Bug 1955722

Summary:	crond core dumps after updating /usr/lib64/libnss_winbind.so library
Product:	Red Hat Enterprise Linux 7	Reporter:	jas
Component:	cronie	Assignee:	Jan Staněk <jstanek>
Status:	CLOSED WONTFIX	QA Contact:	RHEL CS Apps Subsystem QE <rhel-cs-apps-subsystem-qe>
Severity:	medium	Docs Contact:
Priority:	unspecified
Version:	7.9	CC:	opohorel
Target Milestone:	rc	Flags:	jas: needinfo-
Target Release:	---
Hardware:	Unspecified
OS:	Linux
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Last Closed:	2021-11-10 10:21:14 UTC	Type:	Bug
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
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Embargoed:

Description jas 2021-04-30 17:33:25 UTC

Description of problem:

We use nss module winbind as our Linux hosts are joined to AD. When a software upgrade is done on winbind, and winbind is replaced, we restart winbind, but if crond previously loaded the old nss-winbind library because it was executing user jobs, then when the new module is put into place, crond will segfault each time it tries to run user jobs. 

Version-Release number of selected component (if applicable):

1.4.11-23

Steps to Reproduce:
1. Start crond
2. Make crond execute a job for a user who is in AD
3. Update nss-winbind library
4. Wait for cron to execute the next cron job. It will segfault.

Expected results:

I would expect that crond would close and re-open the nss library between runs.

Additional info:

If I restart crond after replacing winbind, there is no problem.

Comment 2 Jan Staněk 2021-09-14 10:34:24 UTC

My very rough guess is that crond is keeping old references to user information in it's internal representation (database) of the tasks to execute, and when it tries to switch to the user to actually execute the job, something explodes.

However, without the dumped core, I'm afraid I won't be able to move much further on this. Would you be able to provide one?

Comment 4 Jan Staněk 2021-11-10 10:21:14 UTC

Given no response to the NEEDINFO in 2 months, and RHEL 7 being in limited support phase, I'm not seeing this issue as being likely to get addressed. If this is also a problem in more recent RHEL version(s), feel free to re-open this, or report a new issue against the appropriate RHEL version.