| menu "printk and dmesg options" | 
 |  | 
 | config PRINTK_TIME | 
 | 	bool "Show timing information on printks" | 
 | 	depends on PRINTK | 
 | 	help | 
 | 	  Selecting this option causes time stamps of the printk() | 
 | 	  messages to be added to the output of the syslog() system | 
 | 	  call and at the console. | 
 |  | 
 | 	  The timestamp is always recorded internally, and exported | 
 | 	  to /dev/kmsg. This flag just specifies if the timestamp should | 
 | 	  be included, not that the timestamp is recorded. | 
 |  | 
 | 	  The behavior is also controlled by the kernel command line | 
 | 	  parameter printk.time=1. See Documentation/kernel-parameters.txt | 
 |  | 
 | config DEFAULT_MESSAGE_LOGLEVEL | 
 | 	int "Default message log level (1-7)" | 
 | 	range 1 7 | 
 | 	default "4" | 
 | 	help | 
 | 	  Default log level for printk statements with no specified priority. | 
 |  | 
 | 	  This was hard-coded to KERN_WARNING since at least 2.6.10 but folks | 
 | 	  that are auditing their logs closely may want to set it to a lower | 
 | 	  priority. | 
 |  | 
 | config BOOT_PRINTK_DELAY | 
 | 	bool "Delay each boot printk message by N milliseconds" | 
 | 	depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY | 
 | 	help | 
 | 	  This build option allows you to read kernel boot messages | 
 | 	  by inserting a short delay after each one.  The delay is | 
 | 	  specified in milliseconds on the kernel command line, | 
 | 	  using "boot_delay=N". | 
 |  | 
 | 	  It is likely that you would also need to use "lpj=M" to preset | 
 | 	  the "loops per jiffie" value. | 
 | 	  See a previous boot log for the "lpj" value to use for your | 
 | 	  system, and then set "lpj=M" before setting "boot_delay=N". | 
 | 	  NOTE:  Using this option may adversely affect SMP systems. | 
 | 	  I.e., processors other than the first one may not boot up. | 
 | 	  BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect | 
 | 	  what it believes to be lockup conditions. | 
 |  | 
 | config DYNAMIC_DEBUG | 
 | 	bool "Enable dynamic printk() support" | 
 | 	default n | 
 | 	depends on PRINTK | 
 | 	depends on DEBUG_FS | 
 | 	help | 
 |  | 
 | 	  Compiles debug level messages into the kernel, which would not | 
 | 	  otherwise be available at runtime. These messages can then be | 
 | 	  enabled/disabled based on various levels of scope - per source file, | 
 | 	  function, module, format string, and line number. This mechanism | 
 | 	  implicitly compiles in all pr_debug() and dev_dbg() calls, which | 
 | 	  enlarges the kernel text size by about 2%. | 
 |  | 
 | 	  If a source file is compiled with DEBUG flag set, any | 
 | 	  pr_debug() calls in it are enabled by default, but can be | 
 | 	  disabled at runtime as below.  Note that DEBUG flag is | 
 | 	  turned on by many CONFIG_*DEBUG* options. | 
 |  | 
 | 	  Usage: | 
 |  | 
 | 	  Dynamic debugging is controlled via the 'dynamic_debug/control' file, | 
 | 	  which is contained in the 'debugfs' filesystem. Thus, the debugfs | 
 | 	  filesystem must first be mounted before making use of this feature. | 
 | 	  We refer the control file as: <debugfs>/dynamic_debug/control. This | 
 | 	  file contains a list of the debug statements that can be enabled. The | 
 | 	  format for each line of the file is: | 
 |  | 
 | 		filename:lineno [module]function flags format | 
 |  | 
 | 	  filename : source file of the debug statement | 
 | 	  lineno : line number of the debug statement | 
 | 	  module : module that contains the debug statement | 
 | 	  function : function that contains the debug statement | 
 |           flags : '=p' means the line is turned 'on' for printing | 
 |           format : the format used for the debug statement | 
 |  | 
 | 	  From a live system: | 
 |  | 
 | 		nullarbor:~ # cat <debugfs>/dynamic_debug/control | 
 | 		# filename:lineno [module]function flags format | 
 | 		fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012" | 
 | 		fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012" | 
 | 		fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012" | 
 |  | 
 | 	  Example usage: | 
 |  | 
 | 		// enable the message at line 1603 of file svcsock.c | 
 | 		nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' > | 
 | 						<debugfs>/dynamic_debug/control | 
 |  | 
 | 		// enable all the messages in file svcsock.c | 
 | 		nullarbor:~ # echo -n 'file svcsock.c +p' > | 
 | 						<debugfs>/dynamic_debug/control | 
 |  | 
 | 		// enable all the messages in the NFS server module | 
 | 		nullarbor:~ # echo -n 'module nfsd +p' > | 
 | 						<debugfs>/dynamic_debug/control | 
 |  | 
 | 		// enable all 12 messages in the function svc_process() | 
 | 		nullarbor:~ # echo -n 'func svc_process +p' > | 
 | 						<debugfs>/dynamic_debug/control | 
 |  | 
 | 		// disable all 12 messages in the function svc_process() | 
 | 		nullarbor:~ # echo -n 'func svc_process -p' > | 
 | 						<debugfs>/dynamic_debug/control | 
 |  | 
 | 	  See Documentation/dynamic-debug-howto.txt for additional information. | 
 |  | 
 | endmenu # "printk and dmesg options" | 
 |  | 
 | menu "Compile-time checks and compiler options" | 
 |  | 
 | config DEBUG_INFO | 
 | 	bool "Compile the kernel with debug info" | 
 | 	depends on DEBUG_KERNEL && !COMPILE_TEST | 
 | 	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 | 
 | 	help | 
 | 	  Enable the __deprecated logic in the kernel build. | 
 | 	  Disable this to suppress the "warning: 'foo' is deprecated | 
 | 	  (declared at kernel/power/somefile.c:1234)" messages. | 
 |  | 
 | config ENABLE_MUST_CHECK | 
 | 	bool "Enable __must_check logic" | 
 | 	default y | 
 | 	help | 
 | 	  Enable the __must_check logic in the kernel build.  Disable this to | 
 | 	  suppress the "warning: ignoring return value of 'foo', declared with | 
 | 	  attribute warn_unused_result" messages. | 
 |  | 
 | config FRAME_WARN | 
 | 	int "Warn for stack frames larger than (needs gcc 4.4)" | 
 | 	range 0 8192 | 
 | 	default 1024 if !64BIT | 
 | 	default 2048 if 64BIT | 
 | 	help | 
 | 	  Tell gcc to warn at build time for stack frames larger than this. | 
 | 	  Setting this too low will cause a lot of warnings. | 
 | 	  Setting it to 0 disables the warning. | 
 | 	  Requires gcc 4.4 | 
 |  | 
 | config STRIP_ASM_SYMS | 
 | 	bool "Strip assembler-generated symbols during link" | 
 | 	default n | 
 | 	help | 
 | 	  Strip internal assembler-generated symbols during a link (symbols | 
 | 	  that look like '.Lxxx') so they don't pollute the output of | 
 | 	  get_wchan() and suchlike. | 
 |  | 
 | config READABLE_ASM | 
 |         bool "Generate readable assembler code" | 
 |         depends on DEBUG_KERNEL | 
 |         help | 
 |           Disable some compiler optimizations that tend to generate human unreadable | 
 |           assembler output. This may make the kernel slightly slower, but it helps | 
 |           to keep kernel developers who have to stare a lot at assembler listings | 
 |           sane. | 
 |  | 
 | config UNUSED_SYMBOLS | 
 | 	bool "Enable unused/obsolete exported symbols" | 
 | 	default y if X86 | 
 | 	help | 
 | 	  Unused but exported symbols make the kernel needlessly bigger.  For | 
 | 	  that reason most of these unused exports will soon be removed.  This | 
 | 	  option is provided temporarily to provide a transition period in case | 
 | 	  some external kernel module needs one of these symbols anyway. If you | 
 | 	  encounter such a case in your module, consider if you are actually | 
 | 	  using the right API.  (rationale: since nobody in the kernel is using | 
 | 	  this in a module, there is a pretty good chance it's actually the | 
 | 	  wrong interface to use).  If you really need the symbol, please send a | 
 | 	  mail to the linux kernel mailing list mentioning the symbol and why | 
 | 	  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 | 
 | 	help | 
 | 	  This option will extract the user-visible kernel headers whenever | 
 | 	  building the kernel, and will run basic sanity checks on them to | 
 | 	  ensure that exported files do not attempt to include files which | 
 | 	  were not exported, etc. | 
 |  | 
 | 	  If you're making modifications to header files which are | 
 | 	  relevant for userspace, say 'Y', and check the headers | 
 | 	  exported to $(INSTALL_HDR_PATH) (usually 'usr/include' in | 
 | 	  your build tree), to make sure they're suitable. | 
 |  | 
 | config DEBUG_SECTION_MISMATCH | 
 | 	bool "Enable full Section mismatch analysis" | 
 | 	help | 
 | 	  The section mismatch analysis checks if there are illegal | 
 | 	  references from one section to another section. | 
 | 	  During linktime or runtime, some sections are dropped; | 
 | 	  any use of code/data previously in these sections would | 
 | 	  most likely result in an oops. | 
 | 	  In the code, functions and variables are annotated with | 
 | 	  __init,, etc. (see the full list in include/linux/init.h), | 
 | 	  which results in the code/data being placed in specific sections. | 
 | 	  The section mismatch analysis is always performed after a full | 
 | 	  kernel build, and enabling this option causes the following | 
 | 	  additional steps to occur: | 
 | 	  - Add the option -fno-inline-functions-called-once to gcc commands. | 
 | 	    When inlining a function annotated with __init in a non-init | 
 | 	    function, we would lose the section information and thus | 
 | 	    the analysis would not catch the illegal reference. | 
 | 	    This option tells gcc to inline less (but it does result in | 
 | 	    a larger kernel). | 
 | 	  - Run the section mismatch analysis for each module/built-in.o file. | 
 | 	    When we run the section mismatch analysis on vmlinux.o, we | 
 | 	    lose valueble information about where the mismatch was | 
 | 	    introduced. | 
 | 	    Running the analysis for each module/built-in.o file | 
 | 	    tells where the mismatch happens much closer to the | 
 | 	    source. The drawback is that the same mismatch is | 
 | 	    reported at least twice. | 
 | 	  - 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 || METAG) || \ | 
 | 		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 MAGIC_SYSRQ_DEFAULT_ENABLE | 
 | 	hex "Enable magic SysRq key functions by default" | 
 | 	depends on MAGIC_SYSRQ | 
 | 	default 0x1 | 
 | 	help | 
 | 	  Specifies which SysRq key functions are enabled by default. | 
 | 	  This may be set to 1 or 0 to enable or disable them all, or | 
 | 	  to a bitmask as described in Documentation/sysrq.txt. | 
 |  | 
 | config DEBUG_KERNEL | 
 | 	bool "Kernel debugging" | 
 | 	help | 
 | 	  Say Y here if you are developing drivers or trying to debug and | 
 | 	  identify kernel problems. | 
 |  | 
 | menu "Memory Debugging" | 
 |  | 
 | source mm/Kconfig.debug | 
 |  | 
 | 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 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 && 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 && !METAG | 
 | 	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 artificial 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 memory-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 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 "lib/Kconfig.kmemcheck" | 
 |  | 
 | endmenu # "Memory Debugging" | 
 |  | 
 | config DEBUG_SHIRQ | 
 | 	bool "Debug shared IRQ handlers" | 
 | 	depends on DEBUG_KERNEL | 
 | 	help | 
 | 	  Enable this to generate a spurious interrupt as soon as a shared | 
 | 	  interrupt handler is registered, and just before one is deregistered. | 
 | 	  Drivers ought to be able to handle interrupts coming in at those | 
 | 	  points; some don't and need to be caught. | 
 |  | 
 | menu "Debug Lockups and Hangs" | 
 |  | 
 | config LOCKUP_DETECTOR | 
 | 	bool "Detect Hard and Soft Lockups" | 
 | 	depends on DEBUG_KERNEL && !S390 | 
 | 	help | 
 | 	  Say Y here to enable the kernel to act as a watchdog to detect | 
 | 	  hard and soft lockups. | 
 |  | 
 | 	  Softlockups are bugs that cause the kernel to loop in kernel | 
 | 	  mode for more than 20 seconds, without giving other tasks a | 
 | 	  chance to run.  The current stack trace is displayed upon | 
 | 	  detection and the system will stay locked up. | 
 |  | 
 | 	  Hardlockups are bugs that cause the CPU to loop in kernel mode | 
 | 	  for more than 10 seconds, without letting other interrupts have a | 
 | 	  chance to run.  The current stack trace is displayed upon detection | 
 | 	  and the system will stay locked up. | 
 |  | 
 | 	  The overhead should be minimal.  A periodic hrtimer runs to | 
 | 	  generate interrupts and kick the watchdog task every 4 seconds. | 
 | 	  An NMI is generated every 10 seconds or so to check for hardlockups. | 
 |  | 
 | 	  The frequency of hrtimer and NMI events and the soft and hard lockup | 
 | 	  thresholds can be controlled through the sysctl watchdog_thresh. | 
 |  | 
 | config HARDLOCKUP_DETECTOR | 
 | 	def_bool y | 
 | 	depends on LOCKUP_DETECTOR && !HAVE_NMI_WATCHDOG | 
 | 	depends on PERF_EVENTS && HAVE_PERF_EVENTS_NMI | 
 |  | 
 | config BOOTPARAM_HARDLOCKUP_PANIC | 
 | 	bool "Panic (Reboot) On Hard Lockups" | 
 | 	depends on HARDLOCKUP_DETECTOR | 
 | 	help | 
 | 	  Say Y here to enable the kernel to panic on "hard lockups", | 
 | 	  which are bugs that cause the kernel to loop in kernel | 
 | 	  mode with interrupts disabled for more than 10 seconds (configurable | 
 | 	  using the watchdog_thresh sysctl). | 
 |  | 
 | 	  Say N if unsure. | 
 |  | 
 | config BOOTPARAM_HARDLOCKUP_PANIC_VALUE | 
 | 	int | 
 | 	depends on HARDLOCKUP_DETECTOR | 
 | 	range 0 1 | 
 | 	default 0 if !BOOTPARAM_HARDLOCKUP_PANIC | 
 | 	default 1 if BOOTPARAM_HARDLOCKUP_PANIC | 
 |  | 
 | config BOOTPARAM_SOFTLOCKUP_PANIC | 
 | 	bool "Panic (Reboot) On Soft Lockups" | 
 | 	depends on LOCKUP_DETECTOR | 
 | 	help | 
 | 	  Say Y here to enable the kernel to panic on "soft lockups", | 
 | 	  which are bugs that cause the kernel to loop in kernel | 
 | 	  mode for more than 20 seconds (configurable using the watchdog_thresh | 
 | 	  sysctl), without giving other tasks a chance to run. | 
 |  | 
 | 	  The panic can be used in combination with panic_timeout, | 
 | 	  to cause the system to reboot automatically after a | 
 | 	  lockup has been detected. This feature is useful for | 
 | 	  high-availability systems that have uptime guarantees and | 
 | 	  where a lockup must be resolved ASAP. | 
 |  | 
 | 	  Say N if unsure. | 
 |  | 
 | config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE | 
 | 	int | 
 | 	depends on LOCKUP_DETECTOR | 
 | 	range 0 1 | 
 | 	default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC | 
 | 	default 1 if BOOTPARAM_SOFTLOCKUP_PANIC | 
 |  | 
 | 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 | 
 |  | 
 | endmenu # "Debug lockups and hangs" | 
 |  | 
 | config PANIC_ON_OOPS | 
 | 	bool "Panic on Oops" | 
 | 	help | 
 | 	  Say Y here to enable the kernel to panic when it oopses. This | 
 | 	  has the same effect as setting oops=panic on the kernel command | 
 | 	  line. | 
 |  | 
 | 	  This feature is useful to ensure that the kernel does not do | 
 | 	  anything erroneous after an oops which could result in data | 
 | 	  corruption or other issues. | 
 |  | 
 | 	  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 PANIC_TIMEOUT | 
 | 	int "panic timeout" | 
 | 	default 0 | 
 | 	help | 
 | 	  Set the timeout value (in seconds) until a reboot occurs when the | 
 | 	  the kernel panics. If n = 0, then we wait forever. A timeout | 
 | 	  value n > 0 will wait n seconds before rebooting, while a timeout | 
 | 	  value n < 0 will reboot immediately. | 
 |  | 
 | 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_PREEMPT | 
 | 	bool "Debug preemptible kernel" | 
 | 	depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT | 
 | 	default y | 
 | 	help | 
 | 	  If you say Y here then the kernel will use a debug variant of the | 
 | 	  commonly used smp_processor_id() function and will print warnings | 
 | 	  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 | 
 | 	help | 
 | 	 This allows rt mutex semantics violations and rt mutex related | 
 | 	 deadlocks (lockups) to be detected and reported automatically. | 
 |  | 
 | config DEBUG_PI_LIST | 
 | 	bool | 
 | 	default y | 
 | 	depends on DEBUG_RT_MUTEXES | 
 |  | 
 | config RT_MUTEX_TESTER | 
 | 	bool "Built-in scriptable tester for rt-mutexes" | 
 | 	depends on DEBUG_KERNEL && RT_MUTEXES | 
 | 	help | 
 | 	  This option enables a rt-mutex tester. | 
 |  | 
 | config DEBUG_SPINLOCK | 
 | 	bool "Spinlock and rw-lock debugging: basic checks" | 
 | 	depends on DEBUG_KERNEL | 
 | 	select UNINLINE_SPIN_UNLOCK | 
 | 	help | 
 | 	  Say Y here and build SMP to catch missing spinlock initialization | 
 | 	  and certain other kinds of spinlock errors commonly made.  This is | 
 | 	  best used in conjunction with the NMI watchdog so that spinlock | 
 | 	  deadlocks are also debuggable. | 
 |  | 
 | config DEBUG_MUTEXES | 
 | 	bool "Mutex debugging: basic checks" | 
 | 	depends on DEBUG_KERNEL | 
 | 	help | 
 | 	 This feature allows mutex semantics violations to be detected and | 
 | 	 reported. | 
 |  | 
 | config DEBUG_WW_MUTEX_SLOWPATH | 
 | 	bool "Wait/wound mutex debugging: Slowpath testing" | 
 | 	depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT | 
 | 	select DEBUG_LOCK_ALLOC | 
 | 	select DEBUG_SPINLOCK | 
 | 	select DEBUG_MUTEXES | 
 | 	help | 
 | 	 This feature enables slowpath testing for w/w mutex users by | 
 | 	 injecting additional -EDEADLK wound/backoff cases. Together with | 
 | 	 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this | 
 | 	 will test all possible w/w mutex interface abuse with the | 
 | 	 exception of simply not acquiring all the required locks. | 
 |  | 
 | config DEBUG_LOCK_ALLOC | 
 | 	bool "Lock debugging: detect incorrect freeing of live locks" | 
 | 	depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT | 
 | 	select DEBUG_SPINLOCK | 
 | 	select DEBUG_MUTEXES | 
 | 	select LOCKDEP | 
 | 	help | 
 | 	 This feature will check whether any held lock (spinlock, rwlock, | 
 | 	 mutex or rwsem) is incorrectly freed by the kernel, via any of the | 
 | 	 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(), | 
 | 	 vfree(), etc.), whether a live lock is incorrectly reinitialized via | 
 | 	 spin_lock_init()/mutex_init()/etc., or whether there is any lock | 
 | 	 held during task exit. | 
 |  | 
 | config PROVE_LOCKING | 
 | 	bool "Lock debugging: prove locking correctness" | 
 | 	depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT | 
 | 	select LOCKDEP | 
 | 	select DEBUG_SPINLOCK | 
 | 	select DEBUG_MUTEXES | 
 | 	select DEBUG_LOCK_ALLOC | 
 | 	select TRACE_IRQFLAGS | 
 | 	default n | 
 | 	help | 
 | 	 This feature enables the kernel to prove that all locking | 
 | 	 that occurs in the kernel runtime is mathematically | 
 | 	 correct: that under no circumstance could an arbitrary (and | 
 | 	 not yet triggered) combination of observed locking | 
 | 	 sequences (on an arbitrary number of CPUs, running an | 
 | 	 arbitrary number of tasks and interrupt contexts) cause a | 
 | 	 deadlock. | 
 |  | 
 | 	 In short, this feature enables the kernel to report locking | 
 | 	 related deadlocks before they actually occur. | 
 |  | 
 | 	 The proof does not depend on how hard and complex a | 
 | 	 deadlock scenario would be to trigger: how many | 
 | 	 participant CPUs, tasks and irq-contexts would be needed | 
 | 	 for it to trigger. The proof also does not depend on | 
 | 	 timing: if a race and a resulting deadlock is possible | 
 | 	 theoretically (no matter how unlikely the race scenario | 
 | 	 is), it will be proven so and will immediately be | 
 | 	 reported by the kernel (once the event is observed that | 
 | 	 makes the deadlock theoretically possible). | 
 |  | 
 | 	 If a deadlock is impossible (i.e. the locking rules, as | 
 | 	 observed by the kernel, are mathematically correct), the | 
 | 	 kernel reports nothing. | 
 |  | 
 | 	 NOTE: this feature can also be enabled for rwlocks, mutexes | 
 | 	 and rwsems - in which case all dependencies between these | 
 | 	 different locking variants are observed and mapped too, and | 
 | 	 the proof of observed correctness is also maintained for an | 
 | 	 arbitrary combination of these separate locking variants. | 
 |  | 
 | 	 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 && !ARC | 
 | 	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_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. | 
 |  | 
 | endmenu # lock debugging | 
 |  | 
 | config TRACE_IRQFLAGS | 
 | 	bool | 
 | 	help | 
 | 	  Enables hooks to interrupt enabling and disabling for | 
 | 	  either tracing or lock debugging. | 
 |  | 
 | config STACKTRACE | 
 | 	bool | 
 | 	depends on STACKTRACE_SUPPORT | 
 |  | 
 | config DEBUG_KOBJECT | 
 | 	bool "kobject debugging" | 
 | 	depends on DEBUG_KERNEL | 
 | 	help | 
 | 	  If you say Y here, some extra kobject debugging messages will be sent | 
 | 	  to the syslog.  | 
 |  | 
 | config DEBUG_KOBJECT_RELEASE | 
 | 	bool "kobject release debugging" | 
 | 	depends on DEBUG_OBJECTS_TIMERS | 
 | 	help | 
 | 	  kobjects are reference counted objects.  This means that their | 
 | 	  last reference count put is not predictable, and the kobject can | 
 | 	  live on past the point at which a driver decides to drop it's | 
 | 	  initial reference to the kobject gained on allocation.  An | 
 | 	  example of this would be a struct device which has just been | 
 | 	  unregistered. | 
 |  | 
 | 	  However, some buggy drivers assume that after such an operation, | 
 | 	  the memory backing the kobject can be immediately freed.  This | 
 | 	  goes completely against the principles of a refcounted object. | 
 |  | 
 | 	  If you say Y here, the kernel will delay the release of kobjects | 
 | 	  on the last reference count to improve the visibility of this | 
 | 	  kind of kobject release bug. | 
 |  | 
 | config HAVE_DEBUG_BUGVERBOSE | 
 | 	bool | 
 |  | 
 | config DEBUG_BUGVERBOSE | 
 | 	bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT | 
 | 	depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE) | 
 | 	default y | 
 | 	help | 
 | 	  Say Y here to make BUG() panics output the file name and line number | 
 | 	  of the BUG call as well as the EIP and oops trace.  This aids | 
 | 	  debugging but costs about 70-100K of memory. | 
 |  | 
 | config DEBUG_WRITECOUNT | 
 | 	bool "Debug filesystem writers count" | 
 | 	depends on DEBUG_KERNEL | 
 | 	help | 
 | 	  Enable this to catch wrong use of the writers count in struct | 
 | 	  vfsmount.  This will increase the size of each file struct by | 
 | 	  32 bits. | 
 |  | 
 | 	  If unsure, say N. | 
 |  | 
 | config DEBUG_LIST | 
 | 	bool "Debug linked list manipulation" | 
 | 	depends on DEBUG_KERNEL | 
 | 	help | 
 | 	  Enable this to turn on extended checks in the linked-list | 
 | 	  walking routines. | 
 |  | 
 | 	  If unsure, say N. | 
 |  | 
 | config DEBUG_SG | 
 | 	bool "Debug SG table operations" | 
 | 	depends on DEBUG_KERNEL | 
 | 	help | 
 | 	  Enable this to turn on checks on scatter-gather tables. This can | 
 | 	  help find problems with drivers that do not properly initialize | 
 | 	  their sg tables. | 
 |  | 
 | 	  If unsure, say N. | 
 |  | 
 | config DEBUG_NOTIFIERS | 
 | 	bool "Debug notifier call chains" | 
 | 	depends on DEBUG_KERNEL | 
 | 	help | 
 | 	  Enable this to turn on sanity checking for notifier call chains. | 
 | 	  This is most useful for kernel developers to make sure that | 
 | 	  modules properly unregister themselves from notifier chains. | 
 | 	  This is a relatively cheap check but if you care about maximum | 
 | 	  performance, say N. | 
 |  | 
 | config DEBUG_CREDENTIALS | 
 | 	bool "Debug credential management" | 
 | 	depends on DEBUG_KERNEL | 
 | 	help | 
 | 	  Enable this to turn on some debug checking for credential | 
 | 	  management.  The additional code keeps track of the number of | 
 | 	  pointers from task_structs to any given cred struct, and checks to | 
 | 	  see that this number never exceeds the usage count of the cred | 
 | 	  struct. | 
 |  | 
 | 	  Furthermore, if SELinux is enabled, this also checks that the | 
 | 	  security pointer in the cred struct is never seen to be invalid. | 
 |  | 
 | 	  If unsure, say N. | 
 |  | 
 | 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 | 
 | 	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 RCU_STALL_COMMON | 
 | 	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 | 
 | 	select TRACE_CLOCK | 
 | 	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 DEBUG_BLOCK_EXT_DEVT | 
 |         bool "Force extended block device numbers and spread them" | 
 | 	depends on DEBUG_KERNEL | 
 | 	depends on BLOCK | 
 | 	default n | 
 | 	help | 
 | 	  BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON | 
 | 	  SOME DISTRIBUTIONS.  DO NOT ENABLE THIS UNLESS YOU KNOW WHAT | 
 | 	  YOU ARE DOING.  Distros, please enable this and fix whatever | 
 | 	  is broken. | 
 |  | 
 | 	  Conventionally, block device numbers are allocated from | 
 | 	  predetermined contiguous area.  However, extended block area | 
 | 	  may introduce non-contiguous block device numbers.  This | 
 | 	  option forces most block device numbers to be allocated from | 
 | 	  the extended space and spreads them to discover kernel or | 
 | 	  userland code paths which assume predetermined contiguous | 
 | 	  device number allocation. | 
 |  | 
 | 	  Note that turning on this debug option shuffles all the | 
 | 	  device numbers for all IDE and SCSI devices including libata | 
 | 	  ones, so root partition specified using device number | 
 | 	  directly (via rdev or root=MAJ:MIN) won't work anymore. | 
 | 	  Textual device names (root=/dev/sdXn) will continue to work. | 
 |  | 
 | 	  Say N if you are unsure. | 
 |  | 
 | config NOTIFIER_ERROR_INJECTION | 
 | 	tristate "Notifier error injection" | 
 | 	depends on DEBUG_KERNEL | 
 | 	select DEBUG_FS | 
 | 	help | 
 | 	  This option provides the ability to inject artificial errors to | 
 | 	  specified notifier chain callbacks. It is useful to test the error | 
 | 	  handling of notifier call chain failures. | 
 |  | 
 | 	  Say N if unsure. | 
 |  | 
 | config CPU_NOTIFIER_ERROR_INJECT | 
 | 	tristate "CPU notifier error injection module" | 
 | 	depends on HOTPLUG_CPU && NOTIFIER_ERROR_INJECTION | 
 | 	help | 
 | 	  This option provides a kernel module that can be used to test | 
 | 	  the error handling of the cpu notifiers by injecting artificial | 
 | 	  errors to CPU notifier chain callbacks.  It is controlled through | 
 | 	  debugfs interface under /sys/kernel/debug/notifier-error-inject/cpu | 
 |  | 
 | 	  If the notifier call chain should be failed with some events | 
 | 	  notified, write the error code to "actions/<notifier event>/error". | 
 |  | 
 | 	  Example: Inject CPU offline error (-1 == -EPERM) | 
 |  | 
 | 	  # cd /sys/kernel/debug/notifier-error-inject/cpu | 
 | 	  # echo -1 > actions/CPU_DOWN_PREPARE/error | 
 | 	  # echo 0 > /sys/devices/system/cpu/cpu1/online | 
 | 	  bash: echo: write error: Operation not permitted | 
 |  | 
 | 	  To compile this code as a module, choose M here: the module will | 
 | 	  be called cpu-notifier-error-inject. | 
 |  | 
 | 	  If unsure, say N. | 
 |  | 
 | config PM_NOTIFIER_ERROR_INJECT | 
 | 	tristate "PM notifier error injection module" | 
 | 	depends on PM && NOTIFIER_ERROR_INJECTION | 
 | 	default m if PM_DEBUG | 
 | 	help | 
 | 	  This option provides the ability to inject artificial errors to | 
 | 	  PM notifier chain callbacks.  It is controlled through debugfs | 
 | 	  interface /sys/kernel/debug/notifier-error-inject/pm | 
 |  | 
 | 	  If the notifier call chain should be failed with some events | 
 | 	  notified, write the error code to "actions/<notifier event>/error". | 
 |  | 
 | 	  Example: Inject PM suspend error (-12 = -ENOMEM) | 
 |  | 
 | 	  # cd /sys/kernel/debug/notifier-error-inject/pm/ | 
 | 	  # echo -12 > actions/PM_SUSPEND_PREPARE/error | 
 | 	  # echo mem > /sys/power/state | 
 | 	  bash: echo: write error: Cannot allocate memory | 
 |  | 
 | 	  To compile this code as a module, choose M here: the module will | 
 | 	  be called pm-notifier-error-inject. | 
 |  | 
 | 	  If unsure, say N. | 
 |  | 
 | config OF_RECONFIG_NOTIFIER_ERROR_INJECT | 
 | 	tristate "OF reconfig notifier error injection module" | 
 | 	depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION | 
 | 	help | 
 | 	  This option provides the ability to inject artificial errors to | 
 | 	  OF reconfig notifier chain callbacks.  It is controlled | 
 | 	  through debugfs interface under | 
 | 	  /sys/kernel/debug/notifier-error-inject/OF-reconfig/ | 
 |  | 
 | 	  If the notifier call chain should be failed with some events | 
 | 	  notified, write the error code to "actions/<notifier event>/error". | 
 |  | 
 | 	  To compile this code as a module, choose M here: the module will | 
 | 	  be called of-reconfig-notifier-error-inject. | 
 |  | 
 | 	  If unsure, say N. | 
 |  | 
 | config FAULT_INJECTION | 
 | 	bool "Fault-injection framework" | 
 | 	depends on DEBUG_KERNEL | 
 | 	help | 
 | 	  Provide fault-injection framework. | 
 | 	  For more details, see Documentation/fault-injection/. | 
 |  | 
 | config FAILSLAB | 
 | 	bool "Fault-injection capability for kmalloc" | 
 | 	depends on FAULT_INJECTION | 
 | 	depends on SLAB || SLUB | 
 | 	help | 
 | 	  Provide fault-injection capability for kmalloc. | 
 |  | 
 | config FAIL_PAGE_ALLOC | 
 | 	bool "Fault-injection capabilitiy for alloc_pages()" | 
 | 	depends on FAULT_INJECTION | 
 | 	help | 
 | 	  Provide fault-injection capability for alloc_pages(). | 
 |  | 
 | config FAIL_MAKE_REQUEST | 
 | 	bool "Fault-injection capability for disk IO" | 
 | 	depends on FAULT_INJECTION && BLOCK | 
 | 	help | 
 | 	  Provide fault-injection capability for disk IO. | 
 |  | 
 | config FAIL_IO_TIMEOUT | 
 | 	bool "Fault-injection capability for faking disk interrupts" | 
 | 	depends on FAULT_INJECTION && BLOCK | 
 | 	help | 
 | 	  Provide fault-injection capability on end IO handling. This | 
 | 	  will make the block layer "forget" an interrupt as configured, | 
 | 	  thus exercising the error handling. | 
 |  | 
 | 	  Only works with drivers that use the generic timeout handling, | 
 | 	  for others it wont do anything. | 
 |  | 
 | config FAIL_MMC_REQUEST | 
 | 	bool "Fault-injection capability for MMC IO" | 
 | 	select DEBUG_FS | 
 | 	depends on FAULT_INJECTION && MMC | 
 | 	help | 
 | 	  Provide fault-injection capability for MMC IO. | 
 | 	  This will make the mmc core return data errors. This is | 
 | 	  useful to test the error handling in the mmc block device | 
 | 	  and to test how the mmc host driver handles retries from | 
 | 	  the block device. | 
 |  | 
 | config FAULT_INJECTION_DEBUG_FS | 
 | 	bool "Debugfs entries for fault-injection capabilities" | 
 | 	depends on FAULT_INJECTION && SYSFS && DEBUG_FS | 
 | 	help | 
 | 	  Enable configuration of fault-injection capabilities via debugfs. | 
 |  | 
 | config FAULT_INJECTION_STACKTRACE_FILTER | 
 | 	bool "stacktrace filter for fault-injection capabilities" | 
 | 	depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT | 
 | 	depends on !X86_64 | 
 | 	select STACKTRACE | 
 | 	select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND && !ARC | 
 | 	help | 
 | 	  Provide stacktrace filter for fault-injection capabilities | 
 |  | 
 | config LATENCYTOP | 
 | 	bool "Latency measuring infrastructure" | 
 | 	depends on HAVE_LATENCYTOP_SUPPORT | 
 | 	depends on DEBUG_KERNEL | 
 | 	depends on STACKTRACE_SUPPORT | 
 | 	depends on PROC_FS | 
 | 	select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND && !ARC | 
 | 	select KALLSYMS | 
 | 	select KALLSYMS_ALL | 
 | 	select STACKTRACE | 
 | 	select SCHEDSTATS | 
 | 	select SCHED_DEBUG | 
 | 	help | 
 | 	  Enable this option if you want to use the LatencyTOP tool | 
 | 	  to find out which userspace is blocking on what kernel operations. | 
 |  | 
 | config ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS | 
 | 	bool | 
 |  | 
 | config DEBUG_STRICT_USER_COPY_CHECKS | 
 | 	bool "Strict user copy size checks" | 
 | 	depends on ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS | 
 | 	depends on DEBUG_KERNEL && !TRACE_BRANCH_PROFILING | 
 | 	help | 
 | 	  Enabling this option turns a certain set of sanity checks for user | 
 | 	  copy operations into compile time failures. | 
 |  | 
 | 	  The copy_from_user() etc checks are there to help test if there | 
 | 	  are sufficient security checks on the length argument of | 
 | 	  the copy operation, by having gcc prove that the argument is | 
 | 	  within bounds. | 
 |  | 
 | 	  If unsure, say N. | 
 |  | 
 | 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 DEBUG_KERNEL | 
 | 	help | 
 | 	  A benchmark measuring the performance of the rbtree library. | 
 | 	  Also includes rbtree invariant checks. | 
 |  | 
 | config INTERVAL_TREE_TEST | 
 | 	tristate "Interval tree test" | 
 | 	depends on m && DEBUG_KERNEL | 
 | 	help | 
 | 	  A benchmark measuring the performance of the interval tree library | 
 |  | 
 | config PERCPU_TEST | 
 | 	tristate "Per cpu operations test" | 
 | 	depends on m && DEBUG_KERNEL | 
 | 	help | 
 | 	  Enable this option to build test module which validates per-cpu | 
 | 	  operations. | 
 |  | 
 | 	  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 TEST_STRING_HELPERS | 
 | 	tristate "Test functions located in the string_helpers module at runtime" | 
 |  | 
 | 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 | 
 | 	help | 
 | 	  If you want to debug problems which hang or crash the kernel early | 
 | 	  on boot and the crashing machine has a FireWire port, you can use | 
 | 	  this feature to remotely access the memory of the crashed machine | 
 | 	  over FireWire. This employs remote DMA as part of the OHCI1394 | 
 | 	  specification which is now the standard for FireWire controllers. | 
 |  | 
 | 	  With remote DMA, you can monitor the printk buffer remotely using | 
 | 	  firescope and access all memory below 4GB using fireproxy from gdb. | 
 | 	  Even controlling a kernel debugger is possible using remote DMA. | 
 |  | 
 | 	  Usage: | 
 |  | 
 | 	  If ohci1394_dma=early is used as boot parameter, it will initialize | 
 | 	  all OHCI1394 controllers which are found in the PCI config space. | 
 |  | 
 | 	  As all changes to the FireWire bus such as enabling and disabling | 
 | 	  devices cause a bus reset and thereby disable remote DMA for all | 
 | 	  devices, be sure to have the cable plugged and FireWire enabled on | 
 | 	  the debugging host before booting the debug target for debugging. | 
 |  | 
 | 	  This code (~1k) is freed after boot. By then, the firewire stack | 
 | 	  in charge of the OHCI-1394 controllers should be used instead. | 
 |  | 
 | 	  See Documentation/debugging-via-ohci1394.txt for more information. | 
 |  | 
 | config BUILD_DOCSRC | 
 | 	bool "Build targets in Documentation/ tree" | 
 | 	depends on HEADERS_CHECK | 
 | 	help | 
 | 	  This option attempts to build objects from the source files in the | 
 | 	  kernel Documentation/ tree. | 
 |  | 
 | 	  Say N if you are unsure. | 
 |  | 
 | config DMA_API_DEBUG | 
 | 	bool "Enable debugging of DMA-API usage" | 
 | 	depends on HAVE_DMA_API_DEBUG | 
 | 	help | 
 | 	  Enable this option to debug the use of the DMA API by device drivers. | 
 | 	  With this option you will be able to detect common bugs in device | 
 | 	  drivers like double-freeing of DMA mappings or freeing mappings that | 
 | 	  were never allocated. | 
 |  | 
 | 	  This also attempts to catch cases where a page owned by DMA is | 
 | 	  accessed by the cpu in a way that could cause data corruption.  For | 
 | 	  example, this enables cow_user_page() to check that the source page is | 
 | 	  not undergoing DMA. | 
 |  | 
 | 	  This option causes a performance degradation.  Use only if you want to | 
 | 	  debug device drivers and dma interactions. | 
 |  | 
 | 	  If unsure, say N. | 
 |  | 
 | config TEST_MODULE | 
 | 	tristate "Test module loading with 'hello world' module" | 
 | 	default n | 
 | 	depends on m | 
 | 	help | 
 | 	  This builds the "test_module" module that emits "Hello, world" | 
 | 	  on printk when loaded. It is designed to be used for basic | 
 | 	  evaluation of the module loading subsystem (for example when | 
 | 	  validating module verification). It lacks any extra dependencies, | 
 | 	  and will not normally be loaded by the system unless explicitly | 
 | 	  requested by name. | 
 |  | 
 | 	  If unsure, say N. | 
 |  | 
 | config TEST_USER_COPY | 
 | 	tristate "Test user/kernel boundary protections" | 
 | 	default n | 
 | 	depends on m | 
 | 	help | 
 | 	  This builds the "test_user_copy" module that runs sanity checks | 
 | 	  on the copy_to/from_user infrastructure, making sure basic | 
 | 	  user/kernel boundary testing is working. If it fails to load, | 
 | 	  a regression has been detected in the user/kernel memory boundary | 
 | 	  protections. | 
 |  | 
 | 	  If unsure, say N. | 
 |  | 
 | source "samples/Kconfig" | 
 |  | 
 | source "lib/Kconfig.kgdb" | 
 |  |