Get the reasons for a tainted Linux kernel

Get-KernelTaint.sh

#!/usr/bin/env bash

# Get-KernelTaint.sh
#
# This script checks the kernel taint status by reading the value from
# /proc/sys/kernel/tainted. It interprets the taint flags and prints
# corresponding messages to indicate the reason for the taint.
# It also provides a summary of the taint status.
#
# License: MIT
#
# https://www.kernel.org/doc/html/latest/admin-guide/tainted-kernels.html
#
# | Bit | Log | Number | Reason that got the kernel tainted                    |
# |-----|-----|--------|-------------------------------------------------------|
# | 0   | G/P | 1      | proprietary module was loaded                         |
# | 1   | _/F | 2      | module was force loaded                               |
# | 2   | _/S | 4      | kernel running on an out of specification system      |
# | 3   | _/R | 8      | module was force unloaded                             |
# | 4   | _/M | 16     | processor reported a Machine Check Exception (MCE)    |
# | 5   | _/B | 32     | bad page referenced or some unexpected page flags     |
# | 6   | _/U | 64     | taint requested by userspace application              |
# | 7   | _/D | 128    | kernel died recently, i.e. there was an OOPS or BUG   |
# | 8   | _/A | 256    | ACPI table overridden by user                         |
# | 9   | _/W | 512    | kernel issued warning                                 |
# | 10  | _/C | 1024   | staging driver was loaded                             |
# | 11  | _/I | 2048   | workaround for bug in platform firmware applied       |
# | 12  | _/O | 4096   | externally-built (“out-of-tree”) module was loaded    |
# | 13  | _/E | 8192   | unsigned module was loaded                            |
# | 14  | _/L | 16384  | soft lockup occurred                                  |
# | 15  | _/K | 32768  | kernel has been live patched                          |
# | 16  | _/X | 65536  | auxiliary taint, defined for and used by distros      |
# | 17  | _/T | 131072 | kernel was built with the struct randomization plugin |
# | 18  | _/N | 262144 | an in-kernel test has been run                        |
# | 19  | _/J | 524288 | userspace used a mutating debug operation in fwctl    |

_taint_found=false

declare -A taint_reasons=(
    [0]="Proprietary module was loaded"
    [1]="Module was force loaded"
    [2]="Kernel running on an out of specification system"
    [3]="Module was force unloaded"
    [4]="Processor reported a Machine Check Exception (MCE)"
    [5]="Bad page referenced or some unexpected page flags"
    [6]="Taint requested by userspace application"
    [7]="Kernel died recently, i.e. there was an OOPS or BUG"
    [8]="ACPI table overridden by user"
    [9]="Kernel issued warning"
    [10]="Staging driver was loaded"
    [11]="Workaround for bug in platform firmware applied"
    [12]="Externally-built ('out-of-tree') module was loaded"
    [13]="Unsigned module was loaded"
    [14]="Soft lockup occurred"
    [15]="Kernel has been live patched"
    [16]="Auxiliary taint, defined for and used by distros"
    [17]="Kernel was built with the struct randomization plugin"
    [18]="An in-kernel test has been run"
    [19]="Userspace used a mutating debug operation in fwctl"
)

for _bit in "${!taint_reasons[@]}"; do
    if ((($(cat /proc/sys/kernel/tainted) >> _bit & 1) == 1)); then
        echo "Kernel is tainted: ${taint_reasons[$_bit]}"
        _taint_found=true
    fi
done

if [[ "${_taint_found}" == false ]]; then
    echo "[Info] Kernel is not tainted"
    exit 0
else
    echo "[Error] Kernel is tainted"
    exit 1
fi