Date:   Fri, 11 Feb 2022 17:10:00 +0100
From:   Paul Menzel <pmenzel@...gen.mpg.de>
To:     Luiz Augusto von Dentz <luiz.dentz@...il.com>
Cc:     Marcel Holtmann <marcel@...tmann.org>,
        Johan Hedberg <johan.hedberg@...il.com>,
        linux-bluetooth@...r.kernel.org,
        LKML <linux-kernel@...r.kernel.org>,
        Takashi Iwai <tiwai@...e.com>
Subject: Re: Unable to transfer big files to Nokia N9

Dear Luiz,


Am 16.01.22 um 14:27 schrieb Paul Menzel:

[…]

> It turns out there was a regression in Linux 5.16-rc1.
> 
> 
> Am 20.12.21 um 22:31 schrieb Paul Menzel:
> 
>> Am 01.12.21 um 23:07 schrieb Paul Menzel:
>>
>>> Am 01.12.21 um 19:29 schrieb Luiz Augusto von Dentz:
>>>
>>>> On Wed, Dec 1, 2021 at 9:39 AM Paul Menzel <pmenzel@...gen.mpg.de> 
>>>> wrote:
>>>
>>>>> For the first time, I wanted to transfer a 2 MB PDF file from a Dell
>>>>> Latitude E7250 with Debian sid/unstable with Linux 5.16-rc1 to a Nokia
>>>>> N9 (MeeGo/Harmattan). Using the package *bluez-obexd* 5.61-1 and GNOME
>>>>> 41, the device was found, and paired fine. Then I selected to transfer
>>>>> the 2 MB file, and after starting for a second, it timed out after the
>>>>> progress bar moves forward ones and failed.
>>>>>
>>>>> The systemd journal contains:
>>>>>
>>>>>       obexd[21139]: Transfer(0x56243fe4f790) Error: Timed out 
>>>>> waiting for response
>>>>>
>>>>> Testing with a a 5 byte test text file, worked fine. Also testing 
>>>>> with a
>>>>> Galaly M32, both files were transferred without problems (though 
>>>>> slowly
>>>>> with 32 KB/s.)
>>>>>
>>>>> Trying to connect to the device with bluetoothctl failed for me, 
>>>>> and the
>>>>> journal contained, it failed.
>>>>>
>>>>>       $ bluetoothctl
>>>>>       Agent registered
>>>>>       [bluetooth]# connect 40:98:4E:5B:CE:XX
>>>>>       Attempting to connect to 40:98:4E:5B:CE:XX
>>>>>       Failed to connect: org.bluez.Error.Failed
>>>>>
>>>>>       bluetoothd[21104]: src/service.c:btd_service_connect() 
>>>>> a2dp-source profile connect failed for 40:98:4E:5B:CE:B3: Protocol 
>>>>> not available
>>>>>
>>>>> As the Nokia N9 was once pretty popular in the Linux community, I am
>>>>> pretty sure, it used to work fine in the past, and there is some
>>>>> regression. It’d be great, if you could give me some hints how to
>>>>> further debug the issue.
>>>>
>>>> We will need some logs, obexd and btmon, if possible.
>>>
>>> I only managed to get the btmon trace [1]. I did `sudo modprobe -r 
>>> btusb` and `sudo btmon -w /dev/shm/trace.log`.
>>>
>>> Linux messages:
>>>
>>>      [29880.100381] calling  btusb_driver_init+0x0/0x1000 [btusb] @ 
>>> 28716
>>>      [29880.239603] usbcore: registered new interface driver btusb
>>>      [29880.239608] initcall btusb_driver_init+0x0/0x1000 [btusb] 
>>> returned 0 after 135952 usecs
>>>      [29880.240706] Bluetooth: hci0: unexpected event for opcode 0x0500
>>>      [29880.241598] Bluetooth: hci0: Legacy ROM 2.5 revision 1.0 
>>> build 3 week 17 2014
>>>      [29880.241605] Bluetooth: hci0: Intel device is already patched. 
>>> patch num: 32
>>>
>>>  From the system journal:
>>>
>>>      Dez 01 22:52:19 ersatz obexd[21139]: Transfer(0x56243fe53dd0) 
>>> Error: Timed out waiting for response
>>
>> Were you able to see anything in the attached logs? If the obexd logs 
>> are missing, can you please tell how I should capture them?
>>
>> I also tested with Ubuntu 20.04 (*linux-image-5.11.0-27-generic*) and 
>> 21.10 (*linux-image-5.13.0-19-generic*) live systems booted from a USB 
>> storage device, and transferring `/usr/bin/systemctl` 
>> (`/lib/systemd/systemd`) with size of 1.8 MB worked fine.
>>
>> Could there be a regression in that area? Unfortunately, it’s not easy 
>> for me to do a bisection on the device at hand.
>>
>> (Would it be possible to do with QEMU and USB controller and Bluetooth 
>> device passthrough? How can I transfer the file on the command line so 
>> I wouldn’t need to install a desktop environment?)
> 
> Turns out, that is indeed possible [2], but turned out to be cumbersome, 
> as I hit the regression [3], which seems to have been fixed by commit 
> 95655456e7ce (Bluetooth: btintel: Fix broken LED quirk for legacy ROM 
> devices) merged in the current Linux 5.17 cycle this week.
> 
> As a work around, I applied a hunk from Takashi’s patch.
> 
> -       { USB_DEVICE(0x8087, 0x0a2a), .driver_info = 
> BTUSB_INTEL_COMBINED },
> +       { USB_DEVICE(0x8087, 0x0a2a), .driver_info = BTUSB_INTEL_COMBINED |
> + BTUSB_INTEL_BROKEN_INITIAL_NCMD },
> 
> My problem with the Nokia N9 is still present in Linus’ master branch.
> 
> Then I built a minimal Linux kernel for QEMU, and ran:
> 
>      qemu-system-x86_64 -cpu host -m 2G -enable-kvm \
>        -usb -device usb-host,vendorid=0x8087,productid=0x0a2a \
>        -drive file=/dev/shm/debian-64.img,format=raw,if=virtio \
>        -net nic -net user,hostfwd=tcp::22223-:22 \
>        -kernel /dev/shm/bzImage -append "root=/dev/vda1 rw quiet"
> 
> In the Debian sid/unstable VM, I used
> 
>      ssh root@...alhost -p 22223
> 
> I once had to pair the VM with the Nokia N9 in bluetoothctl, and then 
> started `/usr/libexec/bluetooth/obexd`, and ran `obexctl`, and connected 
> first with `connect`, and then ran `send /lib/systemd/systemd` to 
> transfer the file. In the problematic cases it stopped/hung after the 
> first progress message.
> 
>      # obexctl
>      [NEW] Client /org/bluez/obex
>      [obex]# connect 40:98:4E:5B:CE:XX
>      Attempting to connect to 40:98:4E:5B:CE:XX
>      [NEW] Session /org/bluez/obex/client/session0 [default]
>      [NEW] ObjectPush /org/bluez/obex/client/session0
>      Connection successful
>      [40:98:4E:5B:CE:XX]# send /lib/systemd/systemd
>      Attempting to send /lib/systemd/systemd to /org/bluez/obex/client/session0
>      [NEW] Transfer /org/bluez/obex/client/session0/transfer0
>      Transfer /org/bluez/obex/client/session0/transfer0
>          Status: queued
>          Name: systemd
>          Size: 1841712
>          Filename: /lib/systemd/systemd
>          Session: /org/bluez/obex/client/session0
>      [CHG] Transfer /org/bluez/obex/client/session0/transfer0 Status: active
>      [CHG] Transfer /org/bluez/obex/client/session0/transfer0 Transferred: 32737 (@32KB/s 00:55)
>      [CHG] Transfer /org/bluez/obex/client/session0/transfer0 Status: error
>      [DEL] Transfer /org/bluez/obex/client/session0/transfer0
> 
> Some manual bisection of Linux releases, verified, that the regression 
> was introduced in Linux 5.16-rc1. (Lucky me, I started using Bluetooth 
> with the Nokia with Linux 5.16-rc1.) Then I verified it was introduced 
> by the Bluetooth pull request for Linux 5.16. Then I picked commit 
> 81be03e026dc0c16dc1c64e088b2a53b73caa895 due to the commit message, and 
> bisected from there, and it turns out, that this commit is actually 
> introducing the regression.
> 
>      $ git bisect good
>      81be03e026dc0c16dc1c64e088b2a53b73caa895 is the first bad commit
>      commit 81be03e026dc0c16dc1c64e088b2a53b73caa895
>      Author: Luiz Augusto von Dentz <luiz.von.dentz@...el.com>
>      Date:   Fri Sep 3 15:27:32 2021 -0700
> 
>          Bluetooth: RFCOMM: Replace use of memcpy_from_msg with bt_skb_sendmmsg
> 
>          This makes use of bt_skb_sendmmsg instead using memcpy_from_msg which
>          is not considered safe to be used when lock_sock is held.
> 
>          Also make rfcomm_dlc_send handle skb with fragments and queue them all
>          atomically.
> 
>          Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@...el.com>
>          Signed-off-by: Marcel Holtmann <marcel@...tmann.org>
> 
>       net/bluetooth/rfcomm/core.c | 50 ++++++++++++++++++++++++++++++++++++++-------
>       net/bluetooth/rfcomm/sock.c | 46 +++++++++--------------------------------
>       2 files changed, 53 insertions(+), 43 deletions(-)
> 
> Unfortunately, the patch does not cleanly revert, so users have to wait 
> until an expert can take a look, and come up with a fix.

The revert required one more revert [4]. You asked for logs, which I had 
already provided in my response to your request. I tried it again, and 
attached it to [5]. As written there, I failed to get logs for obexd.


Kind regards,

Paul


> PS: For the records:
> 
>      $ git bisect log
>      # bad: [81be03e026dc0c16dc1c64e088b2a53b73caa895] Bluetooth: RFCOMM: Replace use of memcpy_from_msg with bt_skb_sendmmsg
>      # good: [49d8a5606428ca0962d09050a5af81461ff90fbb] Bluetooth: fix init and cleanup of sco_conn.timeout_work
>      git bisect start '81be03e026dc0' 'HEAD^'
>      # good: [904c139a2517191e48f9cb1bb2d611ae59434009] Bluetooth: Add support for msbc coding format
>      git bisect good 904c139a2517191e48f9cb1bb2d611ae59434009
>      # good: [8bba13b1d08d42e2e8308924fa5c1551a7b2b011] Bluetooth: btintel: Fix incorrect out of memory check
>      git bisect good 8bba13b1d08d42e2e8308924fa5c1551a7b2b011
>      # good: [38f64f650dc0e44c146ff88d15a7339efa325918] Bluetooth: Add bt_skb_sendmsg helper
>      git bisect good 38f64f650dc0e44c146ff88d15a7339efa325918
>      # good: [0771cbb3b97d3c1d68eecd7f00055f599954c34e] Bluetooth: SCO: Replace use of memcpy_from_msg with bt_skb_sendmsg
>      git bisect good 0771cbb3b97d3c1d68eecd7f00055f599954c34e
>      # first bad commit: [81be03e026dc0c16dc1c64e088b2a53b73caa895] Bluetooth: RFCOMM: Replace use of memcpy_from_msg with bt_skb_sendmmsg


>>> [1]: https://owww.molgen.mpg.de/~pmenzel/trace.log.7z
> [2]: https://lore.kernel.org/linux-bluetooth/5891f0d5-8d51-9da5-7663-718f301490b1@molgen.mpg.de/T/#u
> [3]: https://lore.kernel.org/linux-bluetooth/20211202162256.31837-1-tiwai@suse.de/ [4]: 
https://lore.kernel.org/linux-bluetooth/20220208221911.57058-1-pmenzel@molgen.mpg.de/
[5]: https://bugzilla.kernel.org/show_bug.cgi?id=215594

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