[Bug 1899633] Re: Repeated kernel warnings/stacktraces with kernel 5.4 and newer
Confirmed that with v4l2loopback-dkms 0.12.3-1ubuntu0.1, configured devices are not correctly advertised. This breaks Zoom, Cheese, etc. Compiling v4l2loopback from upstream source works correctly. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1899633 Title: Repeated kernel warnings/stacktraces with kernel 5.4 and newer To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/v4l2loopback/+bug/1899633/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1899633] Re: Repeated kernel warnings/stacktraces with kernel 5.4 and newer
Right now, the only app that appears to work with the new module is Chromium. Which was where I was testing because that seemed more demanding. Will be working on the regression on bug 1901491. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1899633 Title: Repeated kernel warnings/stacktraces with kernel 5.4 and newer To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/v4l2loopback/+bug/1899633/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1899633] Re: Repeated kernel warnings/stacktraces with kernel 5.4 and newer
Can confirm, this change prevents Zoom from listing my v4l2lsink from OBS. I had to downgrade to the "base" package so that my co-workers can continue to see my stupid effects and overlays. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1899633 Title: Repeated kernel warnings/stacktraces with kernel 5.4 and newer To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/v4l2loopback/+bug/1899633/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1899633] Re: Repeated kernel warnings/stacktraces with kernel 5.4 and newer
No, looking quickly at the code that should be set in the capabilities returned by the query capabilities call. But not in the static device_caps. And if that is added back, one cannot drop that flag for exclusive_caps functionality without triggering repeated kernel warnings. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1899633 Title: Repeated kernel warnings/stacktraces with kernel 5.4 and newer To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/v4l2loopback/+bug/1899633/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1899633] Re: Repeated kernel warnings/stacktraces with kernel 5.4 and newer
Would loading the new module with exclusive_caps=1 work as a quick work- around. I guess I missed adding the caps explicitly in the query function. So that relies on thing being set as device caps. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1899633 Title: Repeated kernel warnings/stacktraces with kernel 5.4 and newer To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/v4l2loopback/+bug/1899633/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1899633] Re: Repeated kernel warnings/stacktraces with kernel 5.4 and newer
The last fix also broke v4l2loopback for me. Most applications seem to check the V4L2_CAP_VIDEO_CAPTURE flag (eg Firefox: https://hg.mozilla.org/releases/mozilla- release/file/aac9479c6a32ce3b95556da24f3b00c00e145506/media/webrtc/trunk/webrtc/modules/video_capture/linux/device_info_linux.cc#l386), which is now unset by the fix. This means apps such as Firefox do not detect virtual cameras created by v4l2loopback with this patch. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1899633 Title: Repeated kernel warnings/stacktraces with kernel 5.4 and newer To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/v4l2loopback/+bug/1899633/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1899633] Re: Repeated kernel warnings/stacktraces with kernel 5.4 and newer
This fix has rendered v4l2loopback obsolete. Indeed, the device is no longer detected by any applications (e.g. VLC, Firefox, etc.). I had to revert to the previous version to be able to use it again. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1899633 Title: Repeated kernel warnings/stacktraces with kernel 5.4 and newer To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/v4l2loopback/+bug/1899633/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1899633] Re: Repeated kernel warnings/stacktraces with kernel 5.4 and newer
This bug was fixed in the package v4l2loopback - 0.12.3-1ubuntu0.1 --- v4l2loopback (0.12.3-1ubuntu0.1) focal; urgency=medium * Fix kernel warnings triggered by vidioc_querycap (LP: #1899633). -- Stefan Bader Tue, 13 Oct 2020 15:07:55 +0200 ** Changed in: v4l2loopback (Ubuntu Focal) Status: Fix Committed => Fix Released -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1899633 Title: Repeated kernel warnings/stacktraces with kernel 5.4 and newer To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/v4l2loopback/+bug/1899633/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1899633] Re: Repeated kernel warnings/stacktraces with kernel 5.4 and newer
$ dpkg -l|grep v4l2loop ii v4l2loopback-dkms 0.12.3-1ubuntu0.1 all Source for the v4l2loopback driver (DKMS) ii v4l2loopback-utils 0.12.3-1ubuntu0.1 all Commandline utilities for the for the v4l2-loopback module $ dkms status|grep v4l2 v4l2loopback, 0.12.3, 5.4.0-51-generic, x86_64: installed v4l2loopback, 0.12.3, 5.4.0-52-generic, x86_64: installed $ modprobe v4l2loopback exclusive_caps=1 $ dmesg|grep v4l2-ioctl I already was using the updated code, so I repeated the steps in a VM with the current version of the driver and got the following in dmesg: [ 471.604470] WARNING: CPU: 1 PID: 18911 at drivers/media/v4l2-core/v4l2-ioctl.c:1064 v4l_querycap+0x8b/0xa0 [videodev] [ 471.604602] WARNING: CPU: 1 PID: 18911 at drivers/media/v4l2-core/v4l2-ioctl.c:1069 v4l_querycap+0x8f/0xa0 [videodev] ** Tags removed: verification-needed verification-needed-focal ** Tags added: verification-done verification-done-focal -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1899633 Title: Repeated kernel warnings/stacktraces with kernel 5.4 and newer To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/v4l2loopback/+bug/1899633/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1899633] Re: Repeated kernel warnings/stacktraces with kernel 5.4 and newer
Hello Stefan, or anyone else affected, Accepted v4l2loopback into focal-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/v4l2loopback/0.12.3-1ubuntu0.1 in a few hours, and then in the -proposed repository. Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation on how to enable and use -proposed. Your feedback will aid us getting this update out to other Ubuntu users. If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested, what testing has been performed on the package and change the tag from verification-needed- focal to verification-done-focal. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification- failed-focal. In either case, without details of your testing we will not be able to proceed. Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance for helping! N.B. The updated package will be released to -updates after the bug(s) fixed by this package have been verified and the package has been in -proposed for a minimum of 7 days. ** Changed in: v4l2loopback (Ubuntu Focal) Status: In Progress => Fix Committed ** Tags added: verification-needed verification-needed-focal -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1899633 Title: Repeated kernel warnings/stacktraces with kernel 5.4 and newer To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/v4l2loopback/+bug/1899633/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1899633] Re: Repeated kernel warnings/stacktraces with kernel 5.4 and newer
Thanks for the updated debdiff as requested, LGTM now. Some minor cleanup 0.12.3-1ubuntu1 -> 0.12.3-1ubuntu0.1 Further I think we should add DKMS rebuild with the Focal kernel as test-step explicitly (it will be done on install of the upgrade anyway, but to be formally correct) ** Description changed: Release: 20.04/Focal Fossa [SRU Justification] Impact: Starting with kernel version 5.4 the v4l2-core started to add sanity checking on drivers when querying capabilities. First drivers are not supposed to modify an initially set device_caps attribute. And second, the returned set of capabilities must be a superset of those in device_caps. The v4l2loopback module fails on both checks which results in repeated warnings (with additional stack trace) starting with: - WARNING: CPU: 2 PID: 7234 at drivers/media/v4l2-core/v4l2-ioctl.c:1064 v4l_querycap+0x8f/0xa0 [videodev] - WARNING: CPU: 2 PID: 7234 at drivers/media/v4l2-core/v4l2-ioctl.c:1069 v4l_querycap+0x8f/0xa0 [videodev] - Fix: The proposed fix adds compat code which stops modifying device_caps - after initial setup for kernel versions 5.4 and later. Also for those - versions the initial setup excludes V4L2_CAP_VIDEO_CAPTURE and - V4L2_CAP_VIDEO_OUTPUT as those capabilities might be optionally set when - calling v4l_querycap() to indicate readyness. + Fix: + The proposed fix adds compat code which stops modifying device_caps after initial setup for kernel versions 5.4 and later. Also for those versions the initial setup excludes V4L2_CAP_VIDEO_CAPTURE and V4L2_CAP_VIDEO_OUTPUT as those capabilities might be optionally set when calling v4l_querycap() to indicate readyness. - Testcase: Inserting the DKMS module the following way should start showing the above warnings: - sudo modprobe v4l2loopback exclusive_caps=1 - Once the fixed version is used, there should no longer be any warnings. + Testcase: + #1 +DKMS build the updated version (should be implicitly done on an +upgrade of v4l2loopback) +But one can try to rebuild explicitly and check if any warnings are +given. This would be extra useful if a pre 5.4 kernel could be used as +well (not officially part of focal, therefore optional) - Regression Potential: The change affects the internal device_caps - variable only. If that is unexpectedly used by anything external (the - kernel code should be assumed to expect the modified form) the loopback - device might become unusable for recording/playback. I have been using - the modified driver for a while now as v4l2sink in obs-studio and saw - now issues. + #2 +Inserting the DKMS module the following way should start showing the +above warnings: + $ sudo modprobe v4l2loopback exclusive_caps=1 +Once the fixed version is used, there should no longer be any warnings. + + Regression Potential: + The change affects the internal device_caps variable only. If that is unexpectedly used by anything external (the kernel code should be assumed to expect the modified form) the loopback device might become unusable for recording/playback. I have been using the modified driver for a while now as v4l2sink in obs-studio and saw now issues. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1899633 Title: Repeated kernel warnings/stacktraces with kernel 5.4 and newer To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/v4l2loopback/+bug/1899633/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1899633] Re: Repeated kernel warnings/stacktraces with kernel 5.4 and newer
FYI: I was on the receiving end of a video call using this updated driver - I can confirm it works. Reviewed, made some minor fixups (version as mentioned), extended the SRU template n the description and sponsored into Focal-proposed -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1899633 Title: Repeated kernel warnings/stacktraces with kernel 5.4 and newer To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/v4l2loopback/+bug/1899633/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1899633] Re: Repeated kernel warnings/stacktraces with kernel 5.4 and newer
The kernel check was added in [1] v5.4-rc1 by: Author: Hans Verkuil Date: Tue Jul 23 04:21:25 2019 -0400 media: v4l2-dev/ioctl: require non-zero device_caps, verify sane querycap results Now that all V4L2 drivers set device_caps in struct video_device, we can add a check for this to ensure all future drivers fill this in. Also verify that when the querycap ioctl is called the driver didn't mess with the device_caps value and that capabilities is a superset of device_caps. Signed-off-by: Hans Verkuil Reviewed-by: Sakari Ailus [hverkuil-ci...@xs4all.nl: fix too-long line] Signed-off-by: Mauro Carvalho Chehab [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=3c1350501c21db8e3b1a38d9e97db29694305c3b ** Patch added: "v2: clarify why upstreaming is not needed" https://bugs.launchpad.net/ubuntu/+source/v4l2loopback/+bug/1899633/+attachment/5424119/+files/focal-proposed-fix.debdiff ** Patch removed: "focal-proposed-fix.debdiff" https://bugs.launchpad.net/ubuntu/+source/v4l2loopback/+bug/1899633/+attachment/5421730/+files/focal-proposed-fix.debdiff -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1899633 Title: Repeated kernel warnings/stacktraces with kernel 5.4 and newer To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/v4l2loopback/+bug/1899633/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1899633] Re: Repeated kernel warnings/stacktraces with kernel 5.4 and newer
Test build uploaded to: https://launchpad.net/~smb/+archive/ubuntu/focal/+packages The attached debdiff contains the proposed adjustments to the DKMS package. ** Patch added: "focal-proposed-fix.debdiff" https://bugs.launchpad.net/ubuntu/+source/v4l2loopback/+bug/1899633/+attachment/5421730/+files/focal-proposed-fix.debdiff -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1899633 Title: Repeated kernel warnings/stacktraces with kernel 5.4 and newer To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/v4l2loopback/+bug/1899633/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1899633] Re: Repeated kernel warnings/stacktraces with kernel 5.4 and newer
The 20.10 version (0.12.5-1) was reworked considerably and I was told by someone else that it would not exhibit those warnings. ** Changed in: v4l2loopback (Ubuntu) Status: In Progress => Fix Released ** Changed in: v4l2loopback (Ubuntu) Assignee: Stefan Bader (smb) => (unassigned) -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1899633 Title: Repeated kernel warnings/stacktraces with kernel 5.4 and newer To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/v4l2loopback/+bug/1899633/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
