| |
| config PRINTK_TIME |
| bool "Show timing information on printks" |
| depends on PRINTK |
| help |
| Selecting this option causes timing information to be |
| included in printk output. This allows you to measure |
| the interval between kernel operations, including bootup |
| operations. This is useful for identifying long delays |
| in kernel startup. |
| |
| 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 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 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_KERNEL |
| bool "Kernel debugging" |
| help |
| Say Y here if you are developing drivers or trying to debug and |
| identify kernel problems. |
| |
| config LOG_BUF_SHIFT |
| int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" if DEBUG_KERNEL |
| range 12 21 |
| default 17 if S390 || LOCKDEP |
| default 16 if X86_NUMAQ || IA64 |
| default 15 if SMP |
| default 14 |
| help |
| Select kernel log buffer size as a power of 2. |
| Defaults and Examples: |
| 17 => 128 KB for S/390 |
| 16 => 64 KB for x86 NUMAQ or IA-64 |
| 15 => 32 KB for SMP |
| 14 => 16 KB for uniprocessor |
| 13 => 8 KB |
| 12 => 4 KB |
| |
| config DETECT_SOFTLOCKUP |
| bool "Detect Soft Lockups" |
| depends on DEBUG_KERNEL && !S390 |
| default y |
| help |
| Say Y here to enable the kernel to detect "soft lockups", |
| which are bugs that cause the kernel to loop in kernel |
| mode for more than 10 seconds, without giving other tasks a |
| chance to run. |
| |
| When a soft-lockup is detected, the kernel will print the |
| current stack trace (which you should report), but the |
| system will stay locked up. This feature has negligible |
| overhead. |
| |
| (Note that "hard lockups" are separate type of bugs that |
| can be detected via the NMI-watchdog, on platforms that |
| support it.) |
| |
| 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 DEBUG_SLAB |
| bool "Debug slab memory allocations" |
| depends on DEBUG_KERNEL && SLAB |
| 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 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. |
| |
| 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 |
| 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_RWSEMS |
| bool "RW-sem debugging: basic checks" |
| depends on DEBUG_KERNEL |
| help |
| This feature allows read-write semaphore semantics violations to |
| be detected and reported. |
| |
| 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 DEBUG_RWSEMS |
| 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_RWSEMS |
| select DEBUG_LOCK_ALLOC |
| 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 !X86 |
| select KALLSYMS |
| select KALLSYMS_ALL |
| |
| 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 TRACE_IRQFLAGS |
| depends on DEBUG_KERNEL |
| bool |
| default y |
| depends on TRACE_IRQFLAGS_SUPPORT |
| depends on PROVE_LOCKING |
| |
| config DEBUG_SPINLOCK_SLEEP |
| bool "Spinlock debugging: sleep-inside-spinlock checking" |
| depends on DEBUG_KERNEL |
| help |
| If you say Y here, various routines which may sleep will become very |
| noisy if they are called with a spinlock held. |
| |
| 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. |
| |
| config STACKTRACE |
| bool |
| depends on DEBUG_KERNEL |
| 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_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 DEBUG_BUGVERBOSE |
| bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EMBEDDED |
| depends on BUG |
| depends on ARM || ARM26 || AVR32 || M32R || M68K || SPARC32 || SPARC64 || FRV || SUPERH || GENERIC_BUG |
| default !EMBEDDED |
| 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_INFO |
| bool "Compile the kernel with debug info" |
| depends on DEBUG_KERNEL |
| help |
| If you say Y here the resulting kernel image will include |
| debugging info resulting in a larger kernel image. |
| Say Y here only if you plan to debug the kernel. |
| |
| If unsure, say N. |
| |
| config DEBUG_FS |
| bool "Debug Filesystem" |
| depends on SYSFS |
| 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. |
| |
| If unsure, say N. |
| |
| 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_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 FRAME_POINTER |
| bool "Compile the kernel with frame pointers" |
| depends on DEBUG_KERNEL && (X86 || CRIS || M68K || M68KNOMMU || FRV || UML || S390 || AVR32 || SUPERH) |
| default y if DEBUG_INFO && UML |
| help |
| If you say Y here the resulting kernel image will be slightly larger |
| and slower, but it might give very useful debugging information on |
| some architectures or if you use external debuggers. |
| If you don't debug the kernel, you can say N. |
| |
| config UNWIND_INFO |
| bool "Compile the kernel with frame unwind information" |
| depends on !IA64 && !PARISC && !ARM |
| depends on !MODULES || !(MIPS || PPC || SUPERH || V850) |
| help |
| If you say Y here the resulting kernel image will be slightly larger |
| but not slower, and it will give very useful debugging information. |
| If you don't debug the kernel, you can say N, but we may not be able |
| to solve problems without frame unwind information or frame pointers. |
| |
| config STACK_UNWIND |
| bool "Stack unwind support" |
| depends on UNWIND_INFO |
| depends on X86 |
| help |
| This enables more precise stack traces, omitting all unrelated |
| occurrences of pointers into kernel code from the dump. |
| |
| config FORCED_INLINING |
| bool "Force gcc to inline functions marked 'inline'" |
| depends on DEBUG_KERNEL |
| default y |
| help |
| This option determines if the kernel forces gcc to inline the functions |
| developers have marked 'inline'. Doing so takes away freedom from gcc to |
| do what it thinks is best, which is desirable for the gcc 3.x series of |
| compilers. The gcc 4.x series have a rewritten inlining algorithm and |
| disabling this option will generate a smaller kernel there. Hopefully |
| this algorithm is so good that allowing gcc4 to make the decision can |
| become the default in the future, until then this option is there to |
| test gcc for this. |
| |
| 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 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 start automatically |
| at boot time (you probably don't). |
| Say M if you want the RCU torture tests to build as a module. |
| Say N if you are unsure. |
| |
| config LKDTM |
| tristate "Linux Kernel Dump Test Tool Module" |
| depends on KPROBES |
| 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 |
| drivers/misc/lkdtm.c |
| |
| config FAULT_INJECTION |
| bool |
| |
| config FAULT_INJECTION_DEBUG_FS |
| bool "Debugfs entries for fault-injection capabilities" |
| depends on FAULT_INJECTION && SYSFS |
| select DEBUG_FS |
| help |
| This option enable configuration of fault-injection capabilities via |
| debugfs. |
| |
