Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Received-SPF: Pass (protection.outlook.com: domain of nvidia.com designates
 216.228.117.161 as permitted sender) receiver=protection.outlook.com;
 client-ip=216.228.117.161; helo=mail.nvidia.com; pr=C
From:   Haotien Hsu <haotienh@nvidia.com>
To:     Mathias Nyman <mathias.nyman@intel.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Thierry Reding <thierry.reding@gmail.com>,
        Jonathan Hunter <jonathanh@nvidia.com>,
        Philipp Zabel <p.zabel@pengutronix.de>,
        <linux-usb@vger.kernel.org>, <linux-tegra@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>
CC:     JC Kuo <jckuo@nvidia.com>, Wayne Chang <waynec@nvidia.com>,
        Haotien Hsu <haotienh@nvidia.com>
Subject: [PATCH v5] usb: xhci: tegra: fix sleep in atomic call
Date:   Mon, 27 Mar 2023 17:55:48 +0800
Message-ID: <20230327095548.1599470-1-haotienh@nvidia.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Content-Type: text/plain
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 27 Mar 2023 09:56:16.0017
 (UTC)
X-MS-Exchange-CrossTenant-Network-Message-Id: 79f2771e-5235-44eb-013f-08db2ea9819c
X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a
X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=43083d15-7273-40c1-b7db-39efd9ccc17a;Ip=[216.228.117.161];Helo=[mail.nvidia.com]
X-MS-Exchange-CrossTenant-AuthSource: CO1NAM11FT084.eop-nam11.prod.protection.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Anonymous
X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem
X-MS-Exchange-Transport-CrossTenantHeadersStamped: SA0PR12MB4589
X-Spam-Status: No, score=-0.2 required=5.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED,
        DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,FORGED_SPF_HELO,
        RCVD_IN_DNSWL_NONE,RCVD_IN_MSPIKE_H2,SPF_HELO_PASS,SPF_NONE
        autolearn=unavailable autolearn_force=no version=3.4.6
X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on
        lindbergh.monkeyblade.net
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

From: Wayne Chang <waynec@nvidia.com>

When we set the dual-role port to Host mode, we observed the following
splat:
[  167.057718] BUG: sleeping function called from invalid context at
include/linux/sched/mm.h:229
[  167.057872] Workqueue: events tegra_xusb_usb_phy_work
[  167.057954] Call trace:
[  167.057962]  dump_backtrace+0x0/0x210
[  167.057996]  show_stack+0x30/0x50
[  167.058020]  dump_stack_lvl+0x64/0x84
[  167.058065]  dump_stack+0x14/0x34
[  167.058100]  __might_resched+0x144/0x180
[  167.058140]  __might_sleep+0x64/0xd0
[  167.058171]  slab_pre_alloc_hook.constprop.0+0xa8/0x110
[  167.058202]  __kmalloc_track_caller+0x74/0x2b0
[  167.058233]  kvasprintf+0xa4/0x190
[  167.058261]  kasprintf+0x58/0x90
[  167.058285]  tegra_xusb_find_port_node.isra.0+0x58/0xd0
[  167.058334]  tegra_xusb_find_port+0x38/0xa0
[  167.058380]  tegra_xusb_padctl_get_usb3_companion+0x38/0xd0
[  167.058430]  tegra_xhci_id_notify+0x8c/0x1e0
[  167.058473]  notifier_call_chain+0x88/0x100
[  167.058506]  atomic_notifier_call_chain+0x44/0x70
[  167.058537]  tegra_xusb_usb_phy_work+0x60/0xd0
[  167.058581]  process_one_work+0x1dc/0x4c0
[  167.058618]  worker_thread+0x54/0x410
[  167.058650]  kthread+0x188/0x1b0
[  167.058672]  ret_from_fork+0x10/0x20

The function tegra_xusb_padctl_get_usb3_companion eventually calls
tegra_xusb_find_port and this in turn calls kasprintf which might sleep
and so cannot be called from an atomic context.

Fix this by moving the call to tegra_xusb_padctl_get_usb3_companion to
the tegra_xhci_id_work function where it is really needed.

Fixes: f836e7843036 ("usb: xhci-tegra: Add OTG support")
Cc: stable@vger.kernel.org
Signed-off-by: Wayne Chang <waynec@nvidia.com>
Signed-off-by: Haotien Hsu <haotienh@nvidia.com>
---
V4 -> V5: Update commit message and code layout with 100 columns
V3 -> V4: Remove copyright change from this patch
V2 -> V3: Add version information
V1 -> V2: Add "Fixes" and "Cc:" lines and update copyright years
---
 drivers/usb/host/xhci-tegra.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/usb/host/xhci-tegra.c b/drivers/usb/host/xhci-tegra.c
index 1ff22f675930..a88c39e525c2 100644
--- a/drivers/usb/host/xhci-tegra.c
+++ b/drivers/usb/host/xhci-tegra.c
@@ -1360,6 +1360,9 @@ static void tegra_xhci_id_work(struct work_struct *work)
 
 	mutex_unlock(&tegra->lock);
 
+	tegra->otg_usb3_port = tegra_xusb_padctl_get_usb3_companion(tegra->padctl,
+								    tegra->otg_usb2_port);
+
 	if (tegra->host_mode) {
 		/* switch to host mode */
 		if (tegra->otg_usb3_port >= 0) {
@@ -1474,9 +1477,6 @@ static int tegra_xhci_id_notify(struct notifier_block *nb,
 	}
 
 	tegra->otg_usb2_port = tegra_xusb_get_usb2_port(tegra, usbphy);
-	tegra->otg_usb3_port = tegra_xusb_padctl_get_usb3_companion(
-							tegra->padctl,
-							tegra->otg_usb2_port);
 
 	tegra->host_mode = (usbphy->last_event == USB_EVENT_ID) ? true : false;
 
-- 
2.25.1