diff options
| -rw-r--r-- | arch/x86/Kconfig.debug | 88 | ||||
| -rw-r--r-- | lib/Kconfig.debug | 4 | ||||
| -rw-r--r-- | mm/Kconfig.debug | 1 |
3 files changed, 91 insertions, 2 deletions
diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug index d105f29bb6bb..3951ebb5f843 100644 --- a/arch/x86/Kconfig.debug +++ b/arch/x86/Kconfig.debug @@ -260,6 +260,94 @@ config DEFAULT_IO_DELAY_TYPE default IO_DELAY_TYPE_NONE endif +menuconfig KMEMCHECK + bool "kmemcheck: trap use of uninitialized memory" + depends on DEBUG_KERNEL + depends on !X86_USE_3DNOW + depends on SLUB || SLAB + depends on !CC_OPTIMIZE_FOR_SIZE + depends on !FUNCTION_TRACER + select FRAME_POINTER + select STACKTRACE + default n + help + This option enables tracing of dynamically allocated kernel memory + to see if memory is used before it has been given an initial value. + Be aware that this requires half of your memory for bookkeeping and + will insert extra code at *every* read and write to tracked memory + thus slow down the kernel code (but user code is unaffected). + + The kernel may be started with kmemcheck=0 or kmemcheck=1 to disable + or enable kmemcheck at boot-time. If the kernel is started with + kmemcheck=0, the large memory and CPU overhead is not incurred. + +choice + prompt "kmemcheck: default mode at boot" + depends on KMEMCHECK + default KMEMCHECK_ONESHOT_BY_DEFAULT + help + This option controls the default behaviour of kmemcheck when the + kernel boots and no kmemcheck= parameter is given. + +config KMEMCHECK_DISABLED_BY_DEFAULT + bool "disabled" + depends on KMEMCHECK + +config KMEMCHECK_ENABLED_BY_DEFAULT + bool "enabled" + depends on KMEMCHECK + +config KMEMCHECK_ONESHOT_BY_DEFAULT + bool "one-shot" + depends on KMEMCHECK + help + In one-shot mode, only the first error detected is reported before + kmemcheck is disabled. + +endchoice + +config KMEMCHECK_QUEUE_SIZE + int "kmemcheck: error queue size" + depends on KMEMCHECK + default 64 + help + Select the maximum number of errors to store in the queue. Since + errors can occur virtually anywhere and in any context, we need a + temporary storage area which is guarantueed not to generate any + other faults. The queue will be emptied as soon as a tasklet may + be scheduled. If the queue is full, new error reports will be + lost. + +config KMEMCHECK_SHADOW_COPY_SHIFT + int "kmemcheck: shadow copy size (5 => 32 bytes, 6 => 64 bytes)" + depends on KMEMCHECK + range 2 8 + default 5 + help + Select the number of shadow bytes to save along with each entry of + the queue. These bytes indicate what parts of an allocation are + initialized, uninitialized, etc. and will be displayed when an + error is detected to help the debugging of a particular problem. + +config KMEMCHECK_PARTIAL_OK + bool "kmemcheck: allow partially uninitialized memory" + depends on KMEMCHECK + default y + help + This option works around certain GCC optimizations that produce + 32-bit reads from 16-bit variables where the upper 16 bits are + thrown away afterwards. This may of course also hide some real + bugs. + +config KMEMCHECK_BITOPS_OK + bool "kmemcheck: allow bit-field manipulation" + depends on KMEMCHECK + default n + help + This option silences warnings that would be generated for bit-field + accesses where not all the bits are initialized at the same time. + This may also hide some real bugs. + config DEBUG_BOOT_PARAMS bool "Debug boot parameters" depends on DEBUG_KERNEL diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 116a35051be6..399ba811ba18 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -300,7 +300,7 @@ config DEBUG_OBJECTS_ENABLE_DEFAULT config DEBUG_SLAB bool "Debug slab memory allocations" - depends on DEBUG_KERNEL && SLAB + depends on DEBUG_KERNEL && SLAB && !KMEMCHECK help Say Y here to have the kernel do limited verification on memory allocation as well as poisoning memory on free to catch use of freed @@ -312,7 +312,7 @@ config DEBUG_SLAB_LEAK config SLUB_DEBUG_ON bool "SLUB debugging on by default" - depends on SLUB && SLUB_DEBUG + depends on SLUB && SLUB_DEBUG && !KMEMCHECK default n help Boot with debugging on by default. SLUB boots by default with diff --git a/mm/Kconfig.debug b/mm/Kconfig.debug index bb01e298f260..aa99fd1f7109 100644 --- a/mm/Kconfig.debug +++ b/mm/Kconfig.debug @@ -2,6 +2,7 @@ config DEBUG_PAGEALLOC bool "Debug page memory allocations" depends on DEBUG_KERNEL && ARCH_SUPPORTS_DEBUG_PAGEALLOC depends on !HIBERNATION || !PPC && !SPARC + depends on !KMEMCHECK ---help--- Unmap pages from the kernel linear mapping after free_pages(). This results in a large slowdown, but helps to find certain types |