diff options
Diffstat (limited to 'Documentation/admin-guide/tainted-kernels.rst')
| -rw-r--r-- | Documentation/admin-guide/tainted-kernels.rst | 18 |
1 files changed, 16 insertions, 2 deletions
diff --git a/Documentation/admin-guide/tainted-kernels.rst b/Documentation/admin-guide/tainted-kernels.rst index ceeed7b0798d..ed1f8f1e86c5 100644 --- a/Documentation/admin-guide/tainted-kernels.rst +++ b/Documentation/admin-guide/tainted-kernels.rst @@ -34,7 +34,7 @@ name of the command ('Comm:') that triggered the event:: You'll find a 'Not tainted: ' there if the kernel was not tainted at the time of the event; if it was, then it will print 'Tainted: ' and characters -either letters or blanks. In above example it looks like this:: +either letters or blanks. In the example above it looks like this:: Tainted: P W O @@ -52,7 +52,7 @@ At runtime, you can query the tainted state by reading tainted; any other number indicates the reasons why it is. The easiest way to decode that number is the script ``tools/debugging/kernel-chktaint``, which your distribution might ship as part of a package called ``linux-tools`` or -``kernel-tools``; if it doesn't you can download the script from +``kernel-tools``; if it doesn't, you can download the script from `git.kernel.org <https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/plain/tools/debugging/kernel-chktaint>`_ and execute it with ``sh kernel-chktaint``, which would print something like this on the machine that had the statements in the logs that were quoted earlier:: @@ -100,6 +100,8 @@ Bit Log Number Reason that got the kernel tainted 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 === === ====== ======================================================== Note: The character ``_`` is representing a blank in this table to make reading @@ -133,6 +135,12 @@ More detailed explanation for tainting scsi/snic on something else than x86_64, scsi/ips on non x86/x86_64/itanium, have broken firmware settings for the irqchip/irq-gic on arm64 ...). + - x86/x86_64: Microcode late loading is dangerous and will result in + tainting the kernel. It requires that all CPUs rendezvous to make sure + the update happens when the system is as quiescent as possible. However, + a higher priority MCE/SMI/NMI can move control flow away from that + rendezvous and interrupt the update, which can be detrimental to the + machine. 3) ``R`` if a module was force unloaded by ``rmmod -f``, ``' '`` if all modules were unloaded normally. @@ -175,3 +183,9 @@ More detailed explanation for tainting produce extremely unusual kernel structure layouts (even performance pathological ones), which is important to know when debugging. Set at build time. + + 18) ``N`` if an in-kernel test, such as a KUnit test, has been run. + + 19) ``J`` if userspace opened /dev/fwctl/* and performed a FWTCL_RPC_DEBUG_WRITE + to use the devices debugging features. Device debugging features could + cause the device to malfunction in undefined ways. |