config HAVE_ARCH_KMEMCHECK
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bool
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if HAVE_ARCH_KMEMCHECK
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menuconfig KMEMCHECK
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bool "kmemcheck: trap use of uninitialized memory"
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depends on DEBUG_KERNEL
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depends on !X86_USE_3DNOW
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depends on SLUB || SLAB
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depends on !CC_OPTIMIZE_FOR_SIZE
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depends on !FUNCTION_TRACER
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select FRAME_POINTER
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select STACKTRACE
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default n
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help
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This option enables tracing of dynamically allocated kernel memory
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to see if memory is used before it has been given an initial value.
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Be aware that this requires half of your memory for bookkeeping and
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will insert extra code at *every* read and write to tracked memory
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thus slow down the kernel code (but user code is unaffected).
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The kernel may be started with kmemcheck=0 or kmemcheck=1 to disable
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or enable kmemcheck at boot-time. If the kernel is started with
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kmemcheck=0, the large memory and CPU overhead is not incurred.
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choice
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prompt "kmemcheck: default mode at boot"
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depends on KMEMCHECK
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default KMEMCHECK_ONESHOT_BY_DEFAULT
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help
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This option controls the default behaviour of kmemcheck when the
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kernel boots and no kmemcheck= parameter is given.
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config KMEMCHECK_DISABLED_BY_DEFAULT
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bool "disabled"
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depends on KMEMCHECK
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config KMEMCHECK_ENABLED_BY_DEFAULT
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bool "enabled"
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depends on KMEMCHECK
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config KMEMCHECK_ONESHOT_BY_DEFAULT
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bool "one-shot"
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depends on KMEMCHECK
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help
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In one-shot mode, only the first error detected is reported before
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kmemcheck is disabled.
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endchoice
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config KMEMCHECK_QUEUE_SIZE
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int "kmemcheck: error queue size"
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depends on KMEMCHECK
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default 64
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help
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Select the maximum number of errors to store in the queue. Since
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errors can occur virtually anywhere and in any context, we need a
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temporary storage area which is guarantueed not to generate any
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other faults. The queue will be emptied as soon as a tasklet may
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be scheduled. If the queue is full, new error reports will be
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lost.
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config KMEMCHECK_SHADOW_COPY_SHIFT
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int "kmemcheck: shadow copy size (5 => 32 bytes, 6 => 64 bytes)"
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depends on KMEMCHECK
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range 2 8
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default 5
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help
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Select the number of shadow bytes to save along with each entry of
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the queue. These bytes indicate what parts of an allocation are
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initialized, uninitialized, etc. and will be displayed when an
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error is detected to help the debugging of a particular problem.
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config KMEMCHECK_PARTIAL_OK
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bool "kmemcheck: allow partially uninitialized memory"
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depends on KMEMCHECK
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default y
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help
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This option works around certain GCC optimizations that produce
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32-bit reads from 16-bit variables where the upper 16 bits are
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thrown away afterwards. This may of course also hide some real
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bugs.
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config KMEMCHECK_BITOPS_OK
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bool "kmemcheck: allow bit-field manipulation"
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depends on KMEMCHECK
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default n
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help
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This option silences warnings that would be generated for bit-field
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accesses where not all the bits are initialized at the same time.
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This may also hide some real bugs.
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endif
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