On Sun, 28 Jun 2020 10:41:41 +0200 Salvatore Bonaccorso
<car...@debian.org> wrote:
Hi Simon,
Hi Salvatore, thanks for looking into this.
On Sun, Jun 28, 2020 at 01:01:01AM +0100, Simon John wrote:
> This looks a likely culprit:
>
> https://bugzilla.kernel.org/show_bug.cgi?id=207489
The issue you are seeing now seems different, though afaics.
The fixing commit from the above reference, 8be8f932e3db ("kvm:
ioapic: Restrict lazy EOI update to edge-triggered interrupts") was
applied in v5.7-rc3, which was as well backported to v5.6.13.
Yes, I was going to patch the kernel but noticed its already got that
patch. I also tried passing through only one pci device and not the usb
device but it didn't help, so probably isn't that issue.
Now you kernel is tained, can you check if you see the issue as well
when not loading the modules which taint the kernel?
I removed virtualbox which was tainting the kernel, confirmed cat
/proc/sys/kernel/tainted returned 0 after a reboot.
I still managed to trigger the issue though, which then tainted the
kernel itself, output from kernel-chktaint:
Kernel is "tainted" for the following reasons:
* kernel died recently, i.e. there was an OOPS or BUG (#7)
* kernel issued warning (#9)
* soft lockup occurred (#14)
For a more detailed explanation of the various taint flags see
Documentation/admin-guide/tainted-kernels.rst in the the Linux kernel
sources
or https://kernel.org/doc/html/latest/admin-guide/tainted-kernels.html
Raw taint value as int/string: 17024/'G D W L '
The kvm-pit process was using 100% of a cpu core, i've never even
noticed that process before, looks like the culprit now?:
watchdog: BUG: soft lockup - CPU#7 stuck for 22s! [kvm-pit/2888:2913]
CPU: 7 PID: 2913 Comm: kvm-pit/2888 Tainted: G D W
5.7.0-1-amd64 #1 Debian 5.7.6-1
I've added a strace and dmesg to the gist here:
https://gist.github.com/sej7278/766043a69c76308f84cfa14b3f3a924f
Any other diagnostics I can run?
Next, if it still does show up, does it show up as well in current
mainline?
Not sure what you mean there, do you mean upstream kernel.org kernel -
i'm not sure how i'd run that.
Regards.
--
Simon John
