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user35042
Asked: 2013-02-02 08:21:48 +0800 CST

How to determine if a Debian upgrade updated the kernel

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Let's say I have just done an aptitude safe-upgrade on a Debian system, but I was not paying attention so I did not notice if the kernel was updated or not.

How can I now determine if there was a kernel upgrade and a reboot is in order?

debian

4 Answers

  1. Best Answer

    Compare the running kernel (uname -a) to the files in /boot and see if there is a newer version.

    • 6

  2. Aptitude logs to /var/log/aptitude and apt-get logs to /var/log/dpkg.log. If you've installed a new kernel the installation of the package should be recorded in one or both of those log files.

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  3. Check menuentry entries in your /boot/grub/grub.conf

    check the time stamp of the kernel/vmlinuz* , grub.conf ... and see if it was recently updated.

    Look at your /var/log/audit/audit.log and search for any file modifications in /boot

    ...I can go on and on ... -:)

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  4. This is a good clue:

    cat /var/run/reboot-required*; uname -a | awk '{print "linux-image-"$3}';

    If the top version is higher than the bottom version then you likely have an updated kernel (and will have to reboot to activate it).

    This script uses apt to get a bit more definitive:

    #!/usr/bin/env bash

# 2021062101


# Read currently operating kernel
uname -a | awk '{print "linux-headers-" $3}' > /tmp/kernelversions_currentoperating_kernel.txt
currentoperating_kernel=`cat /tmp/kernelversions_currentoperating_kernel.txt`

# Read latest installed kernel
apt list --installed 2> /dev/null | grep linux-headers | grep amd64 | grep -v linux-headers-amd64 | tail -1 | aw
k -F\/ '{print $1}' > /tmp/kernelversions_latestinstalled_kernel.txt
latestinstalled_kernel=`cat /tmp/kernelversions_latestinstalled_kernel.txt`

# Read latest available kernel
apt list 2> /dev/null | grep linux-headers | grep amd64 | grep -v .bpo | grep -v "\-all" | grep -v "\-cloud" | g
rep -v "\-rt" | grep -v linux-headers-amd64 | tail -1 | awk -F\/ '{print $1}' > /tmp/kernelversions_latestavaila
ble_kernel.txt
latestavailable_kernel=`cat /tmp/kernelversions_latestavailable_kernel.txt`


# Print kernel versions
echo "CURRENTLY OPERATING KERNEL: " $currentoperating_kernel
echo "LATEST INSTALLED KERNEL:    " $latestinstalled_kernel
echo "LATEST AVAILABLE KERNEL:    " $latestavailable_kernel
echo
echo


# Delete temporary files
rm /tmp/kernelversions*

    Check the LATEST INSTALLED KERNEL. If it is a higher number than CURRENTLY OPERATING KERNEL, then new kernel was installed, but you'll need to reboot to activate it.

    I wrote it to exclude cloud and rt kernel versions. You might need to modify some of the grep statements if you use those.

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