From nobody Thu Jan 1 12:25:30 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9F7D7CDB474 for ; Mon, 23 Oct 2023 08:02:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229530AbjJWICs (ORCPT ); Mon, 23 Oct 2023 04:02:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51810 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229452AbjJWICr (ORCPT ); Mon, 23 Oct 2023 04:02:47 -0400 Received: from TWMBX02.aspeed.com (mail.aspeedtech.com [211.20.114.72]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 75BB4A6 for ; Mon, 23 Oct 2023 01:02:43 -0700 (PDT) Received: from TWMBX02.aspeed.com (192.168.0.24) by TWMBX02.aspeed.com (192.168.0.24) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Mon, 23 Oct 2023 16:02:38 +0800 Received: from twmbx02.aspeed.com (192.168.10.10) by TWMBX02.aspeed.com (192.168.0.24) with Microsoft SMTP Server id 15.0.1497.2 via Frontend Transport; Mon, 23 Oct 2023 16:02:38 +0800 From: Billy Tsai To: , , , CC: Subject: [PATCH v1] i3c/master/mipi-i3c-hci: Fix a kernel panic for accessing DAT_data. Date: Mon, 23 Oct 2023 16:02:37 +0800 Message-ID: <20231023080237.560936-1-billy_tsai@aspeedtech.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Received-SPF: Fail (TWMBX02.aspeed.com: domain of billy_tsai@aspeedtech.com does not designate 192.168.10.10 as permitted sender) receiver=TWMBX02.aspeed.com; client-ip=192.168.10.10; helo=twmbx02.aspeed.com; Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" The `i3c_master_bus_init` function may attach the I2C devices before the I3C bus initialization. In this flow, the DAT `alloc_entry`` will be used before the DAT `init`. Additionally, if the `i3c_master_bus_init` fails, the DAT `cleanup` will execute before the device is detached, which will execue DAT `free_entry` function. The above scenario can cause the driver to use DAT_data when it is NULL. Signed-off-by: Billy Tsai --- drivers/i3c/master/mipi-i3c-hci/dat_v1.c | 29 ++++++++++++++++-------- 1 file changed, 19 insertions(+), 10 deletions(-) diff --git a/drivers/i3c/master/mipi-i3c-hci/dat_v1.c b/drivers/i3c/master/= mipi-i3c-hci/dat_v1.c index 97bb49ff5b53..47b9b4d4ed3f 100644 --- a/drivers/i3c/master/mipi-i3c-hci/dat_v1.c +++ b/drivers/i3c/master/mipi-i3c-hci/dat_v1.c @@ -64,15 +64,17 @@ static int hci_dat_v1_init(struct i3c_hci *hci) return -EOPNOTSUPP; } =20 - /* use a bitmap for faster free slot search */ - hci->DAT_data =3D bitmap_zalloc(hci->DAT_entries, GFP_KERNEL); - if (!hci->DAT_data) - return -ENOMEM; - - /* clear them */ - for (dat_idx =3D 0; dat_idx < hci->DAT_entries; dat_idx++) { - dat_w0_write(dat_idx, 0); - dat_w1_write(dat_idx, 0); + if (!hci->DAT_data) { + /* use a bitmap for faster free slot search */ + hci->DAT_data =3D bitmap_zalloc(hci->DAT_entries, GFP_KERNEL); + if (!hci->DAT_data) + return -ENOMEM; + + /* clear them */ + for (dat_idx =3D 0; dat_idx < hci->DAT_entries; dat_idx++) { + dat_w0_write(dat_idx, 0); + dat_w1_write(dat_idx, 0); + } } =20 return 0; @@ -87,7 +89,13 @@ static void hci_dat_v1_cleanup(struct i3c_hci *hci) static int hci_dat_v1_alloc_entry(struct i3c_hci *hci) { unsigned int dat_idx; + int ret; =20 + if (!hci->DAT_data) { + ret =3D hci_dat_v1_init(hci); + if (ret) + return ret; + } dat_idx =3D find_first_zero_bit(hci->DAT_data, hci->DAT_entries); if (dat_idx >=3D hci->DAT_entries) return -ENOENT; @@ -103,7 +111,8 @@ static void hci_dat_v1_free_entry(struct i3c_hci *hci, = unsigned int dat_idx) { dat_w0_write(dat_idx, 0); dat_w1_write(dat_idx, 0); - __clear_bit(dat_idx, hci->DAT_data); + if (hci->DAT_data) + __clear_bit(dat_idx, hci->DAT_data); } =20 static void hci_dat_v1_set_dynamic_addr(struct i3c_hci *hci, --=20 2.25.1