Bug#903554: libc6: segfault in ld-2.24.so when running 'xl' from Xen, only on Skylake CPUs (upstream bug BZ#22636)
Package: libc6
Version: 2.24-11+deb9u3
Severity: normal
Dear Maintainer,
When I use 'xl create' or 'xl destroy' to manage Xen domUs, xl segfaults
with:
(gdb) run create /etc/xen/domU.cfg
Starting program: /usr/lib/xen-4.8/bin/xl create /etc/xen/domU.cfg
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
Parsing config from /etc/xen/domU.cfg
[New Thread 0x7ffff7ff4700 (LWP 3311)]
Thread 2 "xl" received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0x7ffff7ff4700 (LWP 3311)]
0x00007ffff7de2ff5 in _dl_lookup_symbol_x (undef_name=0x7ffff5478c63 "_Unwind_Find_FDE", undef_map=0x555555788310,
ref=ref@entry=0x7ffff7ff2128, symbol_scope=0x555555788668, version=0x555555788a50, type_class=type_class@entry=1, flags=5,
skip_map=0x0) at dl-lookup.c:833
Despite the segfault, it seems that the domU is running fine, which
might explain why this wasn't reported yet AFAIK.
In the exact same software environment, I cannot reproduce this on
pre-Skylake CPUs.
I could confirm that:
- upgrading glibc to 2.26-5 fixes the problem.
- 2.26-4 is still affected.
I looked at the changes between 2.26-4 and 2.26-5.
My initial guess was that this was BZ#22715 due to the link with
AVX-512. But backporting the fix (which is already in
release/2.24/master but not in the stretch package) did not solve the
issue.
However, backporting the fix for BZ#22636 fixed the issue (specifically
I backported
771c846a71d9ee14aa3b91fd184026482da585d9..abf2e34ee6a9cf1b7e5afddd13971754e5c5fa82
, from the release/2.25/master branch).
Could you please backport this fix to the stretch package?
Thanks!
Lucas
-- System Information:
Debian Release: 9.4
APT prefers stable-updates
APT policy: (500, 'stable-updates'), (500, 'stable')
Architecture: amd64 (x86_64)
Kernel: Linux 4.9.0-6-amd64 (SMP w/64 CPU cores)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8) (ignored: LC_ALL set to en_US.UTF-8), LANGUAGE=en_US:en (charmap=UTF-8) (ignored: LC_ALL set to en_US.UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
Versions of packages libc6 depends on:
ii libgcc1 1:6.3.0-18+deb9u1
libc6 recommends no packages.
Versions of packages libc6 suggests:
ii debconf [debconf-2.0] 1.5.61
pn glibc-doc <none>
ii libc-l10n 2.24-11+deb9u3
ii locales 2.24-11+deb9u3
-- debconf information:
glibc/disable-screensaver:
glibc/upgrade: true
glibc/restart-failed:
glibc/restart-services:
glibc/kernel-not-supported:
glibc/kernel-too-old:
libraries/restart-without-asking: false
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