After set subgid map you should relogin or manually apply a new map to
the current session using newgidmap. Most probably that's the cause of
your issue. LXC does not handle such issue properly.
On Sun, 07 Apr 2019 11:21:57 +0000 [email protected] wrote:
Package: lxc
Version: 1:3.1.0+really3.0.3-6
Severity: normal
Dear Maintainer,
sadly I can no longer reproduce this. It just started to work.
Apologies for this rudimentary bug report.
> What led up to the situation?
I installed 'lxc' and configured usage of unprivileged container.
Afterwards, I created a new unprivileged container and tried to start it
with:
>> $ lxc-create -t download -n debian-download -- -d debian -r buster -a
>> amd64
>> $ lxc-start -n debian-download
>> $ lxc-start -n debian-download --foreground
Command two failed, but suggested adding `--foreground`, thus I tried
that.
However, command three failed with a segmentation fault.
> What exactly did you do (or not do) that was effective (or
> ineffective)?
Unsure how to debug this, I installed valgrind, lxc-dbgsym, and
liblxc1-dbgsym.
Finally, I tried to execute:
>> $ valgrind --tool=memcheck -- lxc-start -n debian-download
>> --foreground
Which resulted in the following stderr/valgrind output:
==21455== Memcheck, a memory error detector
==21455== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et
al.
==21455== Using Valgrind-3.14.0 and LibVEX; rerun with -h for copyright
info
==21455== Command: lxc-start -n debian-download --foreground
==21455==
==21455== Warning: noted but unhandled ioctl 0x5441 with no
size/direction hints.
==21455== This could cause spurious value errors to appear.
==21455== See README_MISSING_SYSCALL_OR_IOCTL for guidance on writing
a proper wrapper.
==21455== Invalid read of size 8
==21455== at 0x4879AFD: cgfsng_payload_create (cgfsng.c:1318)
==21455== by 0x48C171E: lxc_spawn (start.c:1645)
==21455== by 0x48C171E: __lxc_start (start.c:1949)
==21455== by 0x48C2C26: lxc_start (start.c:2065)
==21455== by 0x48A9F26: do_lxcapi_start (lxccontainer.c:1096)
==21455== by 0x48AA9C0: lxcapi_start (lxccontainer.c:1130)
==21455== by 0x10A4EB: main (lxc_start.c:328)
==21455== Address 0x0 is not stack'd, malloc'd or (recently) free'd
==21455==
==21455==
==21455== Process terminating with default action of signal 11 (SIGSEGV)
