Can you attach ftrace dump here?
$ sudo trace-cmd record -p function --module uvcvideo
--
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
https://bugs.launchpad.net/bugs/1827452
Title:
null pointer dereference in uvcvideo
To manage n
If you encounter uvc_disconnect then you may have a different issue
than I do. I can clearly see via debugging that uvc_disconnect is
never reached. In my case the disconnect is happening in
usb/core/hub.c:usb_disconnect. The comment on top if this function
says "This call is synchronous, and may
The issue is that uvc_disconnect() set the USB intf to NULL, but still
kept the uvcvideo device registered, hence a NULL pointer deference
happens afterward.
--
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
https://bugs.launchpad.net/bu
Sorry I kept the thin USB extension cable that I used to reproduce this. I
will try the patch in #23 over the next week or so when I can find time. I
still don't think it will have any effect though as the issue seems to be
in usbcore. Happy to see once and for all.
John
On Tue, Jan 18, 2022 a
And one more tool that might help you get a more reliable repro:
https://github.com/HexHive/USBFuzz - likely would need modification to
target this specific problem, however. More details here:
https://www.usenix.org/conference/usenixsecurity20/presentation/peng
--
You received this bug notificat
Ah, I suppose I could try booting off of a Live USB.
It'd be a fair amount of effort, but if you're looking for a more
reliable test jig, you might try using a Teensy 2.0++ or similar.
They've been used in the past for similar purposes (e.g.
https://fail0verflow.com/blog/2014/hubcap-chromecast-roo
Unfortunately at the moment I no longer have access to a box that's
running Ubuntu (or any linux) on bare metal. I suppose I can give it a
try with USB passthrough in a VM over the weekend, perhaps?
Also it's been ages since I've built and booted a custom kernel. Does
Ubuntu have an easy method fo
Benjamin,
Can you please test my patch in comment #23? Thanks in advance.
--
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
https://bugs.launchpad.net/bugs/1827452
Title:
null pointer dereference in uvcvideo
To manage notifications
** Tags added: patch
--
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
https://bugs.launchpad.net/bugs/1827452
Title:
null pointer dereference in uvcvideo
To manage notifications about this bug go to:
https://bugs.launchpad.net/ubunt
I wasn't aware that I could change the status of this bug. It's clear to
me from the comments above that others have observed it, so I've gone
ahead and switched it from "Expired" to "Confirmed."
** Changed in: linux (Ubuntu)
Status: Expired => Confirmed
--
You received this bug notificat
Sorry this only seems reproducible in a scenario a USB switch or cable that
doesn't support enough amps for the device. Any device or webcam which
overloads its power supply and then disconnects during UVC initialization
will disconnect itself during a critical period in the kernel where an
interr
I read at [1] about the issue.
@kaihengfeng, I suggest to send the patch upstream for review even with
no tests. Maybe there will be testers on the Linux kernel mailing list.
[1]: https://etbe.coker.com.au/2022/01/09/video-conferencing-lca/
--
You received this bug notification because you are
I am pretty sure it's called.
Can someone else try it?
--
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
https://bugs.launchpad.net/bugs/1827452
Title:
null pointer dereference in uvcvideo
To manage notifications about this bug go t
Sorry I've been reluctant to test it since that code block is never even
hit during the issue.
--
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
https://bugs.launchpad.net/bugs/1827452
Title:
null pointer dereference in uvcvideo
To m
Can someone please test the patch in #23?
--
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
https://bugs.launchpad.net/bugs/1827452
Title:
null pointer dereference in uvcvideo
To manage notifications about this bug go to:
https://bug
Test take 2.
** Patch added: "lp1827452-take2.patch"
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1827452/+attachment/5446102/+files/lp1827452-take2.patch
--
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
https://bugs.launch
Well, it should.
And I get it all wrong. I thought there's a race, but the NULL pointer
dereference actually happened long after the disconnect.
--
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
https://bugs.launchpad.net/bugs/1827452
@kaihengfeng
The usb disconnect comes directly via interrupt. Execution doesn't hit
uvc_disconnect and this patch has no effect. :/
--
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
https://bugs.launchpad.net/bugs/1827452
Title:
null
Thanks I finally managed to set up the same test cable and give this
patch a go. I still see the same error - third attempt in the trace
attached. I'm still of the opinion that this would need to be fixed in
usbcore.
** Attachment added: "dmesg failure on 3rd attempt"
https://bugs.launchpad.
Thanks I will test as soon as I get some time (weekend). I have to hook
up my shoddy tester USB cable and compile a fresh kernel but in the
meantime trying to get business wrapped up before holidays.
--
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribe
Can someone please test it?
--
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
https://bugs.launchpad.net/bugs/1827452
Title:
null pointer dereference in uvcvideo
To manage notifications about this bug go to:
https://bugs.launchpad.ne
Please test this patch.
Only compile tested.
** Patch added: "lp1827452.patch"
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1827452/+attachment/5443008/+files/lp1827452.patch
--
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu
There it is: https://lore.kernel.org/linux-
media/CAO5W59geLtP7kHJkW=ELusAcd9==ceqhsuzznukfradtkxz...@mail.gmail.com/
--
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
https://bugs.launchpad.net/bugs/1827452
Title:
null pointer derefe
Yes this was the original thread. Alan was helpful and responsive but
in the end he suggested I contact the uvcvideo maintainers which I did
and got nowhere.
https://lore.kernel.org/linux-
usb/20201123152654.gb708...@rowland.harvard.edu/#t
The 2nd patch was to uvcvideo maintainers Laurent Pincha
https://lore.kernel.org/linux-
usb/20201112192302.ga287...@rowland.harvard.edu/
Just attach the full dmesg for maintainers to debug.
--
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
https://bugs.launchpad.net/bugs/1827452
Title:
nul
I shared the stack trace. Was there a reply somewhere I didn't get? Is
it on lkms? Link?
With UVC trace on:
[ 638.729455] uvcvideo: uvc_v4l2_open
[ 638.824646] uvcvideo: Resuming interface 0
[ 638.824648] uvcvideo: Resuming interface 1
[ 638.825644] uvcvideo: uvc_v4l2_release
[ 638.898089]
The maintainer merely wants to see the stack trace...
--
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
https://bugs.launchpad.net/bugs/1827452
Title:
null pointer dereference in uvcvideo
To manage notifications about this bug go to:
For what it's worth, as a dev who's spent plenty of time hacking the
kernel in a prior job, I really appreciate the effort. Hopefully it
won't be completely in vain.
--
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
https://bugs.launchpa
Hi latest on this. I've played with about 50 custom kernel patches here
and I can see exactly what happens. When uvcvideo looks for webcam
devices it finds a perfectly healthy idle webcam on the USB hub (even
built-in hub). Then when it starts a stream the webcam obviously
requires more power.
Update again.
The kernel maintainers have been helpful but prefer NULL checking to be done in
the drivers, not in the kernel. I've explored further with some test builds
and it turns out the NULL is actually on the dev config interfaces (usb.c:281
current line). During initialization the Logit
Hi John,
thanks for the fix!
Let's wait for some good news.
--
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
https://bugs.launchpad.net/bugs/1827452
Title:
null pointer dereference in uvcvideo
To manage notifications about this bug
Update on this. Pretty sure I managed to find the line in the kernel
triggering this. I've submitted a PR to the kernel USB maintainers.
Hopefully tested and merged soon.
https://github.com/torvalds/linux/commit/a40519014549f60969c8e67a2fd91426db05fe04
--
You received this bug notification bec
I know this is closed but I've been having this same issue for months as
well. In fact I tried a different webcam from a different vendor and I
see the same behaviour.
Linux 5.8.18-200.fc32.x86_64 #1 SMP Mon Nov 2 19:49:11 UTC 2020 x86_64
x86_64 x86_64 GNU/Linux
Just adding this for the record,
[Expired for linux (Ubuntu) because there has been no activity for 60
days.]
** Changed in: linux (Ubuntu)
Status: Incomplete => Expired
--
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
https://bugs.launchpad.net/bugs/1827452
T
Would it be possible for you to test the latest upstream kernel? Refer
to https://wiki.ubuntu.com/KernelMainlineBuilds . Please test the latest
v5.1-2 kernel[1].
If this bug is fixed in the mainline kernel, please add the following
tag 'kernel-fixed-upstream'.
If the mainline kernel does not fix
To be clear, the line below (taken from the longer log output above) was
not due to me physically disconnecting the camera. I disconnected it
after capturing the kernel log.
[ 938.125745] usb 3-3: USB disconnect, device number 5
--
You received this bug notification because you are a member of U
36 matches
Mail list logo
