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authorThorsten Leemhuis <linux@leemhuis.info>2019-01-08 20:40:07 +0100
committerJonathan Corbet <corbet@lwn.net>2019-01-08 16:33:47 -0700
commit896dd323abbf6a9980d8aca2656b6c4bf5352c3b (patch)
treeb640e8cd5112db716c9e87fa4ef014eca2a56c70 /Documentation/sysctl
parent4ab5a5d2a4a2289c2af07accbec7170ca5671f41 (diff)
downloadlinux-896dd323abbf6a9980d8aca2656b6c4bf5352c3b.tar.bz2
docs: Revamp tainted-kernels.rst to make it more comprehensible
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During review of v1 (see above) a number of existing issues with the text were raised, like outdated usages as well as incomplete or missing descriptions.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>
Diffstat (limited to 'Documentation/sysctl')
-rw-r--r--Documentation/sysctl/kernel.txt50
1 files changed, 22 insertions, 28 deletions
diff --git a/Documentation/sysctl/kernel.txt b/Documentation/sysctl/kernel.txt
index 1b8775298cf7..b279b824b887 100644
--- a/Documentation/sysctl/kernel.txt
+++ b/Documentation/sysctl/kernel.txt
@@ -93,7 +93,7 @@ show up in /proc/sys/kernel:
- stop-a [ SPARC only ]
- sysrq ==> Documentation/admin-guide/sysrq.rst
- sysctl_writes_strict
-- tainted
+- tainted ==> Documentation/admin-guide/tainted-kernels.rst
- threads-max
- unknown_nmi_panic
- watchdog
@@ -1002,39 +1002,33 @@ compilation sees a 1% slowdown, other systems and workloads may vary.
1: kernel stack erasing is enabled (default), it is performed before
returning to the userspace at the end of syscalls.
-
==============================================================
-tainted:
+tainted
Non-zero if the kernel has been tainted. Numeric values, which can be
ORed together. The letters are seen in "Tainted" line of Oops reports.
- 1 (P): A module with a non-GPL license has been loaded, this
- includes modules with no license.
- Set by modutils >= 2.4.9 and module-init-tools.
- 2 (F): A module was force loaded by insmod -f.
- Set by modutils >= 2.4.9 and module-init-tools.
- 4 (S): Unsafe SMP processors: SMP with CPUs not designed for SMP.
- 8 (R): A module was forcibly unloaded from the system by rmmod -f.
- 16 (M): A hardware machine check error occurred on the system.
- 32 (B): A bad page was discovered on the system.
- 64 (U): The user has asked that the system be marked "tainted". This
- could be because they are running software that directly modifies
- the hardware, or for other reasons.
- 128 (D): The system has died.
- 256 (A): The ACPI DSDT has been overridden with one supplied by the user
- instead of using the one provided by the hardware.
- 512 (W): A kernel warning has occurred.
- 1024 (C): A module from drivers/staging was loaded.
- 2048 (I): The system is working around a severe firmware bug.
- 4096 (O): An out-of-tree module has been loaded.
- 8192 (E): An unsigned module has been loaded in a kernel supporting module
- signature.
- 16384 (L): A soft lockup has previously occurred on the system.
- 32768 (K): The kernel has been live patched.
- 65536 (X): Auxiliary taint, defined and used by for distros.
-131072 (T): The kernel was built with the struct randomization plugin.
+ 1 (P): proprietary module was loaded
+ 2 (F): module was force loaded
+ 4 (S): SMP kernel oops on an officially SMP incapable processor
+ 8 (R): module was force unloaded
+ 16 (M): processor reported a Machine Check Exception (MCE)
+ 32 (B): bad page referenced or some unexpected page flags
+ 64 (U): taint requested by userspace application
+ 128 (D): kernel died recently, i.e. there was an OOPS or BUG
+ 256 (A): an ACPI table was overridden by user
+ 512 (W): kernel issued warning
+ 1024 (C): staging driver was loaded
+ 2048 (I): workaround for bug in platform firmware applied
+ 4096 (O): externally-built ("out-of-tree") module was loaded
+ 8192 (E): unsigned module was loaded
+ 16384 (L): soft lockup occurred
+ 32768 (K): kernel has been live patched
+ 65536 (X): Auxiliary taint, defined and used by for distros
+131072 (T): The kernel was built with the struct randomization plugin
+
+See Documentation/admin-guide/tainted-kernels.rst for more information.
==============================================================