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 DEBUG_KERNEL
  27         bool "Kernel debugging"
  28         help
  29           Say Y here if you are developing drivers or trying to debug and
  30           identify kernel problems.
  31
  32 config LOG_BUF_SHIFT
  33         int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" if DEBUG_KERNEL
  34         range 12 21
  35         default 17 if S390
  36         default 16 if X86_NUMAQ || IA64
  37         default 15 if SMP
  38         default 14
  39         help
  40           Select kernel log buffer size as a power of 2.
  41           Defaults and Examples:
  42                      17 => 128 KB for S/390
  43                      16 => 64 KB for x86 NUMAQ or IA-64
  44                      15 => 32 KB for SMP
  45                      14 => 16 KB for uniprocessor
  46                      13 =>  8 KB
  47                      12 =>  4 KB
  48
  49 config DETECT_SOFTLOCKUP
  50         bool "Detect Soft Lockups"
  51         depends on DEBUG_KERNEL
  52         default y
  53         help
  54           Say Y here to enable the kernel to detect "soft lockups",
  55           which are bugs that cause the kernel to loop in kernel
  56           mode for more than 10 seconds, without giving other tasks a
  57           chance to run.
  58
  59           When a soft-lockup is detected, the kernel will print the
  60           current stack trace (which you should report), but the
  61           system will stay locked up. This feature has negligible
  62           overhead.
  63
  64           (Note that "hard lockups" are separate type of bugs that
  65            can be detected via the NMI-watchdog, on platforms that
  66            support it.)
  67
  68 config SCHEDSTATS
  69         bool "Collect scheduler statistics"
  70         depends on DEBUG_KERNEL && PROC_FS
  71         help
  72           If you say Y here, additional code will be inserted into the
  73           scheduler and related routines to collect statistics about
  74           scheduler behavior and provide them in /proc/schedstat.  These
  75           stats may be useful for both tuning and debugging the scheduler
  76           If you aren't debugging the scheduler or trying to tune a specific
  77           application, you can say N to avoid the very slight overhead
  78           this adds.
  79
  80 config DEBUG_SLAB
  81         bool "Debug slab memory allocations"
  82         depends on DEBUG_KERNEL && SLAB
  83         help
  84           Say Y here to have the kernel do limited verification on memory
  85           allocation as well as poisoning memory on free to catch use of freed
  86           memory. This can make kmalloc/kfree-intensive workloads much slower.
  87
  88 config DEBUG_SLAB_LEAK
  89         bool "Memory leak debugging"
  90         depends on DEBUG_SLAB
  91
  92 config DEBUG_PREEMPT
  93         bool "Debug preemptible kernel"
  94         depends on DEBUG_KERNEL && PREEMPT
  95         default y
  96         help
  97           If you say Y here then the kernel will use a debug variant of the
  98           commonly used smp_processor_id() function and will print warnings
  99           if kernel code uses it in a preemption-unsafe way. Also, the kernel
 100           will detect preemption count underflows.
 101
 102 config DEBUG_MUTEXES
 103         bool "Mutex debugging, deadlock detection"
 104         default n
 105         depends on DEBUG_KERNEL
 106         help
 107          This allows mutex semantics violations and mutex related deadlocks
 108          (lockups) to be detected and reported automatically.
 109
 110 config DEBUG_RT_MUTEXES
 111         bool "RT Mutex debugging, deadlock detection"
 112         depends on DEBUG_KERNEL && RT_MUTEXES
 113         help
 114          This allows rt mutex semantics violations and rt mutex related
 115          deadlocks (lockups) to be detected and reported automatically.
 116
 117 config DEBUG_PI_LIST
 118         bool
 119         default y
 120         depends on DEBUG_RT_MUTEXES
 121
 122 config RT_MUTEX_TESTER
 123         bool "Built-in scriptable tester for rt-mutexes"
 124         depends on DEBUG_KERNEL && RT_MUTEXES
 125         help
 126           This option enables a rt-mutex tester.
 127
 128 config DEBUG_SPINLOCK
 129         bool "Spinlock debugging"
 130         depends on DEBUG_KERNEL
 131         help
 132           Say Y here and build SMP to catch missing spinlock initialization
 133           and certain other kinds of spinlock errors commonly made.  This is
 134           best used in conjunction with the NMI watchdog so that spinlock
 135           deadlocks are also debuggable.
 136
 137 config DEBUG_SPINLOCK_SLEEP
 138         bool "Sleep-inside-spinlock checking"
 139         depends on DEBUG_KERNEL
 140         help
 141           If you say Y here, various routines which may sleep will become very
 142           noisy if they are called with a spinlock held.
 143
 144 config DEBUG_KOBJECT
 145         bool "kobject debugging"
 146         depends on DEBUG_KERNEL
 147         help
 148           If you say Y here, some extra kobject debugging messages will be sent
 149           to the syslog.
 150
 151 config DEBUG_HIGHMEM
 152         bool "Highmem debugging"
 153         depends on DEBUG_KERNEL && HIGHMEM
 154         help
 155           This options enables addition error checking for high memory systems.
 156           Disable for production systems.
 157
 158 config DEBUG_BUGVERBOSE
 159         bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EMBEDDED
 160         depends on BUG
 161         depends on ARM || ARM26 || M32R || M68K || SPARC32 || SPARC64 || X86_32 || FRV
 162         default !EMBEDDED
 163         help
 164           Say Y here to make BUG() panics output the file name and line number
 165           of the BUG call as well as the EIP and oops trace.  This aids
 166           debugging but costs about 70-100K of memory.
 167
 168 config DEBUG_INFO
 169         bool "Compile the kernel with debug info"
 170         depends on DEBUG_KERNEL
 171         help
 172           If you say Y here the resulting kernel image will include
 173           debugging info resulting in a larger kernel image.
 174           Say Y here only if you plan to debug the kernel.
 175
 176           If unsure, say N.
 177
 178 config DEBUG_FS
 179         bool "Debug Filesystem"
 180         depends on SYSFS
 181         help
 182           debugfs is a virtual file system that kernel developers use to put
 183           debugging files into.  Enable this option to be able to read and
 184           write to these files.
 185
 186           If unsure, say N.
 187
 188 config DEBUG_VM
 189         bool "Debug VM"
 190         depends on DEBUG_KERNEL
 191         help
 192           Enable this to turn on extended checks in the virtual-memory system
 193           that may impact performance.
 194
 195           If unsure, say N.
 196
 197 config FRAME_POINTER
 198         bool "Compile the kernel with frame pointers"
 199         depends on DEBUG_KERNEL && (X86 || CRIS || M68K || M68KNOMMU || FRV || UML)
 200         default y if DEBUG_INFO && UML
 201         help
 202           If you say Y here the resulting kernel image will be slightly larger
 203           and slower, but it might give very useful debugging information on
 204           some architectures or if you use external debuggers.
 205           If you don't debug the kernel, you can say N.
 206
 207 config UNWIND_INFO
 208         bool "Compile the kernel with frame unwind information"
 209         depends on !IA64 && !PARISC
 210         depends on !MODULES || !(MIPS || PPC || SUPERH || V850)
 211         help
 212           If you say Y here the resulting kernel image will be slightly larger
 213           but not slower, and it will give very useful debugging information.
 214           If you don't debug the kernel, you can say N, but we may not be able
 215           to solve problems without frame unwind information or frame pointers.
 216
 217 config STACK_UNWIND
 218         bool "Stack unwind support"
 219         depends on UNWIND_INFO
 220         depends on X86
 221         help
 222           This enables more precise stack traces, omitting all unrelated
 223           occurrences of pointers into kernel code from the dump.
 224
 225 config FORCED_INLINING
 226         bool "Force gcc to inline functions marked 'inline'"
 227         depends on DEBUG_KERNEL
 228         default y
 229         help
 230           This option determines if the kernel forces gcc to inline the functions
 231           developers have marked 'inline'. Doing so takes away freedom from gcc to
 232           do what it thinks is best, which is desirable for the gcc 3.x series of
 233           compilers. The gcc 4.x series have a rewritten inlining algorithm and
 234           disabling this option will generate a smaller kernel there. Hopefully
 235           this algorithm is so good that allowing gcc4 to make the decision can
 236           become the default in the future, until then this option is there to
 237           test gcc for this.
 238
 239 config RCU_TORTURE_TEST
 240         tristate "torture tests for RCU"
 241         depends on DEBUG_KERNEL
 242         default n
 243         help
 244           This option provides a kernel module that runs torture tests
 245           on the RCU infrastructure.  The kernel module may be built
 246           after the fact on the running kernel to be tested, if desired.
 247
 248           Say Y here if you want RCU torture tests to start automatically
 249           at boot time (you probably don't).
 250           Say M if you want the RCU torture tests to build as a module.
 251           Say N if you are unsure.