| Tainted kernels |
| --------------- |
| |
| Some oops reports contain the string **'Tainted: '** after the program |
| counter. This indicates that the kernel has been tainted by some |
| mechanism. The string is followed by a series of position-sensitive |
| characters, each representing a particular tainted value. |
| |
| 1) ``G`` if all modules loaded have a GPL or compatible license, ``P`` if |
| any proprietary module has been loaded. Modules without a |
| MODULE_LICENSE or with a MODULE_LICENSE that is not recognised by |
| insmod as GPL compatible are assumed to be proprietary. |
| |
| 2) ``F`` if any module was force loaded by ``insmod -f``, ``' '`` if all |
| modules were loaded normally. |
| |
| 3) ``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. |
| |
| 4) ``R`` if a module was force unloaded by ``rmmod -f``, ``' '`` if all |
| modules were unloaded normally. |
| |
| 5) ``M`` if any processor has reported a Machine Check Exception, |
| ``' '`` if no Machine Check Exceptions have occurred. |
| |
| 6) ``B`` if a page-release function has found a bad page reference or |
| some unexpected page flags. |
| |
| 7) ``U`` if a user or user application specifically requested that the |
| Tainted flag be set, ``' '`` otherwise. |
| |
| 8) ``D`` if the kernel has died recently, i.e. there was an OOPS or BUG. |
| |
| 9) ``A`` if the ACPI table has been overridden. |
| |
| 10) ``W`` if a warning has previously been issued by the kernel. |
| (Though some warnings may set more specific taint flags.) |
| |
| 11) ``C`` if a staging driver has been loaded. |
| |
| 12) ``I`` if the kernel is working around a severe bug in the platform |
| firmware (BIOS or similar). |
| |
| 13) ``O`` if an externally-built ("out-of-tree") module has been loaded. |
| |
| 14) ``E`` if an unsigned module has been loaded in a kernel supporting |
| module signature. |
| |
| 15) ``L`` if a soft lockup has previously occurred on the system. |
| |
| 16) ``K`` if the kernel has been live patched. |
| |
| The primary reason for the **'Tainted: '** string is to tell kernel |
| debuggers if this is a clean kernel or if anything unusual has |
| occurred. Tainting is permanent: even if an offending module is |
| unloaded, the tainted value remains to indicate that the kernel is not |
| trustworthy. |