when looking into our pc pool with 44 machines, in around 2-5 sessions the System Menu is missing after a crash of indicator-session-service, making the users unable to log out using the mouse.
There are arround 100 ubuntu machines for students with 32000 real users from an active directory. The users cannot see any users real name.
I wasn't able to find the right debug symbols, but in the disassembly it looks like a crash in service.c:321 .
In the attached crash dump the instruction pointer points to 0x4120a0 in memory, which should be the get_current_realname function.
static const char *
get_current_real_name (IndicatorSessionService * self)
{
GHashTableIter iter;
gpointer key, value;
/* is it the guest? */
if (indicator_session_guest_is_active (self->priv->backend_guest))
return _("Guest");
/* is it a user? */
g_hash_table_iter_init (&iter, self->priv->users);
while (g_hash_table_iter_next (&iter, &key, &value))
{
IndicatorSessionUser * user = value;
if (user->is_current_user) // SEGFAULT PROBABLY HERE (movzx edx, byte ptr [r13]), r13=user ist NULL
return get_user_label (user);
}
return "";
}
The strange thing is: before inserting into the hashmap, every user is checked to be != NULL. So maybe I guessed the wrong function, or there are threading issues.
Disassembly:
0x0000000000412081 <+1484>: mov r13,rax
0x0000000000412084 <+1487>: setne al
0x0000000000412087 <+1490>: test al,al
0x0000000000412089 <+1492>: je 0x411f56 <_start+1185>
0x000000000041208f <+1498>: jmp 0x411f51 <_start+1180>
0x0000000000412094 <+1503>: nop DWORD PTR [rax+0x0]
0x0000000000412098 <+1507>: mov r13,QWORD PTR [rdx+0x20]
0x000000000041209c <+1511>: mov rsi,QWORD PTR [rdx+0x18]
=> 0x00000000004120a0 <+1515>: movzx edx,BYTE PTR [r13+0x0]
0x00000000004120a5 <+1520>: test dl,dl
0x00000000004120a7 <+1522>: je 0x4120d6 <_start+1569>
0x00000000004120a9 <+1524>: mov rax,QWORD PTR [rip+0x248770] # 0x65a820 <g_ascii_table>
0x00000000004120b0 <+1531>: test BYTE PTR [rax+rdx*2+0x1],0x1
0x00000000004120b5 <+1536>: je 0x411f51 <_start+1180>
0x00000000004120bb <+1542>: mov rdx,r13
0x00000000004120be <+1545>: jmp 0x4120cb <_start+1558>
Some command output:
$> lsb_release -rd
Description: Ubuntu 14.04.3 LTS
Release: 14.04
Package version:
$> dpkg -l | grep indicator-session
ii indicator-session 12.10.5+14.04.20150404-0ubuntu1 amd64 indicator showing session management, status and user switching
~$> gsettings list-recursively com.canonical.indicator.session
com.canonical.indicator.session show-real-name-on-panel false
com.canonical.indicator.session suppress-logout-menuitem false
com.canonical.indicator.session suppress-restart-menuitem false
com.canonical.indicator.session suppress-shutdown-menuitem false
com.canonical.indicator.session suppress-logout-restart-shutdown false
com.canonical.indicator.session user-show-menu false
~$> wbinfo -u | wc -l
127390
iw18ejyg@cip-54-54: ~$> python -c 'print(__import__("pwd").getpwnam("iw18ejyg"))'
pwd.struct_passwd(pw_name='iw18ejyg', pw_passwd='*', pw_uid=1069023, pw_gid=1000513, pw_gecos='', pw_dir='/home/stud/iw18ejyg', pw_shell='/bin/bash')
using another machine with the same package selection, home directory, user id, but user information with real name from ldap+kerberos, I never observed this crash.