Eventually it is an "Program terminated with signal SIGSYS, Bad system call"
So we need to find what is bad about it.
(gdb) info threads
Id Target Id Frame
* 1 Thread 0x7f2321fe6700 (LWP 17325) 0x00007f2325ae00bf in
__pthread_setaffinity_new (th=<optimized out>, cpusetsize=cpusetsize@entry=128,
cpuset=cpus
et@entry=0x7f2321fe5680) at
../sysdeps/unix/sysv/linux/pthread_setaffinity.c:34
2 Thread 0x7f2323ad3500 (LWP 17322) 0x00007f2326fe0fb7 in
dri_bind_extensions (dri=dri@entry=0x55a59a7583e0,
matches=matches@entry=0x7f2326fec34
0 <dri_core_extensions>, extensions=<optimized out>) at
../src/gbm/backends/dri/gbm_dri.c:286
3 Thread 0x7f2323acf700 (LWP 17323) syscall () at
../sysdeps/unix/sysv/linux/x86_64/syscall.S:38
A discussion with the kernel team pointed to seccomp at first:
...
<apw> grep it appears that seccomp is the only thing which triggers that signal
The stack in the breaking cases uses this by default
-sandbox on,obsolete=deny,elevateprivileges=deny,spawn=deny,resourcecontrol=deny
resourcecontrol is defined as:
"Disable process affinity and schedular priority"
Interestingly that is the global default, the qemu://system qemu also runs with
the same.
I'd assume that:
libgl1-mesa-dri:amd64: /usr/lib/x86_64-linux-gnu/dri/i965_dri.so
behaves differently depending if it is on a local UI session or not.
And it gets punished as soon as it tries to set-affinity which it might only do
in that case.
Implemented by
-
https://git.qemu.org/?p=qemu.git;a=commit;h=24f8cdc5722476e12d8e39d71f66311b4fa971c1
Similar issue being fixed last year
-
https://git.qemu.org/?p=qemu.git;a=commit;h=056de1e894155fbb99e7b43c1c4382d4920cf437
Libvirt has no means to fin-control it (yet), only to switch the hole
feature of sandboxing on/off.
That matches what we see - it fails on init when spawning threads - most
likely there it will set the affinity.
--
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
https://bugs.launchpad.net/bugs/1815889
Title:
qemu-system-x86_64 crashed with signal 31 in
__pthread_setaffinity_new()
To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/qemu/+bug/1815889/+subscriptions
--
ubuntu-bugs mailing list
[email protected]
https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
