help
The section mismatch analysis checks if there are illegal
references from one section to another section.
- Linux will during link or during runtime drop some sections
- and any use of code/data previously in these sections will
+ During linktime or runtime, some sections are dropped;
+ any use of code/data previously in these sections would
most likely result in an oops.
- In the code functions and variables are annotated with
- __init, __devinit etc. (see full list in include/linux/init.h)
+ In the code, functions and variables are annotated with
+ __init, __devinit, etc. (see the full list in include/linux/init.h),
which results in the code/data being placed in specific sections.
- The section mismatch analysis is always done after a full
- kernel build but enabling this option will in addition
- do the following:
- - Add the option -fno-inline-functions-called-once to gcc
- When inlining a function annotated __init in a non-init
- function we would lose the section information and thus
+ The section mismatch analysis is always performed after a full
+ kernel build, and enabling this option causes the following
+ additional steps to occur:
+ - Add the option -fno-inline-functions-called-once to gcc commands.
+ When inlining a function annotated with __init in a non-init
+ function, we would lose the section information and thus
the analysis would not catch the illegal reference.
- This option tells gcc to inline less but will also
- result in a larger kernel.
- - Run the section mismatch analysis for each module/built-in.o
- When we run the section mismatch analysis on vmlinux.o we
+ This option tells gcc to inline less (but it does result in
+ a larger kernel).
+ - Run the section mismatch analysis for each module/built-in.o file.
+ When we run the section mismatch analysis on vmlinux.o, we
lose valueble information about where the mismatch was
introduced.
Running the analysis for each module/built-in.o file
- will tell where the mismatch happens much closer to the
- source. The drawback is that we will report the same
- mismatch at least twice.
- - Enable verbose reporting from modpost to help solving
- the section mismatches reported.
+ tells where the mismatch happens much closer to the
+ source. The drawback is that the same mismatch is
+ reported at least twice.
+ - Enable verbose reporting from modpost in order to help resolve
+ the section mismatches that are reported.
config DEBUG_KERNEL
bool "Kernel debugging"
hard and soft lockups.
Softlockups are bugs that cause the kernel to loop in kernel
- mode for more than 60 seconds, without giving other tasks a
+ mode for more than 20 seconds, without giving other tasks a
chance to run. The current stack trace is displayed upon
detection and the system will stay locked up.
Hardlockups are bugs that cause the CPU to loop in kernel mode
- for more than 60 seconds, without letting other interrupts have a
+ for more than 10 seconds, without letting other interrupts have a
chance to run. The current stack trace is displayed upon detection
and the system will stay locked up.
The overhead should be minimal. A periodic hrtimer runs to
- generate interrupts and kick the watchdog task every 10-12 seconds.
- An NMI is generated every 60 seconds or so to check for hardlockups.
+ generate interrupts and kick the watchdog task every 4 seconds.
+ An NMI is generated every 10 seconds or so to check for hardlockups.
+
+ The frequency of hrtimer and NMI events and the soft and hard lockup
+ thresholds can be controlled through the sysctl watchdog_thresh.
config HARDLOCKUP_DETECTOR
def_bool LOCKUP_DETECTOR && PERF_EVENTS && HAVE_PERF_EVENTS_NMI && \
- !ARCH_HAS_NMI_WATCHDOG
+ !HAVE_NMI_WATCHDOG
config BOOTPARAM_HARDLOCKUP_PANIC
bool "Panic (Reboot) On Hard Lockups"
help
Say Y here to enable the kernel to panic on "hard lockups",
which are bugs that cause the kernel to loop in kernel
- mode with interrupts disabled for more than 60 seconds.
+ mode with interrupts disabled for more than 10 seconds (configurable
+ using the watchdog_thresh sysctl).
Say N if unsure.
help
Say Y here to enable the kernel to panic on "soft lockups",
which are bugs that cause the kernel to loop in kernel
- mode for more than 60 seconds, without giving other tasks a
- chance to run.
+ mode for more than 20 seconds (configurable using the watchdog_thresh
+ sysctl), without giving other tasks a chance to run.
The panic can be used in combination with panic_timeout,
to cause the system to reboot automatically after a
config DETECT_HUNG_TASK
bool "Detect Hung Tasks"
depends on DEBUG_KERNEL
- default DETECT_SOFTLOCKUP
+ default LOCKUP_DETECTOR
help
Say Y here to enable the kernel to detect "hung tasks",
which are bugs that cause the task to be stuck in
enabled then all held locks will also be reported. This
feature has negligible overhead.
+config DEFAULT_HUNG_TASK_TIMEOUT
+ int "Default timeout for hung task detection (in seconds)"
+ depends on DETECT_HUNG_TASK
+ default 120
+ help
+ This option controls the default timeout (in seconds) used
+ to determine when a task has become non-responsive and should
+ be considered hung.
+
+ It can be adjusted at runtime via the kernel.hung_task_timeout_secs
+ sysctl or by writing a value to
+ /proc/sys/kernel/hung_task_timeout_secs.
+
+ A timeout of 0 disables the check. The default is two minutes.
+ Keeping the default should be fine in most cases.
+
config BOOTPARAM_HUNG_TASK_PANIC
bool "Panic (Reboot) On Hung Tasks"
depends on DETECT_HUNG_TASK
config DEBUG_OBJECTS_RCU_HEAD
bool "Debug RCU callbacks objects"
- depends on DEBUG_OBJECTS && PREEMPT
+ depends on DEBUG_OBJECTS
help
Enable this to turn on debugging of RCU list heads (call_rcu() usage).
config DEBUG_KMEMLEAK
bool "Kernel memory leak detector"
- depends on DEBUG_KERNEL && EXPERIMENTAL && !MEMORY_HOTPLUG && \
- (X86 || ARM || PPC || S390 || SPARC64 || SUPERH || MICROBLAZE || TILE)
+ depends on DEBUG_KERNEL && EXPERIMENTAL && \
+ (X86 || ARM || PPC || MIPS || S390 || SPARC64 || SUPERH || MICROBLAZE || TILE)
- select DEBUG_FS if SYSFS
+ select DEBUG_FS
select STACKTRACE if STACKTRACE_SUPPORT
select KALLSYMS
select CRC32
config DEBUG_SPINLOCK
bool "Spinlock and rw-lock debugging: basic checks"
depends on DEBUG_KERNEL
+ select UNINLINE_SPIN_UNLOCK
help
Say Y here and build SMP to catch missing spinlock initialization
and certain other kinds of spinlock errors commonly made. This is
Enables hooks to interrupt enabling and disabling for
either tracing or lock debugging.
-config DEBUG_SPINLOCK_SLEEP
- bool "Spinlock debugging: sleep-inside-spinlock checking"
+config DEBUG_ATOMIC_SLEEP
+ bool "Sleep inside atomic section checking"
+ select PREEMPT_COUNT
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.
+ noisy if they are called inside atomic sections: when a spinlock is
+ held, inside an rcu read side critical section, inside preempt disabled
+ sections, inside an interrupt, etc...
config DEBUG_LOCKING_API_SELFTESTS
bool "Locking API boot-time self-tests"
bool
depends on STACKTRACE_SUPPORT
+config DEBUG_STACK_USAGE
+ bool "Stack utilization instrumentation"
+ depends on DEBUG_KERNEL
+ help
+ Enables the display of the minimum amount of free stack which each
+ task has ever had available in the sysrq-T and sysrq-P debug output.
+
+ This option will slow down process creation somewhat.
+
config DEBUG_KOBJECT
bool "kobject debugging"
depends on DEBUG_KERNEL
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
+ FRV || SUPERH || GENERIC_BUG || BLACKFIN || MN10300 || TILE
default y
help
Say Y here to make BUG() panics output the file name and line number
#
# Select this config option from the architecture Kconfig, if it
-# it is preferred to always offer frame pointers as a config
+# is preferred to always offer frame pointers as a config
# option on the architecture (regardless of KERNEL_DEBUG):
#
config ARCH_WANT_FRAME_POINTERS
larger and slower, but it gives very useful debugging information
in case of kernel bugs. (precise oopses/stacktraces/warnings)
+config UNWIND_INFO
+ bool "Compile the kernel with frame unwind information"
+ depends on !IA64 && !PARISC && !ARM
+ depends on !MODULES || !(MIPS || PPC || SUPERH || V850)
+ help
+ If you say Y here the resulting kernel image will be slightly larger
+ but not slower, and it will give very useful debugging information.
+ If you don't debug the kernel, you can say N, but we may not be able
+ to solve problems without frame unwind information or frame pointers.
+
+config STACK_UNWIND
+ bool "Stack unwind support"
+ depends on UNWIND_INFO
+ depends on X86
+ help
+ This enables more precise stack traces, omitting all unrelated
+ occurrences of pointers into kernel code from the dump.
+
config BOOT_PRINTK_DELAY
bool "Delay each boot printk message by N milliseconds"
depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
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
+ BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect
what it believes to be lockup conditions.
config RCU_TORTURE_TEST
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
+ depends on TREE_RCU || TREE_PREEMPT_RCU
range 3 300
default 60
help
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
+ depends on TREE_PREEMPT_RCU
default y
help
This option causes RCU to printk detailed per-task information
Say Y if you want to enable such checks.
+config RCU_CPU_STALL_INFO
+ bool "Print additional diagnostics on RCU CPU stall"
+ depends on (TREE_RCU || TREE_PREEMPT_RCU) && DEBUG_KERNEL
+ default n
+ help
+ For each stalled CPU that is aware of the current RCU grace
+ period, print out additional per-CPU diagnostic information
+ regarding scheduling-clock ticks, idle state, and,
+ for RCU_FAST_NO_HZ kernels, idle-entry state.
+
+ Say N if you are unsure.
+
+ Say Y if you want to enable such diagnostics.
+
+config RCU_TRACE
+ bool "Enable tracing for RCU"
+ depends on DEBUG_KERNEL
+ help
+ This option provides tracing in RCU which presents stats
+ in debugfs for debugging RCU implementation.
+
+ Say Y here if you want to enable RCU tracing
+ Say N if you are unsure.
+
config KPROBES_SANITY_TEST
bool "Kprobes sanity tests"
depends on DEBUG_KERNEL
To ensure that generic code follows the above rules, this
option forces all percpu variables to be defined as weak.
+config DEBUG_PER_CPU_MAPS
+ bool "Debug access to per_cpu maps"
+ depends on DEBUG_KERNEL
+ depends on SMP
+ help
+ Say Y to verify that the per_cpu map being accessed has
+ been set up. This adds a fair amount of code to kernel memory
+ and decreases performance.
+
+ Say N if unsure.
+
config LKDTM
tristate "Linux Kernel Dump Test Tool Module"
depends on DEBUG_FS
Only works with drivers that use the generic timeout handling,
for others it wont do anything.
+config FAIL_MMC_REQUEST
+ bool "Fault-injection capability for MMC IO"
+ select DEBUG_FS
+ depends on FAULT_INJECTION && MMC
+ help
+ Provide fault-injection capability for MMC IO.
+ This will make the mmc core return data errors. This is
+ useful to test the error handling in the mmc block device
+ and to test how the mmc host driver handles retries from
+ the block device.
+
config FAULT_INJECTION_DEBUG_FS
bool "Debugfs entries for fault-injection capabilities"
depends on FAULT_INJECTION && SYSFS && DEBUG_FS
depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
depends on !X86_64
select STACKTRACE
- select FRAME_POINTER if !PPC && !S390 && !MICROBLAZE
+ select FRAME_POINTER if !PPC && !S390 && !MICROBLAZE && !X86 && !ARM_UNWIND
+ select UNWIND_INFO if X86 && !FRAME_POINTER
help
Provide stacktrace filter for fault-injection capabilities
depends on DEBUG_KERNEL
depends on STACKTRACE_SUPPORT
depends on PROC_FS
- select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE
+ select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !X86 && !ARM_UNWIND
+ select UNWIND_INFO if X86 && !FRAME_POINTER
select KALLSYMS
select KALLSYMS_ALL
select STACKTRACE
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
projects / linux-flexiantxendom0-3.2.10.git / blobdiff