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[65.112.8.24]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-6eb3ef0ed7dsm58440546d6.25.2025.03.25.09.41.21 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 25 Mar 2025 09:41:22 -0700 (PDT) Date: Tue, 25 Mar 2025 12:41:19 -0400 From: Alan Stern To: Wolfram Sang , syzbot , 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 Message-ID: References: <67e1a1f5.050a0220.a7ebc.0029.GAE@google.com> Precedence: bulk X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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