AIX Open Source

Originally posted by: MartinVrskovy

On one of our system we are using
sudo_ids-1.8.27-2.ppc
openldap-2.4.46.-1.ppc

to get sudo rights from ldap.

After update AIX to AIX 7.1 TL 5 SP 3 we are facing strange behavior only for some users ( from LDAP )

when running sudo -l command, its sometimes run well,but sometimes we are getting memory fault (bash) or segmentation fault (ksh) error.

$ while : ; do sudo -l 1>/dev/null && echo "Sudo command works OK";done
Memory fault
Memory fault
Memory fault
Memory fault
Memory fault
Memory fault
Memory fault
Memory fault
Sudo command works OK
Sudo command works OK
Memory fault
Memory fault
Sudo command works OK
Memory fault
Memory fault
Memory fault
Memory fault
Sudo command works OK
Memory fault
Sudo command works OK
Memory fault
Memory fault
Memory fault
Memory fault
Memory fault
Memory fault

running sudo -l as root is working fine all the time, same as for some different users.

Originally posted by: Johann-Georg Dengel

Hi all, I've experienced the same behavior!

Has anybody an idea/hint for remediation or work around?
Thanks for any suggestions ...

Originally posted by: Edward Davignon

For memory related problems on AIX, I usually start with

/usr/bin/ulimit -Sa

or

\ulimit -Sa

and

grep -p "^default:" /etc/security/limits

grep -p "^$username:" /etc/security/limits

then check

/usr/bin/env > /tmp/env.out.1

and

sudo /usr/bin/env > /tmp/env.out.2

and

sudo su - -c /usr/bin/env > /tmp/env.out.3

to look for differences, in case the TL update expanded size or number of the environment variables.

truss sudo -l

may also give more information.

echo "$LIBPATH"

and

echo "$PATH"

may also show differences between the users who have trouble and those who don't.

Originally posted by: Johann-Georg Dengel

@Edward: Thanks for your suggestions! Of course, we tried the measures you mentioned - but didn't get any clue out of that :(

In the meanwhile we've found the Kernel parameter that causes the trouble:
it is AIXTHREAD_SCOPE=P

As soon as we change it to

AIXTHREAD_SCOPE=S

sudo doesn't crash any longer with the "memory fault"

So far, no idea, why :(

Originally posted by: sangameshm

AIXTHREAD_SCOPE=P sets the M:N Thread Model.

I think M:N model is used just for comparing the performance with 1:1 model.

https://www.ibm.com/support/knowledgecenter/ssw_aix_71/performance/thread_env_vars.html

And i guess the stack traces be mostly similar to the one mentioned here

http://www-01.ibm.com/support/docview.wss?uid=isg1IJ11569

Thanks,

Sangamesh

Originally posted by: Edward Davignon

@Johann-Georg Dengel: I was thinking MALLOCDEBUG options, but it looks like Sangamesh has much better lead on this.