lib/Kconfig.debug

   1
   2 config PRINTK_TIME
   3         bool "Show timing information on printks"
   4         help
   5           Selecting this option causes timing information to be
   6           included in printk output.  This allows you to measure
   7           the interval between kernel operations, including bootup
   8           operations.  This is useful for identifying long delays
   9           in kernel startup.
  10
  11
  12 config MAGIC_SYSRQ
  13         bool "Magic SysRq key"
  14         depends on !UML
  15         help
  16           If you say Y here, you will have some control over the system even
  17           if the system crashes for example during kernel debugging (e.g., you
  18           will be able to flush the buffer cache to disk, reboot the system
  19           immediately or dump some status information). This is accomplished
  20           by pressing various keys while holding SysRq (Alt+PrintScreen). It
  21           also works on a serial console (on PC hardware at least), if you
  22           send a BREAK and then within 5 seconds a command keypress. The
  23           keys are documented in <file:Documentation/sysrq.txt>. Don't say Y
  24           unless you really know what this hack does.
  25
  26 config UNUSED_SYMBOLS
  27         bool "Enable unused/obsolete exported symbols"
  28         default y if X86
  29         help
  30           Unused but exported symbols make the kernel needlessly bigger.  For
  31           that reason most of these unused exports will soon be removed.  This
  32           option is provided temporarily to provide a transition period in case
  33           some external kernel module needs one of these symbols anyway. If you
  34           encounter such a case in your module, consider if you are actually
  35           using the right API.  (rationale: since nobody in the kernel is using
  36           this in a module, there is a pretty good chance it's actually the
  37           wrong interface to use).  If you really need the symbol, please send a
  38           mail to the linux kernel mailing list mentioning the symbol and why
  39           you really need it, and what the merge plan to the mainline kernel for
  40           your module is.
  41
  42 config DEBUG_KERNEL
  43         bool "Kernel debugging"
  44         help
  45           Say Y here if you are developing drivers or trying to debug and
  46           identify kernel problems.
  47
  48 config LOG_BUF_SHIFT
  49         int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" if DEBUG_KERNEL
  50         range 12 21
  51         default 17 if S390
  52         default 16 if X86_NUMAQ || IA64
  53         default 15 if SMP
  54         default 14
  55         help
  56           Select kernel log buffer size as a power of 2.
  57           Defaults and Examples:
  58                      17 => 128 KB for S/390
  59                      16 => 64 KB for x86 NUMAQ or IA-64
  60                      15 => 32 KB for SMP
  61                      14 => 16 KB for uniprocessor
  62                      13 =>  8 KB
  63                      12 =>  4 KB
  64
  65 config DETECT_SOFTLOCKUP
  66         bool "Detect Soft Lockups"
  67         depends on DEBUG_KERNEL
  68         default y
  69         help
  70           Say Y here to enable the kernel to detect "soft lockups",
  71           which are bugs that cause the kernel to loop in kernel
  72           mode for more than 10 seconds, without giving other tasks a
  73           chance to run.
  74
  75           When a soft-lockup is detected, the kernel will print the
  76           current stack trace (which you should report), but the
  77           system will stay locked up. This feature has negligible
  78           overhead.
  79
  80           (Note that "hard lockups" are separate type of bugs that
  81            can be detected via the NMI-watchdog, on platforms that
  82            support it.)
  83
  84 config SCHEDSTATS
  85         bool "Collect scheduler statistics"
  86         depends on DEBUG_KERNEL && PROC_FS
  87         help
  88           If you say Y here, additional code will be inserted into the
  89           scheduler and related routines to collect statistics about
  90           scheduler behavior and provide them in /proc/schedstat.  These
  91           stats may be useful for both tuning and debugging the scheduler
  92           If you aren't debugging the scheduler or trying to tune a specific
  93           application, you can say N to avoid the very slight overhead
  94           this adds.
  95
  96 config DEBUG_SLAB
  97         bool "Debug slab memory allocations"
  98         depends on DEBUG_KERNEL && SLAB
  99         help
 100           Say Y here to have the kernel do limited verification on memory
 101           allocation as well as poisoning memory on free to catch use of freed
 102           memory. This can make kmalloc/kfree-intensive workloads much slower.
 103
 104 config DEBUG_SLAB_LEAK
 105         bool "Memory leak debugging"
 106         depends on DEBUG_SLAB
 107
 108 config DEBUG_PREEMPT
 109         bool "Debug preemptible kernel"
 110         depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT
 111         default y
 112         help
 113           If you say Y here then the kernel will use a debug variant of the
 114           commonly used smp_processor_id() function and will print warnings
 115           if kernel code uses it in a preemption-unsafe way. Also, the kernel
 116           will detect preemption count underflows.
 117
 118 config DEBUG_RT_MUTEXES
 119         bool "RT Mutex debugging, deadlock detection"
 120         depends on DEBUG_KERNEL && RT_MUTEXES
 121         help
 122          This allows rt mutex semantics violations and rt mutex related
 123          deadlocks (lockups) to be detected and reported automatically.
 124
 125 config DEBUG_PI_LIST
 126         bool
 127         default y
 128         depends on DEBUG_RT_MUTEXES
 129
 130 config RT_MUTEX_TESTER
 131         bool "Built-in scriptable tester for rt-mutexes"
 132         depends on DEBUG_KERNEL && RT_MUTEXES
 133         help
 134           This option enables a rt-mutex tester.
 135
 136 config DEBUG_SPINLOCK
 137         bool "Spinlock debugging"
 138         depends on DEBUG_KERNEL
 139         help
 140           Say Y here and build SMP to catch missing spinlock initialization
 141           and certain other kinds of spinlock errors commonly made.  This is
 142           best used in conjunction with the NMI watchdog so that spinlock
 143           deadlocks are also debuggable.
 144
 145 config DEBUG_SPINLOCK_SLEEP
 146         bool "Sleep-inside-spinlock checking"
 147         depends on DEBUG_KERNEL
 148         help
 149           If you say Y here, various routines which may sleep will become very
 150           noisy if they are called with a spinlock held.
 151
 152 config DEBUG_LOCKING_API_SELFTESTS
 153         bool "Locking API boot-time self-tests"
 154         depends on DEBUG_KERNEL
 155         help
 156           Say Y here if you want the kernel to run a short self-test during
 157           bootup. The self-test checks whether common types of locking bugs
 158           are detected by debugging mechanisms or not. (if you disable
 159           lock debugging then those bugs wont be detected of course.)
 160           The following locking APIs are covered: spinlocks, rwlocks,
 161           mutexes and rwsems.
 162
 163 config STACKTRACE
 164         bool
 165         depends on STACKTRACE_SUPPORT
 166
 167 config DEBUG_KOBJECT
 168         bool "kobject debugging"
 169         depends on DEBUG_KERNEL
 170         help
 171           If you say Y here, some extra kobject debugging messages will be sent
 172           to the syslog.
 173
 174 config DEBUG_HIGHMEM
 175         bool "Highmem debugging"
 176         depends on DEBUG_KERNEL && HIGHMEM
 177         help
 178           This options enables addition error checking for high memory systems.
 179           Disable for production systems.
 180
 181 config DEBUG_BUGVERBOSE
 182         bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EMBEDDED
 183         depends on BUG
 184         depends on ARM || ARM26 || M32R || M68K || SPARC32 || SPARC64 || X86_32 || FRV
 185         default !EMBEDDED
 186         help
 187           Say Y here to make BUG() panics output the file name and line number
 188           of the BUG call as well as the EIP and oops trace.  This aids
 189           debugging but costs about 70-100K of memory.
 190
 191 config DEBUG_INFO
 192         bool "Compile the kernel with debug info"
 193         depends on DEBUG_KERNEL
 194         help
 195           If you say Y here the resulting kernel image will include
 196           debugging info resulting in a larger kernel image.
 197           Say Y here only if you plan to debug the kernel.
 198
 199           If unsure, say N.
 200
 201 config DEBUG_FS
 202         bool "Debug Filesystem"
 203         depends on SYSFS
 204         help
 205           debugfs is a virtual file system that kernel developers use to put
 206           debugging files into.  Enable this option to be able to read and
 207           write to these files.
 208
 209           If unsure, say N.
 210
 211 config DEBUG_VM
 212         bool "Debug VM"
 213         depends on DEBUG_KERNEL
 214         help
 215           Enable this to turn on extended checks in the virtual-memory system
 216           that may impact performance.
 217
 218           If unsure, say N.
 219
 220 config FRAME_POINTER
 221         bool "Compile the kernel with frame pointers"
 222         depends on DEBUG_KERNEL && (X86 || CRIS || M68K || M68KNOMMU || FRV || UML || S390)
 223         default y if DEBUG_INFO && UML
 224         help
 225           If you say Y here the resulting kernel image will be slightly larger
 226           and slower, but it might give very useful debugging information on
 227           some architectures or if you use external debuggers.
 228           If you don't debug the kernel, you can say N.
 229
 230 config UNWIND_INFO
 231         bool "Compile the kernel with frame unwind information"
 232         depends on !IA64 && !PARISC
 233         depends on !MODULES || !(MIPS || PPC || SUPERH || V850)
 234         help
 235           If you say Y here the resulting kernel image will be slightly larger
 236           but not slower, and it will give very useful debugging information.
 237           If you don't debug the kernel, you can say N, but we may not be able
 238           to solve problems without frame unwind information or frame pointers.
 239
 240 config STACK_UNWIND
 241         bool "Stack unwind support"
 242         depends on UNWIND_INFO
 243         depends on X86
 244         help
 245           This enables more precise stack traces, omitting all unrelated
 246           occurrences of pointers into kernel code from the dump.
 247
 248 config FORCED_INLINING
 249         bool "Force gcc to inline functions marked 'inline'"
 250         depends on DEBUG_KERNEL
 251         default y
 252         help
 253           This option determines if the kernel forces gcc to inline the functions
 254           developers have marked 'inline'. Doing so takes away freedom from gcc to
 255           do what it thinks is best, which is desirable for the gcc 3.x series of
 256           compilers. The gcc 4.x series have a rewritten inlining algorithm and
 257           disabling this option will generate a smaller kernel there. Hopefully
 258           this algorithm is so good that allowing gcc4 to make the decision can
 259           become the default in the future, until then this option is there to
 260           test gcc for this.
 261
 262 config RCU_TORTURE_TEST
 263         tristate "torture tests for RCU"
 264         depends on DEBUG_KERNEL
 265         default n
 266         help
 267           This option provides a kernel module that runs torture tests
 268           on the RCU infrastructure.  The kernel module may be built
 269           after the fact on the running kernel to be tested, if desired.
 270
 271           Say Y here if you want RCU torture tests to start automatically
 272           at boot time (you probably don't).
 273           Say M if you want the RCU torture tests to build as a module.
 274           Say N if you are unsure.