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authorVegard Nossum <vegard.nossum@gmail.com>2008-04-04 00:51:41 +0200
committerVegard Nossum <vegard.nossum@gmail.com>2009-06-15 15:49:15 +0200
commit7d46d9e6dbffe8780aa8430a63543d3f7ba92860 (patch)
tree4475ceed7a49fccd1e2d609aaf181eed87c1e072
parentb1eeab67682a5e397aecf172046b3a8bd4808ae4 (diff)
kmemcheck: enable in the x86 Kconfig
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>
-rw-r--r--arch/x86/Kconfig.debug88
-rw-r--r--lib/Kconfig.debug4
-rw-r--r--mm/Kconfig.debug1
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