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Mon, 12 Jan 2026 05:31:21 -0800 (PST) Message-ID: <86bdd498-2012-4bb1-956b-47d91c2a334e@gmail.com> Date: Mon, 12 Jan 2026 21:31:18 +0800 Precedence: bulk X-Mailing-List: linux-i2c@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [syzbot] [usb?] INFO: task hung in i2c_tiny_usb_disconnect To: syzbot References: <6963d09e.050a0220.eaf7.0070.GAE@google.com> Content-Language: en-US From: Wei Peng Cc: linux-kernel@vger.kernel.org, linux-i2c@vger.kernel.org In-Reply-To: <6963d09e.050a0220.eaf7.0070.GAE@google.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit |Sorry! Please ignore the previous patch. It was sent by mistake. The correct patch is attached below. |#syz test diff --git a/drivers/i2c/busses/i2c-tiny-usb.c b/drivers/i2c/busses/i2c-tiny-usb.c index 57dfe5f1a7d9..79b7c97514c9 100644 --- a/drivers/i2c/busses/i2c-tiny-usb.c +++ b/drivers/i2c/busses/i2c-tiny-usb.c @@ -12,6 +12,7 @@ #include #include #include +#include /* include interfaces to usb layer */ #include @@ -172,6 +173,8 @@ struct i2c_tiny_usb { struct usb_device *usb_dev; /* the usb device for this device */ struct usb_interface *interface; /* the interface for this device */ struct i2c_adapter adapter; /* i2c related things */ + bool disconnected; /* set to true on disconnect */ + struct work_struct release_work; /* work struct to release the adapter */ }; static int usb_read(struct i2c_adapter *adapter, int cmd, @@ -184,6 +187,11 @@ static int usb_read(struct i2c_adapter *adapter, int cmd, if (!dmadata) return -ENOMEM; + if (READ_ONCE(dev->disconnected)) { + kfree(dmadata); + return -ENODEV; + } + /* do control transfer */ ret = usb_control_msg(dev->usb_dev, usb_rcvctrlpipe(dev->usb_dev, 0), cmd, USB_TYPE_VENDOR | USB_RECIP_INTERFACE | @@ -204,6 +212,11 @@ static int usb_write(struct i2c_adapter *adapter, int cmd, if (!dmadata) return -ENOMEM; + if (READ_ONCE(dev->disconnected)) { + kfree(dmadata); + return -ENODEV; + } + /* do control transfer */ ret = usb_control_msg(dev->usb_dev, usb_sndctrlpipe(dev->usb_dev, 0), cmd, USB_TYPE_VENDOR | USB_RECIP_INTERFACE, @@ -219,6 +232,15 @@ static void i2c_tiny_usb_free(struct i2c_tiny_usb *dev) kfree(dev); } +static void i2c_tiny_usb_release(struct work_struct *work) +{ + struct i2c_tiny_usb *dev = container_of(work, struct i2c_tiny_usb, + release_work); + + i2c_del_adapter(&dev->adapter); + i2c_tiny_usb_free(dev); +} + static int i2c_tiny_usb_probe(struct usb_interface *interface, const struct usb_device_id *id) { @@ -268,6 +290,8 @@ static int i2c_tiny_usb_probe(struct usb_interface *interface, dev->adapter.dev.parent = &dev->interface->dev; + INIT_WORK(&dev->release_work, i2c_tiny_usb_release); + /* and finally attach to i2c layer */ i2c_add_adapter(&dev->adapter); @@ -287,9 +311,9 @@ static void i2c_tiny_usb_disconnect(struct usb_interface *interface) { struct i2c_tiny_usb *dev = usb_get_intfdata(interface); - i2c_del_adapter(&dev->adapter); usb_set_intfdata(interface, NULL); - i2c_tiny_usb_free(dev); + WRITE_ONCE(dev->disconnected, true); + queue_work(system_long_wq, &dev->release_work); dev_dbg(&interface->dev, "disconnected\n"); }