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-rw-r--r--Documentation/admin-guide/tainted-kernels.rst36
1 files changed, 28 insertions, 8 deletions
diff --git a/Documentation/admin-guide/tainted-kernels.rst b/Documentation/admin-guide/tainted-kernels.rst
index 71e9184a9079..92a8a07f5c43 100644
--- a/Documentation/admin-guide/tainted-kernels.rst
+++ b/Documentation/admin-guide/tainted-kernels.rst
@@ -38,7 +38,7 @@ either letters or blanks. In above example it looks like this::
Tainted: P W O
-The meaning of those characters is explained in the table below. In tis case
+The meaning of those characters is explained in the table below. In this case
the kernel got tainted earlier because a proprietary Module (``P``) was loaded,
a warning occurred (``W``), and an externally-built module was loaded (``O``).
To decode other letters use the table below.
@@ -61,7 +61,7 @@ this on the machine that had the statements in the logs that were quoted earlier
* Proprietary module was loaded (#0)
* Kernel issued warning (#9)
* Externally-built ('out-of-tree') module was loaded (#12)
- See Documentation/admin-guide/tainted-kernels.rst in the the Linux kernel or
+ See Documentation/admin-guide/tainted-kernels.rst in the Linux kernel or
https://www.kernel.org/doc/html/latest/admin-guide/tainted-kernels.html for
a more details explanation of the various taint flags.
Raw taint value as int/string: 4609/'P W O '
@@ -84,7 +84,7 @@ 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 SMP kernel oops on an officially SMP incapable processor
+ 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
@@ -100,6 +100,7 @@ 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
=== === ====== ========================================================
Note: The character ``_`` is representing a blank in this table to make reading
@@ -116,10 +117,29 @@ More detailed explanation for tainting
1) ``F`` if any module was force loaded by ``insmod -f``, ``' '`` if all
modules were loaded normally.
- 2) ``S`` if the oops occurred on an SMP kernel running on hardware that
- hasn't been certified as safe to run multiprocessor.
- Currently this occurs only on various Athlons that are not
- SMP capable.
+ 2) ``S`` if the kernel is running on a processor or system that is out of
+ specification: hardware has been put into an unsupported configuration,
+ therefore proper execution cannot be guaranteed.
+ Kernel will be tainted if, for example:
+
+ - on x86: PAE is forced through forcepae on intel CPUs (such as Pentium M)
+ which do not report PAE but may have a functional implementation, an SMP
+ kernel is running on non officially capable SMP Athlon CPUs, MSRs are
+ being poked at from userspace.
+ - on arm: kernel running on certain CPUs (such as Keystone 2) without
+ having certain kernel features enabled.
+ - on arm64: there are mismatched hardware features between CPUs, the
+ bootloader has booted CPUs in different modes.
+ - certain drivers are being used on non supported architectures (such as
+ 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.
@@ -130,7 +150,7 @@ More detailed explanation for tainting
5) ``B`` If a page-release function has found a bad page reference or some
unexpected page flags. This indicates a hardware problem or a kernel bug;
there should be other information in the log indicating why this tainting
- occured.
+ occurred.
6) ``U`` if a user or user application specifically requested that the
Tainted flag be set, ``' '`` otherwise.