mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-11-24 20:40:52 +07:00
7664c5a1da
This patch adds common handling for kernel BUGs, for use by architectures as they wish. The code is derived from arch/powerpc. The advantages of having common BUG handling are: - consistent BUG reporting across architectures - shared implementation of out-of-line file/line data - implement CONFIG_DEBUG_BUGVERBOSE consistently This means that in inline impact of BUG is just the illegal instruction itself, which is an improvement for i386 and x86-64. A BUG is represented in the instruction stream as an illegal instruction, which has file/line information associated with it. This extra information is stored in the __bug_table section in the ELF file. When the kernel gets an illegal instruction, it first confirms it might possibly be from a BUG (ie, in kernel mode, the right illegal instruction). It then calls report_bug(). This searches __bug_table for a matching instruction pointer, and if found, prints the corresponding file/line information. If report_bug() determines that it wasn't a BUG which caused the trap, it returns BUG_TRAP_TYPE_NONE. Some architectures (powerpc) implement WARN using the same mechanism; if the illegal instruction was the result of a WARN, then report_bug(Q) returns CONFIG_DEBUG_BUGVERBOSE; otherwise it returns BUG_TRAP_TYPE_BUG. lib/bug.c keeps a list of loaded modules which can be searched for __bug_table entries. The architecture must call module_bug_finalize()/module_bug_cleanup() from its corresponding module_finalize/cleanup functions. Unsetting CONFIG_DEBUG_BUGVERBOSE will reduce the kernel size by some amount. At the very least, filename and line information will not be recorded for each but, but architectures may decide to store no extra information per BUG at all. Unfortunately, gcc doesn't have a general way to mark an asm() as noreturn, so architectures will generally have to include an infinite loop (or similar) in the BUG code, so that gcc knows execution won't continue beyond that point. gcc does have a __builtin_trap() operator which may be useful to achieve the same effect, unfortunately it cannot be used to actually implement the BUG itself, because there's no way to get the instruction's address for use in generating the __bug_table entry. [randy.dunlap@oracle.com: Handle BUG=n, GENERIC_BUG=n to prevent build errors] [bunk@stusta.de: include/linux/bug.h must always #include <linux/module.h] Signed-off-by: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Andi Kleen <ak@muc.de> Cc: Hugh Dickens <hugh@veritas.com> Cc: Michael Ellerman <michael@ellerman.id.au> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
416 lines
14 KiB
Plaintext
416 lines
14 KiB
Plaintext
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config PRINTK_TIME
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bool "Show timing information on printks"
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depends on PRINTK
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help
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Selecting this option causes timing information to be
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included in printk output. This allows you to measure
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the interval between kernel operations, including bootup
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operations. This is useful for identifying long delays
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in kernel startup.
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config ENABLE_MUST_CHECK
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bool "Enable __must_check logic"
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default y
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help
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Enable the __must_check logic in the kernel build. Disable this to
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suppress the "warning: ignoring return value of 'foo', declared with
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attribute warn_unused_result" messages.
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config MAGIC_SYSRQ
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bool "Magic SysRq key"
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depends on !UML
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help
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If you say Y here, you will have some control over the system even
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if the system crashes for example during kernel debugging (e.g., you
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will be able to flush the buffer cache to disk, reboot the system
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immediately or dump some status information). This is accomplished
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by pressing various keys while holding SysRq (Alt+PrintScreen). It
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also works on a serial console (on PC hardware at least), if you
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send a BREAK and then within 5 seconds a command keypress. The
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keys are documented in <file:Documentation/sysrq.txt>. Don't say Y
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unless you really know what this hack does.
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config UNUSED_SYMBOLS
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bool "Enable unused/obsolete exported symbols"
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default y if X86
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help
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Unused but exported symbols make the kernel needlessly bigger. For
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that reason most of these unused exports will soon be removed. This
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option is provided temporarily to provide a transition period in case
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some external kernel module needs one of these symbols anyway. If you
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encounter such a case in your module, consider if you are actually
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using the right API. (rationale: since nobody in the kernel is using
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this in a module, there is a pretty good chance it's actually the
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wrong interface to use). If you really need the symbol, please send a
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mail to the linux kernel mailing list mentioning the symbol and why
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you really need it, and what the merge plan to the mainline kernel for
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your module is.
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config DEBUG_KERNEL
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bool "Kernel debugging"
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help
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Say Y here if you are developing drivers or trying to debug and
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identify kernel problems.
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config LOG_BUF_SHIFT
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int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" if DEBUG_KERNEL
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range 12 21
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default 17 if S390 || LOCKDEP
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default 16 if X86_NUMAQ || IA64
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default 15 if SMP
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default 14
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help
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Select kernel log buffer size as a power of 2.
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Defaults and Examples:
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17 => 128 KB for S/390
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16 => 64 KB for x86 NUMAQ or IA-64
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15 => 32 KB for SMP
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14 => 16 KB for uniprocessor
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13 => 8 KB
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12 => 4 KB
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config DETECT_SOFTLOCKUP
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bool "Detect Soft Lockups"
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depends on DEBUG_KERNEL && !S390
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default y
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help
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Say Y here to enable the kernel to detect "soft lockups",
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which are bugs that cause the kernel to loop in kernel
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mode for more than 10 seconds, without giving other tasks a
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chance to run.
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When a soft-lockup is detected, the kernel will print the
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current stack trace (which you should report), but the
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system will stay locked up. This feature has negligible
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overhead.
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(Note that "hard lockups" are separate type of bugs that
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can be detected via the NMI-watchdog, on platforms that
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support it.)
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config SCHEDSTATS
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bool "Collect scheduler statistics"
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depends on DEBUG_KERNEL && PROC_FS
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help
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If you say Y here, additional code will be inserted into the
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scheduler and related routines to collect statistics about
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scheduler behavior and provide them in /proc/schedstat. These
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stats may be useful for both tuning and debugging the scheduler
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If you aren't debugging the scheduler or trying to tune a specific
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application, you can say N to avoid the very slight overhead
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this adds.
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config DEBUG_SLAB
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bool "Debug slab memory allocations"
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depends on DEBUG_KERNEL && SLAB
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help
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Say Y here to have the kernel do limited verification on memory
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allocation as well as poisoning memory on free to catch use of freed
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memory. This can make kmalloc/kfree-intensive workloads much slower.
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config DEBUG_SLAB_LEAK
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bool "Memory leak debugging"
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depends on DEBUG_SLAB
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config DEBUG_PREEMPT
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bool "Debug preemptible kernel"
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depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT
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default y
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help
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If you say Y here then the kernel will use a debug variant of the
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commonly used smp_processor_id() function and will print warnings
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if kernel code uses it in a preemption-unsafe way. Also, the kernel
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will detect preemption count underflows.
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config DEBUG_RT_MUTEXES
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bool "RT Mutex debugging, deadlock detection"
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depends on DEBUG_KERNEL && RT_MUTEXES
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help
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This allows rt mutex semantics violations and rt mutex related
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deadlocks (lockups) to be detected and reported automatically.
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config DEBUG_PI_LIST
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bool
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default y
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depends on DEBUG_RT_MUTEXES
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config RT_MUTEX_TESTER
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bool "Built-in scriptable tester for rt-mutexes"
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depends on DEBUG_KERNEL && RT_MUTEXES
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help
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This option enables a rt-mutex tester.
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config DEBUG_SPINLOCK
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bool "Spinlock and rw-lock debugging: basic checks"
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depends on DEBUG_KERNEL
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help
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Say Y here and build SMP to catch missing spinlock initialization
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and certain other kinds of spinlock errors commonly made. This is
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best used in conjunction with the NMI watchdog so that spinlock
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deadlocks are also debuggable.
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config DEBUG_MUTEXES
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bool "Mutex debugging: basic checks"
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depends on DEBUG_KERNEL
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help
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This feature allows mutex semantics violations to be detected and
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reported.
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config DEBUG_RWSEMS
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bool "RW-sem debugging: basic checks"
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depends on DEBUG_KERNEL
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help
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This feature allows read-write semaphore semantics violations to
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be detected and reported.
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config DEBUG_LOCK_ALLOC
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bool "Lock debugging: detect incorrect freeing of live locks"
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depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
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select DEBUG_SPINLOCK
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select DEBUG_MUTEXES
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select DEBUG_RWSEMS
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select LOCKDEP
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help
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This feature will check whether any held lock (spinlock, rwlock,
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mutex or rwsem) is incorrectly freed by the kernel, via any of the
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memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
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vfree(), etc.), whether a live lock is incorrectly reinitialized via
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spin_lock_init()/mutex_init()/etc., or whether there is any lock
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held during task exit.
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config PROVE_LOCKING
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bool "Lock debugging: prove locking correctness"
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depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
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select LOCKDEP
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select DEBUG_SPINLOCK
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select DEBUG_MUTEXES
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select DEBUG_RWSEMS
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select DEBUG_LOCK_ALLOC
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default n
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help
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This feature enables the kernel to prove that all locking
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that occurs in the kernel runtime is mathematically
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correct: that under no circumstance could an arbitrary (and
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not yet triggered) combination of observed locking
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sequences (on an arbitrary number of CPUs, running an
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arbitrary number of tasks and interrupt contexts) cause a
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deadlock.
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In short, this feature enables the kernel to report locking
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related deadlocks before they actually occur.
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The proof does not depend on how hard and complex a
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deadlock scenario would be to trigger: how many
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participant CPUs, tasks and irq-contexts would be needed
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for it to trigger. The proof also does not depend on
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timing: if a race and a resulting deadlock is possible
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theoretically (no matter how unlikely the race scenario
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is), it will be proven so and will immediately be
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reported by the kernel (once the event is observed that
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makes the deadlock theoretically possible).
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If a deadlock is impossible (i.e. the locking rules, as
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observed by the kernel, are mathematically correct), the
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kernel reports nothing.
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NOTE: this feature can also be enabled for rwlocks, mutexes
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and rwsems - in which case all dependencies between these
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different locking variants are observed and mapped too, and
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the proof of observed correctness is also maintained for an
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arbitrary combination of these separate locking variants.
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For more details, see Documentation/lockdep-design.txt.
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config LOCKDEP
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bool
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depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
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select STACKTRACE
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select FRAME_POINTER if !X86
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select KALLSYMS
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select KALLSYMS_ALL
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config DEBUG_LOCKDEP
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bool "Lock dependency engine debugging"
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depends on DEBUG_KERNEL && LOCKDEP
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help
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If you say Y here, the lock dependency engine will do
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additional runtime checks to debug itself, at the price
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of more runtime overhead.
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config TRACE_IRQFLAGS
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depends on DEBUG_KERNEL
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bool
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default y
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depends on TRACE_IRQFLAGS_SUPPORT
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depends on PROVE_LOCKING
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config DEBUG_SPINLOCK_SLEEP
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bool "Spinlock debugging: sleep-inside-spinlock checking"
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depends on DEBUG_KERNEL
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help
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If you say Y here, various routines which may sleep will become very
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noisy if they are called with a spinlock held.
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config DEBUG_LOCKING_API_SELFTESTS
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bool "Locking API boot-time self-tests"
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depends on DEBUG_KERNEL
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help
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Say Y here if you want the kernel to run a short self-test during
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bootup. The self-test checks whether common types of locking bugs
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are detected by debugging mechanisms or not. (if you disable
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lock debugging then those bugs wont be detected of course.)
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The following locking APIs are covered: spinlocks, rwlocks,
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mutexes and rwsems.
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config STACKTRACE
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bool
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depends on DEBUG_KERNEL
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depends on STACKTRACE_SUPPORT
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config DEBUG_KOBJECT
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bool "kobject debugging"
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depends on DEBUG_KERNEL
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help
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If you say Y here, some extra kobject debugging messages will be sent
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to the syslog.
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config DEBUG_HIGHMEM
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bool "Highmem debugging"
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depends on DEBUG_KERNEL && HIGHMEM
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help
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This options enables addition error checking for high memory systems.
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Disable for production systems.
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config DEBUG_BUGVERBOSE
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bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EMBEDDED
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depends on BUG
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depends on ARM || ARM26 || AVR32 || M32R || M68K || SPARC32 || SPARC64 || X86_32 || FRV || SUPERH || GENERIC_BUG
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default !EMBEDDED
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help
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Say Y here to make BUG() panics output the file name and line number
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of the BUG call as well as the EIP and oops trace. This aids
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debugging but costs about 70-100K of memory.
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config DEBUG_INFO
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bool "Compile the kernel with debug info"
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depends on DEBUG_KERNEL
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help
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If you say Y here the resulting kernel image will include
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debugging info resulting in a larger kernel image.
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Say Y here only if you plan to debug the kernel.
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If unsure, say N.
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config DEBUG_FS
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bool "Debug Filesystem"
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depends on SYSFS
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help
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debugfs is a virtual file system that kernel developers use to put
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debugging files into. Enable this option to be able to read and
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write to these files.
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If unsure, say N.
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config DEBUG_VM
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bool "Debug VM"
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depends on DEBUG_KERNEL
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help
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Enable this to turn on extended checks in the virtual-memory system
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that may impact performance.
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If unsure, say N.
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config DEBUG_LIST
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bool "Debug linked list manipulation"
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depends on DEBUG_KERNEL
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help
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Enable this to turn on extended checks in the linked-list
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walking routines.
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If unsure, say N.
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config FRAME_POINTER
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bool "Compile the kernel with frame pointers"
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depends on DEBUG_KERNEL && (X86 || CRIS || M68K || M68KNOMMU || FRV || UML || S390 || AVR32 || SUPERH)
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default y if DEBUG_INFO && UML
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help
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If you say Y here the resulting kernel image will be slightly larger
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and slower, but it might give very useful debugging information on
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some architectures or if you use external debuggers.
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If you don't debug the kernel, you can say N.
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config UNWIND_INFO
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bool "Compile the kernel with frame unwind information"
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depends on !IA64 && !PARISC && !ARM
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depends on !MODULES || !(MIPS || PPC || SUPERH || V850)
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help
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If you say Y here the resulting kernel image will be slightly larger
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but not slower, and it will give very useful debugging information.
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If you don't debug the kernel, you can say N, but we may not be able
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to solve problems without frame unwind information or frame pointers.
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config STACK_UNWIND
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bool "Stack unwind support"
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depends on UNWIND_INFO
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depends on X86
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help
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This enables more precise stack traces, omitting all unrelated
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occurrences of pointers into kernel code from the dump.
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config FORCED_INLINING
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bool "Force gcc to inline functions marked 'inline'"
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depends on DEBUG_KERNEL
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default y
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help
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This option determines if the kernel forces gcc to inline the functions
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developers have marked 'inline'. Doing so takes away freedom from gcc to
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do what it thinks is best, which is desirable for the gcc 3.x series of
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compilers. The gcc 4.x series have a rewritten inlining algorithm and
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disabling this option will generate a smaller kernel there. Hopefully
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this algorithm is so good that allowing gcc4 to make the decision can
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become the default in the future, until then this option is there to
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test gcc for this.
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config HEADERS_CHECK
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bool "Run 'make headers_check' when building vmlinux"
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depends on !UML
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help
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This option will extract the user-visible kernel headers whenever
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building the kernel, and will run basic sanity checks on them to
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ensure that exported files do not attempt to include files which
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were not exported, etc.
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If you're making modifications to header files which are
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relevant for userspace, say 'Y', and check the headers
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exported to $(INSTALL_HDR_PATH) (usually 'usr/include' in
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your build tree), to make sure they're suitable.
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config RCU_TORTURE_TEST
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tristate "torture tests for RCU"
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depends on DEBUG_KERNEL
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default n
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help
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This option provides a kernel module that runs torture tests
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on the RCU infrastructure. The kernel module may be built
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after the fact on the running kernel to be tested, if desired.
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Say Y here if you want RCU torture tests to start automatically
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at boot time (you probably don't).
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Say M if you want the RCU torture tests to build as a module.
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Say N if you are unsure.
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config LKDTM
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tristate "Linux Kernel Dump Test Tool Module"
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depends on KPROBES
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default n
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help
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This module enables testing of the different dumping mechanisms by
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inducing system failures at predefined crash points.
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If you don't need it: say N
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Choose M here to compile this code as a module. The module will be
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called lkdtm.
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Documentation on how to use the module can be found in
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drivers/misc/lkdtm.c
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