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From: Wolfram Sang <wsa+renesas@sang-engineering.com>
To: Alan Stern <stern@rowland.harvard.edu>
Cc: syzbot <syzbot+c38e5e60d0041a99dbf5@syzkaller.appspotmail.com>,
	gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org,
	linux-usb@vger.kernel.org, syzkaller-bugs@googlegroups.com,
	linux-i2c@vger.kernel.org
Subject: Re: [syzbot] [usb?] WARNING in dib0700_i2c_xfer/usb_submit_urb
Date: Tue, 25 Mar 2025 17:59:10 +0100	[thread overview]
Message-ID: <Z-Lg3glmnzA44R_H@shikoro> (raw)
In-Reply-To: <ecdc37c4-b178-4e43-bfbf-45bd3ed29ff2@rowland.harvard.edu>

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> > > 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.

Yes, that would be more convervative. Does USB allow zero-length writes?

> 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.)

As I also don't know the hardware, I suggest to leave them empty. 0
means "no quirk".


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  reply	other threads:[~2025-03-25 16:59 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-03-24 18:18 [syzbot] [usb?] WARNING in dib0700_i2c_xfer/usb_submit_urb syzbot
2025-03-24 19:08 ` Alan Stern
2025-03-24 19:19   ` Wolfram Sang
2025-03-25 16:41     ` Alan Stern
2025-03-25 16:59       ` Wolfram Sang [this message]
2025-03-25 17:47         ` Alan Stern
2025-03-25 19:07           ` syzbot
2025-03-25 19:28             ` [PATCH] media: dvb: usb: Fix " Alan Stern
2025-03-25 19:56               ` Wolfram Sang
2025-03-25 21:47                 ` Alan Stern
2025-03-25 22:17                   ` Wolfram Sang
2025-03-26 15:28                     ` [PATCH v2] " Alan Stern
2025-03-26 15:54                       ` Wolfram Sang
2025-03-26 16:04                         ` Alan Stern
2025-03-26 21:32                           ` Wolfram Sang
2025-03-27 16:10                             ` [PATCH v2 resend] " Alan Stern
2025-03-28 15:45                               ` Wolfram Sang
2025-03-29  2:08                                 ` Alan Stern
2025-03-29  6:05                                   ` Wolfram Sang
2025-03-29 14:31                                     ` Alan Stern

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