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I've got a linux box running Redhat Enterprise WS version 3, with kernel: 2.4.21-9.0.1.ELsmp. My account has working sudo privileges that I can use to run single commands as root. I've tested this and it works with no problems. However, I can't use either the 'su' command or 'sudo su - root'. When I run 'su' and type in root's password I get a segmentation fault. When I try 'sudo su - root' and type in my password I get

free(): invalid pointer 0x########!
Segmentation fault (core dumped)

and it dumps cores into my working directory. I just recently installed the OS and have had this problem since installation. Does anyone have any ideas why I can't use these functions? Another bit of information, if I log out I can log in as root without any of these problems. Thanks so much.

Seems that something didn't install correctly (corrupt package?).

You may want to look around some more, but I'd suggest formatting, and reinstalling. =(
If the problem persists, there may be something wrong with one of the CD-Roms.
Don't go running off and formating yet. There are lots of things you can do with out having to format. Thats the advantage of linux.

It may be a currupt package but its probably just a user setting error. Hold off till someone who recognizes this problem posts or has an idea of what to do. Someone who answer you by the end of the day.

Just don't go run off and format yet, its not worth the effort.
*backs off* If he doesn't have much done on his system yet, it would be easier and faster than waiting days for an answer. biggrin.gif

"It's easier to burn down your house and salt the earth than to fix a leaky faucet." -Termina
Sorry to be getting side tracked from the question but I just want to say two quick things.

First, Termina, I ment you no insult. Your advice is valid, it would fix the problem, and probably faster than waiting for an answer here.

However, your dodging the problem. Ya, he isn't to dugg in now, but what if the same problem come up down the line and he doesn't want to format? Facing problems head on is the way you learn how to fix work with linux in the future.

Ok, I wont say anything more here unless its actually answering the question.
Same. happy.gif I didn't take it as such, I hope I'm not coming off as too much of an ass. wink.gif

I searched google, and found nothing for this error message and problem (which is a bit weird). Which is why I recommended formatting. =/ I'm sure there's an answer, but probally not one that is worthwhile.
Looked this up at

Reading through the log entries for the error: I am going to give a review of what i found

How many characters is your password?

the person mentioned in bugzilla that his password was 13 characters long.

he ended up changing the password to something shorter and he quit getting the segfault problem

try changing yours and see what happens...

this is what i found out...

if you want to read more about the situation on

(hopefully this isnt you who posted the bug....hehe wouldnt that be funny if it was)

hope this helps

Well you could always try to change your root pasword

start you're computer in single user mode, where it does not ask for a root password, and change you're password there...

Robert B
wait if you use are using your password for you regular username....not roots password...

but then if you su - you have to provide roots password....
thats when you would just log out ....log back in as root..change the password...then log back in as your regular user ...then see if you can use the new password without segfaulting
Thanks for all the replies. The root password is only 8 characters long. And yes, when I use sudo su - root, I am typing in my username's password, not root's. It's only when I type su that I enter root's password. And fortunately it wasn't me who posted the bug. I think it might have something to do with my /etc/pam.d/system-auth file as I've had to alter that to set up my ldap configurations. If anyone has any ideas I could try I'm willing to give them a shot, but I'll definitely go hunting around that file to see what I can find, and if I find anything I'll post back. Thanks so much for all your help so far.

ya if you go the bugzilla link i posted
it has how to edit the file you need
to fix it....

So I think I'm in the same boat as the guy who posted the bug. All my accounts are also created via an ldap set up. Does this mean I'm just screwed and can't do anything to get sudo su - root or su to work? Or are there some patches that work even when the ldap stuff is up and working? Unfortunately for me, if I have to make a decision between su and ldap I have to choose ldap or the machine might as well be a paper weight. Any thoughts on getting su and ldap to work together? Thanks so much.


So I've found a work around that my not be perfect but it is something. If you type 'sudo /bin/sh' or whatever shell you want to use, a prompt will come up for that particular shell and you will be root. As I said, perhaps not as good, but at least it works to give you some amount of root access. Hope this helps someone.

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