From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 77CE82DCF61; Wed, 4 Feb 2026 15:23:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770218622; cv=none; b=fZbi/ABF2Lch0grPczaWWqpiDvr5LdytVx7U8GIcUfADD1TZMArtdG8M5BhdOcE5WSZDEPG0eMw3hDYaFv2RQYTtL6h/HFbShsgBgl32P/L7JiG0lAj7zjBcWz8j62jaNvbv2o89EJyGCAG5qjVDg6dbA22a/BLyeY9qE1B07ls= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770218622; c=relaxed/simple; bh=ZEivupDTlLBTH+Buyb7K6pcho3UgNqQ3EW6TcGLdsIc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=VKWowv1a7kWjW6+eozNm1COCGvNBhOZCfNti7iKCKoIa9v8HA6s4xoNxq6ARabbY+VqoqaaoZdBvtQkGRlWzSo8t0qC69maI/f0yWjkFA+BdPsM5C94T49kim243EUTNFLKSkhRspbvsWI37L78U2LM7JJvvlt1/YeUBB0WEXXs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=InmyqMFx; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="InmyqMFx" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DBF30C4CEF7; Wed, 4 Feb 2026 15:23:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1770218622; bh=ZEivupDTlLBTH+Buyb7K6pcho3UgNqQ3EW6TcGLdsIc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=InmyqMFxSJrMayWWWmYMZo0XSbpiEyXxfrUarX1F4PNc7ASwWBhf6o+v/zfykAC0M 0q5k79KN6d+Kwu2Pw45rEnUWeVZ8CHM07UrJL8wa9goLsNxwfjOynXem1FpgRskNgC y+n+vC0juVEo6D+nnzXNvxK66M4ESl2LT6nS3N/o= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jia-Hong Su , Luiz Augusto von Dentz , Sasha Levin Subject: [PATCH 6.12 02/87] Bluetooth: hci_uart: fix null-ptr-deref in hci_uart_write_work Date: Wed, 4 Feb 2026 15:40:00 +0100 Message-ID: <20260204143846.999685580@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260204143846.906385641@linuxfoundation.org> References: <20260204143846.906385641@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org 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: Jia-Hong Su [ Upstream commit 0c3cd7a0b862c37acbee6d9502107146cc944398 ] hci_uart_set_proto() sets HCI_UART_PROTO_INIT before calling hci_uart_register_dev(), which calls proto->open() to initialize hu->priv. However, if a TTY write wakeup occurs during this window, hci_uart_tx_wakeup() may schedule write_work before hu->priv is initialized, leading to a NULL pointer dereference in hci_uart_write_work() when proto->dequeue() accesses hu->priv. The race condition is: CPU0 CPU1 ---- ---- hci_uart_set_proto() set_bit(HCI_UART_PROTO_INIT) hci_uart_register_dev() tty write wakeup hci_uart_tty_wakeup() hci_uart_tx_wakeup() schedule_work(&hu->write_work) proto->open(hu) // initializes hu->priv hci_uart_write_work() hci_uart_dequeue() proto->dequeue(hu) // accesses hu->priv (NULL!) Fix this by moving set_bit(HCI_UART_PROTO_INIT) after proto->open() succeeds, ensuring hu->priv is initialized before any work can be scheduled. Fixes: 5df5dafc171b ("Bluetooth: hci_uart: Fix another race during initialization") Link: https://lore.kernel.org/linux-bluetooth/6969764f.170a0220.2b9fc4.35a7@mx.google.com/ Signed-off-by: Jia-Hong Su Signed-off-by: Luiz Augusto von Dentz Signed-off-by: Sasha Levin --- drivers/bluetooth/hci_ldisc.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/bluetooth/hci_ldisc.c b/drivers/bluetooth/hci_ldisc.c index 2f322f890b81f..436ee77d4bf2f 100644 --- a/drivers/bluetooth/hci_ldisc.c +++ b/drivers/bluetooth/hci_ldisc.c @@ -685,6 +685,8 @@ static int hci_uart_register_dev(struct hci_uart *hu) return err; } + set_bit(HCI_UART_PROTO_INIT, &hu->flags); + if (test_bit(HCI_UART_INIT_PENDING, &hu->hdev_flags)) return 0; @@ -712,8 +714,6 @@ static int hci_uart_set_proto(struct hci_uart *hu, int id) hu->proto = p; - set_bit(HCI_UART_PROTO_INIT, &hu->flags); - err = hci_uart_register_dev(hu); if (err) { return err; -- 2.51.0