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 7929A3E557D; Tue, 13 Oct 2026 12:21:47 +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=1791894108; cv=none; b=qblx+msXTAoy8iGyM7Sobhepq5+RN2UHXp8zwUFObDqESRauLuFSwry4bytE/H+tyyAgKYPSSw61+JmyV7w9Da8fjEcfunnnV5CDJ62faZ2EzEVFFkHCTg47XhaPcGw0R3pAxZN6oHj74zbdX1W8wuzlkuM4GOYQFzJyuJTt/tc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791894108; c=relaxed/simple; bh=MJcwSufR5HaG8LS+2+0TENLE05V+6Dx23cC8bSliuFs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=KKwenl4jMa/qVodUqk9vJ671UgLzm6nGSDNvaKikZwQcSLZxC6HLt0FNLyMTlI0bl86PkgazpJBaDzvkF9zUb1u7DIip75KM9O2/o71wdveXep9e7zAyu5abiBa416ZO3Q0h+PX/05SuTpchK8b/RqOc3elqYtxug8Nyb0Kq1MU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=LOcoRQv9; 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="LOcoRQv9" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8A54F1F000FF; Tue, 13 Oct 2026 12:21:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1791894107; bh=T3qy9Slj/3f27CJ/ST2jqEzLvR+5iiqeIRSW2gku27Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=LOcoRQv9Kj8KrGXn3hmVBJ+nGC0v+gk44UGK/DX66tnkEqJhlfNthYik5vCSzByxP W1/YkFd6jAF12PQ3aTABpDe6HMPYLmDraPyDX0YquM2YaALtUSNl5FljWcfIDVchuI Kzs41u+7xBvS1cNk2fPG5jYbKL0QQoGOCC004jNU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Karl Mehltretter , Sasha Levin Subject: [PATCH 6.18 450/621] serial: core: clear freed pointers on uart_register_driver() failure Date: Tue, 13 Oct 2026 13:37:25 +0200 Message-ID: <20261013112931.509329185@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261013112920.855194808@linuxfoundation.org> References: <20261013112920.855194808@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 6.18-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 32cdfc59a9ad9..355e7ce6212fc 100644 --- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -2810,8 +2810,10 @@ 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