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kmemcheck: enable in the x86 Kconfig

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let it rip!

Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

[rebased for mainline inclusion]
Signed-off-by: Vegard Nossum <vegardno@ifi.uio.no>
This commit is contained in:
Vegard Nossum 2008-04-04 00:51:41 +02:00
parent b1eeab6768
commit 7d46d9e6db
3 changed files with 91 additions and 2 deletions
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88
arch/x86/Kconfig.debug
View file

@ -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

4
lib/Kconfig.debug
View file

@ -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

1
mm/Kconfig.debug
View file

@ -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