Note: This bug is displayed in read-only format because the product is no longer active in Red Hat Bugzilla.
RHEL Engineering is moving the tracking of its product development work on RHEL 6 through RHEL 9 to Red Hat Jira (issues.redhat.com). If you're a Red Hat customer, please continue to file support cases via the Red Hat customer portal. If you're not, please head to the "RHEL project" in Red Hat Jira and file new tickets here. Individual Bugzilla bugs in the statuses "NEW", "ASSIGNED", and "POST" are being migrated throughout September 2023. Bugs of Red Hat partners with an assigned Engineering Partner Manager (EPM) are migrated in late September as per pre-agreed dates. Bugs against components "kernel", "kernel-rt", and "kpatch" are only migrated if still in "NEW" or "ASSIGNED". If you cannot log in to RH Jira, please consult article #7032570. That failing, please send an e-mail to the RH Jira admins at rh-issues@redhat.com to troubleshoot your issue as a user management inquiry. The email creates a ServiceNow ticket with Red Hat. Individual Bugzilla bugs that are migrated will be moved to status "CLOSED", resolution "MIGRATED", and set with "MigratedToJIRA" in "Keywords". The link to the successor Jira issue will be found under "Links", have a little "two-footprint" icon next to it, and direct you to the "RHEL project" in Red Hat Jira (issue links are of type "https://issues.redhat.com/browse/RHEL-XXXX", where "X" is a digit). This same link will be available in a blue banner at the top of the page informing you that that bug has been migrated.

Bug 1998521

Summary: sosreport can hang with a relative symlink loop
Product: Red Hat Enterprise Linux 8 Reporter: Christophe Besson <cbesson>
Component: sosAssignee: Pavel Moravec <pmoravec>
Status: CLOSED ERRATA QA Contact: Miroslav HradĂ­lek <mhradile>
Severity: low Docs Contact:
Priority: low    
Version: 8.4CC: agk, bmr, cww, jcastillo, mhradile, plambri, rduda, rmetrich, sbradley, theute
Target Milestone: rcKeywords: OtherQA, Triaged
Target Release: ---Flags: pm-rhel: mirror+
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: sos-4.2-1.el8 Doc Type: If docs needed, set a value
Doc Text:
Story Points: ---
Clone Of:
: 2011533 (view as bug list) Environment:
Last Closed: 2022-05-10 15:16:32 UTC Type: Bug
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On:    
Bug Blocks: 2011533    

Description Christophe Besson 2021-08-27 13:14:58 UTC
Description of problem:
sosreport can hang with a relative symlink in /etc/alternatives.
Preventing this behaviour could help.

Version-Release number of selected component (if applicable):
sos-4.0-11.el8.noarch

How reproducible:
100%

Steps to Reproduce:
# mkdir -p /usr/lib/jvm/java-1.8.0-ibm-1.8.0.6.25-1jpp.1.el7.x86_64/jre/bin /usr/lib/jvm/java-1.8.0-ibm-1.8.0.6.25-1jpp.1.el7.x86_64/bin
# echo foobar > /usr/lib/jvm/java-1.8.0-ibm-1.8.0.6.25-1jpp.1.el7.x86_64/bin/javaws
# ln -s ../../bin/javaws /usr/lib/jvm/java-1.8.0-ibm-1.8.0.6.25-1jpp.1.el7.x86_64/jre/bin/javaws
# ln -s /usr/lib/jvm/java-1.8.0-ibm-1.8.0.6.25-1jpp.1.el7.x86_64/jre/bin/javaws /etc/alternatives/javaws
# ln -s /etc/alternatives/javaws /bin/javaws

Actual results:
[plugin:systemd] added cmd output 'timedatectl'
[plugin:systemd] skipped command 'systemd-resolve --status': required services missing: systemd-resolved. 
[plugin:systemd] skipped command 'systemd-resolve --statistics': required services missing: systemd-resolved. 
[plugin:systemd] added cmd output 'systemd-analyze plot'
[plugin:systemd] adding forbidden path '/dev/null'
[plugin:sysvipc] added cmd output 'ipcs'
[plugin:sysvipc] added cmd output 'ipcs -u'
[plugin:tuned] added cmd output 'tuned-adm list'
[plugin:tuned] added cmd output 'tuned-adm active'
[plugin:tuned] added cmd output 'tuned-adm recommend'
[plugin:tuned] added cmd output 'tuned-adm verify'
^C^C

Expected results:
No hang.

Additional info:
# cd /usr/lib/jvm/java-1.8.0-ibm-1.8.0.6.25-1jpp.1.el7.x86_64/jre/bin
# file $(readlink $(readlink $(readlink /bin/javaws)))
../../bin/javaws: ASCII text

# cd /tmp
# file $(readlink $(readlink $(readlink /bin/javaws)))
../../bin/javaws: symbolic link to `/etc/alternatives/javaws'

# grep -c readlink\(.*javaws /tmp/sos.strace
3644066

Note the issue also occurs on RHEL 7.

Comment 2 Pavel Moravec 2021-08-29 20:50:52 UTC
There is a bug even in current upstream (which should affect also Fedora, imho). sos enters infinite loop in sos/report/plugins/unpackaged.py : 

            for root, dirs, files in os.walk(path, topdown=True):
                if exclude:
                    for e in exclude:
                        dirs[:] = [d for d in dirs if d not in e]
                for name in files:
                    path = os.path.join(root, name)
                    try:
                        while stat.S_ISLNK(os.lstat(path).st_mode):
                            path = os.path.abspath(os.readlink(path))


where the latest while cycle alters among:

/bin/javaws
/etc/alternatives/javaws
/usr/lib/jvm/java-1.8.0-ibm-1.8.0.6.25-1jpp.1.el7.x86_64/jre/bin/javaws
/bin/javaws
..


Simple solution imho:

                    from pathlib import Path
                    try:
                        while stat.S_ISLNK(os.lstat(path).st_mode):
                            path = Path(path).resolve()
                    except Exception:
                        continue

(I will think if it cant have a gotcha tomorrow)

Comment 3 Pavel Moravec 2021-08-29 21:07:29 UTC
I forgot to mention an evident workaround: disable unpackaged plugin:

sos report -n unpackaged .. (other options)

Comment 6 Pavel Moravec 2022-01-04 22:32:54 UTC
Hello,
would you be so kind to verify, if candidate build:

https://people.redhat.com/pmoravec/sos-4.2-8/

does fix the reported problem properly? We are on short with QE capacity and any help is more than welcomed.

(*ideally* verify it on both RHEL8 and RHEL9 (cloned bz2011533), but either verification is welcomed)

Comment 7 Christophe Besson 2022-01-12 10:06:49 UTC
> does fix the reported problem properly? We are on short with QE capacity and any help is more than welcomed.

np, will do on el8 and el9 beta and will let you know.

Comment 8 Christophe Besson 2022-01-13 14:15:10 UTC
Tested with the latest 4.2-8 on el8 and el9 beta and the issue does not appear anymore on both releases.

Comment 9 Christophe Besson 2022-01-13 14:15:59 UTC
I forgot to mention I checked on the latest rhel 8.5.

Comment 12 errata-xmlrpc 2022-05-10 15:16:32 UTC
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory (sos bug fix and enhancement update), and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHEA-2022:1998