HxQl4uO2s1SnIzwOBLb5C3RCg0S 0Xqr8YkqQyOsgYvjTZlSjmqIJmhC1l9jkSAWyU0E= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Karl Mehltretter , Sasha Levin Subject: [PATCH 6.12 667/869] serial: core: clear freed pointers on uart_register_driver() failure Date: Sat, 17 Oct 2026 17:58:28 +0200 Message-ID: <20261017160054.092547099@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261017160036.979869304@linuxfoundation.org> References: <20261017160036.979869304@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Karl Mehltretter [ Upstream commit 61a2fb25551be0375bc16ef2a70c987dfca26183 ] uart_register_driver() leaves drv->state pointing to freed memory when tty_alloc_driver() fails. If tty_register_driver() fails, drv->tty_driver also retains a pointer after its reference is dropped. Drivers that use drv->state as an "already registered" flag can then skip registration on the next probe and pass the freed state to uart_add_one_port(). This issue was found with failslab on QEMU's raspi1ap board by failing registration and binding the PL011 port again. Clear both pointers on their failure paths, as uart_unregister_driver() already does. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Fixes: 9e845abfc8a8 ("serial: fix NULL pointer dereference") Assisted-by: Claude:claude-fable-5 Signed-off-by: Karl Mehltretter Link: https://patch.msgid.link/20260731181844.11330-3-kmehltretter@gmail.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/tty/serial/serial_core.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c index 816f83141afd3..2da161227200a 100644 --- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -2861,8 +2861,10 @@ int uart_register_driver(struct uart_driver *drv) for (i = 0; i < drv->nr; i++) tty_port_destroy(&drv->state[i].port); tty_driver_kref_put(normal); + drv->tty_driver = NULL; out_kfree: kfree(drv->state); + drv->state = NULL; out: return retval; } -- 2.53.0