Getting Started, Documentation, Tips & Tricks

Cannot start in Single user mode on 6.5.27

stuart
From Cambridge, UK
Who joined Aug. 23, 2004, 5:37 p.m.
Wrote the following at July 7, 2005, 12:46 a.m...
My Octane has 6.5.27 installed, and I've recently found that I can't drop down to single user mode. What seems to be happening is that sulogin is correctly invoked and asks for a password, but then segfaults if the correct password is entered.

If I run sulogin from a shell, it always prints "Login incorrect" even if I do enter the correct root password. Shadow passwords are enabled... I don't know if this makes a difference.

When sulogin crashes it does create a core file, but I'm not sure how to analyse these on IRIX... using gdb I get:

Code: Select all

$ gdb
GNU gdb 5.3
Copyright 2002 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB.  Type "show warranty" for details.
This GDB was configured as "mips-sgi-irix6.5".
(gdb) core core.postinst_detected
Core was generated by `sulogin'.
Program terminated with signal 11, Segmentation fault.
warning: Warning: GDB can't find the start of the function at 0xfa49ce0.

GDB is unable to find the start of the function at 0xfa49ce0
and thus can't determine the size of that function's stack frame.
This means that GDB may be unable to access that stack frame, or
the frames below it.
This problem is most likely caused by an invalid program counter or
stack pointer.
However, if you think GDB should simply search farther back
from 0xfa49ce0 for code which looks like the beginning of a
function, you can increase the range of the search using the `set
heuristic-fence-post' command.
#0  0x0fa49ce0 in ?? ()
(gdb) bt
#0  0x0fa49ce0 in ?? ()
warning: Warning: GDB can't find the start of the function at 0x10001ba0.


Any suggestions of how I might pull more useful information from this core, or what else I can try to actually get single user mode working?
stuart
From Cambridge, UK
Who joined Aug. 23, 2004, 5:37 p.m.
Wrote the following at July 7, 2005, 2:34 a.m...
I'm going to try reinstalling eoe.sw.base, which provides /sbin/sulogin...
cjones
From NASA Langley Research Center
Who joined April 27, 2004, 11:11 a.m.
Wrote the following at July 7, 2005, 6:24 a.m...
I've got an octane that I was planning upgrading from 6.5.21 to .27.... so I'd very much like to hear how your problem works out stuart!

Thanks,

-chris
foetz
Moderator
Who joined April 14, 2003, 4:34 a.m.
Wrote the following at July 7, 2005, 9:26 a.m...
stuart wrote: I'm going to try reinstalling eoe.sw.base, which provides /sbin/sulogin...


maybe your password or the shadow file is corrupted?
r-a-c.de
stuart
From Cambridge, UK
Who joined Aug. 23, 2004, 5:37 p.m.
Wrote the following at July 7, 2005, 9:40 a.m...
cjones wrote: I've got an octane that I was planning upgrading from 6.5.21 to .27.... so I'd very much like to hear how your problem works out stuart!


Well, it's fixed - but I'm not quite sure how!

I changed root's entry from a shadow password to a standard one in /etc/passwd, and also reinstalled 6.5.27 eoe.sw.base (and then any patches to 6.5.27, just in case)

After rebooting, I could drop into single user mode - so the problem is fixed. However, something had reverted root to having a shadow password - so this may have been a red herring.

Cheers,
Stuart