Red Hat Bugzilla – Bug 431907
5.2: service iscsi stop on a busy target causes a soft CPU lockup on ppc64.
Last modified: 2014-08-22 19:13:12 EDT
Description of problem: If you install the 20080206.nightly on a ppc64 box with
the latest iscsi-initiator-utils, executing service iscsi stop on a busy target
will cause a soft lockup.
Version-Release number of selected component (if applicable):
How reproducible:Every time
Steps to Reproduce:
1. Install 5.2
2. Install latest iscsi-initiator-utils
3. Add this to /etc/iscsi/iscsid.conf: node.conn.iscsi.HeaderDigest = None
4. --login to the target build files systen and mount it.
5. Do IO to iscsi LUN and the do service iscsi stop.
Actual results: You will encounter a soft lokup.
Target system was ibm-js21-01.lab.boston.redhat.com.
Expected results: We should only get some IO errors on the iscsi LUN.
Actual test script was:
while [ $x -lt 100 ]
mount /dev/sdb1 /mnt/sdb
if [ $status != 0 ]; then
echo "Mount FAILED"
dd if=/dev/zero of=/mnt/sdb/file bs=1024 count=1000000&
service iscsi stop
service iscsi start
Created attachment 294258 [details]
It a piece of the /var/log/messages file with several examples of the lockup.
Can you run with a kernel that has LOCKDEP enabled? That might determine what
is causing CPUs to get stuck.
The log is a bit weird: there appear to be soft lockups occurring in
vprintk(). This suggests that either someone's holding the spinlock and not
letting go, or that another CPU is hammering the printk's so hard that the
faulting CPU isn't getting a look in. If this is running in a virtual
partition on a ppc64 machine, then the yield-to-hypervisor nature of spinlocks
there may be exacerbating the situation.
This is not a blocker or RHEL 5.2. Moving out to RHEL 5.2 for further
This request was evaluated by Red Hat Product Management for
inclusion, but this component is not scheduled to be updated in
the current Red Hat Enterprise Linux release. If you would like
this request to be reviewed for the next minor release, ask your
support representative to set the next rhel-x.y flag to "?".
Unfortunately the previous automated notification about the
non-inclusion of this request in Red Hat Enterprise Linux 5.3 used
the wrong text template. It should have read: this request has been
reviewed by Product Management and is not planned for inclusion
in the current minor release of Red Hat Enterprise Linux.
If you would like this request to be reviewed for the next minor
release, ask your support representative to set the next rhel-x.y
flag to "?" or raise an exception.
This bug/component is not included in scope for RHEL-5.11.0 which is the last RHEL5 minor release. This Bugzilla will soon be CLOSED as WONTFIX (at the end of RHEL5.11 development phase (Apr 22, 2014)). Please contact your account manager or support representative in case you need to escalate this bug.
That sounds like the best plan.