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         default y
 113         depends on DEBUG_KERNEL && RT_MUTEXES
 114         help
 115          This allows rt mutex semantics violations and rt mutex related
 116          deadlocks (lockups) to be detected and reported automatically.
 117
 118 config DEBUG_PI_LIST
 119         bool
 120         default y
 121         depends on DEBUG_RT_MUTEXES
 122
 123 config DEBUG_SPINLOCK
 124         bool "Spinlock debugging"
 125         depends on DEBUG_KERNEL
 126         help
 127           Say Y here and build SMP to catch missing spinlock initialization
 128           and certain other kinds of spinlock errors commonly made.  This is
 129           best used in conjunction with the NMI watchdog so that spinlock
 130           deadlocks are also debuggable.
 131
 132 config DEBUG_SPINLOCK_SLEEP
 133         bool "Sleep-inside-spinlock checking"
 134         depends on DEBUG_KERNEL
 135         help
 136           If you say Y here, various routines which may sleep will become very
 137           noisy if they are called with a spinlock held.
 138
 139 config DEBUG_KOBJECT
 140         bool "kobject debugging"
 141         depends on DEBUG_KERNEL
 142         help
 143           If you say Y here, some extra kobject debugging messages will be sent
 144           to the syslog.
 145
 146 config DEBUG_HIGHMEM
 147         bool "Highmem debugging"
 148         depends on DEBUG_KERNEL && HIGHMEM
 149         help
 150           This options enables addition error checking for high memory systems.
 151           Disable for production systems.
 152
 153 config DEBUG_BUGVERBOSE
 154         bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EMBEDDED
 155         depends on BUG
 156         depends on ARM || ARM26 || M32R || M68K || SPARC32 || SPARC64 || X86_32 || FRV
 157         default !EMBEDDED
 158         help
 159           Say Y here to make BUG() panics output the file name and line number
 160           of the BUG call as well as the EIP and oops trace.  This aids
 161           debugging but costs about 70-100K of memory.
 162
 163 config DEBUG_INFO
 164         bool "Compile the kernel with debug info"
 165         depends on DEBUG_KERNEL
 166         help
 167           If you say Y here the resulting kernel image will include
 168           debugging info resulting in a larger kernel image.
 169           Say Y here only if you plan to debug the kernel.
 170
 171           If unsure, say N.
 172
 173 config DEBUG_FS
 174         bool "Debug Filesystem"
 175         depends on SYSFS
 176         help
 177           debugfs is a virtual file system that kernel developers use to put
 178           debugging files into.  Enable this option to be able to read and
 179           write to these files.
 180
 181           If unsure, say N.
 182
 183 config DEBUG_VM
 184         bool "Debug VM"
 185         depends on DEBUG_KERNEL
 186         help
 187           Enable this to turn on extended checks in the virtual-memory system
 188           that may impact performance.
 189
 190           If unsure, say N.
 191
 192 config FRAME_POINTER
 193         bool "Compile the kernel with frame pointers"
 194         depends on DEBUG_KERNEL && (X86 || CRIS || M68K || M68KNOMMU || FRV || UML)
 195         default y if DEBUG_INFO && UML
 196         help
 197           If you say Y here the resulting kernel image will be slightly larger
 198           and slower, but it might give very useful debugging information on
 199           some architectures or if you use external debuggers.
 200           If you don't debug the kernel, you can say N.
 201
 202 config UNWIND_INFO
 203         bool "Compile the kernel with frame unwind information"
 204         depends on !IA64 && !PARISC
 205         depends on !MODULES || !(MIPS || PPC || SUPERH || V850)
 206         help
 207           If you say Y here the resulting kernel image will be slightly larger
 208           but not slower, and it will give very useful debugging information.
 209           If you don't debug the kernel, you can say N, but we may not be able
 210           to solve problems without frame unwind information or frame pointers.
 211
 212 config STACK_UNWIND
 213         bool "Stack unwind support"
 214         depends on UNWIND_INFO
 215         depends on X86
 216         help
 217           This enables more precise stack traces, omitting all unrelated
 218           occurrences of pointers into kernel code from the dump.
 219
 220 config FORCED_INLINING
 221         bool "Force gcc to inline functions marked 'inline'"
 222         depends on DEBUG_KERNEL
 223         default y
 224         help
 225           This option determines if the kernel forces gcc to inline the functions
 226           developers have marked 'inline'. Doing so takes away freedom from gcc to
 227           do what it thinks is best, which is desirable for the gcc 3.x series of
 228           compilers. The gcc 4.x series have a rewritten inlining algorithm and
 229           disabling this option will generate a smaller kernel there. Hopefully
 230           this algorithm is so good that allowing gcc4 to make the decision can
 231           become the default in the future, until then this option is there to
 232           test gcc for this.
 233
 234 config RCU_TORTURE_TEST
 235         tristate "torture tests for RCU"
 236         depends on DEBUG_KERNEL
 237         default n
 238         help
 239           This option provides a kernel module that runs torture tests
 240           on the RCU infrastructure.  The kernel module may be built
 241           after the fact on the running kernel to be tested, if desired.
 242
 243           Say Y here if you want RCU torture tests to start automatically
 244           at boot time (you probably don't).
 245           Say M if you want the RCU torture tests to build as a module.
 246           Say N if you are unsure.