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"
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
config LOG_BUF_SHIFT
int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" if DEBUG_KERNEL
range 12 21
- default 17 if S390
+ default 17 if S390 || LOCKDEP
default 16 if X86_NUMAQ || IA64
default 15 if SMP
default 14
config DEBUG_PREEMPT
bool "Debug preemptible kernel"
- depends on DEBUG_KERNEL && PREEMPT
+ 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
if kernel code uses it in a preemption-unsafe way. Also, the kernel
will detect preemption count underflows.
-config DEBUG_MUTEXES
- bool "Mutex debugging, deadlock detection"
+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_KERNEL
+ 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 allows mutex semantics violations and mutex related deadlocks
- (lockups) to be detected and reported automatically.
+ This option enables a rt-mutex tester.
config DEBUG_SPINLOCK
- bool "Spinlock debugging"
+ bool "Spinlock and rw-lock debugging: basic checks"
depends on DEBUG_KERNEL
help
Say Y here and build SMP to catch missing spinlock initialization
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 "Sleep-inside-spinlock checking"
+ 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
config DEBUG_BUGVERBOSE
bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EMBEDDED
depends on BUG
- depends on ARM || ARM26 || M32R || M68K || SPARC32 || SPARC64 || X86_32 || FRV
+ depends on ARM || ARM26 || AVR32 || M32R || M68K || SPARC32 || SPARC64 || X86_32 || FRV || SUPERH
default !EMBEDDED
help
Say Y here to make BUG() panics output the file name and line number
If unsure, say N.
-config DEBUG_IOREMAP
- bool "Enable ioremap() debugging"
- depends on DEBUG_KERNEL && PARISC
- help
- Enabling this option will cause the kernel to distinguish between
- ioremapped and physical addresses. It will print a backtrace (at
- most one every 10 seconds), hopefully allowing you to see which
- drivers need work. Fixing all these problems is a prerequisite
- for turning on USE_HPPA_IOREMAP. The warnings are harmless;
- the kernel has enough information to fix the broken drivers
- automatically, but we'd like to make it more efficient by not
- having to do that.
-
config DEBUG_FS
bool "Debug Filesystem"
- depends on DEBUG_KERNEL && SYSFS
+ 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
config FRAME_POINTER
bool "Compile the kernel with frame pointers"
- depends on DEBUG_KERNEL && (X86 || CRIS || M68K || M68KNOMMU || FRV || UML)
+ 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
config UNWIND_INFO
bool "Compile the kernel with frame unwind information"
- depends on !IA64
- depends on !MODULES || !(MIPS || PARISC || PPC || SUPERH || SPARC64 || V850)
+ depends on !IA64 && !PARISC
+ 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