Em Thu, 20 Sep 2018 00:07:09 -0400 Dan Ziemba <zman0900@xxxxxxxxx> escreveu: > I reported this on bugzilla also a few days ago, but I'm not sure if > that is actually the right place to report, so copying to the mailing > list... I saw a report on BZ, but haven't time yet to dig into it. Those days, it is usually better to report via the ML. > > 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. There's something really weird on it: that patch changes a code that it is only called when the device is streaming. It shouldn't be causing GFP/kernel panic, depending if the machine was booted with or without it. Perhaps it would be a side effect due to some changes at the USB subsystem? There are some changes happening there changing some locks. I see one minor issue there: it is using GFP_ATOMIC instead of GFP_KERNEL. Could you please try to change this line: stream->buf_list[stream->buf_num] = kzalloc(size, GFP_ATOMIC); to stream->buf_list[stream->buf_num] = kzalloc(size, GFP_KERNEL); Also, it would be great if you could post the GPF logs. > > > 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 > > Bugzilla: > https://bugzilla.kernel.org/show_bug.cgi?id=201055 > > Arch bug: > https://bugs.archlinux.org/task/59990 > > > Thanks, > Dan Ziemba > > Thanks, Mauro
