linux-kernel - RE: [REGRESSION] usb: gadget: f_fs: Allow scatter-gather buffers

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <02E7334B1630744CBDC55DA8586225837F884D53@ORSMSX103.amr.corp.intel.com>
Date:   Mon, 20 May 2019 16:23:28 +0000
From:   "Yang, Fei" <fei.yang@...el.com>
To:     Andrzej Pietrasiewicz <andrzej.p@...labora.com>,
        John Stultz <john.stultz@...aro.org>
CC:     Felipe Balbi <balbi@...nel.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Chen Yu <chenyu56@...wei.com>,
        lkml <linux-kernel@...r.kernel.org>,
        Linux USB List <linux-usb@...r.kernel.org>,
        Amit Pundir <amit.pundir@...aro.org>,
        Marek Szyprowski <m.szyprowski@...sung.com>,
        "kernel@...labora.com" <kernel@...labora.com>
Subject: RE: [REGRESSION] usb: gadget: f_fs: Allow scatter-gather buffers

>> One question that comes to my mind is this: Does the USB transmission 
>> stall (e.g. endpoint stall) or not? In other words, is adb connection 
>> broken because USB stops transmitting anything, or because the data is 
>> transmitted but its integrity is broken during transmission and that 
>> causes adb/adbd confusion which results in stopping their operation? 
>> Does anything keep happening on FunctionFS when adb connection is 
>> broken?
>
>Any discoveries about the problem?

In my debugging, I'm seeing a lot of requests queued up through ffs_epfile_io (returning -EIOCBQUEUED), but
only a few of them came back through ffs_epfile_async_io_complete -> ffs_user_copy_worker.
I don’t think there is a USB transmission stall though, because if I manually disable io_data->use_sg, everything
goes back to normal. So it looks more likely to be a buffer handling problem in the DWC3 driver.

-Fei

>
>Andrzej