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Text File | 2007-04-12 | 14.5 KB | 432 lines

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_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 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 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_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 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 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 DEBUG_KERNEL 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 "Fault-injection framework" depends on DEBUG_KERNEL && STACKTRACE_SUPPORT select STACKTRACE select FRAME_POINTER help Provide fault-injection framework. For more details, see Documentation/fault-injection/. config FAILSLAB bool "Fault-injection capability for kmalloc" depends on FAULT_INJECTION help Provide fault-injection capability for kmalloc. config FAIL_PAGE_ALLOC bool "Fault-injection capabilitiy for alloc_pages()" depends on FAULT_INJECTION help Provide fault-injection capability for alloc_pages(). config FAIL_MAKE_REQUEST bool "Fault-injection capability for disk IO" depends on FAULT_INJECTION help Provide fault-injection capability for disk IO. config FAULT_INJECTION_DEBUG_FS bool "Debugfs entries for fault-injection capabilities" depends on FAULT_INJECTION && SYSFS && DEBUG_FS help Enable configuration of fault-injection capabilities via debugfs.