lib/Kconfig.kmemcheck

   1 config HAVE_ARCH_KMEMCHECK
   2         bool
   3
   4 menuconfig KMEMCHECK
   5         bool "kmemcheck: trap use of uninitialized memory"
   6         depends on DEBUG_KERNEL
   7         depends on !X86_USE_3DNOW
   8         depends on SLUB || SLAB
   9         depends on !CC_OPTIMIZE_FOR_SIZE
  10         depends on !FUNCTION_TRACER
  11         select FRAME_POINTER
  12         select STACKTRACE
  13         default n
  14         help
  15           This option enables tracing of dynamically allocated kernel memory
  16           to see if memory is used before it has been given an initial value.
  17           Be aware that this requires half of your memory for bookkeeping and
  18           will insert extra code at *every* read and write to tracked memory
  19           thus slow down the kernel code (but user code is unaffected).
  20
  21           The kernel may be started with kmemcheck=0 or kmemcheck=1 to disable
  22           or enable kmemcheck at boot-time. If the kernel is started with
  23           kmemcheck=0, the large memory and CPU overhead is not incurred.
  24
  25 choice
  26         prompt "kmemcheck: default mode at boot"
  27         depends on KMEMCHECK
  28         default KMEMCHECK_ONESHOT_BY_DEFAULT
  29         help
  30           This option controls the default behaviour of kmemcheck when the
  31           kernel boots and no kmemcheck= parameter is given.
  32
  33 config KMEMCHECK_DISABLED_BY_DEFAULT
  34         bool "disabled"
  35         depends on KMEMCHECK
  36
  37 config KMEMCHECK_ENABLED_BY_DEFAULT
  38         bool "enabled"
  39         depends on KMEMCHECK
  40
  41 config KMEMCHECK_ONESHOT_BY_DEFAULT
  42         bool "one-shot"
  43         depends on KMEMCHECK
  44         help
  45           In one-shot mode, only the first error detected is reported before
  46           kmemcheck is disabled.
  47
  48 endchoice
  49
  50 config KMEMCHECK_QUEUE_SIZE
  51         int "kmemcheck: error queue size"
  52         depends on KMEMCHECK
  53         default 64
  54         help
  55           Select the maximum number of errors to store in the queue. Since
  56           errors can occur virtually anywhere and in any context, we need a
  57           temporary storage area which is guarantueed not to generate any
  58           other faults. The queue will be emptied as soon as a tasklet may
  59           be scheduled. If the queue is full, new error reports will be
  60           lost.
  61
  62 config KMEMCHECK_SHADOW_COPY_SHIFT
  63         int "kmemcheck: shadow copy size (5 => 32 bytes, 6 => 64 bytes)"
  64         depends on KMEMCHECK
  65         range 2 8
  66         default 5
  67         help
  68           Select the number of shadow bytes to save along with each entry of
  69           the queue. These bytes indicate what parts of an allocation are
  70           initialized, uninitialized, etc. and will be displayed when an
  71           error is detected to help the debugging of a particular problem.
  72
  73 config KMEMCHECK_PARTIAL_OK
  74         bool "kmemcheck: allow partially uninitialized memory"
  75         depends on KMEMCHECK
  76         default y
  77         help
  78           This option works around certain GCC optimizations that produce
  79           32-bit reads from 16-bit variables where the upper 16 bits are
  80           thrown away afterwards. This may of course also hide some real
  81           bugs.
  82
  83 config KMEMCHECK_BITOPS_OK
  84         bool "kmemcheck: allow bit-field manipulation"
  85         depends on KMEMCHECK
  86         default n
  87         help
  88           This option silences warnings that would be generated for bit-field
  89           accesses where not all the bits are initialized at the same time.
  90           This may also hide some real bugs.
  91