Bug#555505: segfault in gdm on first login

[Clayton]

On Wed, 11 Nov 2009 17:15:19 +0100
Josselin Mouette <joss at debian.org> wrote:

> Le mardi 10 novembre 2009 à 10:35 +0800, clayton a écrit : 
> > This may be related to http://bugs.debian.org/480469 as well....
> > 
> > The first time I login with GDM I get a black screen followed by a 
> > re-display of the GDM login prompt. Thereafter login works. I am
> > seeing this in syslog at the time of the GDM failure:
> > 
> > acpid: client connected from 2278[0:0]
> > acpid: 1 client rule loaded
> > kernel: [  179.880427] gdm[2271]: segfault at bfe61a85 ip b75a72da
> > sp bfbee680 error 4 in libc-2.10.1.so[b7534000+141000]
> 
> It would be interesting to have a backtrace for that. If you could
> start up gdm by hand in a gdb session and obtain it, it would be
> great.

Delighted to!! I also confirmed in the process that this happens only
once on boot. Logging out and restarting gdm are not sufficient to
trigger a second incident. Hope this gdb of gdm helps:

(gdb) cont
Continuing.

Program received signal SIGUSR2, User defined signal 2.
0xb8070424 in __kernel_vsyscall ()
(gdb) backtrace
#0  0xb8070424 in __kernel_vsyscall ()
#1  0xb77b1f33 in __write_nocancel ()
#from /lib/i686/cmov/libpthread.so.0 2  0x08071271 in ?? ()
#3  0x0806179d in ?? ()
#4  0x08061b26 in ?? ()
#5  0x080648c0 in ?? ()
#6  0x08078072 in ?? ()
#7  0x08066255 in ?? ()
#8  0x0806b440 in ?? ()
#9  0x0805ce08 in ?? ()
#10 0x08051ea2 in ?? ()
#11 0x080529b8 in ?? ()
#12 0xb7571b35 in __libc_start_main () from /lib/i686/cmov/libc.so.6
#13 0x0804fc91 in ?? ()
(gdb)

(gdb) cont
Continuing.

Program received signal SIGSEGV, Segmentation fault.
0xb75ce2da in strcmp () from /lib/i686/cmov/libc.so.6
(gdb) backtrace
#0  0xb75ce2da in strcmp () from /lib/i686/cmov/libc.so.6
#1  0xb75e55bf in ?? () from /lib/i686/cmov/libc.so.6
#2  0xb75e5760 in ?? () from /lib/i686/cmov/libc.so.6
#3  0xb75e674b in ?? () from /lib/i686/cmov/libc.so.6
#4  0xb75e602e in ?? () from /lib/i686/cmov/libc.so.6
#5  0xb75e468c in localtime_r () from /lib/i686/cmov/libc.so.6
#6  0xb762602b in __vsyslog_chk () from /lib/i686/cmov/libc.so.6
#7  0xb7626597 in syslog () from /lib/i686/cmov/libc.so.6
#8  0xb8054566 in pam_vsyslog () from /lib/libpam.so.0
#9  0xb8054682 in pam_syslog () from /lib/libpam.so.0
#10 0xb70d1dc6 in pam_sm_open_session ()
#from /lib/security/pam_ck_connector.so 11 0xb804f4cd in ?? ()
#from /lib/libpam.so.0 12 0xb80537eb in pam_open_session ()
#from /lib/libpam.so.0 13 0x0807879f in ?? ()
#14 0x08066255 in ?? ()
#15 0x0806b440 in ?? ()
#16 0x0805ce08 in ?? ()
#17 0x08051ea2 in ?? ()
#18 0x080529b8 in ?? ()
#19 0xb7571b35 in __libc_start_main () from /lib/i686/cmov/libc.so.6
#20 0x0804fc91 in ?? ()
(gdb)