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