Red Hat Bugzilla – Bug 37631
su command generates
Last modified: 2007-04-18 12:32:50 EDT
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User-Agent: Mozilla/4.77 [en] (X11; U; Linux 2.4.2-2 i686)
After a normal upgrade from 7.0 to 7.1, executing the su command
generates a "File size limit exceeded". I can log in as root and
get this error by su'ing to another user. Same error logged in as user
and su'ing to root.
Steps to Reproduce:
1.login as root.
2.start a terminal window.
3.enter the su command.
Actual Results: [root@guitunes /root]% su
File size limit exceeded
Expected Results: It should have switched me to the user babcock.
This same error message happens when I try to run the
netscape email system. Netscape crashes and this error
My log files seem awfully large:
but rerunning logrotate -f doesn't seem to clear them up.
A typo in the bug report.
In Actual Results:
The first line should read:
[root@guitunes /root]% su babcock
I can't reproduce this. Please attach the output of
"strace su babcock".
Created attachment 16410 [details]
strace su babcock output
This looks weird, the xauth socket refcount seems to be getting too large.
Does this still happen if you run "rm -rf /root/.xauth" as root?
After running "rm -rf /root/.xauth" as root, the first su babcock
works. When I exit that shell, I get a "bus error" but it worked and
I was babcock. However, the second run gets the file size error
and the large unix:0 file reappeared. (> 40Mb)
Assigning to XFree86, since xauth seems to be doing something odd.
Are you doing anything odd that might cause this?
Nothing that I know of. I have been using Red Hat Linux since last summer and
not had the problem. I'll review my xconfiguration and see if I can pick up
anything. It is interesting that I get the same error message when I try to run
netscape now also. (But I can't strace the netscape command to find what
file is causing it.)
I tried a reconfigure of the X-windows system and this did not help.
It appears to be something about xauth that is causing this to happen.
Any further help would be greatly appreciated. I'm still not able to fully
use my 7.1 upgrade.
This problem is with my maximum file size as set somewhere. I have tried
building a large
file and it gives the same error message when it reaches the 40Mb size. Running
as root can reset root's file size limit to unlimited. But I can't seem to set
my user account's
file size limit above 40000. No ulimit command is in .bash-profile for this
Any other places that control the user's file size limit?
I found where the file size limit is being set to 40000. It is in the file
However, when I change that to 1000000, and reboot the system,
I still get an error with the su command. Only now the file
~babcock/.xauth/refcount/root/guitunes/unix:0 is 1024000000
in size. So, it just keeps bumping this file up to this large size
so that the next su command fails with the "File size limit exceeded".
The file that is causing this error:
that is over 1Gb in size contains a cookie at the
front and then is filled with zeros. Following
is an octal dump of the file:
guitunes % od unix:0 | more
0000000 020061 062471 031542 033067 031141 061065 063064 062460
0000020 033061 033463 062544 062060 031545 062465 031465 032471
0000040 061542 000000 000000 000000 000000 000000 000000 000000
0000060 000000 000000 000000 000000 000000 000000 000000 000000
This file contains 1024000000 bytes.
An xauth list gives the same cookie as this file contains. So somhow
this file is not being closed properly when using the su command.
I upgraded from RedHat 7.0 to 7.1 yesterday and experienced this same exact
problem: the xauth refcount file was as large as ulimit would let it be, and
su would bus error upon exit, not cleaning up the file.
I am pretty sure the problem is with pam_xauth trying to forward an invalid
key returned from xauth. When I did an xauth list, there were many entries
that were no longer valid (i.e. displays that no longer exist). By using
xauth delete to empty my .Xauthority file, the refcount file problem went away
and su works fine now. In hindsight, I should have saved a copy of my
.Xauthority file, but it is gone now.
I tried a similar tactic. Here is the results of my xauth list:
guitunes % xauth list
guitunes/unix:0 MIT-MAGIC-COOKIE-1 bcda56b0f12ac55555ab56f897c2cad0
guitunes:0 MIT-MAGIC-COOKIE-1 bcda56b0f12ac55555ab56f897c2cad0
When I did xauth remove unix:0, the first line went away
and my su command worked ok! However, I couldn't do any
x clients. Even an xhost + command said I didn't have
authority to connect to the X server. So, I logged out
and logged back in and the /unix:0 line reappeared in the
.Xauthority file (xauth list), and x clients worked again,
BUT su again fails. I can't seem to remove just the second
display from the file. If I delete the .Xauthority file
and log out, it is simply rebuilt when I log back in.
So, I'm still stumped.
I was able to remove this problem. It took a reformat of my hard
drive and a brand new installation of RedHat 7.1
su works fine now!