Commit
d23d33ea0f ("x86/microcode: Taint and warn on late loading")
started tainting the kernel after microcode late loading.
There is some history behind why x86 microcode started doing the late
loading stop_machine() rendezvous. Document the whole situation.
No functional changes.
[ bp: Fix typos, heavily massage. ]
Signed-off-by: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220813223825.3164861-2-ashok.raj@intel.com
Most in-kernel tests (such as KUnit tests) are not supposed to run on
production systems: they may do deliberately illegal things to trigger
errors, and have security implications (for example, KUnit assertions
will often deliberately leak kernel addresses).
Add a new taint type, TAINT_TEST to signal that a test has been run.
This will be printed as 'N' (originally for kuNit, as every other
sensible letter was taken.)
This should discourage people from running these tests on production
systems, and to make it easier to tell if tests have been run
accidentally (by loading the wrong configuration, etc.)
Acked-by: Luis Chamberlain <mcgrof@kernel.org>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: David Gow <davidgow@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
Here's a patch updating the meaning of TAINT_CPU_OUT_OF_SPEC after
Borislav introduced changes in a7e1f67ed2 and upcoming patches in tip.
TAINT_CPU_OUT_OF_SPEC now means a bit more what it implies as the
flag isn't set just because of a CPU misconfiguration or mismatch.
Historically it was for SMP kernel oops on an officially SMP incapable
processor but now it also covers CPUs whose MSRs have been incorrectly
poked at from userspace, drivers being used on non supported
architectures, broken firmware, mismatched CPUs, ...
Update documentation and script to reflect that.
Signed-off-by: Mathieu Chouquet-Stringer <me@mathieu.digital>
Link: https://lore.kernel.org/r/20201202153244.709752-1-me@mathieu.digital
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Add a section about decoding /proc/sys/kernel/tainted, create a more
understandable intro and a hopefully explain better the tainted flags in
bugs, oops or panics messages. Only thing missing then is a table that
quickly describes the various bits and taint flags before going into more
detail, so add that as well.
That table is partly based on a section from Documentation/sysctl/kernel.txt,
but a bit more compact. To avoid confusion I added the shortened version to
kernel.txt; the same table is used in three different places now:
./tools/debugging/kernel-chktaint,
Documentation/admin-guide/tainted-kernels.rst and
Documentation/sysctl/kernel.txt
During review of v1 (see above) a number of existing issues with the text
were raised, like outdated usages as well as incomplete or missing
descriptions. Address most of those as well.
Signed-off-by: Thorsten Leemhuis <linux@leemhuis.info>
[jc: tightened up changelog]
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Without this patch, the points 1-9 in the list are rendered as an HTML
blockquote containing a list, causing them to be indented further than
the rest of the list.
While at it, also fix the quotation marks around G and P.
Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
The tainted kernels info is not directly related to
the oops tracing. So, let's move it to a separate file.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Ashok Raj