99172a2f9e
Cite Documentation/kernel-parameters.txt for an alternative to building with PRINTK_TIME compiled in. Signed-off-by: Jim Cromie <jim.cromie@gmail.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
1231 lines
42 KiB
Plaintext
1231 lines
42 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. Or add printk.time=1 at boot-time.
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See Documentation/kernel-parameters.txt
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config ENABLE_WARN_DEPRECATED
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bool "Enable __deprecated logic"
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default y
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help
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Enable the __deprecated logic in the kernel build.
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Disable this to suppress the "warning: 'foo' is deprecated
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(declared at kernel/power/somefile.c:1234)" messages.
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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 FRAME_WARN
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int "Warn for stack frames larger than (needs gcc 4.4)"
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range 0 8192
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default 1024 if !64BIT
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default 2048 if 64BIT
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help
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Tell gcc to warn at build time for stack frames larger than this.
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Setting this too low will cause a lot of warnings.
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Setting it to 0 disables the warning.
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Requires gcc 4.4
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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 STRIP_ASM_SYMS
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bool "Strip assembler-generated symbols during link"
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default n
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help
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Strip internal assembler-generated symbols during a link (symbols
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that look like '.Lxxx') so they don't pollute the output of
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get_wchan() and suchlike.
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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_FS
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bool "Debug Filesystem"
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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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For detailed documentation on the debugfs API, see
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Documentation/DocBook/filesystems.
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If unsure, say N.
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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 DEBUG_SECTION_MISMATCH
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bool "Enable full Section mismatch analysis"
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depends on UNDEFINED || (BLACKFIN)
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default y
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# This option is on purpose disabled for now.
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# It will be enabled when we are down to a reasonable number
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# of section mismatch warnings (< 10 for an allyesconfig build)
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help
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The section mismatch analysis checks if there are illegal
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references from one section to another section.
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Linux will during link or during runtime drop some sections
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and any use of code/data previously in these sections will
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most likely result in an oops.
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In the code functions and variables are annotated with
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__init, __devinit etc. (see full list in include/linux/init.h)
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which results in the code/data being placed in specific sections.
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The section mismatch analysis is always done after a full
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kernel build but enabling this option will in addition
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do the following:
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- Add the option -fno-inline-functions-called-once to gcc
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When inlining a function annotated __init in a non-init
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function we would lose the section information and thus
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the analysis would not catch the illegal reference.
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This option tells gcc to inline less but will also
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result in a larger kernel.
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- Run the section mismatch analysis for each module/built-in.o
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When we run the section mismatch analysis on vmlinux.o we
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lose valueble information about where the mismatch was
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introduced.
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Running the analysis for each module/built-in.o file
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will tell where the mismatch happens much closer to the
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source. The drawback is that we will report the same
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mismatch at least twice.
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- Enable verbose reporting from modpost to help solving
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the section mismatches reported.
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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 DEBUG_SHIRQ
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bool "Debug shared IRQ handlers"
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depends on DEBUG_KERNEL && GENERIC_HARDIRQS
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help
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Enable this to generate a spurious interrupt as soon as a shared
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interrupt handler is registered, and just before one is deregistered.
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Drivers ought to be able to handle interrupts coming in at those
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points; some don't and need to be caught.
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config LOCKUP_DETECTOR
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bool "Detect Hard and Soft Lockups"
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depends on DEBUG_KERNEL && !S390
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help
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Say Y here to enable the kernel to act as a watchdog to detect
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hard and soft lockups.
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Softlockups are bugs that cause the kernel to loop in kernel
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mode for more than 60 seconds, without giving other tasks a
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chance to run. The current stack trace is displayed upon
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detection and the system will stay locked up.
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Hardlockups are bugs that cause the CPU to loop in kernel mode
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for more than 60 seconds, without letting other interrupts have a
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chance to run. The current stack trace is displayed upon detection
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and the system will stay locked up.
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The overhead should be minimal. A periodic hrtimer runs to
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generate interrupts and kick the watchdog task every 10-12 seconds.
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An NMI is generated every 60 seconds or so to check for hardlockups.
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config HARDLOCKUP_DETECTOR
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def_bool LOCKUP_DETECTOR && PERF_EVENTS && HAVE_PERF_EVENTS_NMI && \
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!ARCH_HAS_NMI_WATCHDOG
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config BOOTPARAM_SOFTLOCKUP_PANIC
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bool "Panic (Reboot) On Soft Lockups"
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depends on LOCKUP_DETECTOR
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help
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Say Y here to enable the kernel to panic on "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 60 seconds, without giving other tasks a
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chance to run.
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The panic can be used in combination with panic_timeout,
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to cause the system to reboot automatically after a
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lockup has been detected. This feature is useful for
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high-availability systems that have uptime guarantees and
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where a lockup must be resolved ASAP.
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Say N if unsure.
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config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
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int
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depends on LOCKUP_DETECTOR
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range 0 1
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default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
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default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
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config DETECT_HUNG_TASK
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bool "Detect Hung Tasks"
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depends on DEBUG_KERNEL
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default DETECT_SOFTLOCKUP
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help
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Say Y here to enable the kernel to detect "hung tasks",
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which are bugs that cause the task to be stuck in
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uninterruptible "D" state indefinitiley.
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When a hung task is detected, the kernel will print the
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current stack trace (which you should report), but the
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task will stay in uninterruptible state. If lockdep is
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enabled then all held locks will also be reported. This
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feature has negligible overhead.
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config BOOTPARAM_HUNG_TASK_PANIC
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bool "Panic (Reboot) On Hung Tasks"
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depends on DETECT_HUNG_TASK
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help
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Say Y here to enable the kernel to panic on "hung tasks",
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which are bugs that cause the kernel to leave a task stuck
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in uninterruptible "D" state.
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The panic can be used in combination with panic_timeout,
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to cause the system to reboot automatically after a
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hung task has been detected. This feature is useful for
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high-availability systems that have uptime guarantees and
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where a hung tasks must be resolved ASAP.
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Say N if unsure.
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config BOOTPARAM_HUNG_TASK_PANIC_VALUE
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int
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depends on DETECT_HUNG_TASK
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range 0 1
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default 0 if !BOOTPARAM_HUNG_TASK_PANIC
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default 1 if BOOTPARAM_HUNG_TASK_PANIC
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config SCHED_DEBUG
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bool "Collect scheduler debugging info"
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depends on DEBUG_KERNEL && PROC_FS
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default y
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help
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If you say Y here, the /proc/sched_debug file will be provided
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that can help debug the scheduler. The runtime overhead of this
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option is minimal.
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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 TIMER_STATS
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bool "Collect kernel timers 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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timer routines to collect statistics about kernel timers being
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reprogrammed. The statistics can be read from /proc/timer_stats.
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The statistics collection is started by writing 1 to /proc/timer_stats,
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writing 0 stops it. This feature is useful to collect information
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about timer usage patterns in kernel and userspace. This feature
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is lightweight if enabled in the kernel config but not activated
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(it defaults to deactivated on bootup and will only be activated
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if some application like powertop activates it explicitly).
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config DEBUG_OBJECTS
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bool "Debug object operations"
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depends on DEBUG_KERNEL
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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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kernel to track the life time of various objects and validate
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the operations on those objects.
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config DEBUG_OBJECTS_SELFTEST
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bool "Debug objects selftest"
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depends on DEBUG_OBJECTS
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help
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This enables the selftest of the object debug code.
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config DEBUG_OBJECTS_FREE
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bool "Debug objects in freed memory"
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depends on DEBUG_OBJECTS
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help
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This enables checks whether a k/v free operation frees an area
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which contains an object which has not been deactivated
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properly. This can make kmalloc/kfree-intensive workloads
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much slower.
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config DEBUG_OBJECTS_TIMERS
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bool "Debug timer objects"
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depends on DEBUG_OBJECTS
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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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timer routines to track the life time of timer objects and
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validate the timer operations.
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config DEBUG_OBJECTS_WORK
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bool "Debug work objects"
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depends on DEBUG_OBJECTS
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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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work queue routines to track the life time of work objects and
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validate the work operations.
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config DEBUG_OBJECTS_RCU_HEAD
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bool "Debug RCU callbacks objects"
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depends on DEBUG_OBJECTS && PREEMPT
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help
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Enable this to turn on debugging of RCU list heads (call_rcu() usage).
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config DEBUG_OBJECTS_PERCPU_COUNTER
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bool "Debug percpu counter objects"
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depends on DEBUG_OBJECTS
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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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percpu counter routines to track the life time of percpu counter
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objects and validate the percpu counter operations.
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config DEBUG_OBJECTS_ENABLE_DEFAULT
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int "debug_objects bootup default value (0-1)"
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range 0 1
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default "1"
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depends on DEBUG_OBJECTS
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help
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Debug objects boot parameter default value
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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 && !KMEMCHECK
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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 SLUB_DEBUG_ON
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bool "SLUB debugging on by default"
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depends on SLUB && SLUB_DEBUG && !KMEMCHECK
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default n
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help
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Boot with debugging on by default. SLUB boots by default with
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the runtime debug capabilities switched off. Enabling this is
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equivalent to specifying the "slub_debug" parameter on boot.
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There is no support for more fine grained debug control like
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possible with slub_debug=xxx. SLUB debugging may be switched
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off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
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"slub_debug=-".
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config SLUB_STATS
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default n
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bool "Enable SLUB performance statistics"
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depends on SLUB && SYSFS
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help
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SLUB statistics are useful to debug SLUBs allocation behavior in
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order find ways to optimize the allocator. This should never be
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enabled for production use since keeping statistics slows down
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the allocator by a few percentage points. The slabinfo command
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supports the determination of the most active slabs to figure
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out which slabs are relevant to a particular load.
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Try running: slabinfo -DA
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config DEBUG_KMEMLEAK
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bool "Kernel memory leak detector"
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depends on DEBUG_KERNEL && EXPERIMENTAL && !MEMORY_HOTPLUG && \
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(X86 || ARM || PPC || S390 || SPARC64 || SUPERH || MICROBLAZE || TILE)
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select DEBUG_FS if SYSFS
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select STACKTRACE if STACKTRACE_SUPPORT
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select KALLSYMS
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select CRC32
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help
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Say Y here if you want to enable the memory leak
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detector. The memory allocation/freeing is traced in a way
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similar to the Boehm's conservative garbage collector, the
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difference being that the orphan objects are not freed but
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only shown in /sys/kernel/debug/kmemleak. Enabling this
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feature will introduce an overhead to memory
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allocations. See Documentation/kmemleak.txt for more
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details.
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Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
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of finding leaks due to the slab objects poisoning.
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In order to access the kmemleak file, debugfs needs to be
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mounted (usually at /sys/kernel/debug).
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config DEBUG_KMEMLEAK_EARLY_LOG_SIZE
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int "Maximum kmemleak early log entries"
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depends on DEBUG_KMEMLEAK
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range 200 40000
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default 400
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help
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Kmemleak must track all the memory allocations to avoid
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reporting false positives. Since memory may be allocated or
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freed before kmemleak is initialised, an early log buffer is
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used to store these actions. If kmemleak reports "early log
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buffer exceeded", please increase this value.
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config DEBUG_KMEMLEAK_TEST
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tristate "Simple test for the kernel memory leak detector"
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depends on DEBUG_KMEMLEAK
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help
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Say Y or M here to build a test for the kernel memory leak
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detector. This option enables a module that explicitly leaks
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memory.
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If unsure, say N.
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config DEBUG_KMEMLEAK_DEFAULT_OFF
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bool "Default kmemleak to off"
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depends on DEBUG_KMEMLEAK
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help
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Say Y here to disable kmemleak by default. It can then be enabled
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on the command line via kmemleak=on.
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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_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 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_LOCK_ALLOC
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select TRACE_IRQFLAGS
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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
|
|
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 PROVE_RCU
|
|
bool "RCU debugging: prove RCU correctness"
|
|
depends on PROVE_LOCKING
|
|
default n
|
|
help
|
|
This feature enables lockdep extensions that check for correct
|
|
use of RCU APIs. This is currently under development. Say Y
|
|
if you want to debug RCU usage or help work on the PROVE_RCU
|
|
feature.
|
|
|
|
Say N if you are unsure.
|
|
|
|
config PROVE_RCU_REPEATEDLY
|
|
bool "RCU debugging: don't disable PROVE_RCU on first splat"
|
|
depends on PROVE_RCU
|
|
default n
|
|
help
|
|
By itself, PROVE_RCU will disable checking upon issuing the
|
|
first warning (or "splat"). This feature prevents such
|
|
disabling, allowing multiple RCU-lockdep warnings to be printed
|
|
on a single reboot.
|
|
|
|
Say Y to allow multiple RCU-lockdep warnings per boot.
|
|
|
|
Say N if you are unsure.
|
|
|
|
config SPARSE_RCU_POINTER
|
|
bool "RCU debugging: sparse-based checks for pointer usage"
|
|
default n
|
|
help
|
|
This feature enables the __rcu sparse annotation for
|
|
RCU-protected pointers. This annotation will cause sparse
|
|
to flag any non-RCU used of annotated pointers. This can be
|
|
helpful when debugging RCU usage. Please note that this feature
|
|
is not intended to enforce code cleanliness; it is instead merely
|
|
a debugging aid.
|
|
|
|
Say Y to make sparse flag questionable use of RCU-protected pointers
|
|
|
|
Say N if you are unsure.
|
|
|
|
config LOCKDEP
|
|
bool
|
|
depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
|
|
select STACKTRACE
|
|
select FRAME_POINTER if !MIPS && !PPC && !ARM_UNWIND && !S390 && !MICROBLAZE
|
|
select KALLSYMS
|
|
select KALLSYMS_ALL
|
|
|
|
config LOCK_STAT
|
|
bool "Lock usage statistics"
|
|
depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
|
|
select LOCKDEP
|
|
select DEBUG_SPINLOCK
|
|
select DEBUG_MUTEXES
|
|
select DEBUG_LOCK_ALLOC
|
|
default n
|
|
help
|
|
This feature enables tracking lock contention points
|
|
|
|
For more details, see Documentation/lockstat.txt
|
|
|
|
This also enables lock events required by "perf lock",
|
|
subcommand of perf.
|
|
If you want to use "perf lock", you also need to turn on
|
|
CONFIG_EVENT_TRACING.
|
|
|
|
CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
|
|
(CONFIG_LOCKDEP defines "acquire" and "release" events.)
|
|
|
|
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
|
|
bool
|
|
help
|
|
Enables hooks to interrupt enabling and disabling for
|
|
either tracing or lock debugging.
|
|
|
|
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 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 && EXPERT
|
|
depends on BUG
|
|
depends on ARM || AVR32 || M32R || M68K || SPARC32 || SPARC64 || \
|
|
FRV || SUPERH || GENERIC_BUG || BLACKFIN || MN10300
|
|
default y
|
|
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.
|
|
This adds debug symbols to the kernel and modules (gcc -g), and
|
|
is needed if you intend to use kernel crashdump or binary object
|
|
tools like crash, kgdb, LKCD, gdb, etc on the kernel.
|
|
Say Y here only if you plan to debug the kernel.
|
|
|
|
If unsure, say N.
|
|
|
|
config DEBUG_INFO_REDUCED
|
|
bool "Reduce debugging information"
|
|
depends on DEBUG_INFO
|
|
help
|
|
If you say Y here gcc is instructed to generate less debugging
|
|
information for structure types. This means that tools that
|
|
need full debugging information (like kgdb or systemtap) won't
|
|
be happy. But if you merely need debugging information to
|
|
resolve line numbers there is no loss. Advantage is that
|
|
build directory object sizes shrink dramatically over a full
|
|
DEBUG_INFO build and compile times are reduced too.
|
|
Only works with newer gcc versions.
|
|
|
|
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_VIRTUAL
|
|
bool "Debug VM translations"
|
|
depends on DEBUG_KERNEL && X86
|
|
help
|
|
Enable some costly sanity checks in virtual to page code. This can
|
|
catch mistakes with virt_to_page() and friends.
|
|
|
|
If unsure, say N.
|
|
|
|
config DEBUG_NOMMU_REGIONS
|
|
bool "Debug the global anon/private NOMMU mapping region tree"
|
|
depends on DEBUG_KERNEL && !MMU
|
|
help
|
|
This option causes the global tree of anonymous and private mapping
|
|
regions to be regularly checked for invalid topology.
|
|
|
|
config DEBUG_WRITECOUNT
|
|
bool "Debug filesystem writers count"
|
|
depends on DEBUG_KERNEL
|
|
help
|
|
Enable this to catch wrong use of the writers count in struct
|
|
vfsmount. This will increase the size of each file struct by
|
|
32 bits.
|
|
|
|
If unsure, say N.
|
|
|
|
config DEBUG_MEMORY_INIT
|
|
bool "Debug memory initialisation" if EXPERT
|
|
default !EXPERT
|
|
help
|
|
Enable this for additional checks during memory initialisation.
|
|
The sanity checks verify aspects of the VM such as the memory model
|
|
and other information provided by the architecture. Verbose
|
|
information will be printed at KERN_DEBUG loglevel depending
|
|
on the mminit_loglevel= command-line option.
|
|
|
|
If unsure, say Y
|
|
|
|
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 TEST_LIST_SORT
|
|
bool "Linked list sorting test"
|
|
depends on DEBUG_KERNEL
|
|
help
|
|
Enable this to turn on 'list_sort()' function test. This test is
|
|
executed only once during system boot, so affects only boot time.
|
|
|
|
If unsure, say N.
|
|
|
|
config DEBUG_SG
|
|
bool "Debug SG table operations"
|
|
depends on DEBUG_KERNEL
|
|
help
|
|
Enable this to turn on checks on scatter-gather tables. This can
|
|
help find problems with drivers that do not properly initialize
|
|
their sg tables.
|
|
|
|
If unsure, say N.
|
|
|
|
config DEBUG_NOTIFIERS
|
|
bool "Debug notifier call chains"
|
|
depends on DEBUG_KERNEL
|
|
help
|
|
Enable this to turn on sanity checking for notifier call chains.
|
|
This is most useful for kernel developers to make sure that
|
|
modules properly unregister themselves from notifier chains.
|
|
This is a relatively cheap check but if you care about maximum
|
|
performance, say N.
|
|
|
|
config DEBUG_CREDENTIALS
|
|
bool "Debug credential management"
|
|
depends on DEBUG_KERNEL
|
|
help
|
|
Enable this to turn on some debug checking for credential
|
|
management. The additional code keeps track of the number of
|
|
pointers from task_structs to any given cred struct, and checks to
|
|
see that this number never exceeds the usage count of the cred
|
|
struct.
|
|
|
|
Furthermore, if SELinux is enabled, this also checks that the
|
|
security pointer in the cred struct is never seen to be invalid.
|
|
|
|
If unsure, say N.
|
|
|
|
#
|
|
# Select this config option from the architecture Kconfig, if it
|
|
# it is preferred to always offer frame pointers as a config
|
|
# option on the architecture (regardless of KERNEL_DEBUG):
|
|
#
|
|
config ARCH_WANT_FRAME_POINTERS
|
|
bool
|
|
help
|
|
|
|
config FRAME_POINTER
|
|
bool "Compile the kernel with frame pointers"
|
|
depends on DEBUG_KERNEL && \
|
|
(CRIS || M68K || FRV || UML || \
|
|
AVR32 || SUPERH || BLACKFIN || MN10300) || \
|
|
ARCH_WANT_FRAME_POINTERS
|
|
default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
|
|
help
|
|
If you say Y here the resulting kernel image will be slightly
|
|
larger and slower, but it gives very useful debugging information
|
|
in case of kernel bugs. (precise oopses/stacktraces/warnings)
|
|
|
|
config BOOT_PRINTK_DELAY
|
|
bool "Delay each boot printk message by N milliseconds"
|
|
depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
|
|
help
|
|
This build option allows you to read kernel boot messages
|
|
by inserting a short delay after each one. The delay is
|
|
specified in milliseconds on the kernel command line,
|
|
using "boot_delay=N".
|
|
|
|
It is likely that you would also need to use "lpj=M" to preset
|
|
the "loops per jiffie" value.
|
|
See a previous boot log for the "lpj" value to use for your
|
|
system, and then set "lpj=M" before setting "boot_delay=N".
|
|
NOTE: Using this option may adversely affect SMP systems.
|
|
I.e., processors other than the first one may not boot up.
|
|
BOOT_PRINTK_DELAY also may cause DETECT_SOFTLOCKUP to detect
|
|
what it believes to be lockup conditions.
|
|
|
|
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 be built into
|
|
the kernel.
|
|
Say M if you want the RCU torture tests to build as a module.
|
|
Say N if you are unsure.
|
|
|
|
config RCU_TORTURE_TEST_RUNNABLE
|
|
bool "torture tests for RCU runnable by default"
|
|
depends on RCU_TORTURE_TEST = y
|
|
default n
|
|
help
|
|
This option provides a way to build the RCU torture tests
|
|
directly into the kernel without them starting up at boot
|
|
time. You can use /proc/sys/kernel/rcutorture_runnable
|
|
to manually override this setting. This /proc file is
|
|
available only when the RCU torture tests have been built
|
|
into the kernel.
|
|
|
|
Say Y here if you want the RCU torture tests to start during
|
|
boot (you probably don't).
|
|
Say N here if you want the RCU torture tests to start only
|
|
after being manually enabled via /proc.
|
|
|
|
config RCU_CPU_STALL_DETECTOR
|
|
bool "Check for stalled CPUs delaying RCU grace periods"
|
|
depends on TREE_RCU || TREE_PREEMPT_RCU
|
|
default y
|
|
help
|
|
This option causes RCU to printk information on which
|
|
CPUs are delaying the current grace period, but only when
|
|
the grace period extends for excessive time periods.
|
|
|
|
Say N if you want to disable such checks.
|
|
|
|
Say Y if you are unsure.
|
|
|
|
config RCU_CPU_STALL_TIMEOUT
|
|
int "RCU CPU stall timeout in seconds"
|
|
depends on RCU_CPU_STALL_DETECTOR
|
|
range 3 300
|
|
default 60
|
|
help
|
|
If a given RCU grace period extends more than the specified
|
|
number of seconds, a CPU stall warning is printed. If the
|
|
RCU grace period persists, additional CPU stall warnings are
|
|
printed at more widely spaced intervals.
|
|
|
|
config RCU_CPU_STALL_DETECTOR_RUNNABLE
|
|
bool "RCU CPU stall checking starts automatically at boot"
|
|
depends on RCU_CPU_STALL_DETECTOR
|
|
default y
|
|
help
|
|
If set, start checking for RCU CPU stalls immediately on
|
|
boot. Otherwise, RCU CPU stall checking must be manually
|
|
enabled.
|
|
|
|
Say Y if you are unsure.
|
|
|
|
Say N if you wish to suppress RCU CPU stall checking during boot.
|
|
|
|
config RCU_CPU_STALL_VERBOSE
|
|
bool "Print additional per-task information for RCU_CPU_STALL_DETECTOR"
|
|
depends on RCU_CPU_STALL_DETECTOR && TREE_PREEMPT_RCU
|
|
default y
|
|
help
|
|
This option causes RCU to printk detailed per-task information
|
|
for any tasks that are stalling the current RCU grace period.
|
|
|
|
Say N if you are unsure.
|
|
|
|
Say Y if you want to enable such checks.
|
|
|
|
config KPROBES_SANITY_TEST
|
|
bool "Kprobes sanity tests"
|
|
depends on DEBUG_KERNEL
|
|
depends on KPROBES
|
|
default n
|
|
help
|
|
This option provides for testing basic kprobes functionality on
|
|
boot. A sample kprobe, jprobe and kretprobe are inserted and
|
|
verified for functionality.
|
|
|
|
Say N if you are unsure.
|
|
|
|
config BACKTRACE_SELF_TEST
|
|
tristate "Self test for the backtrace code"
|
|
depends on DEBUG_KERNEL
|
|
default n
|
|
help
|
|
This option provides a kernel module that can be used to test
|
|
the kernel stack backtrace code. This option is not useful
|
|
for distributions or general kernels, but only for kernel
|
|
developers working on architecture code.
|
|
|
|
Note that if you want to also test saved backtraces, you will
|
|
have to enable STACKTRACE as well.
|
|
|
|
Say N if you are unsure.
|
|
|
|
config DEBUG_BLOCK_EXT_DEVT
|
|
bool "Force extended block device numbers and spread them"
|
|
depends on DEBUG_KERNEL
|
|
depends on BLOCK
|
|
default n
|
|
help
|
|
BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
|
|
SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
|
|
YOU ARE DOING. Distros, please enable this and fix whatever
|
|
is broken.
|
|
|
|
Conventionally, block device numbers are allocated from
|
|
predetermined contiguous area. However, extended block area
|
|
may introduce non-contiguous block device numbers. This
|
|
option forces most block device numbers to be allocated from
|
|
the extended space and spreads them to discover kernel or
|
|
userland code paths which assume predetermined contiguous
|
|
device number allocation.
|
|
|
|
Note that turning on this debug option shuffles all the
|
|
device numbers for all IDE and SCSI devices including libata
|
|
ones, so root partition specified using device number
|
|
directly (via rdev or root=MAJ:MIN) won't work anymore.
|
|
Textual device names (root=/dev/sdXn) will continue to work.
|
|
|
|
Say N if you are unsure.
|
|
|
|
config DEBUG_FORCE_WEAK_PER_CPU
|
|
bool "Force weak per-cpu definitions"
|
|
depends on DEBUG_KERNEL
|
|
help
|
|
s390 and alpha require percpu variables in modules to be
|
|
defined weak to work around addressing range issue which
|
|
puts the following two restrictions on percpu variable
|
|
definitions.
|
|
|
|
1. percpu symbols must be unique whether static or not
|
|
2. percpu variables can't be defined inside a function
|
|
|
|
To ensure that generic code follows the above rules, this
|
|
option forces all percpu variables to be defined as weak.
|
|
|
|
config LKDTM
|
|
tristate "Linux Kernel Dump Test Tool Module"
|
|
depends on DEBUG_FS
|
|
depends on BLOCK
|
|
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
|
|
Documentation/fault-injection/provoke-crashes.txt
|
|
|
|
config CPU_NOTIFIER_ERROR_INJECT
|
|
tristate "CPU notifier error injection module"
|
|
depends on HOTPLUG_CPU && DEBUG_KERNEL
|
|
help
|
|
This option provides a kernel module that can be used to test
|
|
the error handling of the cpu notifiers
|
|
|
|
To compile this code as a module, choose M here: the module will
|
|
be called cpu-notifier-error-inject.
|
|
|
|
If unsure, say N.
|
|
|
|
config FAULT_INJECTION
|
|
bool "Fault-injection framework"
|
|
depends on DEBUG_KERNEL
|
|
help
|
|
Provide fault-injection framework.
|
|
For more details, see Documentation/fault-injection/.
|
|
|
|
config FAILSLAB
|
|
bool "Fault-injection capability for kmalloc"
|
|
depends on FAULT_INJECTION
|
|
depends on SLAB || SLUB
|
|
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 && BLOCK
|
|
help
|
|
Provide fault-injection capability for disk IO.
|
|
|
|
config FAIL_IO_TIMEOUT
|
|
bool "Fault-injection capability for faking disk interrupts"
|
|
depends on FAULT_INJECTION && BLOCK
|
|
help
|
|
Provide fault-injection capability on end IO handling. This
|
|
will make the block layer "forget" an interrupt as configured,
|
|
thus exercising the error handling.
|
|
|
|
Only works with drivers that use the generic timeout handling,
|
|
for others it wont do anything.
|
|
|
|
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.
|
|
|
|
config FAULT_INJECTION_STACKTRACE_FILTER
|
|
bool "stacktrace filter for fault-injection capabilities"
|
|
depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
|
|
depends on !X86_64
|
|
select STACKTRACE
|
|
select FRAME_POINTER if !PPC && !S390 && !MICROBLAZE
|
|
help
|
|
Provide stacktrace filter for fault-injection capabilities
|
|
|
|
config LATENCYTOP
|
|
bool "Latency measuring infrastructure"
|
|
depends on HAVE_LATENCYTOP_SUPPORT
|
|
depends on DEBUG_KERNEL
|
|
depends on STACKTRACE_SUPPORT
|
|
depends on PROC_FS
|
|
select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE
|
|
select KALLSYMS
|
|
select KALLSYMS_ALL
|
|
select STACKTRACE
|
|
select SCHEDSTATS
|
|
select SCHED_DEBUG
|
|
help
|
|
Enable this option if you want to use the LatencyTOP tool
|
|
to find out which userspace is blocking on what kernel operations.
|
|
|
|
config SYSCTL_SYSCALL_CHECK
|
|
bool "Sysctl checks"
|
|
depends on SYSCTL
|
|
---help---
|
|
sys_sysctl uses binary paths that have been found challenging
|
|
to properly maintain and use. This enables checks that help
|
|
you to keep things correct.
|
|
|
|
source mm/Kconfig.debug
|
|
source kernel/trace/Kconfig
|
|
|
|
config PROVIDE_OHCI1394_DMA_INIT
|
|
bool "Remote debugging over FireWire early on boot"
|
|
depends on PCI && X86
|
|
help
|
|
If you want to debug problems which hang or crash the kernel early
|
|
on boot and the crashing machine has a FireWire port, you can use
|
|
this feature to remotely access the memory of the crashed machine
|
|
over FireWire. This employs remote DMA as part of the OHCI1394
|
|
specification which is now the standard for FireWire controllers.
|
|
|
|
With remote DMA, you can monitor the printk buffer remotely using
|
|
firescope and access all memory below 4GB using fireproxy from gdb.
|
|
Even controlling a kernel debugger is possible using remote DMA.
|
|
|
|
Usage:
|
|
|
|
If ohci1394_dma=early is used as boot parameter, it will initialize
|
|
all OHCI1394 controllers which are found in the PCI config space.
|
|
|
|
As all changes to the FireWire bus such as enabling and disabling
|
|
devices cause a bus reset and thereby disable remote DMA for all
|
|
devices, be sure to have the cable plugged and FireWire enabled on
|
|
the debugging host before booting the debug target for debugging.
|
|
|
|
This code (~1k) is freed after boot. By then, the firewire stack
|
|
in charge of the OHCI-1394 controllers should be used instead.
|
|
|
|
See Documentation/debugging-via-ohci1394.txt for more information.
|
|
|
|
config FIREWIRE_OHCI_REMOTE_DMA
|
|
bool "Remote debugging over FireWire with firewire-ohci"
|
|
depends on FIREWIRE_OHCI
|
|
help
|
|
This option lets you use the FireWire bus for remote debugging
|
|
with help of the firewire-ohci driver. It enables unfiltered
|
|
remote DMA in firewire-ohci.
|
|
See Documentation/debugging-via-ohci1394.txt for more information.
|
|
|
|
If unsure, say N.
|
|
|
|
config BUILD_DOCSRC
|
|
bool "Build targets in Documentation/ tree"
|
|
depends on HEADERS_CHECK
|
|
help
|
|
This option attempts to build objects from the source files in the
|
|
kernel Documentation/ tree.
|
|
|
|
Say N if you are unsure.
|
|
|
|
config DYNAMIC_DEBUG
|
|
bool "Enable dynamic printk() support"
|
|
default n
|
|
depends on PRINTK
|
|
depends on DEBUG_FS
|
|
help
|
|
|
|
Compiles debug level messages into the kernel, which would not
|
|
otherwise be available at runtime. These messages can then be
|
|
enabled/disabled based on various levels of scope - per source file,
|
|
function, module, format string, and line number. This mechanism
|
|
implicitly enables all pr_debug() and dev_dbg() calls. The impact of
|
|
this compile option is a larger kernel text size of about 2%.
|
|
|
|
Usage:
|
|
|
|
Dynamic debugging is controlled via the 'dynamic_debug/control' file,
|
|
which is contained in the 'debugfs' filesystem. Thus, the debugfs
|
|
filesystem must first be mounted before making use of this feature.
|
|
We refer the control file as: <debugfs>/dynamic_debug/control. This
|
|
file contains a list of the debug statements that can be enabled. The
|
|
format for each line of the file is:
|
|
|
|
filename:lineno [module]function flags format
|
|
|
|
filename : source file of the debug statement
|
|
lineno : line number of the debug statement
|
|
module : module that contains the debug statement
|
|
function : function that contains the debug statement
|
|
flags : 'p' means the line is turned 'on' for printing
|
|
format : the format used for the debug statement
|
|
|
|
From a live system:
|
|
|
|
nullarbor:~ # cat <debugfs>/dynamic_debug/control
|
|
# filename:lineno [module]function flags format
|
|
fs/aio.c:222 [aio]__put_ioctx - "__put_ioctx:\040freeing\040%p\012"
|
|
fs/aio.c:248 [aio]ioctx_alloc - "ENOMEM:\040nr_events\040too\040high\012"
|
|
fs/aio.c:1770 [aio]sys_io_cancel - "calling\040cancel\012"
|
|
|
|
Example usage:
|
|
|
|
// enable the message at line 1603 of file svcsock.c
|
|
nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
|
|
<debugfs>/dynamic_debug/control
|
|
|
|
// enable all the messages in file svcsock.c
|
|
nullarbor:~ # echo -n 'file svcsock.c +p' >
|
|
<debugfs>/dynamic_debug/control
|
|
|
|
// enable all the messages in the NFS server module
|
|
nullarbor:~ # echo -n 'module nfsd +p' >
|
|
<debugfs>/dynamic_debug/control
|
|
|
|
// enable all 12 messages in the function svc_process()
|
|
nullarbor:~ # echo -n 'func svc_process +p' >
|
|
<debugfs>/dynamic_debug/control
|
|
|
|
// disable all 12 messages in the function svc_process()
|
|
nullarbor:~ # echo -n 'func svc_process -p' >
|
|
<debugfs>/dynamic_debug/control
|
|
|
|
See Documentation/dynamic-debug-howto.txt for additional information.
|
|
|
|
config DMA_API_DEBUG
|
|
bool "Enable debugging of DMA-API usage"
|
|
depends on HAVE_DMA_API_DEBUG
|
|
help
|
|
Enable this option to debug the use of the DMA API by device drivers.
|
|
With this option you will be able to detect common bugs in device
|
|
drivers like double-freeing of DMA mappings or freeing mappings that
|
|
were never allocated.
|
|
This option causes a performance degredation. Use only if you want
|
|
to debug device drivers. If unsure, say N.
|
|
|
|
config ATOMIC64_SELFTEST
|
|
bool "Perform an atomic64_t self-test at boot"
|
|
help
|
|
Enable this option to test the atomic64_t functions at boot.
|
|
|
|
If unsure, say N.
|
|
|
|
config ASYNC_RAID6_TEST
|
|
tristate "Self test for hardware accelerated raid6 recovery"
|
|
depends on ASYNC_RAID6_RECOV
|
|
select ASYNC_MEMCPY
|
|
---help---
|
|
This is a one-shot self test that permutes through the
|
|
recovery of all the possible two disk failure scenarios for a
|
|
N-disk array. Recovery is performed with the asynchronous
|
|
raid6 recovery routines, and will optionally use an offload
|
|
engine if one is available.
|
|
|
|
If unsure, say N.
|
|
|
|
source "samples/Kconfig"
|
|
|
|
source "lib/Kconfig.kgdb"
|
|
|
|
source "lib/Kconfig.kmemcheck"
|