[RFC][PATCH 0/7] Put "Kernel hacking" Kconfig menu on a diet

[RFC][PATCH 0/7] Put "Kernel hacking" Kconfig menu on a diet

[Dave Hansen]

I think the "Kernel Hacking" menu has gotten a bit out of hand.  It
is over 120 lines long on my system with everything enabled and
options are scattered around it haphazardly.

	http://sr71.net/~dave/linux/kconfig-horror.png

Let's try to introduce some sanity.

[RFC][PATCH 1/7] move debugfs to filesystems menu (fs/Kconfig)

[Dave Hansen]

debugfs may have started out as a kernel hacking kind of option.  But,
today, it is an integral part of lots of facilities like tracing that
are far from kernel hacking.  Let's move it out of the very cluttered
"Kernel Hacking" menu and but it next to its real family: other
filesystems like sysfs, configfs, or /proc.

Also, "Debug filesystem" sounds like a debugging option _for_
filesystems code, not a filesystem for debugging.  We also never call
it "the debug filesystem."  We always say "debugfs", so reflect the
fact that we _call_ it debugfs in the menu text.

Signed-off-by: Dave Hansen <dave@linux.vnet.ibm.com>
---

 linux-2.6.git-dave/fs/Kconfig        |   12 ++++++++++++
 linux-2.6.git-dave/lib/Kconfig.debug |   12 ------------
 2 files changed, 12 insertions(+), 12 deletions(-)

diff -puN lib/Kconfig.debug~be-clear-about-debugfs lib/Kconfig.debug
--- linux-2.6.git/lib/Kconfig.debug~be-clear-about-debugfs	2012-12-14 13:32:20.782780277 -0500
+++ linux-2.6.git-dave/lib/Kconfig.debug	2012-12-14 13:32:22.890797974 -0500
@@ -99,18 +99,6 @@ config UNUSED_SYMBOLS
 	  you really need it, and what the merge plan to the mainline kernel for
 	  your module is.
 
-config DEBUG_FS
-	bool "Debug Filesystem"
-	help
-	  debugfs is a virtual file system that kernel developers use to put
-	  debugging files into.  Enable this option to be able to read and
-	  write to these files.
-
-	  For detailed documentation on the debugfs API, see
-	  Documentation/DocBook/filesystems.
-
-	  If unsure, say N.
-
 config HEADERS_CHECK
 	bool "Run 'make headers_check' when building vmlinux"
 	depends on !UML
diff -puN fs/Kconfig~be-clear-about-debugfs fs/Kconfig
--- linux-2.6.git/fs/Kconfig~be-clear-about-debugfs	2012-12-14 13:32:20.782780277 -0500
+++ linux-2.6.git-dave/fs/Kconfig	2012-12-14 13:32:22.890797974 -0500
@@ -176,6 +176,18 @@ config HUGETLBFS
 config HUGETLB_PAGE
 	def_bool HUGETLBFS
 
+config DEBUG_FS
+	bool "Debug Filesystem (debugfs)"
+	help
+	  debugfs is a virtual file system that kernel developers use to put
+	  debugging files into.  Enable this option to be able to read and
+	  write to these files.
+
+	  For detailed documentation on the debugfs API, see
+	  Documentation/DocBook/filesystems.
+
+	  If unsure, say N.
+
 source "fs/configfs/Kconfig"
 
 endmenu
_

[RFC][PATCH 2/7] consolidate per-arch stack overflow debugging options

[Dave Hansen]

Several architectures have similar stack debugging config options.
They all pretty much do the same thing, some with slightly
differing help text.

This patch changes the architectures to instead enable a Kconfig
boolean, and then use that boolean in the generic Kconfig.debug
to present the actual menu option.

Signed-off-by: Dave Hansen <dave@linux.vnet.ibm.com>
---

 linux-2.6.git-dave/arch/blackfin/Kconfig       |    1 +
 linux-2.6.git-dave/arch/blackfin/Kconfig.debug |    7 -------
 linux-2.6.git-dave/arch/frv/Kconfig            |    1 +
 linux-2.6.git-dave/arch/frv/Kconfig.debug      |    4 ----
 linux-2.6.git-dave/arch/m32r/Kconfig           |    1 +
 linux-2.6.git-dave/arch/m32r/Kconfig.debug     |    7 -------
 linux-2.6.git-dave/arch/mips/Kconfig           |    1 +
 linux-2.6.git-dave/arch/mips/Kconfig.debug     |    9 ---------
 linux-2.6.git-dave/arch/mn10300/Kconfig        |    1 +
 linux-2.6.git-dave/arch/mn10300/Kconfig.debug  |    4 ----
 linux-2.6.git-dave/arch/powerpc/Kconfig        |    1 +
 linux-2.6.git-dave/arch/powerpc/Kconfig.debug  |    7 -------
 linux-2.6.git-dave/arch/tile/Kconfig           |    1 +
 linux-2.6.git-dave/arch/tile/Kconfig.debug     |    7 -------
 linux-2.6.git-dave/arch/x86/Kconfig            |    1 +
 linux-2.6.git-dave/arch/x86/Kconfig.debug      |   10 ----------
 linux-2.6.git-dave/lib/Kconfig.debug           |   21 +++++++++++++++++++++
 17 files changed, 29 insertions(+), 55 deletions(-)

diff -puN arch/blackfin/Kconfig~consolidat-stack-debugging-configs arch/blackfin/Kconfig
--- linux-2.6.git/arch/blackfin/Kconfig~consolidat-stack-debugging-configs	2012-12-10 11:26:13.963147904 -0500
+++ linux-2.6.git-dave/arch/blackfin/Kconfig	2012-12-10 11:26:13.999148224 -0500
@@ -45,6 +45,7 @@ config BLACKFIN
 	select ARCH_USES_GETTIMEOFFSET if !GENERIC_CLOCKEVENTS
 	select HAVE_MOD_ARCH_SPECIFIC
 	select MODULES_USE_ELF_RELA
+	select HAVE_DEBUG_STACKOVERFLOW
 
 config GENERIC_CSUM
 	def_bool y
diff -puN arch/blackfin/Kconfig.debug~consolidat-stack-debugging-configs arch/blackfin/Kconfig.debug
--- linux-2.6.git/arch/blackfin/Kconfig.debug~consolidat-stack-debugging-configs	2012-12-10 11:26:13.963147904 -0500
+++ linux-2.6.git-dave/arch/blackfin/Kconfig.debug	2012-12-10 11:26:13.999148224 -0500
@@ -2,13 +2,6 @@ menu "Kernel hacking"
 
 source "lib/Kconfig.debug"
 
-config DEBUG_STACKOVERFLOW
-	bool "Check for stack overflows"
-	depends on DEBUG_KERNEL
-	help
-	  This option will cause messages to be printed if free stack space
-	  drops below a certain limit.
-
 config DEBUG_VERBOSE
 	bool "Verbose fault messages"
 	default y
diff -puN arch/frv/Kconfig~consolidat-stack-debugging-configs arch/frv/Kconfig
--- linux-2.6.git/arch/frv/Kconfig~consolidat-stack-debugging-configs	2012-12-10 11:26:13.967147938 -0500
+++ linux-2.6.git-dave/arch/frv/Kconfig	2012-12-10 11:26:13.999148224 -0500
@@ -14,6 +14,7 @@ config FRV
 	select ARCH_WANT_IPC_PARSE_VERSION
 	select GENERIC_KERNEL_THREAD
 	select GENERIC_KERNEL_EXECVE
+	select HAVE_DEBUG_STACKOVERFLOW
 
 config ZONE_DMA
 	bool
diff -puN arch/frv/Kconfig.debug~consolidat-stack-debugging-configs arch/frv/Kconfig.debug
--- linux-2.6.git/arch/frv/Kconfig.debug~consolidat-stack-debugging-configs	2012-12-10 11:26:13.967147938 -0500
+++ linux-2.6.git-dave/arch/frv/Kconfig.debug	2012-12-10 11:26:13.999148224 -0500
@@ -2,10 +2,6 @@ menu "Kernel hacking"
 
 source "lib/Kconfig.debug"
 
-config DEBUG_STACKOVERFLOW
-	bool "Check for stack overflows"
-	depends on DEBUG_KERNEL
-
 config GDBSTUB
 	bool "Remote GDB kernel debugging"
 	depends on DEBUG_KERNEL
diff -puN arch/m32r/Kconfig~consolidat-stack-debugging-configs arch/m32r/Kconfig
--- linux-2.6.git/arch/m32r/Kconfig~consolidat-stack-debugging-configs	2012-12-10 11:26:13.971147973 -0500
+++ linux-2.6.git-dave/arch/m32r/Kconfig	2012-12-10 11:26:13.999148224 -0500
@@ -15,6 +15,7 @@ config M32R
 	select GENERIC_ATOMIC64
 	select ARCH_USES_GETTIMEOFFSET
 	select MODULES_USE_ELF_RELA
+	select HAVE_DEBUG_STACKOVERFLOW
 
 config SBUS
 	bool
diff -puN arch/m32r/Kconfig.debug~consolidat-stack-debugging-configs arch/m32r/Kconfig.debug
--- linux-2.6.git/arch/m32r/Kconfig.debug~consolidat-stack-debugging-configs	2012-12-10 11:26:13.971147973 -0500
+++ linux-2.6.git-dave/arch/m32r/Kconfig.debug	2012-12-10 11:26:13.999148224 -0500
@@ -2,13 +2,6 @@ menu "Kernel hacking"
 
 source "lib/Kconfig.debug"
 
-config DEBUG_STACKOVERFLOW
-	bool "Check for stack overflows"
-	depends on DEBUG_KERNEL
-	help
-	  This option will cause messages to be printed if free stack space
-	  drops below a certain limit.
-
 config DEBUG_PAGEALLOC
 	bool "Debug page memory allocations"
 	depends on DEBUG_KERNEL && BROKEN
diff -puN arch/mips/Kconfig~consolidat-stack-debugging-configs arch/mips/Kconfig
--- linux-2.6.git/arch/mips/Kconfig~consolidat-stack-debugging-configs	2012-12-10 11:26:13.975148010 -0500
+++ linux-2.6.git-dave/arch/mips/Kconfig	2012-12-10 11:26:13.999148224 -0500
@@ -40,6 +40,7 @@ config MIPS
 	select HAVE_MOD_ARCH_SPECIFIC
 	select MODULES_USE_ELF_REL
 	select MODULES_USE_ELF_RELA if 64BIT
+	select HAVE_DEBUG_STACKOVERFLOW
 
 menu "Machine selection"
 
diff -puN arch/mips/Kconfig.debug~consolidat-stack-debugging-configs arch/mips/Kconfig.debug
--- linux-2.6.git/arch/mips/Kconfig.debug~consolidat-stack-debugging-configs	2012-12-10 11:26:13.975148010 -0500
+++ linux-2.6.git-dave/arch/mips/Kconfig.debug	2012-12-10 11:26:13.999148224 -0500
@@ -67,15 +67,6 @@ config CMDLINE_OVERRIDE
 
 	  Normally, you will choose 'N' here.
 
-config DEBUG_STACKOVERFLOW
-	bool "Check for stack overflows"
-	depends on DEBUG_KERNEL
-	help
-	  This option will cause messages to be printed if free stack space
-	  drops below a certain limit(2GB on MIPS). The debugging option
-	  provides another way to check stack overflow happened on kernel mode
-	  stack usually caused by nested interruption.
-
 config SMTC_IDLE_HOOK_DEBUG
 	bool "Enable additional debug checks before going into CPU idle loop"
 	depends on DEBUG_KERNEL && MIPS_MT_SMTC
diff -puN arch/mn10300/Kconfig~consolidat-stack-debugging-configs arch/mn10300/Kconfig
--- linux-2.6.git/arch/mn10300/Kconfig~consolidat-stack-debugging-configs	2012-12-10 11:26:13.979148046 -0500
+++ linux-2.6.git-dave/arch/mn10300/Kconfig	2012-12-10 11:26:13.999148224 -0500
@@ -10,6 +10,7 @@ config MN10300
 	select GENERIC_CLOCKEVENTS
 	select GENERIC_KERNEL_THREAD
 	select MODULES_USE_ELF_RELA
+	select HAVE_DEBUG_STACKOVERFLOW
 
 config AM33_2
 	def_bool n
diff -puN arch/mn10300/Kconfig.debug~consolidat-stack-debugging-configs arch/mn10300/Kconfig.debug
--- linux-2.6.git/arch/mn10300/Kconfig.debug~consolidat-stack-debugging-configs	2012-12-10 11:26:13.979148046 -0500
+++ linux-2.6.git-dave/arch/mn10300/Kconfig.debug	2012-12-10 11:26:13.999148224 -0500
@@ -2,10 +2,6 @@ menu "Kernel hacking"
 
 source "lib/Kconfig.debug"
 
-config DEBUG_STACKOVERFLOW
-	bool "Check for stack overflows"
-	depends on DEBUG_KERNEL
-
 config DEBUG_DECOMPRESS_KERNEL
 	bool "Using serial port during decompressing kernel"
 	depends on DEBUG_KERNEL
diff -puN arch/powerpc/Kconfig~consolidat-stack-debugging-configs arch/powerpc/Kconfig
--- linux-2.6.git/arch/powerpc/Kconfig~consolidat-stack-debugging-configs	2012-12-10 11:26:13.983148082 -0500
+++ linux-2.6.git-dave/arch/powerpc/Kconfig	2012-12-10 11:26:59.899558241 -0500
@@ -144,6 +144,7 @@ config PPC
 	select GENERIC_KERNEL_THREAD
 	select HAVE_MOD_ARCH_SPECIFIC
 	select MODULES_USE_ELF_RELA
+	select HAVE_DEBUG_STACKOVERFLOW
 
 config EARLY_PRINTK
 	bool
diff -puN arch/powerpc/Kconfig.debug~consolidat-stack-debugging-configs arch/powerpc/Kconfig.debug
--- linux-2.6.git/arch/powerpc/Kconfig.debug~consolidat-stack-debugging-configs	2012-12-10 11:26:13.983148082 -0500
+++ linux-2.6.git-dave/arch/powerpc/Kconfig.debug	2012-12-10 11:26:13.999148224 -0500
@@ -28,13 +28,6 @@ config PRINT_STACK_DEPTH
 	  too small and stack traces cause important information to
 	  scroll off the screen.
 
-config DEBUG_STACKOVERFLOW
-	bool "Check for stack overflows"
-	depends on DEBUG_KERNEL
-	help
-	  This option will cause messages to be printed if free stack space
-	  drops below a certain limit.
-
 config HCALL_STATS
 	bool "Hypervisor call instrumentation"
 	depends on PPC_PSERIES && DEBUG_FS && TRACEPOINTS
diff -puN arch/tile/Kconfig~consolidat-stack-debugging-configs arch/tile/Kconfig
--- linux-2.6.git/arch/tile/Kconfig~consolidat-stack-debugging-configs	2012-12-10 11:26:13.987148118 -0500
+++ linux-2.6.git-dave/arch/tile/Kconfig	2012-12-10 11:27:06.835620193 -0500
@@ -21,6 +21,7 @@ config TILE
 	select ARCH_HAVE_NMI_SAFE_CMPXCHG
 	select GENERIC_CLOCKEVENTS
 	select MODULES_USE_ELF_RELA
+	select HAVE_DEBUG_STACKOVERFLOW
 
 # FIXME: investigate whether we need/want these options.
 #	select HAVE_IOREMAP_PROT
diff -puN arch/tile/Kconfig.debug~consolidat-stack-debugging-configs arch/tile/Kconfig.debug
--- linux-2.6.git/arch/tile/Kconfig.debug~consolidat-stack-debugging-configs	2012-12-10 11:26:13.987148118 -0500
+++ linux-2.6.git-dave/arch/tile/Kconfig.debug	2012-12-10 11:26:14.003148261 -0500
@@ -14,13 +14,6 @@ config EARLY_PRINTK
 	  with klogd/syslogd. You should normally N here,
 	  unless you want to debug such a crash.
 
-config DEBUG_STACKOVERFLOW
-	bool "Check for stack overflows"
-	depends on DEBUG_KERNEL
-	help
-	  This option will cause messages to be printed if free stack space
-	  drops below a certain limit.
-
 config DEBUG_EXTRA_FLAGS
 	string "Additional compiler arguments when building with '-g'"
 	depends on DEBUG_INFO
diff -puN arch/x86/Kconfig~consolidat-stack-debugging-configs arch/x86/Kconfig
--- linux-2.6.git/arch/x86/Kconfig~consolidat-stack-debugging-configs	2012-12-10 11:26:13.991148152 -0500
+++ linux-2.6.git-dave/arch/x86/Kconfig	2012-12-10 11:27:31.911844173 -0500
@@ -112,6 +112,7 @@ config X86
 	select GENERIC_KERNEL_EXECVE
 	select MODULES_USE_ELF_REL if X86_32
 	select MODULES_USE_ELF_RELA if X86_64
+	select HAVE_DEBUG_STACKOVERFLOW
 
 config INSTRUCTION_DECODER
 	def_bool y
diff -puN arch/x86/Kconfig.debug~consolidat-stack-debugging-configs arch/x86/Kconfig.debug
--- linux-2.6.git/arch/x86/Kconfig.debug~consolidat-stack-debugging-configs	2012-12-10 11:26:13.991148152 -0500
+++ linux-2.6.git-dave/arch/x86/Kconfig.debug	2012-12-10 11:28:38.856442056 -0500
@@ -59,16 +59,6 @@ config EARLY_PRINTK_DBGP
 	  with klogd/syslogd or the X server. You should normally N here,
 	  unless you want to debug such a crash. You need usb debug device.
 
-config DEBUG_STACKOVERFLOW
-	bool "Check for stack overflows"
-	depends on DEBUG_KERNEL
-	---help---
-	  Say Y here if you want to check the overflows of kernel, IRQ
-	  and exception stacks. This option will cause messages of the
-	  stacks in detail when free stack space drops below a certain
-	  limit.
-	  If in doubt, say "N".
-
 config X86_PTDUMP
 	bool "Export kernel pagetable layout to userspace via debugfs"
 	depends on DEBUG_KERNEL
diff -puN lib/Kconfig.debug~consolidat-stack-debugging-configs lib/Kconfig.debug
--- linux-2.6.git/lib/Kconfig.debug~consolidat-stack-debugging-configs	2012-12-10 11:26:13.995148187 -0500
+++ linux-2.6.git-dave/lib/Kconfig.debug	2012-12-10 11:28:38.856442056 -0500
@@ -1464,6 +1464,27 @@ config ASYNC_RAID6_TEST
 
 	  If unsure, say N.
 
+config HAVE_DEBUG_STACKOVERFLOW
+	bool
+
+config DEBUG_STACKOVERFLOW
+	bool "Check for stack overflows"
+	depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
+	---help---
+	  Say Y here if you want to check for overflows of kernel, IRQ
+	  and exception stacks (if your archicture uses them). This
+	  option will show detailed messages if free stack space drops
+	  below a certain limit.
+
+	  These kinds of bugs usually occur when call-chains in the
+	  kernel get too deep, especially when interrupts are
+	  involved.
+
+	  Use this in cases where you see apparently random memory
+	  corruption, especially if it appears in 'struct thread_info'
+
+	  If in doubt, say "N".
+
 source "samples/Kconfig"
 
 source "lib/Kconfig.kgdb"
_

[RFC][PATCH 3/7] order memory debugging Kconfig options

[Dave Hansen]

There are a *LOT* of memory debugging options.  They are just scattered
all over the "Kernel Hacking" menu.  Sure, "memory debugging" is a very
vague term and it's going to be hard to make absolute rules about what
goes in here, but this has to be better than what we had before.

This does, however, leave out the architecture-specific memory
debugging options (like x86's DEBUG_SET_MODULE_RONX).  There would need
to be some substantial changes to move those in here.  Kconfig can not
easily mix arch-specific and generic options together: it really
requires a file per-architecture, and I think having an
arch/foo/Kconfig.debug-memory might be taking things a bit too far

Signed-off-by: Dave Hansen <dave@linux.vnet.ibm.com>
---

 linux-2.6.git-dave/arch/x86/Kconfig.debug |    2 
 linux-2.6.git-dave/lib/Kconfig.debug      |  702 +++++++++++++++---------------
 2 files changed, 357 insertions(+), 347 deletions(-)

diff -puN arch/x86/Kconfig.debug~order-memory-debugging-options arch/x86/Kconfig.debug
--- linux-2.6.git/arch/x86/Kconfig.debug~order-memory-debugging-options	2012-12-10 11:27:44.047952567 -0500
+++ linux-2.6.git-dave/arch/x86/Kconfig.debug	2012-12-10 11:27:44.063952709 -0500
@@ -61,7 +61,7 @@ config EARLY_PRINTK_DBGP
 
 config X86_PTDUMP
 	bool "Export kernel pagetable layout to userspace via debugfs"
-	depends on DEBUG_KERNEL
+	depends on DEBUG_MEMORY
 	select DEBUG_FS
 	---help---
 	  Say Y here if you want to show the kernel pagetable layout in a
diff -puN lib/Kconfig.debug~order-memory-debugging-options lib/Kconfig.debug
--- linux-2.6.git/lib/Kconfig.debug~order-memory-debugging-options	2012-12-10 11:27:44.059952672 -0500
+++ linux-2.6.git-dave/lib/Kconfig.debug	2012-12-10 11:28:38.668440377 -0500
@@ -173,6 +173,285 @@ config DEBUG_KERNEL
 	  Say Y here if you are developing drivers or trying to debug and
 	  identify kernel problems.
 
+menuconfig DEBUG_MEMORY
+	bool "Memory Debugging"
+	def_bool y
+	depends on DEBUG_KERNEL
+	help
+	  Say Y here if you are trying to debug memory issues like memory
+	  corruption or memory leaks.
+
+if DEBUG_MEMORY
+
+source mm/Kconfig.debug
+
+config DEBUG_OBJECTS
+	bool "Debug object operations"
+	help
+	  If you say Y here, additional code will be inserted into the
+	  kernel to track the life time of various objects and validate
+	  the operations on those objects.
+
+config DEBUG_OBJECTS_SELFTEST
+	bool "Debug objects selftest"
+	depends on DEBUG_OBJECTS
+	help
+	  This enables the selftest of the object debug code.
+
+config DEBUG_OBJECTS_FREE
+	bool "Debug objects in freed memory"
+	depends on DEBUG_OBJECTS
+	help
+	  This enables checks whether a k/v free operation frees an area
+	  which contains an object which has not been deactivated
+	  properly. This can make kmalloc/kfree-intensive workloads
+	  much slower.
+
+config DEBUG_OBJECTS_TIMERS
+	bool "Debug timer objects"
+	depends on DEBUG_OBJECTS
+	help
+	  If you say Y here, additional code will be inserted into the
+	  timer routines to track the life time of timer objects and
+	  validate the timer operations.
+
+config DEBUG_OBJECTS_WORK
+	bool "Debug work objects"
+	depends on DEBUG_OBJECTS
+	help
+	  If you say Y here, additional code will be inserted into the
+	  work queue routines to track the life time of work objects and
+	  validate the work operations.
+
+config DEBUG_OBJECTS_RCU_HEAD
+	bool "Debug RCU callbacks objects"
+	depends on DEBUG_OBJECTS
+	help
+	  Enable this to turn on debugging of RCU list heads (call_rcu() usage).
+
+config DEBUG_OBJECTS_PERCPU_COUNTER
+	bool "Debug percpu counter objects"
+	depends on DEBUG_OBJECTS
+	help
+	  If you say Y here, additional code will be inserted into the
+	  percpu counter routines to track the life time of percpu counter
+	  objects and validate the percpu counter operations.
+
+config DEBUG_OBJECTS_ENABLE_DEFAULT
+	int "debug_objects bootup default value (0-1)"
+        range 0 1
+        default "1"
+        depends on DEBUG_OBJECTS
+        help
+          Debug objects boot parameter default value
+
+config DEBUG_SLAB
+	bool "Debug slab memory allocations"
+	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
+	  memory. This can make kmalloc/kfree-intensive workloads much slower.
+
+config DEBUG_SLAB_LEAK
+	bool "Memory leak debugging"
+	depends on DEBUG_SLAB
+
+config SLUB_DEBUG_ON
+	bool "SLUB debugging on by default"
+	depends on SLUB && SLUB_DEBUG && !KMEMCHECK
+	default n
+	help
+	  Boot with debugging on by default. SLUB boots by default with
+	  the runtime debug capabilities switched off. Enabling this is
+	  equivalent to specifying the "slub_debug" parameter on boot.
+	  There is no support for more fine grained debug control like
+	  possible with slub_debug=xxx. SLUB debugging may be switched
+	  off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
+	  "slub_debug=-".
+
+config SLUB_STATS
+	default n
+	bool "Enable SLUB performance statistics"
+	depends on SLUB && SYSFS
+	help
+	  SLUB statistics are useful to debug SLUBs allocation behavior in
+	  order find ways to optimize the allocator. This should never be
+	  enabled for production use since keeping statistics slows down
+	  the allocator by a few percentage points. The slabinfo command
+	  supports the determination of the most active slabs to figure
+	  out which slabs are relevant to a particular load.
+	  Try running: slabinfo -DA
+
+config HAVE_DEBUG_KMEMLEAK
+	bool
+
+config DEBUG_KMEMLEAK
+	bool "Kernel memory leak detector"
+	depends on DEBUG_KERNEL && EXPERIMENTAL && HAVE_DEBUG_KMEMLEAK
+	select DEBUG_FS
+	select STACKTRACE if STACKTRACE_SUPPORT
+	select KALLSYMS
+	select CRC32
+	help
+	  Say Y here if you want to enable the memory leak
+	  detector. The memory allocation/freeing is traced in a way
+	  similar to the Boehm's conservative garbage collector, the
+	  difference being that the orphan objects are not freed but
+	  only shown in /sys/kernel/debug/kmemleak. Enabling this
+	  feature will introduce an overhead to memory
+	  allocations. See Documentation/kmemleak.txt for more
+	  details.
+
+	  Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
+	  of finding leaks due to the slab objects poisoning.
+
+	  In order to access the kmemleak file, debugfs needs to be
+	  mounted (usually at /sys/kernel/debug).
+
+config DEBUG_KMEMLEAK_EARLY_LOG_SIZE
+	int "Maximum kmemleak early log entries"
+	depends on DEBUG_KMEMLEAK
+	range 200 40000
+	default 400
+	help
+	  Kmemleak must track all the memory allocations to avoid
+	  reporting false positives. Since memory may be allocated or
+	  freed before kmemleak is initialised, an early log buffer is
+	  used to store these actions. If kmemleak reports "early log
+	  buffer exceeded", please increase this value.
+
+config DEBUG_KMEMLEAK_TEST
+	tristate "Simple test for the kernel memory leak detector"
+	depends on DEBUG_KMEMLEAK && m
+	help
+	  This option enables a module that explicitly leaks memory.
+
+	  If unsure, say N.
+
+config DEBUG_KMEMLEAK_DEFAULT_OFF
+	bool "Default kmemleak to off"
+	depends on DEBUG_KMEMLEAK
+	help
+	  Say Y here to disable kmemleak by default. It can then be enabled
+	  on the command line via kmemleak=on.
+
+config DEBUG_STACK_USAGE
+	bool "Stack utilization instrumentation"
+	depends on DEBUG_KERNEL && !IA64 && !PARISC
+	help
+	  Enables the display of the minimum amount of free stack which each
+	  task has ever had available in the sysrq-T and sysrq-P debug output.
+
+	  This option will slow down process creation somewhat.
+
+config DEBUG_VM
+	bool "Debug VM"
+	depends on DEBUG_KERNEL
+	help
+	  Enable this to turn on extended checks in the virtual-memory system
+          that may impact performance.
+
+	  If unsure, say N.
+
+config DEBUG_VM_RB
+	bool "Debug VM red-black trees"
+	depends on DEBUG_VM
+	help
+	  Enable this to turn on more extended checks in the virtual-memory
+	  system that may impact performance.
+
+	  If unsure, say N.
+
+config DEBUG_VIRTUAL
+	bool "Debug VM translations"
+	depends on DEBUG_KERNEL && X86
+	help
+	  Enable some costly sanity checks in virtual to page code. This can
+	  catch mistakes with virt_to_page() and friends.
+
+	  If unsure, say N.
+
+config DEBUG_NOMMU_REGIONS
+	bool "Debug the global anon/private NOMMU mapping region tree"
+	depends on DEBUG_KERNEL && !MMU
+	help
+	  This option causes the global tree of anonymous and private mapping
+	  regions to be regularly checked for invalid topology.
+
+config DEBUG_MEMORY_INIT
+	bool "Debug memory initialisation" if EXPERT
+	default !EXPERT
+	help
+	  Enable this for additional checks during memory initialisation.
+	  The sanity checks verify aspects of the VM such as the memory model
+	  and other information provided by the architecture. Verbose
+	  information will be printed at KERN_DEBUG loglevel depending
+	  on the mminit_loglevel= command-line option.
+
+	  If unsure, say Y
+
+config MEMORY_NOTIFIER_ERROR_INJECT
+	tristate "Memory hotplug notifier error injection module"
+	depends on MEMORY_HOTPLUG_SPARSE && NOTIFIER_ERROR_INJECTION
+	help
+	  This option provides the ability to inject artifical errors to
+	  memory hotplug notifier chain callbacks.  It is controlled through
+	  debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
+
+	  If the notifier call chain should be failed with some events
+	  notified, write the error code to "actions/<notifier event>/error".
+
+	  Example: Inject memory hotplug offline error (-12 == -ENOMEM)
+
+	  # cd /sys/kernel/debug/notifier-error-inject/memory
+	  # echo -12 > actions/MEM_GOING_OFFLINE/error
+	  # echo offline > /sys/devices/system/memory/memoryXXX/state
+	  bash: echo: write error: Cannot allocate memory
+
+	  To compile this code as a module, choose M here: the module will
+	  be called pSeries-reconfig-notifier-error-inject.
+
+	  If unsure, say N.
+
+config DEBUG_PER_CPU_MAPS
+	bool "Debug access to per_cpu maps"
+	depends on DEBUG_KERNEL
+	depends on SMP
+	help
+	  Say Y to verify that the per_cpu map being accessed has
+	  been set up. This adds a fair amount of code to kernel memory
+	  and decreases performance.
+
+	  Say N if unsure.
+
+config DEBUG_HIGHMEM
+	bool "Highmem debugging"
+	depends on DEBUG_KERNEL && HIGHMEM
+	help
+	  This options enables addition error checking for high memory systems.
+	  Disable for production systems.
+
+config DEBUG_STACKOVERFLOW
+	bool "Check for stack overflows"
+	depends on ARCH_ENABLE_DEBUG_STACKOVERFLOW
+	---help---
+	 Say Y here if you want to check for overflows of kernel, IRQ
+	 and exception stacks (if your archicture uses them). This
+	 option will show detailed messages if free stack space drops
+	 below a certain limit.
+
+	 These kinds of bugs usually occur when call-chains in the
+	 kernel get too deep, especially when interrupts are
+	 involved.
+
+	 Use this in cases where you see apparently random memory
+	 corruption, especially if it appears in 'struct thread_info'
+
+source "lib/Kconfig.kmemcheck"
+
+endif # DEBUG_MEMORY
+
 config DEBUG_SHIRQ
 	bool "Debug shared IRQ handlers"
 	depends on DEBUG_KERNEL && GENERIC_HARDIRQS
@@ -267,252 +546,100 @@ config PANIC_ON_OOPS
 
 	  Say N if unsure.
 
-config PANIC_ON_OOPS_VALUE
-	int
-	range 0 1
-	default 0 if !PANIC_ON_OOPS
-	default 1 if PANIC_ON_OOPS
-
-config DETECT_HUNG_TASK
-	bool "Detect Hung Tasks"
-	depends on DEBUG_KERNEL
-	default LOCKUP_DETECTOR
-	help
-	  Say Y here to enable the kernel to detect "hung tasks",
-	  which are bugs that cause the task to be stuck in
-	  uninterruptible "D" state indefinitiley.
-
-	  When a hung task is detected, the kernel will print the
-	  current stack trace (which you should report), but the
-	  task will stay in uninterruptible state. If lockdep is
-	  enabled then all held locks will also be reported. This
-	  feature has negligible overhead.
-
-config DEFAULT_HUNG_TASK_TIMEOUT
-	int "Default timeout for hung task detection (in seconds)"
-	depends on DETECT_HUNG_TASK
-	default 120
-	help
-	  This option controls the default timeout (in seconds) used
-	  to determine when a task has become non-responsive and should
-	  be considered hung.
-
-	  It can be adjusted at runtime via the kernel.hung_task_timeout_secs
-	  sysctl or by writing a value to
-	  /proc/sys/kernel/hung_task_timeout_secs.
-
-	  A timeout of 0 disables the check.  The default is two minutes.
-	  Keeping the default should be fine in most cases.
-
-config BOOTPARAM_HUNG_TASK_PANIC
-	bool "Panic (Reboot) On Hung Tasks"
-	depends on DETECT_HUNG_TASK
-	help
-	  Say Y here to enable the kernel to panic on "hung tasks",
-	  which are bugs that cause the kernel to leave a task stuck
-	  in uninterruptible "D" state.
-
-	  The panic can be used in combination with panic_timeout,
-	  to cause the system to reboot automatically after a
-	  hung task has been detected. This feature is useful for
-	  high-availability systems that have uptime guarantees and
-	  where a hung tasks must be resolved ASAP.
-
-	  Say N if unsure.
-
-config BOOTPARAM_HUNG_TASK_PANIC_VALUE
-	int
-	depends on DETECT_HUNG_TASK
-	range 0 1
-	default 0 if !BOOTPARAM_HUNG_TASK_PANIC
-	default 1 if BOOTPARAM_HUNG_TASK_PANIC
-
-config SCHED_DEBUG
-	bool "Collect scheduler debugging info"
-	depends on DEBUG_KERNEL && PROC_FS
-	default y
-	help
-	  If you say Y here, the /proc/sched_debug file will be provided
-	  that can help debug the scheduler. The runtime overhead of this
-	  option is minimal.
-
-config SCHEDSTATS
-	bool "Collect scheduler statistics"
-	depends on DEBUG_KERNEL && PROC_FS
-	help
-	  If you say Y here, additional code will be inserted into the
-	  scheduler and related routines to collect statistics about
-	  scheduler behavior and provide them in /proc/schedstat.  These
-	  stats may be useful for both tuning and debugging the scheduler
-	  If you aren't debugging the scheduler or trying to tune a specific
-	  application, you can say N to avoid the very slight overhead
-	  this adds.
-
-config TIMER_STATS
-	bool "Collect kernel timers statistics"
-	depends on DEBUG_KERNEL && PROC_FS
-	help
-	  If you say Y here, additional code will be inserted into the
-	  timer routines to collect statistics about kernel timers being
-	  reprogrammed. The statistics can be read from /proc/timer_stats.
-	  The statistics collection is started by writing 1 to /proc/timer_stats,
-	  writing 0 stops it. This feature is useful to collect information
-	  about timer usage patterns in kernel and userspace. This feature
-	  is lightweight if enabled in the kernel config but not activated
-	  (it defaults to deactivated on bootup and will only be activated
-	  if some application like powertop activates it explicitly).
-
-config DEBUG_OBJECTS
-	bool "Debug object operations"
-	depends on DEBUG_KERNEL
-	help
-	  If you say Y here, additional code will be inserted into the
-	  kernel to track the life time of various objects and validate
-	  the operations on those objects.
-
-config DEBUG_OBJECTS_SELFTEST
-	bool "Debug objects selftest"
-	depends on DEBUG_OBJECTS
-	help
-	  This enables the selftest of the object debug code.
-
-config DEBUG_OBJECTS_FREE
-	bool "Debug objects in freed memory"
-	depends on DEBUG_OBJECTS
-	help
-	  This enables checks whether a k/v free operation frees an area
-	  which contains an object which has not been deactivated
-	  properly. This can make kmalloc/kfree-intensive workloads
-	  much slower.
-
-config DEBUG_OBJECTS_TIMERS
-	bool "Debug timer objects"
-	depends on DEBUG_OBJECTS
-	help
-	  If you say Y here, additional code will be inserted into the
-	  timer routines to track the life time of timer objects and
-	  validate the timer operations.
-
-config DEBUG_OBJECTS_WORK
-	bool "Debug work objects"
-	depends on DEBUG_OBJECTS
-	help
-	  If you say Y here, additional code will be inserted into the
-	  work queue routines to track the life time of work objects and
-	  validate the work operations.
-
-config DEBUG_OBJECTS_RCU_HEAD
-	bool "Debug RCU callbacks objects"
-	depends on DEBUG_OBJECTS
-	help
-	  Enable this to turn on debugging of RCU list heads (call_rcu() usage).
-
-config DEBUG_OBJECTS_PERCPU_COUNTER
-	bool "Debug percpu counter objects"
-	depends on DEBUG_OBJECTS
-	help
-	  If you say Y here, additional code will be inserted into the
-	  percpu counter routines to track the life time of percpu counter
-	  objects and validate the percpu counter operations.
-
-config DEBUG_OBJECTS_ENABLE_DEFAULT
-	int "debug_objects bootup default value (0-1)"
-        range 0 1
-        default "1"
-        depends on DEBUG_OBJECTS
-        help
-          Debug objects boot parameter default value
+config PANIC_ON_OOPS_VALUE
+	int
+	range 0 1
+	default 0 if !PANIC_ON_OOPS
+	default 1 if PANIC_ON_OOPS
 
-config DEBUG_SLAB
-	bool "Debug slab memory allocations"
-	depends on DEBUG_KERNEL && SLAB && !KMEMCHECK
+config DETECT_HUNG_TASK
+	bool "Detect Hung Tasks"
+	depends on DEBUG_KERNEL
+	default LOCKUP_DETECTOR
 	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
-	  memory. This can make kmalloc/kfree-intensive workloads much slower.
+	  Say Y here to enable the kernel to detect "hung tasks",
+	  which are bugs that cause the task to be stuck in
+	  uninterruptible "D" state indefinitiley.
 
-config DEBUG_SLAB_LEAK
-	bool "Memory leak debugging"
-	depends on DEBUG_SLAB
+	  When a hung task is detected, the kernel will print the
+	  current stack trace (which you should report), but the
+	  task will stay in uninterruptible state. If lockdep is
+	  enabled then all held locks will also be reported. This
+	  feature has negligible overhead.
 
-config SLUB_DEBUG_ON
-	bool "SLUB debugging on by default"
-	depends on SLUB && SLUB_DEBUG && !KMEMCHECK
-	default n
+config DEFAULT_HUNG_TASK_TIMEOUT
+	int "Default timeout for hung task detection (in seconds)"
+	depends on DETECT_HUNG_TASK
+	default 120
 	help
-	  Boot with debugging on by default. SLUB boots by default with
-	  the runtime debug capabilities switched off. Enabling this is
-	  equivalent to specifying the "slub_debug" parameter on boot.
-	  There is no support for more fine grained debug control like
-	  possible with slub_debug=xxx. SLUB debugging may be switched
-	  off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
-	  "slub_debug=-".
+	  This option controls the default timeout (in seconds) used
+	  to determine when a task has become non-responsive and should
+	  be considered hung.
 
-config SLUB_STATS
-	default n
-	bool "Enable SLUB performance statistics"
-	depends on SLUB && SYSFS
-	help
-	  SLUB statistics are useful to debug SLUBs allocation behavior in
-	  order find ways to optimize the allocator. This should never be
-	  enabled for production use since keeping statistics slows down
-	  the allocator by a few percentage points. The slabinfo command
-	  supports the determination of the most active slabs to figure
-	  out which slabs are relevant to a particular load.
-	  Try running: slabinfo -DA
+	  It can be adjusted at runtime via the kernel.hung_task_timeout_secs
+	  sysctl or by writing a value to
+	  /proc/sys/kernel/hung_task_timeout_secs.
 
-config HAVE_DEBUG_KMEMLEAK
-	bool
+	  A timeout of 0 disables the check.  The default is two minutes.
+	  Keeping the default should be fine in most cases.
 
-config DEBUG_KMEMLEAK
-	bool "Kernel memory leak detector"
-	depends on DEBUG_KERNEL && EXPERIMENTAL && HAVE_DEBUG_KMEMLEAK
-	select DEBUG_FS
-	select STACKTRACE if STACKTRACE_SUPPORT
-	select KALLSYMS
-	select CRC32
+config BOOTPARAM_HUNG_TASK_PANIC
+	bool "Panic (Reboot) On Hung Tasks"
+	depends on DETECT_HUNG_TASK
 	help
-	  Say Y here if you want to enable the memory leak
-	  detector. The memory allocation/freeing is traced in a way
-	  similar to the Boehm's conservative garbage collector, the
-	  difference being that the orphan objects are not freed but
-	  only shown in /sys/kernel/debug/kmemleak. Enabling this
-	  feature will introduce an overhead to memory
-	  allocations. See Documentation/kmemleak.txt for more
-	  details.
+	  Say Y here to enable the kernel to panic on "hung tasks",
+	  which are bugs that cause the kernel to leave a task stuck
+	  in uninterruptible "D" state.
 
-	  Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
-	  of finding leaks due to the slab objects poisoning.
+	  The panic can be used in combination with panic_timeout,
+	  to cause the system to reboot automatically after a
+	  hung task has been detected. This feature is useful for
+	  high-availability systems that have uptime guarantees and
+	  where a hung tasks must be resolved ASAP.
 
-	  In order to access the kmemleak file, debugfs needs to be
-	  mounted (usually at /sys/kernel/debug).
+	  Say N if unsure.
 
-config DEBUG_KMEMLEAK_EARLY_LOG_SIZE
-	int "Maximum kmemleak early log entries"
-	depends on DEBUG_KMEMLEAK
-	range 200 40000
-	default 400
-	help
-	  Kmemleak must track all the memory allocations to avoid
-	  reporting false positives. Since memory may be allocated or
-	  freed before kmemleak is initialised, an early log buffer is
-	  used to store these actions. If kmemleak reports "early log
-	  buffer exceeded", please increase this value.
+config BOOTPARAM_HUNG_TASK_PANIC_VALUE
+	int
+	depends on DETECT_HUNG_TASK
+	range 0 1
+	default 0 if !BOOTPARAM_HUNG_TASK_PANIC
+	default 1 if BOOTPARAM_HUNG_TASK_PANIC
 
-config DEBUG_KMEMLEAK_TEST
-	tristate "Simple test for the kernel memory leak detector"
-	depends on DEBUG_KMEMLEAK && m
+config SCHED_DEBUG
+	bool "Collect scheduler debugging info"
+	depends on DEBUG_KERNEL && PROC_FS
+	default y
 	help
-	  This option enables a module that explicitly leaks memory.
+	  If you say Y here, the /proc/sched_debug file will be provided
+	  that can help debug the scheduler. The runtime overhead of this
+	  option is minimal.
 
-	  If unsure, say N.
+config SCHEDSTATS
+	bool "Collect scheduler statistics"
+	depends on DEBUG_KERNEL && PROC_FS
+	help
+	  If you say Y here, additional code will be inserted into the
+	  scheduler and related routines to collect statistics about
+	  scheduler behavior and provide them in /proc/schedstat.  These
+	  stats may be useful for both tuning and debugging the scheduler
+	  If you aren't debugging the scheduler or trying to tune a specific
+	  application, you can say N to avoid the very slight overhead
+	  this adds.
 
-config DEBUG_KMEMLEAK_DEFAULT_OFF
-	bool "Default kmemleak to off"
-	depends on DEBUG_KMEMLEAK
+config TIMER_STATS
+	bool "Collect kernel timers statistics"
+	depends on DEBUG_KERNEL && PROC_FS
 	help
-	  Say Y here to disable kmemleak by default. It can then be enabled
-	  on the command line via kmemleak=on.
+	  If you say Y here, additional code will be inserted into the
+	  timer routines to collect statistics about kernel timers being
+	  reprogrammed. The statistics can be read from /proc/timer_stats.
+	  The statistics collection is started by writing 1 to /proc/timer_stats,
+	  writing 0 stops it. This feature is useful to collect information
+	  about timer usage patterns in kernel and userspace. This feature
+	  is lightweight if enabled in the kernel config but not activated
+	  (it defaults to deactivated on bootup and will only be activated
+	  if some application like powertop activates it explicitly).
 
 config DEBUG_PREEMPT
 	bool "Debug preemptible kernel"
@@ -739,15 +866,6 @@ config STACKTRACE
 	bool
 	depends on STACKTRACE_SUPPORT
 
-config DEBUG_STACK_USAGE
-	bool "Stack utilization instrumentation"
-	depends on DEBUG_KERNEL && !IA64 && !PARISC
-	help
-	  Enables the display of the minimum amount of free stack which each
-	  task has ever had available in the sysrq-T and sysrq-P debug output.
-
-	  This option will slow down process creation somewhat.
-
 config DEBUG_KOBJECT
 	bool "kobject debugging"
 	depends on DEBUG_KERNEL
@@ -755,13 +873,6 @@ config DEBUG_KOBJECT
 	  If you say Y here, some extra kobject debugging messages will be sent
 	  to the syslog. 
 
-config DEBUG_HIGHMEM
-	bool "Highmem debugging"
-	depends on DEBUG_KERNEL && HIGHMEM
-	help
-	  This options enables addition error checking for high memory systems.
-	  Disable for production systems.
-
 config HAVE_DEBUG_BUGVERBOSE
 	bool
 
@@ -800,40 +911,6 @@ config DEBUG_INFO_REDUCED
 	  DEBUG_INFO build and compile times are reduced too.
 	  Only works with newer gcc versions.
 
-config DEBUG_VM
-	bool "Debug VM"
-	depends on DEBUG_KERNEL
-	help
-	  Enable this to turn on extended checks in the virtual-memory system
-          that may impact performance.
-
-	  If unsure, say N.
-
-config DEBUG_VM_RB
-	bool "Debug VM red-black trees"
-	depends on DEBUG_VM
-	help
-	  Enable this to turn on more extended checks in the virtual-memory
-	  system that may impact performance.
-
-	  If unsure, say N.
-
-config DEBUG_VIRTUAL
-	bool "Debug VM translations"
-	depends on DEBUG_KERNEL && X86
-	help
-	  Enable some costly sanity checks in virtual to page code. This can
-	  catch mistakes with virt_to_page() and friends.
-
-	  If unsure, say N.
-
-config DEBUG_NOMMU_REGIONS
-	bool "Debug the global anon/private NOMMU mapping region tree"
-	depends on DEBUG_KERNEL && !MMU
-	help
-	  This option causes the global tree of anonymous and private mapping
-	  regions to be regularly checked for invalid topology.
-
 config DEBUG_WRITECOUNT
 	bool "Debug filesystem writers count"
 	depends on DEBUG_KERNEL
@@ -844,18 +921,6 @@ config DEBUG_WRITECOUNT
 
 	  If unsure, say N.
 
-config DEBUG_MEMORY_INIT
-	bool "Debug memory initialisation" if EXPERT
-	default !EXPERT
-	help
-	  Enable this for additional checks during memory initialisation.
-	  The sanity checks verify aspects of the VM such as the memory model
-	  and other information provided by the architecture. Verbose
-	  information will be printed at KERN_DEBUG loglevel depending
-	  on the mminit_loglevel= command-line option.
-
-	  If unsure, say Y
-
 config DEBUG_LIST
 	bool "Debug linked list manipulation"
 	depends on DEBUG_KERNEL
@@ -1095,17 +1160,6 @@ config DEBUG_FORCE_WEAK_PER_CPU
 	  To ensure that generic code follows the above rules, this
 	  option forces all percpu variables to be defined as weak.
 
-config DEBUG_PER_CPU_MAPS
-	bool "Debug access to per_cpu maps"
-	depends on DEBUG_KERNEL
-	depends on SMP
-	help
-	  Say Y to verify that the per_cpu map being accessed has
-	  been set up. This adds a fair amount of code to kernel memory
-	  and decreases performance.
-
-	  Say N if unsure.
-
 config LKDTM
 	tristate "Linux Kernel Dump Test Tool Module"
 	depends on DEBUG_FS
@@ -1180,29 +1234,6 @@ config PM_NOTIFIER_ERROR_INJECT
 
 	  If unsure, say N.
 
-config MEMORY_NOTIFIER_ERROR_INJECT
-	tristate "Memory hotplug notifier error injection module"
-	depends on MEMORY_HOTPLUG_SPARSE && NOTIFIER_ERROR_INJECTION
-	help
-	  This option provides the ability to inject artifical errors to
-	  memory hotplug notifier chain callbacks.  It is controlled through
-	  debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
-
-	  If the notifier call chain should be failed with some events
-	  notified, write the error code to "actions/<notifier event>/error".
-
-	  Example: Inject memory hotplug offline error (-12 == -ENOMEM)
-
-	  # cd /sys/kernel/debug/notifier-error-inject/memory
-	  # echo -12 > actions/MEM_GOING_OFFLINE/error
-	  # echo offline > /sys/devices/system/memory/memoryXXX/state
-	  bash: echo: write error: Cannot allocate memory
-
-	  To compile this code as a module, choose M here: the module will
-	  be called pSeries-reconfig-notifier-error-inject.
-
-	  If unsure, say N.
-
 config PSERIES_RECONFIG_NOTIFIER_ERROR_INJECT
 	tristate "pSeries reconfig notifier error injection module"
 	depends on PPC_PSERIES && NOTIFIER_ERROR_INJECTION
@@ -1299,7 +1330,6 @@ config LATENCYTOP
 	  Enable this option if you want to use the LatencyTOP tool
 	  to find out which userspace is blocking on what kernel operations.
 
-source mm/Kconfig.debug
 source kernel/trace/Kconfig
 
 config RBTREE_TEST
@@ -1467,29 +1497,9 @@ config ASYNC_RAID6_TEST
 config HAVE_DEBUG_STACKOVERFLOW
 	bool
 
-config DEBUG_STACKOVERFLOW
-	bool "Check for stack overflows"
-	depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
-	---help---
-	  Say Y here if you want to check for overflows of kernel, IRQ
-	  and exception stacks (if your archicture uses them). This
-	  option will show detailed messages if free stack space drops
-	  below a certain limit.
-
-	  These kinds of bugs usually occur when call-chains in the
-	  kernel get too deep, especially when interrupts are
-	  involved.
-
-	  Use this in cases where you see apparently random memory
-	  corruption, especially if it appears in 'struct thread_info'
-
-	  If in doubt, say "N".
-
 source "samples/Kconfig"
 
 source "lib/Kconfig.kgdb"
 
-source "lib/Kconfig.kmemcheck"
-
 config TEST_KSTRTOX
 	tristate "Test kstrto*() family of functions at runtime"
_

[RFC][PATCH 4/7] consolidate RCU debugging Kconfig options

[Dave Hansen]

These were in two different places, and taking up too much of my
valuable screen real-estate.  Banish them to their own menu.

Signed-off-by: Dave Hansen <dave@linux.vnet.ibm.com>
---

 linux-2.6.git-dave/lib/Kconfig.debug |  160 +++++++++++++++++------------------
 1 file changed, 82 insertions(+), 78 deletions(-)

diff -puN lib/Kconfig.debug~consolidat-rcu-debugging-configs lib/Kconfig.debug
--- linux-2.6.git/lib/Kconfig.debug~consolidat-rcu-debugging-configs	2012-12-14 13:32:32.474878413 -0500
+++ linux-2.6.git-dave/lib/Kconfig.debug	2012-12-14 13:32:49.219018930 -0500
@@ -720,6 +720,8 @@ config PROVE_LOCKING
 
 	 For more details, see Documentation/lockdep-design.txt.
 
+menu "RCU Debugging"
+
 config PROVE_RCU
 	bool "RCU debugging: prove RCU correctness"
 	depends on PROVE_LOCKING
@@ -775,6 +777,86 @@ config SPARSE_RCU_POINTER
 
 	 Say N if you are unsure.
 
+config RCU_TORTURE_TEST
+	tristate "torture tests for RCU"
+	depends on DEBUG_KERNEL
+	default n
+	help
+	  This option provides a kernel module that runs torture tests
+	  on the RCU infrastructure.  The kernel module may be built
+	  after the fact on the running kernel to be tested, if desired.
+
+	  Say Y here if you want RCU torture tests to be built into
+	  the kernel.
+	  Say M if you want the RCU torture tests to build as a module.
+	  Say N if you are unsure.
+
+config RCU_TORTURE_TEST_RUNNABLE
+	bool "torture tests for RCU runnable by default"
+	depends on RCU_TORTURE_TEST = y
+	default n
+	help
+	  This option provides a way to build the RCU torture tests
+	  directly into the kernel without them starting up at boot
+	  time.  You can use /proc/sys/kernel/rcutorture_runnable
+	  to manually override this setting.  This /proc file is
+	  available only when the RCU torture tests have been built
+	  into the kernel.
+
+	  Say Y here if you want the RCU torture tests to start during
+	  boot (you probably don't).
+	  Say N here if you want the RCU torture tests to start only
+	  after being manually enabled via /proc.
+
+config RCU_CPU_STALL_TIMEOUT
+	int "RCU CPU stall timeout in seconds"
+	depends on TREE_RCU || TREE_PREEMPT_RCU
+	range 3 300
+	default 60
+	help
+	  If a given RCU grace period extends more than the specified
+	  number of seconds, a CPU stall warning is printed.  If the
+	  RCU grace period persists, additional CPU stall warnings are
+	  printed at more widely spaced intervals.
+
+config RCU_CPU_STALL_VERBOSE
+	bool "Print additional per-task information for RCU_CPU_STALL_DETECTOR"
+	depends on TREE_PREEMPT_RCU
+	default y
+	help
+	  This option causes RCU to printk detailed per-task information
+	  for any tasks that are stalling the current RCU grace period.
+
+	  Say N if you are unsure.
+
+	  Say Y if you want to enable such checks.
+
+config RCU_CPU_STALL_INFO
+	bool "Print additional diagnostics on RCU CPU stall"
+	depends on (TREE_RCU || TREE_PREEMPT_RCU) && DEBUG_KERNEL
+	default n
+	help
+	  For each stalled CPU that is aware of the current RCU grace
+	  period, print out additional per-CPU diagnostic information
+	  regarding scheduling-clock ticks, idle state, and,
+	  for RCU_FAST_NO_HZ kernels, idle-entry state.
+
+	  Say N if you are unsure.
+
+	  Say Y if you want to enable such diagnostics.
+
+config RCU_TRACE
+	bool "Enable tracing for RCU"
+	depends on DEBUG_KERNEL
+	help
+	  This option provides tracing in RCU which presents stats
+	  in debugfs for debugging RCU implementation.
+
+	  Say Y here if you want to enable RCU tracing
+	  Say N if you are unsure.
+
+endmenu # RCU Debugging
+
 config LOCKDEP
 	bool
 	depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
@@ -990,84 +1072,6 @@ config BOOT_PRINTK_DELAY
 	  BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect
 	  what it believes to be lockup conditions.
 
-config RCU_TORTURE_TEST
-	tristate "torture tests for RCU"
-	depends on DEBUG_KERNEL
-	default n
-	help
-	  This option provides a kernel module that runs torture tests
-	  on the RCU infrastructure.  The kernel module may be built
-	  after the fact on the running kernel to be tested, if desired.
-
-	  Say Y here if you want RCU torture tests to be built into
-	  the kernel.
-	  Say M if you want the RCU torture tests to build as a module.
-	  Say N if you are unsure.
-
-config RCU_TORTURE_TEST_RUNNABLE
-	bool "torture tests for RCU runnable by default"
-	depends on RCU_TORTURE_TEST = y
-	default n
-	help
-	  This option provides a way to build the RCU torture tests
-	  directly into the kernel without them starting up at boot
-	  time.  You can use /proc/sys/kernel/rcutorture_runnable
-	  to manually override this setting.  This /proc file is
-	  available only when the RCU torture tests have been built
-	  into the kernel.
-
-	  Say Y here if you want the RCU torture tests to start during
-	  boot (you probably don't).
-	  Say N here if you want the RCU torture tests to start only
-	  after being manually enabled via /proc.
-
-config RCU_CPU_STALL_TIMEOUT
-	int "RCU CPU stall timeout in seconds"
-	depends on TREE_RCU || TREE_PREEMPT_RCU
-	range 3 300
-	default 21
-	help
-	  If a given RCU grace period extends more than the specified
-	  number of seconds, a CPU stall warning is printed.  If the
-	  RCU grace period persists, additional CPU stall warnings are
-	  printed at more widely spaced intervals.
-
-config RCU_CPU_STALL_VERBOSE
-	bool "Print additional per-task information for RCU_CPU_STALL_DETECTOR"
-	depends on TREE_PREEMPT_RCU
-	default y
-	help
-	  This option causes RCU to printk detailed per-task information
-	  for any tasks that are stalling the current RCU grace period.
-
-	  Say N if you are unsure.
-
-	  Say Y if you want to enable such checks.
-
-config RCU_CPU_STALL_INFO
-	bool "Print additional diagnostics on RCU CPU stall"
-	depends on (TREE_RCU || TREE_PREEMPT_RCU) && DEBUG_KERNEL
-	default n
-	help
-	  For each stalled CPU that is aware of the current RCU grace
-	  period, print out additional per-CPU diagnostic information
-	  regarding scheduling-clock ticks, idle state, and,
-	  for RCU_FAST_NO_HZ kernels, idle-entry state.
-
-	  Say N if you are unsure.
-
-	  Say Y if you want to enable such diagnostics.
-
-config RCU_TRACE
-	bool "Enable tracing for RCU"
-	depends on DEBUG_KERNEL
-	help
-	  This option provides tracing in RCU which presents stats
-	  in debugfs for debugging RCU implementation.
-
-	  Say Y here if you want to enable RCU tracing
-	  Say N if you are unsure.
-
 config KPROBES_SANITY_TEST
 	bool "Kprobes sanity tests"
 	depends on DEBUG_KERNEL
_

[RFC][PATCH 5/7] consolidate runtime testing configs

[Dave Hansen]

These runtime tests are great, except that there are a lot of them,
and they are very rarely needed.  Give them their own menu so that
only the folks who need them will have to go looking for them.

Note that there are some other runtime tests that are not in here,
like for RCU or locking.  This menu should only be used for tests
that do not have a more appropriate home.

Signed-off-by: Dave Hansen <dave@linux.vnet.ibm.com>
---

 linux-2.6.git-dave/lib/Kconfig.debug |  151 ++++++++++++++++++-----------------
 1 file changed, 78 insertions(+), 73 deletions(-)

diff -puN lib/Kconfig.debug~consolidat-runtime-testing-configs lib/Kconfig.debug
--- linux-2.6.git/lib/Kconfig.debug~consolidat-runtime-testing-configs	2012-12-10 11:27:45.267963463 -0500
+++ linux-2.6.git-dave/lib/Kconfig.debug	2012-12-10 11:28:38.316437234 -0500
@@ -1012,15 +1012,6 @@ config DEBUG_LIST
 
 	  If unsure, say N.
 
-config TEST_LIST_SORT
-	bool "Linked list sorting test"
-	depends on DEBUG_KERNEL
-	help
-	  Enable this to turn on 'list_sort()' function test. This test is
-	  executed only once during system boot, so affects only boot time.
-
-	  If unsure, say N.
-
 config DEBUG_SG
 	bool "Debug SG table operations"
 	depends on DEBUG_KERNEL
@@ -1095,33 +1086,6 @@ config BOOT_PRINTK_DELAY
 	  BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect
 	  what it believes to be lockup conditions.
 
-config KPROBES_SANITY_TEST
-	bool "Kprobes sanity tests"
-	depends on DEBUG_KERNEL
-	depends on KPROBES
-	default n
-	help
-	  This option provides for testing basic kprobes functionality on
-	  boot. A sample kprobe, jprobe and kretprobe are inserted and
-	  verified for functionality.
-
-	  Say N if you are unsure.
-
-config BACKTRACE_SELF_TEST
-	tristate "Self test for the backtrace code"
-	depends on DEBUG_KERNEL
-	default n
-	help
-	  This option provides a kernel module that can be used to test
-	  the kernel stack backtrace code. This option is not useful
-	  for distributions or general kernels, but only for kernel
-	  developers working on architecture code.
-
-	  Note that if you want to also test saved backtraces, you will
-	  have to enable STACKTRACE as well.
-
-	  Say N if you are unsure.
-
 config DEBUG_BLOCK_EXT_DEVT
         bool "Force extended block device numbers and spread them"
 	depends on DEBUG_KERNEL
@@ -1164,21 +1128,6 @@ config DEBUG_FORCE_WEAK_PER_CPU
 	  To ensure that generic code follows the above rules, this
 	  option forces all percpu variables to be defined as weak.
 
-config LKDTM
-	tristate "Linux Kernel Dump Test Tool Module"
-	depends on DEBUG_FS
-	depends on BLOCK
-	default n
-	help
-	This module enables testing of the different dumping mechanisms by
-	inducing system failures at predefined crash points.
-	If you don't need it: say N
-	Choose M here to compile this code as a module. The module will be
-	called lkdtm.
-
-	Documentation on how to use the module can be found in
-	Documentation/fault-injection/provoke-crashes.txt
-
 config NOTIFIER_ERROR_INJECTION
 	tristate "Notifier error injection"
 	depends on DEBUG_KERNEL
@@ -1336,6 +1285,59 @@ config LATENCYTOP
 
 source kernel/trace/Kconfig
 
+menu "Runtime Testing"
+
+config LKDTM
+	tristate "Linux Kernel Dump Test Tool Module"
+	depends on DEBUG_FS
+	depends on BLOCK
+	default n
+	help
+	This module enables testing of the different dumping mechanisms by
+	inducing system failures at predefined crash points.
+	If you don't need it: say N
+	Choose M here to compile this code as a module. The module will be
+	called lkdtm.
+
+	Documentation on how to use the module can be found in
+	Documentation/fault-injection/provoke-crashes.txt
+
+config TEST_LIST_SORT
+	bool "Linked list sorting test"
+	depends on DEBUG_KERNEL
+	help
+	  Enable this to turn on 'list_sort()' function test. This test is
+	  executed only once during system boot, so affects only boot time.
+
+	  If unsure, say N.
+
+config KPROBES_SANITY_TEST
+	bool "Kprobes sanity tests"
+	depends on DEBUG_KERNEL
+	depends on KPROBES
+	default n
+	help
+	  This option provides for testing basic kprobes functionality on
+	  boot. A sample kprobe, jprobe and kretprobe are inserted and
+	  verified for functionality.
+
+	  Say N if you are unsure.
+
+config BACKTRACE_SELF_TEST
+	tristate "Self test for the backtrace code"
+	depends on DEBUG_KERNEL
+	default n
+	help
+	  This option provides a kernel module that can be used to test
+	  the kernel stack backtrace code. This option is not useful
+	  for distributions or general kernels, but only for kernel
+	  developers working on architecture code.
+
+	  Note that if you want to also test saved backtraces, you will
+	  have to enable STACKTRACE as well.
+
+	  Say N if you are unsure.
+
 config RBTREE_TEST
 	tristate "Red-Black tree test"
 	depends on m && DEBUG_KERNEL
@@ -1349,6 +1351,31 @@ config INTERVAL_TREE_TEST
 	help
 	  A benchmark measuring the performance of the interval tree library
 
+config ATOMIC64_SELFTEST
+	bool "Perform an atomic64_t self-test at boot"
+	help
+	  Enable this option to test the atomic64_t functions at boot.
+
+	  If unsure, say N.
+
+config ASYNC_RAID6_TEST
+	tristate "Self test for hardware accelerated raid6 recovery"
+	depends on ASYNC_RAID6_RECOV
+	select ASYNC_MEMCPY
+	---help---
+	  This is a one-shot self test that permutes through the
+	  recovery of all the possible two disk failure scenarios for a
+	  N-disk array.  Recovery is performed with the asynchronous
+	  raid6 recovery routines, and will optionally use an offload
+	  engine if one is available.
+
+	  If unsure, say N.
+
+config TEST_KSTRTOX
+	tristate "Test kstrto*() family of functions at runtime"
+
+endmenu # runtime tests
+
 config PROVIDE_OHCI1394_DMA_INIT
 	bool "Remote debugging over FireWire early on boot"
 	depends on PCI && X86
@@ -1478,26 +1505,6 @@ config DMA_API_DEBUG
 	  This option causes a performance degredation.  Use only if you want
 	  to debug device drivers. If unsure, say N.
 
-config ATOMIC64_SELFTEST
-	bool "Perform an atomic64_t self-test at boot"
-	help
-	  Enable this option to test the atomic64_t functions at boot.
-
-	  If unsure, say N.
-
-config ASYNC_RAID6_TEST
-	tristate "Self test for hardware accelerated raid6 recovery"
-	depends on ASYNC_RAID6_RECOV
-	select ASYNC_MEMCPY
-	---help---
-	  This is a one-shot self test that permutes through the
-	  recovery of all the possible two disk failure scenarios for a
-	  N-disk array.  Recovery is performed with the asynchronous
-	  raid6 recovery routines, and will optionally use an offload
-	  engine if one is available.
-
-	  If unsure, say N.
-
 config HAVE_DEBUG_STACKOVERFLOW
 	bool
 
@@ -1505,5 +1512,3 @@ source "samples/Kconfig"
 
 source "lib/Kconfig.kgdb"
 
-config TEST_KSTRTOX
-	tristate "Test kstrto*() family of functions at runtime"
_

[RFC][PATCH 6/7] consolidate compilation option configs

[Dave Hansen]

Again, trying to come up with some common themes of the stuff in
the kernel hacking menu...  There are quite a few options to
tweak compilation in some way, or perform extra compile-time
checks.  Give them their own menu.

The diff here looks a bit funny... makes it look like I'm
moving debugfs even though I'm actually moving the options on
either side of it.

Signed-off-by: Dave Hansen <dave@linux.vnet.ibm.com>
---

 linux-2.6.git-dave/lib/Kconfig.debug |  156 +++++++++++++++++------------------
 1 file changed, 80 insertions(+), 76 deletions(-)

diff -puN lib/Kconfig.debug~consolidate-compilation-configs lib/Kconfig.debug
--- linux-2.6.git/lib/Kconfig.debug~consolidate-compilation-configs	2012-12-14 13:33:04.167144350 -0500
+++ linux-2.6.git-dave/lib/Kconfig.debug	2012-12-14 13:33:04.203144652 -0500
@@ -25,6 +25,34 @@ config DEFAULT_MESSAGE_LOGLEVEL
 	  that are auditing their logs closely may want to set it to a lower
 	  priority.
 
+menu "Compile-time checks and compiler options"
+
+config DEBUG_INFO
+	bool "Compile the kernel with debug info"
+	depends on DEBUG_KERNEL
+	help
+          If you say Y here the resulting kernel image will include
+	  debugging info resulting in a larger kernel image.
+	  This adds debug symbols to the kernel and modules (gcc -g), and
+	  is needed if you intend to use kernel crashdump or binary object
+	  tools like crash, kgdb, LKCD, gdb, etc on the kernel.
+	  Say Y here only if you plan to debug the kernel.
+
+	  If unsure, say N.
+
+config DEBUG_INFO_REDUCED
+	bool "Reduce debugging information"
+	depends on DEBUG_INFO
+	help
+	  If you say Y here gcc is instructed to generate less debugging
+	  information for structure types. This means that tools that
+	  need full debugging information (like kgdb or systemtap) won't
+	  be happy. But if you merely need debugging information to
+	  resolve line numbers there is no loss. Advantage is that
+	  build directory object sizes shrink dramatically over a full
+	  DEBUG_INFO build and compile times are reduced too.
+	  Only works with newer gcc versions.
+
 config ENABLE_WARN_DEPRECATED
 	bool "Enable __deprecated logic"
 	default y
@@ -52,20 +80,6 @@ config FRAME_WARN
 	  Setting it to 0 disables the warning.
 	  Requires gcc 4.4
 
-config MAGIC_SYSRQ
-	bool "Magic SysRq key"
-	depends on !UML
-	help
-	  If you say Y here, you will have some control over the system even
-	  if the system crashes for example during kernel debugging (e.g., you
-	  will be able to flush the buffer cache to disk, reboot the system
-	  immediately or dump some status information). This is accomplished
-	  by pressing various keys while holding SysRq (Alt+PrintScreen). It
-	  also works on a serial console (on PC hardware at least), if you
-	  send a BREAK and then within 5 seconds a command keypress. The
-	  keys are documented in <file:Documentation/sysrq.txt>. Don't say Y
-	  unless you really know what this hack does.
-
 config STRIP_ASM_SYMS
 	bool "Strip assembler-generated symbols during link"
 	default n
@@ -144,6 +158,58 @@ config DEBUG_SECTION_MISMATCH
 	  - Enable verbose reporting from modpost in order to help resolve
 	    the section mismatches that are reported.
 
+#
+# Select this config option from the architecture Kconfig, if it
+# is preferred to always offer frame pointers as a config
+# option on the architecture (regardless of KERNEL_DEBUG):
+#
+config ARCH_WANT_FRAME_POINTERS
+	bool
+	help
+
+config FRAME_POINTER
+	bool "Compile the kernel with frame pointers"
+	depends on DEBUG_KERNEL && \
+		(CRIS || M68K || FRV || UML || \
+		 AVR32 || SUPERH || BLACKFIN || MN10300) || \
+		ARCH_WANT_FRAME_POINTERS
+	default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
+	help
+	  If you say Y here the resulting kernel image will be slightly
+	  larger and slower, but it gives very useful debugging information
+	  in case of kernel bugs. (precise oopses/stacktraces/warnings)
+
+	config DEBUG_FORCE_WEAK_PER_CPU
+	bool "Force weak per-cpu definitions"
+	depends on DEBUG_KERNEL
+	help
+	  s390 and alpha require percpu variables in modules to be
+	  defined weak to work around addressing range issue which
+	  puts the following two restrictions on percpu variable
+	  definitions.
+
+	  1. percpu symbols must be unique whether static or not
+	  2. percpu variables can't be defined inside a function
+
+	  To ensure that generic code follows the above rules, this
+	  option forces all percpu variables to be defined as weak.
+
+endmenu # "Compiler options"
+
+config MAGIC_SYSRQ
+	bool "Magic SysRq key"
+	depends on !UML
+	help
+	  If you say Y here, you will have some control over the system even
+	  if the system crashes for example during kernel debugging (e.g., you
+	  will be able to flush the buffer cache to disk, reboot the system
+	  immediately or dump some status information). This is accomplished
+	  by pressing various keys while holding SysRq (Alt+PrintScreen). It
+	  also works on a serial console (on PC hardware at least), if you
+	  send a BREAK and then within 5 seconds a command keypress. The
+	  keys are documented in <file:Documentation/sysrq.txt>. Don't say Y
+	  unless you really know what this hack does.
+
 config DEBUG_KERNEL
 	bool "Kernel debugging"
 	help
@@ -944,32 +1010,6 @@ config DEBUG_BUGVERBOSE
 	  of the BUG call as well as the EIP and oops trace.  This aids
 	  debugging but costs about 70-100K of memory.
 
-config DEBUG_INFO
-	bool "Compile the kernel with debug info"
-	depends on DEBUG_KERNEL
-	help
-          If you say Y here the resulting kernel image will include
-	  debugging info resulting in a larger kernel image.
-	  This adds debug symbols to the kernel and modules (gcc -g), and
-	  is needed if you intend to use kernel crashdump or binary object
-	  tools like crash, kgdb, LKCD, gdb, etc on the kernel.
-	  Say Y here only if you plan to debug the kernel.
-
-	  If unsure, say N.
-
-config DEBUG_INFO_REDUCED
-	bool "Reduce debugging information"
-	depends on DEBUG_INFO
-	help
-	  If you say Y here gcc is instructed to generate less debugging
-	  information for structure types. This means that tools that
-	  need full debugging information (like kgdb or systemtap) won't
-	  be happy. But if you merely need debugging information to
-	  resolve line numbers there is no loss. Advantage is that
-	  build directory object sizes shrink dramatically over a full
-	  DEBUG_INFO build and compile times are reduced too.
-	  Only works with newer gcc versions.
-
 config DEBUG_WRITECOUNT
 	bool "Debug filesystem writers count"
 	depends on DEBUG_KERNEL
@@ -1024,27 +1064,6 @@ config DEBUG_CREDENTIALS
 
 	  If unsure, say N.
 
-#
-# Select this config option from the architecture Kconfig, if it
-# is preferred to always offer frame pointers as a config
-# option on the architecture (regardless of KERNEL_DEBUG):
-#
-config ARCH_WANT_FRAME_POINTERS
-	bool
-	help
-
-config FRAME_POINTER
-	bool "Compile the kernel with frame pointers"
-	depends on DEBUG_KERNEL && \
-		(CRIS || M68K || FRV || UML || \
-		 AVR32 || SUPERH || BLACKFIN || MN10300) || \
-		ARCH_WANT_FRAME_POINTERS
-	default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
-	help
-	  If you say Y here the resulting kernel image will be slightly
-	  larger and slower, but it gives very useful debugging information
-	  in case of kernel bugs. (precise oopses/stacktraces/warnings)
-
 config BOOT_PRINTK_DELAY
 	bool "Delay each boot printk message by N milliseconds"
 	depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
@@ -1090,21 +1109,6 @@ config DEBUG_BLOCK_EXT_DEVT
 
 	  Say N if you are unsure.
 
-config DEBUG_FORCE_WEAK_PER_CPU
-	bool "Force weak per-cpu definitions"
-	depends on DEBUG_KERNEL
-	help
-	  s390 and alpha require percpu variables in modules to be
-	  defined weak to work around addressing range issue which
-	  puts the following two restrictions on percpu variable
-	  definitions.
-
-	  1. percpu symbols must be unique whether static or not
-	  2. percpu variables can't be defined inside a function
-
-	  To ensure that generic code follows the above rules, this
-	  option forces all percpu variables to be defined as weak.
-
 config NOTIFIER_ERROR_INJECTION
 	tristate "Notifier error injection"
 	depends on DEBUG_KERNEL
_

[RFC][PATCH 7/7] group locking debugging options

[Dave Hansen]

There are quite a few of these, and we want to make sure that
there is one-stop-shopping for lock debugging.  

Signed-off-by: Dave Hansen <dave@linux.vnet.ibm.com>
---

 linux-2.6.git-dave/lib/Kconfig.debug |  120 ++++++++++++++++++-----------------
 1 file changed, 62 insertions(+), 58 deletions(-)

diff -puN lib/Kconfig.debug~order-lock-debugging-options lib/Kconfig.debug
--- linux-2.6.git/lib/Kconfig.debug~order-lock-debugging-options	2012-12-14 13:34:27.967847057 -0500
+++ linux-2.6.git-dave/lib/Kconfig.debug	2012-12-14 13:34:27.971847091 -0500
@@ -694,6 +694,8 @@ config DEBUG_PREEMPT
 	  if kernel code uses it in a preemption-unsafe way. Also, the kernel
 	  will detect preemption count underflows.
 
+menu "Lock Debugging (spinlocks, mutexes, etc...)"
+
 config DEBUG_RT_MUTEXES
 	bool "RT Mutex debugging, deadlock detection"
 	depends on DEBUG_KERNEL && RT_MUTEXES
@@ -786,6 +788,66 @@ config PROVE_LOCKING
 
 	 For more details, see Documentation/lockdep-design.txt.
 
+config LOCKDEP
+	bool
+	depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
+	select STACKTRACE
+	select FRAME_POINTER if !MIPS && !PPC && !ARM_UNWIND && !S390 && !MICROBLAZE
+	select KALLSYMS
+	select KALLSYMS_ALL
+
+config LOCK_STAT
+	bool "Lock usage statistics"
+	depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
+	select LOCKDEP
+	select DEBUG_SPINLOCK
+	select DEBUG_MUTEXES
+	select DEBUG_LOCK_ALLOC
+	default n
+	help
+	 This feature enables tracking lock contention points
+
+	 For more details, see Documentation/lockstat.txt
+
+	 This also enables lock events required by "perf lock",
+	 subcommand of perf.
+	 If you want to use "perf lock", you also need to turn on
+	 CONFIG_EVENT_TRACING.
+
+	 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
+	 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
+
+config DEBUG_LOCKDEP
+	bool "Lock dependency engine debugging"
+	depends on DEBUG_KERNEL && LOCKDEP
+	help
+	  If you say Y here, the lock dependency engine will do
+	  additional runtime checks to debug itself, at the price
+	  of more runtime overhead.
+
+config DEBUG_ATOMIC_SLEEP
+	bool "Sleep inside atomic section checking"
+	select PREEMPT_COUNT
+	depends on DEBUG_KERNEL
+	help
+	  If you say Y here, various routines which may sleep will become very
+	  noisy if they are called inside atomic sections: when a spinlock is
+	  held, inside an rcu read side critical section, inside preempt disabled
+	  sections, inside an interrupt, etc...
+
+config DEBUG_KERNEL_API_SELFTESTS
+	bool "Locking API boot-time self-tests"
+	depends on DEBUG_KERNEL
+	help
+	  Say Y here if you want the kernel to run a short self-test during
+	  bootup. The self-test checks whether common types of locking bugs
+	  are detected by debugging mechanisms or not. (if you disable
+	  lock debugging then those bugs wont be detected of course.)
+	  The following locking APIs are covered: spinlocks, rwlocks,
+	  mutexes and rwsems.
+
+endmenu # lock debugging
+
 menu "RCU Debugging"
 
 config PROVE_RCU
@@ -923,70 +985,12 @@ config RCU_TRACE
 
 endmenu # RCU Debugging
 
-config LOCKDEP
-	bool
-	depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
-	select STACKTRACE
-	select FRAME_POINTER if !MIPS && !PPC && !ARM_UNWIND && !S390 && !MICROBLAZE
-	select KALLSYMS
-	select KALLSYMS_ALL
-
-config LOCK_STAT
-	bool "Lock usage statistics"
-	depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
-	select LOCKDEP
-	select DEBUG_SPINLOCK
-	select DEBUG_MUTEXES
-	select DEBUG_LOCK_ALLOC
-	default n
-	help
-	 This feature enables tracking lock contention points
-
-	 For more details, see Documentation/lockstat.txt
-
-	 This also enables lock events required by "perf lock",
-	 subcommand of perf.
-	 If you want to use "perf lock", you also need to turn on
-	 CONFIG_EVENT_TRACING.
-
-	 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
-	 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
-
-config DEBUG_LOCKDEP
-	bool "Lock dependency engine debugging"
-	depends on DEBUG_KERNEL && LOCKDEP
-	help
-	  If you say Y here, the lock dependency engine will do
-	  additional runtime checks to debug itself, at the price
-	  of more runtime overhead.
-
 config TRACE_IRQFLAGS
 	bool
 	help
 	  Enables hooks to interrupt enabling and disabling for
 	  either tracing or lock debugging.
 
-config DEBUG_ATOMIC_SLEEP
-	bool "Sleep inside atomic section checking"
-	select PREEMPT_COUNT
-	depends on DEBUG_KERNEL
-	help
-	  If you say Y here, various routines which may sleep will become very
-	  noisy if they are called inside atomic sections: when a spinlock is
-	  held, inside an rcu read side critical section, inside preempt disabled
-	  sections, inside an interrupt, etc...
-
-config DEBUG_LOCKING_API_SELFTESTS
-	bool "Locking API boot-time self-tests"
-	depends on DEBUG_KERNEL
-	help
-	  Say Y here if you want the kernel to run a short self-test during
-	  bootup. The self-test checks whether common types of locking bugs
-	  are detected by debugging mechanisms or not. (if you disable
-	  lock debugging then those bugs wont be detected of course.)
-	  The following locking APIs are covered: spinlocks, rwlocks,
-	  mutexes and rwsems.
-
 config STACKTRACE
 	bool
 	depends on STACKTRACE_SUPPORT
_

Re: [RFC][PATCH 0/7] Put "Kernel hacking" Kconfig menu on a diet

[Dave Jones]

On Fri, Dec 14, 2012 at 01:42:00PM -0500, Dave Hansen wrote:
 > I think the "Kernel Hacking" menu has gotten a bit out of hand.  It
 > is over 120 lines long on my system with everything enabled and
 > options are scattered around it haphazardly.
 > 
 > 	http://sr71.net/~dave/linux/kconfig-horror.png
 > 
 > Let's try to introduce some sanity.

Nice.  Perhaps as a follow-on patch, split up the Kconfig.debug into
a handful of files too ?

Thinking it might help prevent things getting so messed up again
when people start adding more options.

	Dave

Re: [RFC][PATCH 4/7] consolidate RCU debugging Kconfig options

[Paul E. McKenney]

On Fri, Dec 14, 2012 at 01:42:05PM -0500, Dave Hansen wrote:
> 
> These were in two different places, and taking up too much of my
> valuable screen real-estate.  Banish them to their own menu.
> 
> Signed-off-by: Dave Hansen <dave@linux.vnet.ibm.com>
> ---
> 
>  linux-2.6.git-dave/lib/Kconfig.debug |  160 +++++++++++++++++------------------
>  1 file changed, 82 insertions(+), 78 deletions(-)

Hello, Dave,

There have been enough changes that the patch refused to apply, so
I forward-ported it as follows and queued it for 3.9.  Please let me
know if there are any problems with the result, shown below.

							Thanx, Paul

------------------------------------------------------------------------

rcu: Consolidate debugging Kconfig options

The RCU-related debugging Kconfig options are in two different places,
and consume too much screen real estate.  This commit therefore
consolidates them into their own menu.

Signed-off-by: Dave Hansen <dave@linux.vnet.ibm.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index a40a36b..ce75d3b 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -605,61 +605,6 @@ config PROVE_LOCKING
 
 	 For more details, see Documentation/lockdep-design.txt.
 
-config PROVE_RCU
-	bool "RCU debugging: prove RCU correctness"
-	depends on PROVE_LOCKING
-	default n
-	help
-	 This feature enables lockdep extensions that check for correct
-	 use of RCU APIs.  This is currently under development.  Say Y
-	 if you want to debug RCU usage or help work on the PROVE_RCU
-	 feature.
-
-	 Say N if you are unsure.
-
-config PROVE_RCU_REPEATEDLY
-	bool "RCU debugging: don't disable PROVE_RCU on first splat"
-	depends on PROVE_RCU
-	default n
-	help
-	 By itself, PROVE_RCU will disable checking upon issuing the
-	 first warning (or "splat").  This feature prevents such
-	 disabling, allowing multiple RCU-lockdep warnings to be printed
-	 on a single reboot.
-
-	 Say Y to allow multiple RCU-lockdep warnings per boot.
-
-	 Say N if you are unsure.
-
-config PROVE_RCU_DELAY
-	bool "RCU debugging: preemptible RCU race provocation"
-	depends on DEBUG_KERNEL && PREEMPT_RCU
-	default n
-	help
-	 There is a class of races that involve an unlikely preemption
-	 of __rcu_read_unlock() just after ->rcu_read_lock_nesting has
-	 been set to INT_MIN.  This feature inserts a delay at that
-	 point to increase the probability of these races.
-
-	 Say Y to increase probability of preemption of __rcu_read_unlock().
-
-	 Say N if you are unsure.
-
-config SPARSE_RCU_POINTER
-	bool "RCU debugging: sparse-based checks for pointer usage"
-	default n
-	help
-	 This feature enables the __rcu sparse annotation for
-	 RCU-protected pointers.  This annotation will cause sparse
-	 to flag any non-RCU used of annotated pointers.  This can be
-	 helpful when debugging RCU usage.  Please note that this feature
-	 is not intended to enforce code cleanliness; it is instead merely
-	 a debugging aid.
-
-	 Say Y to make sparse flag questionable use of RCU-protected pointers
-
-	 Say N if you are unsure.
-
 config LOCKDEP
 	bool
 	depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
@@ -937,6 +882,63 @@ config BOOT_PRINTK_DELAY
 	  BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect
 	  what it believes to be lockup conditions.
 
+menu "RCU Debugging"
+
+config PROVE_RCU
+	bool "RCU debugging: prove RCU correctness"
+	depends on PROVE_LOCKING
+	default n
+	help
+	 This feature enables lockdep extensions that check for correct
+	 use of RCU APIs.  This is currently under development.  Say Y
+	 if you want to debug RCU usage or help work on the PROVE_RCU
+	 feature.
+
+	 Say N if you are unsure.
+
+config PROVE_RCU_REPEATEDLY
+	bool "RCU debugging: don't disable PROVE_RCU on first splat"
+	depends on PROVE_RCU
+	default n
+	help
+	 By itself, PROVE_RCU will disable checking upon issuing the
+	 first warning (or "splat").  This feature prevents such
+	 disabling, allowing multiple RCU-lockdep warnings to be printed
+	 on a single reboot.
+
+	 Say Y to allow multiple RCU-lockdep warnings per boot.
+
+	 Say N if you are unsure.
+
+config PROVE_RCU_DELAY
+	bool "RCU debugging: preemptible RCU race provocation"
+	depends on DEBUG_KERNEL && PREEMPT_RCU
+	default n
+	help
+	 There is a class of races that involve an unlikely preemption
+	 of __rcu_read_unlock() just after ->rcu_read_lock_nesting has
+	 been set to INT_MIN.  This feature inserts a delay at that
+	 point to increase the probability of these races.
+
+	 Say Y to increase probability of preemption of __rcu_read_unlock().
+
+	 Say N if you are unsure.
+
+config SPARSE_RCU_POINTER
+	bool "RCU debugging: sparse-based checks for pointer usage"
+	default n
+	help
+	 This feature enables the __rcu sparse annotation for
+	 RCU-protected pointers.  This annotation will cause sparse
+	 to flag any non-RCU used of annotated pointers.  This can be
+	 helpful when debugging RCU usage.  Please note that this feature
+	 is not intended to enforce code cleanliness; it is instead merely
+	 a debugging aid.
+
+	 Say Y to make sparse flag questionable use of RCU-protected pointers
+
+	 Say N if you are unsure.
+
 config RCU_TORTURE_TEST
 	tristate "torture tests for RCU"
 	depends on DEBUG_KERNEL
@@ -1015,6 +1017,8 @@ config RCU_TRACE
 	  Say Y here if you want to enable RCU tracing
 	  Say N if you are unsure.
 
+endmenu # "RCU Debugging"
+
 config KPROBES_SANITY_TEST
 	bool "Kprobes sanity tests"
 	depends on DEBUG_KERNEL