panic: Taint kernel if tests are run

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>

diff --git a/Documentation/admin-guide/tainted-kernels.rst b/Documentation/admin-guide/tainted-kernels.rst
index ceeed7b..7d80e8c 100644 (file)
--- a/Documentation/admin-guide/tainted-kernels.rst
+++ b/Documentation/admin-guide/tainted-kernels.rst
@@ -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

diff --git a/include/linux/panic.h b/include/linux/panic.h
index e71161d..c7759b3 100644 (file)
--- a/include/linux/panic.h
+++ b/include/linux/panic.h
@@ -68,7 +68,8 @@ static inline void set_arch_panic_timeout(int timeout, int arch_default_timeout)
 #define TAINT_LIVEPATCH                        15
 #define TAINT_AUX                      16
 #define TAINT_RANDSTRUCT               17
-#define TAINT_FLAGS_COUNT              18
+#define TAINT_TEST                     18
+#define TAINT_FLAGS_COUNT              19
 #define TAINT_FLAGS_MAX                        ((1UL << TAINT_FLAGS_COUNT) - 1)
 
 struct taint_flag {

diff --git a/kernel/panic.c b/kernel/panic.c
index a3c758d..6b3369e 100644 (file)
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -428,6 +428,7 @@ const struct taint_flag taint_flags[TAINT_FLAGS_COUNT] = {
        [ TAINT_LIVEPATCH ]             = { 'K', ' ', true },
        [ TAINT_AUX ]                   = { 'X', ' ', true },
        [ TAINT_RANDSTRUCT ]            = { 'T', ' ', true },
+       [ TAINT_TEST ]                  = { 'N', ' ', true },
 };
 
 /**