|Summary:||dvb-usb-v2: General Protection Fault shortly after boot|
|Product:||v4l-dvb||Reporter:||Dan Ziemba (zman0900)|
|Severity:||normal||CC:||crope, mchehab, mkrufky, radek, toso, zman0900|
Description Dan Ziemba 2018-09-09 00:05:15 UTC
Starting with the first 4.18 RC kernel, my system experiences general protection faults leading to kernel panic shortly after the login prompt appears on most boots. Occasionally that doesn't happen and instead numerous other seemingly random stack traces are printed (bad page map, scheduling while atomic, null pointer deref, etc), but either way the system is unusable. This bug remains up through the latest mainline kernel 4.19-rc2. Booting with my USB ATSC tv tuner disconnected prevents the bug from happening. Kernel bisection between v4.17 and 4.18-rc1 shows problem is caused by: 1a0c10ed7bb1 media: dvb-usb-v2: stop using coherent memory for URBs Building both 4.18.6 and 4.19-rc2 with that commit reverted resolves the bug for me. My DVB hardware uses driver mxl111sf: Bus 002 Device 003: ID 2040:c61b Hauppauge Device Descriptor: bLength 18 bDescriptorType 1 bcdUSB 2.00 bDeviceClass 0 bDeviceSubClass 0 bDeviceProtocol 0 bMaxPacketSize0 64 idVendor 0x2040 Hauppauge idProduct 0xc61b bcdDevice 0.00 iManufacturer 1 Hauppauge iProduct 2 WinTV Aero-M Other system info: Arch Linux x86_64 Intel i7-3770 16 GB ram
Comment 1 Victor Toso 2018-10-25 14:05:38 UTC
You could try to see if it fixes the issue for you. https://email@example.com/msg135901.html
Comment 2 Dan Ziemba 2018-12-31 03:38:46 UTC
Sorry for the slow response. I have been running the 4.14 LTS kernel for a while now and forgot to check on this. I just tried out the 4.19.12 kernel as built by Arch Linux, and the TV tuner seems to be working fine. So it seems something between 4.19-rc2 and 4.19.12 has fixed or hidden the problem. But I am now running ZFS on this server, so the kernel is tainted. I guess it could be possible that that is somehow preventing the error from happening.
Comment 3 Dan Ziemba 2019-01-05 19:03:10 UTC
Scratch that, I must have just gotten lucky the day I tried that. Arch has now upgraded their LTS kernel to 4.19.13, and the bug is happening again for me. It is also happening with the standard kernel, which is now at 4.20. Trying to build now with the patch. Looks like there is a v3 here, so I will try that one: https://firstname.lastname@example.org/msg136750.html
Comment 4 Dan Ziemba 2019-01-06 01:44:55 UTC
I have tried the v3 patch and can confirm it works. I used the one from here since the mail-archive.com site seems to mangle tabs: https://www.spinics.net/lists/linux-media/msg143589.html I applied it to Arch's linux-lts 4.19.13-1: https://git.archlinux.org/svntogit/packages.git/tree/trunk?h=packages/linux-lts&id=000049803fe84a4cef272826e95733c3d4777dc8 That built and worked fine. I used it for watching TV for an hour or so while also building Arch's linux 4.20.arch1-1 kernel with the patch applied, so it seems stable. The patched build of 4.20 also ran fine for an hour or so. https://git.archlinux.org/svntogit/packages.git/tree/trunk?h=packages/linux&id=0a8cba33e3b8289624c6b9bf5aae6a9ce2c7cc16 Since 4.19 is an LTS release, please apply this patch there as well as mainline.
Comment 5 Mauro Carvalho Chehab 2019-01-07 14:34:49 UTC
Patch fixing it was merged upstream during the merge window and it is there for Kernel 5.0-rc1. The patch was also merged at stable trees for Kernels 4.19 and 4.20.