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Bug
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Resolution: Done-Errata
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Critical
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rhel-8.10.z
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None
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bash-4.4.20-6.el8_10
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No
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Low
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1
-
rhel-plumbers
-
ssg_core_services
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5
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False
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False
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None
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Plumbers Sprint 1
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Pass
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Automated
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Unspecified
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Unspecified
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Unspecified
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None
Running this script in RHEL8.10.z's bash:
#!/bin/bash
CMD_STRING='"'[kworker/3:0]'"'
date >> /root/dentry.txt
cat /proc/sys/fs/dentry-state >> /root/dentry.txt
for j in {1..50}
do
for i in {1..1000000}
do
echo $i'|'$j"|"$CMD_STRING
done
date >> /root/dentry.txt
cat /proc/sys/fs/dentry-state >> /root/dentry.txt
done
date >> /root/dentry.txt
cat /proc/sys/fs/dentry-state >> /root/dentry.txt
causes a dramatic increase in the number of negative entries in the dentry cache, due to spurious stat() calls seen when stracing the script:
stat("1|1|\"[kworker/", 0x7ffe5ce5d900) = -1 ENOENT
This seems to have been addressed by an upstream bash commit in bash 5.1:
commit 4d2e315490b778707b3a3afdfc514d5083a97a11 (HEAD) Author: Chet Ramey <chet.ramey@case.edu> Date: Fri Jan 18 15:12:37 2019 -0500 Bash-5.0 patch 1: fix pathname expansion of directory names containing backslashes
A customer case indicates that the Splunk tool may be generating many thousands of echos of this type and driving the negative dentry cache to sizes which cause system instability, so this may be worth addressing in 8.10.z.
