Re: [syzbot] [usb?] WARNING in dib0700_i2c_xfer/usb_submit_urb

From: Alan Stern
Date: Tue Mar 25 2025 - 12:44:02 EST


On Mon, Mar 24, 2025 at 08:19:32PM +0100, Wolfram Sang wrote:
>
> > As far as I can tell from the source code, the dib0700 simply isn't able
> > to handle 0-length reads. Should the dib0700_ctrl_rd() routine be
> > changed simply to return 0 in such cases?
>
> The adapter (I assume the one in dvb-usb-i2c.c) should populate an
> i2c_adapter_quirks struct with I2C_AQ_NO_ZERO_LEN and then the core will
> bail out for you.

Or the I2C_AQ_NO_ZERO_LEN_READ flag bit.

What about all the other fields in the i2c_adapter_quirks structure?
How should they be set? (Note: I don't know anything about this driver
or these devices; I'm just chasing down the syzbot bug report.)

Alan Stern