[lxc-users] unprivileged container with systemd?

[Dirk Geschke]

Hi Serge,

now I started lxcfs within gdb:

(gdb) where
#0  0x00007ffff706b610 in __recvmsg_nocancel ()
    at ../sysdeps/unix/syscall-template.S:82
#1  0x0000000000403cdd in recv_creds (sock=8, cred=0x7fffffffe5b0, 
    v=0x7fffffffe5af "1\377\377\377\377\377\377\377\377\377\377\377\377\001")
    at lxcfs.c:799
#2  0x00000000004046f2 in do_write_pids (tpid=27028, 
    contrl=0x60a4c0 "name=systemd", cg=0x60c250 "wheezy/ubuntu-12", 
    file=0x60bad5 "/cgroup.procs", buf=0x62e920 "1\n") at lxcfs.c:1109
#3  0x0000000000404a16 in cg_write (
    path=0x60bab0 "/cgroup/name=systemd/wheezy/ubuntu-12/cgroup.procs", 
    buf=0x7ffff7fd3060 "1\n", size=2, offset=0, fi=0x7fffffffe850)
    at lxcfs.c:1187
#4  0x00000000004069b9 in lxcfs_write (
    path=0x60bab0 "/cgroup/name=systemd/wheezy/ubuntu-12/cgroup.procs", 
    buf=0x7ffff7fd3060 "1\n", size=2, offset=0, fi=0x7fffffffe850)
    at lxcfs.c:2016
#5  0x00007ffff7bb1513 in fuse_fs_write_buf (fs=0x60c040, 
    path=0x60bab0 "/cgroup/name=systemd/wheezy/ubuntu-12/cgroup.procs", 
    buf=buf at entry=0x7fffffffe900, off=off at entry=0, fi=fi at entry=0x7fffffffe850)
    at fuse.c:1878
#6  0x00007ffff7bb1686 in fuse_lib_write_buf (req=0x60aa20, ino=23, 
    buf=0x7fffffffe900, off=0, fi=0x7fffffffe850) at fuse.c:3278
#7  0x00007ffff7bb9209 in do_write_buf (ibuf=0x7fffffffe990, 
    inarg=<optimized out>, nodeid=<optimized out>, req=<optimized out>)
    at fuse_lowlevel.c:1300
#8  fuse_ll_process_buf (data=<optimized out>, buf=0x7fffffffe990, 
    ch=<optimized out>) at fuse_lowlevel.c:2437
#9  0x00007ffff7bb588f in fuse_session_loop (se=0x60b720) at fuse_loop.c:40
#10 0x00007ffff7bade48 in fuse_loop (f=f at entry=0x60bd30) at fuse.c:4313
#11 0x00007ffff7bbd95f in fuse_main_common (argc=<optimized out>, 
    argv=<optimized out>, op=<optimized out>, op_size=<optimized out>, 
    user_data=<optimized out>, compat=<optimized out>) at helper.c:357
#12 0x0000000000406ccd in main (argc=7, argv=0x7fffffffebe8) at lxcfs.c:2158

Do you have any idea what is connected to sock=8? lsof does not
work as long as the fuse mount exist (even so df). So I see the
lxcfs socket:

# netstat -pan |grep 228936
unix  3      [ ]         DGRAM                    228936   26992/lxcfs 		@00073

But what should be on the other side of the socket, hence, what is
not answering here?

Best regards

Dirk

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| Dr. Dirk Geschke       / Plankensteinweg 61    / 85435 Erding        |
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