Bug 2234460

Summary: Slow ssh connection when using password authentication due to a large amount of "close" syscall
Product: Red Hat Enterprise Linux 9 Reporter: Nicolas Bourgeois <nbourgeo>
Component: pamAssignee: Iker Pedrosa <ipedrosa>
Status: CLOSED MIGRATED QA Contact: sssd-qe
Severity: medium Docs Contact:
Priority: unspecified    
Version: unspecifiedCC: cbesson, pbrezina
Target Milestone: rcKeywords: MigratedToJIRA, Triaged
Target Release: ---Flags: pm-rhel: mirror+
Hardware: All   
OS: Linux   
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Last Closed: 2023-09-19 14:04:49 UTC Type: Bug
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description Nicolas Bourgeois 2023-08-24 13:55:03 UTC 
Description of problem:
Connecting via ssh to a server with a password is longer with RHEL 9 compared to RHEL 8



IT seemed to be resolved in RHEL 8 with the patch pam-1.3.1-fds-closing.patch (RHBZ1737812), but the fix has been reverted upstream and is not part of the code anymore.

Version-Release number of selected component (if applicable):
9.0, 9.1 and 9.2

How reproducible:
Connect using a password authentication


Actual results:
With RHEL 9, sshd spends 25% of its time running the close syscall :
	RHEL 9 :
		% time     seconds  usecs/call     calls    errors syscall
		------ ----------- ----------- --------- --------- ----------------
		 71.81    1.680497       35755        47        21 wait4
		 25.48    0.596416           4    131894    131057 close
		  0.48    0.011248          11       979       335 openat
		  0.31    0.007196         359        20           execve
		...

	RHEL 8 :
		% time     seconds  usecs/call     calls    errors syscall
		------ ----------- ----------- --------- --------- ----------------
		 81.89    0.099364        1505        66        31 wait4
		  2.64    0.003209           4       773       208 openat
		  2.53    0.003064         139        22           execve
		  2.26    0.002739          80        34           clone
		  1.21    0.001467          27        53           socket
		  1.09    0.001328          16        80         3 write
		  1.04    0.001260           2       493         2 read
		  0.90    0.001094           2       495           mmap

Is it possible to recreate a patch to correct this behavior?
Comment 5 RHEL Program Management 2023-09-19 14:01:54 UTC 
Issue migration from Bugzilla to Jira is in process at this time. This will be the last message in Jira copied from the Bugzilla bug.
Comment 6 RHEL Program Management 2023-09-19 14:04:49 UTC 
This BZ has been automatically migrated to the issues.redhat.com Red Hat Issue Tracker. All future work related to this report will be managed there.

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