linux-kernel - Re: [syzbot] [usb?] INFO: task hung in i2c_tiny_usb

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Message-Id: <20260114085125.859740-1-coderlogicwei@gmail.com>
Date: Wed, 14 Jan 2026 16:51:25 +0800
From: weipeng <coderlogicwei@...il.com>
To: oneukum@...e.com,
	linux-i2c@...r.kernel.org
Cc: anna-maria@...utronix.de,
	coderlogicwei@...il.com,
	frederic@...nel.org,
	linux-kernel@...r.kernel.org,
	linux-usb@...r.kernel.org,
	syzkaller-bugs@...glegroups.com,
	tglx@...utronix.de
Subject: Re: [syzbot] [usb?] INFO: task hung in i2c_tiny_usb_disconnect

Hi,

i2c_del_adapter in i2c-core-base.c:

> void i2c_del_adapter(struct i2c_adapter *adap)
> {
> ...
> /* wait until all references to the device are gone
>  *
>  * FIXME: This is old code and should ideally be replaced by an
>  * alternative which results in decoupling the lifetime of the struct
>  * device from the i2c_adapter, like spi or netdev do. Any solution
>  * should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled!
>  */
> init_completion(&adap->dev_released);
> device_unregister(&adap->dev);
> wait_for_completion(&adap->dev_released);
> ...
> }

This issue looks like caused by i2c_del_adapter(). It waits for too long so
it may cause the hung.

Thanks,
weipeng