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Diffstat (limited to 'lib/Kconfig.debug')
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diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug new file mode 100644 index 000000000..9a4277034 --- /dev/null +++ b/lib/Kconfig.debug @@ -0,0 +1,2038 @@ +menu "Kernel hacking" + +menu "printk and dmesg options" + +config PRINTK_TIME + bool "Show timing information on printks" + depends on PRINTK + help + Selecting this option causes time stamps of the printk() + messages to be added to the output of the syslog() system + call and at the console. + + The timestamp is always recorded internally, and exported + to /dev/kmsg. This flag just specifies if the timestamp should + be included, not that the timestamp is recorded. + + The behavior is also controlled by the kernel command line + parameter printk.time=1. See Documentation/admin-guide/kernel-parameters.rst + +config CONSOLE_LOGLEVEL_DEFAULT + int "Default console loglevel (1-15)" + range 1 15 + default "7" + help + Default loglevel to determine what will be printed on the console. + + Setting a default here is equivalent to passing in loglevel=<x> in + the kernel bootargs. loglevel=<x> continues to override whatever + value is specified here as well. + + Note: This does not affect the log level of un-prefixed printk() + usage in the kernel. That is controlled by the MESSAGE_LOGLEVEL_DEFAULT + option. + +config CONSOLE_LOGLEVEL_QUIET + int "quiet console loglevel (1-15)" + range 1 15 + default "4" + help + loglevel to use when "quiet" is passed on the kernel commandline. + + When "quiet" is passed on the kernel commandline this loglevel + will be used as the loglevel. IOW passing "quiet" will be the + equivalent of passing "loglevel=<CONSOLE_LOGLEVEL_QUIET>" + +config MESSAGE_LOGLEVEL_DEFAULT + int "Default message log level (1-7)" + range 1 7 + default "4" + help + Default log level for printk statements with no specified priority. + + This was hard-coded to KERN_WARNING since at least 2.6.10 but folks + that are auditing their logs closely may want to set it to a lower + priority. + + Note: This does not affect what message level gets printed on the console + by default. To change that, use loglevel=<x> in the kernel bootargs, + or pick a different CONSOLE_LOGLEVEL_DEFAULT configuration value. + +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 LOCKUP_DETECTOR to detect + what it believes to be lockup conditions. + +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 compiles in all pr_debug() and dev_dbg() calls, which + enlarges the kernel text size by about 2%. + + If a source file is compiled with DEBUG flag set, any + pr_debug() calls in it are enabled by default, but can be + disabled at runtime as below. Note that DEBUG flag is + turned on by many CONFIG_*DEBUG* options. + + 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/admin-guide/dynamic-debug-howto.rst for additional + information. + +endmenu # "printk and dmesg options" + +menu "Compile-time checks and compiler options" + +config DEBUG_INFO + bool "Compile the kernel with debug info" + depends on DEBUG_KERNEL && !COMPILE_TEST + 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_INFO_SPLIT + bool "Produce split debuginfo in .dwo files" + depends on DEBUG_INFO + help + Generate debug info into separate .dwo files. This significantly + reduces the build directory size for builds with DEBUG_INFO, + because it stores the information only once on disk in .dwo + files instead of multiple times in object files and executables. + In addition the debug information is also compressed. + + Requires recent gcc (4.7+) and recent gdb/binutils. + Any tool that packages or reads debug information would need + to know about the .dwo files and include them. + Incompatible with older versions of ccache. + +config DEBUG_INFO_DWARF4 + bool "Generate dwarf4 debuginfo" + depends on DEBUG_INFO + help + Generate dwarf4 debug info. This requires recent versions + of gcc and gdb. It makes the debug information larger. + But it significantly improves the success of resolving + variables in gdb on optimized code. + +config GDB_SCRIPTS + bool "Provide GDB scripts for kernel debugging" + depends on DEBUG_INFO + help + This creates the required links to GDB helper scripts in the + build directory. If you load vmlinux into gdb, the helper + scripts will be automatically imported by gdb as well, and + additional functions are available to analyze a Linux kernel + instance. See Documentation/dev-tools/gdb-kernel-debugging.rst + for further details. + +config ENABLE_MUST_CHECK + bool "Enable __must_check logic" + default y + help + Enable the __must_check logic in the kernel build. Disable this to + suppress the "warning: ignoring return value of 'foo', declared with + attribute warn_unused_result" messages. + +config FRAME_WARN + int "Warn for stack frames larger than (needs gcc 4.4)" + range 0 8192 + default 3072 if KASAN_EXTRA + default 2048 if GCC_PLUGIN_LATENT_ENTROPY + default 1280 if (!64BIT && PARISC) + default 1024 if (!64BIT && !PARISC) + default 2048 if 64BIT + help + Tell gcc to warn at build time for stack frames larger than this. + Setting this too low will cause a lot of warnings. + Setting it to 0 disables the warning. + Requires gcc 4.4 + +config STRIP_ASM_SYMS + bool "Strip assembler-generated symbols during link" + default n + help + Strip internal assembler-generated symbols during a link (symbols + that look like '.Lxxx') so they don't pollute the output of + get_wchan() and suchlike. + +config READABLE_ASM + bool "Generate readable assembler code" + depends on DEBUG_KERNEL + help + Disable some compiler optimizations that tend to generate human unreadable + assembler output. This may make the kernel slightly slower, but it helps + to keep kernel developers who have to stare a lot at assembler listings + sane. + +config UNUSED_SYMBOLS + bool "Enable unused/obsolete exported symbols" + default y if X86 + help + Unused but exported symbols make the kernel needlessly bigger. For + that reason most of these unused exports will soon be removed. This + option is provided temporarily to provide a transition period in case + some external kernel module needs one of these symbols anyway. If you + encounter such a case in your module, consider if you are actually + using the right API. (rationale: since nobody in the kernel is using + this in a module, there is a pretty good chance it's actually the + wrong interface to use). If you really need the symbol, please send a + mail to the linux kernel mailing list mentioning the symbol and why + you really need it, and what the merge plan to the mainline kernel for + your module is. + +config PAGE_OWNER + bool "Track page owner" + depends on DEBUG_KERNEL && STACKTRACE_SUPPORT + select DEBUG_FS + select STACKTRACE + select STACKDEPOT + select PAGE_EXTENSION + help + This keeps track of what call chain is the owner of a page, may + help to find bare alloc_page(s) leaks. Even if you include this + feature on your build, it is disabled in default. You should pass + "page_owner=on" to boot parameter in order to enable it. Eats + a fair amount of memory if enabled. See tools/vm/page_owner_sort.c + for user-space helper. + + If unsure, say N. + +config DEBUG_FS + bool "Debug Filesystem" + help + debugfs is a virtual file system that kernel developers use to put + debugging files into. Enable this option to be able to read and + write to these files. + + For detailed documentation on the debugfs API, see + Documentation/filesystems/. + + If unsure, say N. + +config HEADERS_CHECK + bool "Run 'make headers_check' when building vmlinux" + depends on !UML + help + This option will extract the user-visible kernel headers whenever + building the kernel, and will run basic sanity checks on them to + ensure that exported files do not attempt to include files which + were not exported, etc. + + If you're making modifications to header files which are + relevant for userspace, say 'Y', and check the headers + exported to $(INSTALL_HDR_PATH) (usually 'usr/include' in + your build tree), to make sure they're suitable. + +config DEBUG_SECTION_MISMATCH + bool "Enable full Section mismatch analysis" + help + The section mismatch analysis checks if there are illegal + references from one section to another section. + 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,, 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 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 it does result in + a larger kernel). + - Run the section mismatch analysis for each module/built-in.a file. + When we run the section mismatch analysis on vmlinux.o, we + lose valuable information about where the mismatch was + introduced. + Running the analysis for each module/built-in.a file + 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 SECTION_MISMATCH_WARN_ONLY + bool "Make section mismatch errors non-fatal" + default y + help + If you say N here, the build process will fail if there are any + section mismatch, instead of just throwing warnings. + + If unsure, say Y. + +# +# Select this config option from the architecture Kconfig, if 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 + +config FRAME_POINTER + bool "Compile the kernel with frame pointers" + depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || 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 STACK_VALIDATION + bool "Compile-time stack metadata validation" + depends on HAVE_STACK_VALIDATION + default n + help + Add compile-time checks to validate stack metadata, including frame + pointers (if CONFIG_FRAME_POINTER is enabled). This helps ensure + that runtime stack traces are more reliable. + + This is also a prerequisite for generation of ORC unwind data, which + is needed for CONFIG_UNWINDER_ORC. + + For more information, see + tools/objtool/Documentation/stack-validation.txt. + +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. + +endmenu # "Compiler options" + +config MAGIC_SYSRQ + bool "Magic SysRq key" + depends on !UML + help + If you say Y here, you will have some control over the system even + if the system crashes for example during kernel debugging (e.g., you + will be able to flush the buffer cache to disk, reboot the system + immediately or dump some status information). This is accomplished + by pressing various keys while holding SysRq (Alt+PrintScreen). It + also works on a serial console (on PC hardware at least), if you + send a BREAK and then within 5 seconds a command keypress. The + keys are documented in <file:Documentation/admin-guide/sysrq.rst>. + Don't say Y unless you really know what this hack does. + +config MAGIC_SYSRQ_DEFAULT_ENABLE + hex "Enable magic SysRq key functions by default" + depends on MAGIC_SYSRQ + default 0x1 + help + Specifies which SysRq key functions are enabled by default. + This may be set to 1 or 0 to enable or disable them all, or + to a bitmask as described in Documentation/admin-guide/sysrq.rst. + +config MAGIC_SYSRQ_SERIAL + bool "Enable magic SysRq key over serial" + depends on MAGIC_SYSRQ + default y + help + Many embedded boards have a disconnected TTL level serial which can + generate some garbage that can lead to spurious false sysrq detects. + This option allows you to decide whether you want to enable the + magic SysRq key. + +config DEBUG_KERNEL + bool "Kernel debugging" + help + Say Y here if you are developing drivers or trying to debug and + identify kernel problems. + +menu "Memory Debugging" + +source mm/Kconfig.debug + +config DEBUG_OBJECTS + bool "Debug object operations" + depends on DEBUG_KERNEL + help + If you say Y here, additional code will be inserted into the + kernel to track the life time of various objects and validate + the operations on those objects. + +config DEBUG_OBJECTS_SELFTEST + bool "Debug objects selftest" + depends on DEBUG_OBJECTS + help + This enables the selftest of the object debug code. + +config DEBUG_OBJECTS_FREE + bool "Debug objects in freed memory" + depends on DEBUG_OBJECTS + help + This enables checks whether a k/v free operation frees an area + which contains an object which has not been deactivated + properly. This can make kmalloc/kfree-intensive workloads + much slower. + +config DEBUG_OBJECTS_TIMERS + bool "Debug timer objects" + depends on DEBUG_OBJECTS + help + If you say Y here, additional code will be inserted into the + timer routines to track the life time of timer objects and + validate the timer operations. + +config DEBUG_OBJECTS_WORK + bool "Debug work objects" + depends on DEBUG_OBJECTS + help + If you say Y here, additional code will be inserted into the + work queue routines to track the life time of work objects and + validate the work operations. + +config DEBUG_OBJECTS_RCU_HEAD + bool "Debug RCU callbacks objects" + depends on DEBUG_OBJECTS + help + Enable this to turn on debugging of RCU list heads (call_rcu() usage). + +config DEBUG_OBJECTS_PERCPU_COUNTER + bool "Debug percpu counter objects" + depends on DEBUG_OBJECTS + help + If you say Y here, additional code will be inserted into the + percpu counter routines to track the life time of percpu counter + objects and validate the percpu counter operations. + +config DEBUG_OBJECTS_ENABLE_DEFAULT + int "debug_objects bootup default value (0-1)" + range 0 1 + default "1" + depends on DEBUG_OBJECTS + help + Debug objects boot parameter default value + +config DEBUG_SLAB + bool "Debug slab memory allocations" + depends on DEBUG_KERNEL && SLAB + help + Say Y here to have the kernel do limited verification on memory + allocation as well as poisoning memory on free to catch use of freed + memory. This can make kmalloc/kfree-intensive workloads much slower. + +config DEBUG_SLAB_LEAK + bool "Memory leak debugging" + depends on DEBUG_SLAB + +config SLUB_DEBUG_ON + bool "SLUB debugging on by default" + depends on SLUB && SLUB_DEBUG + default n + help + Boot with debugging on by default. SLUB boots by default with + the runtime debug capabilities switched off. Enabling this is + equivalent to specifying the "slub_debug" parameter on boot. + There is no support for more fine grained debug control like + possible with slub_debug=xxx. SLUB debugging may be switched + off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying + "slub_debug=-". + +config SLUB_STATS + default n + bool "Enable SLUB performance statistics" + depends on SLUB && SYSFS + help + SLUB statistics are useful to debug SLUBs allocation behavior in + order find ways to optimize the allocator. This should never be + enabled for production use since keeping statistics slows down + the allocator by a few percentage points. The slabinfo command + supports the determination of the most active slabs to figure + out which slabs are relevant to a particular load. + Try running: slabinfo -DA + +config HAVE_DEBUG_KMEMLEAK + bool + +config DEBUG_KMEMLEAK + bool "Kernel memory leak detector" + depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK + select DEBUG_FS + select STACKTRACE if STACKTRACE_SUPPORT + select KALLSYMS + select CRC32 + help + Say Y here if you want to enable the memory leak + detector. The memory allocation/freeing is traced in a way + similar to the Boehm's conservative garbage collector, the + difference being that the orphan objects are not freed but + only shown in /sys/kernel/debug/kmemleak. Enabling this + feature will introduce an overhead to memory + allocations. See Documentation/dev-tools/kmemleak.rst for more + details. + + Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances + of finding leaks due to the slab objects poisoning. + + In order to access the kmemleak file, debugfs needs to be + mounted (usually at /sys/kernel/debug). + +config DEBUG_KMEMLEAK_EARLY_LOG_SIZE + int "Maximum kmemleak early log entries" + depends on DEBUG_KMEMLEAK + range 200 40000 + default 16000 + help + Kmemleak must track all the memory allocations to avoid + reporting false positives. Since memory may be allocated or + freed before kmemleak is initialised, an early log buffer is + used to store these actions. If kmemleak reports "early log + buffer exceeded", please increase this value. + +config DEBUG_KMEMLEAK_TEST + tristate "Simple test for the kernel memory leak detector" + depends on DEBUG_KMEMLEAK && m + help + This option enables a module that explicitly leaks memory. + + If unsure, say N. + +config DEBUG_KMEMLEAK_DEFAULT_OFF + bool "Default kmemleak to off" + depends on DEBUG_KMEMLEAK + help + Say Y here to disable kmemleak by default. It can then be enabled + on the command line via kmemleak=on. + +config DEBUG_STACK_USAGE + bool "Stack utilization instrumentation" + depends on DEBUG_KERNEL && !IA64 + 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_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_VM_VMACACHE + bool "Debug VMA caching" + depends on DEBUG_VM + help + Enable this to turn on VMA caching debug information. Doing so + can cause significant overhead, so only enable it in non-production + environments. + + If unsure, say N. + +config DEBUG_VM_RB + bool "Debug VM red-black trees" + depends on DEBUG_VM + help + Enable VM red-black tree debugging information and extra validations. + + If unsure, say N. + +config DEBUG_VM_PGFLAGS + bool "Debug page-flags operations" + depends on DEBUG_VM + help + Enables extra validation on page flags operations. + + If unsure, say N. + +config ARCH_HAS_DEBUG_VIRTUAL + bool + +config DEBUG_VIRTUAL + bool "Debug VM translations" + depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL + 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_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 MEMORY_NOTIFIER_ERROR_INJECT + tristate "Memory hotplug notifier error injection module" + depends on MEMORY_HOTPLUG_SPARSE && NOTIFIER_ERROR_INJECTION + help + This option provides the ability to inject artificial errors to + memory hotplug notifier chain callbacks. It is controlled through + debugfs interface under /sys/kernel/debug/notifier-error-inject/memory + + If the notifier call chain should be failed with some events + notified, write the error code to "actions/<notifier event>/error". + + Example: Inject memory hotplug offline error (-12 == -ENOMEM) + + # cd /sys/kernel/debug/notifier-error-inject/memory + # echo -12 > actions/MEM_GOING_OFFLINE/error + # echo offline > /sys/devices/system/memory/memoryXXX/state + bash: echo: write error: Cannot allocate memory + + To compile this code as a module, choose M here: the module will + be called memory-notifier-error-inject. + + If unsure, say N. + +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 DEBUG_HIGHMEM + bool "Highmem debugging" + depends on DEBUG_KERNEL && HIGHMEM + help + This option enables additional error checking for high memory + systems. Disable for production systems. + +config HAVE_DEBUG_STACKOVERFLOW + bool + +config DEBUG_STACKOVERFLOW + bool "Check for stack overflows" + depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW + ---help--- + Say Y here if you want to check for overflows of kernel, IRQ + and exception stacks (if your architecture uses them). This + option will show detailed messages if free stack space drops + below a certain limit. + + These kinds of bugs usually occur when call-chains in the + kernel get too deep, especially when interrupts are + involved. + + Use this in cases where you see apparently random memory + corruption, especially if it appears in 'struct thread_info' + + If in doubt, say "N". + +source "lib/Kconfig.kasan" + +endmenu # "Memory Debugging" + +config ARCH_HAS_KCOV + bool + help + KCOV does not have any arch-specific code, but currently it is enabled + only for x86_64. KCOV requires testing on other archs, and most likely + disabling of instrumentation for some early boot code. + +config CC_HAS_SANCOV_TRACE_PC + def_bool $(cc-option,-fsanitize-coverage=trace-pc) + +config KCOV + bool "Code coverage for fuzzing" + depends on ARCH_HAS_KCOV + depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS + select DEBUG_FS + select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC + help + KCOV exposes kernel code coverage information in a form suitable + for coverage-guided fuzzing (randomized testing). + + If RANDOMIZE_BASE is enabled, PC values will not be stable across + different machines and across reboots. If you need stable PC values, + disable RANDOMIZE_BASE. + + For more details, see Documentation/dev-tools/kcov.rst. + +config KCOV_ENABLE_COMPARISONS + bool "Enable comparison operands collection by KCOV" + depends on KCOV + depends on $(cc-option,-fsanitize-coverage=trace-cmp) + help + KCOV also exposes operands of every comparison in the instrumented + code along with operand sizes and PCs of the comparison instructions. + These operands can be used by fuzzing engines to improve the quality + of fuzzing coverage. + +config KCOV_INSTRUMENT_ALL + bool "Instrument all code by default" + depends on KCOV + default y + help + If you are doing generic system call fuzzing (like e.g. syzkaller), + then you will want to instrument the whole kernel and you should + say y here. If you are doing more targeted fuzzing (like e.g. + filesystem fuzzing with AFL) then you will want to enable coverage + for more specific subsets of files, and should say n here. + +config DEBUG_SHIRQ + bool "Debug shared IRQ handlers" + depends on DEBUG_KERNEL + help + Enable this to generate a spurious interrupt as soon as a shared + interrupt handler is registered, and just before one is deregistered. + Drivers ought to be able to handle interrupts coming in at those + points; some don't and need to be caught. + +menu "Debug Lockups and Hangs" + +config LOCKUP_DETECTOR + bool + +config SOFTLOCKUP_DETECTOR + bool "Detect Soft Lockups" + depends on DEBUG_KERNEL && !S390 + select LOCKUP_DETECTOR + help + Say Y here to enable the kernel to act as a watchdog to detect + soft lockups. + + Softlockups are bugs that cause the kernel to loop in kernel + 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. + +config BOOTPARAM_SOFTLOCKUP_PANIC + bool "Panic (Reboot) On Soft Lockups" + depends on SOFTLOCKUP_DETECTOR + 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 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 + lockup has been detected. This feature is useful for + high-availability systems that have uptime guarantees and + where a lockup must be resolved ASAP. + + Say N if unsure. + +config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE + int + depends on SOFTLOCKUP_DETECTOR + range 0 1 + default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC + default 1 if BOOTPARAM_SOFTLOCKUP_PANIC + +config HARDLOCKUP_DETECTOR_PERF + bool + select SOFTLOCKUP_DETECTOR + +# +# Enables a timestamp based low pass filter to compensate for perf based +# hard lockup detection which runs too fast due to turbo modes. +# +config HARDLOCKUP_CHECK_TIMESTAMP + bool + +# +# arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard +# lockup detector rather than the perf based detector. +# +config HARDLOCKUP_DETECTOR + bool "Detect Hard Lockups" + depends on DEBUG_KERNEL && !S390 + depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH + select LOCKUP_DETECTOR + select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF + help + Say Y here to enable the kernel to act as a watchdog to detect + hard lockups. + + Hardlockups are bugs that cause the CPU to loop in kernel mode + 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. + +config BOOTPARAM_HARDLOCKUP_PANIC + bool "Panic (Reboot) On Hard Lockups" + depends on HARDLOCKUP_DETECTOR + 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 10 seconds (configurable + using the watchdog_thresh sysctl). + + Say N if unsure. + +config BOOTPARAM_HARDLOCKUP_PANIC_VALUE + int + depends on HARDLOCKUP_DETECTOR + range 0 1 + default 0 if !BOOTPARAM_HARDLOCKUP_PANIC + default 1 if BOOTPARAM_HARDLOCKUP_PANIC + +config DETECT_HUNG_TASK + bool "Detect Hung Tasks" + depends on DEBUG_KERNEL + default SOFTLOCKUP_DETECTOR + help + Say Y here to enable the kernel to detect "hung tasks", + which are bugs that cause the task to be stuck in + uninterruptible "D" state indefinitely. + + When a hung task is detected, the kernel will print the + current stack trace (which you should report), but the + task will stay in uninterruptible state. If lockdep is + 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 + help + Say Y here to enable the kernel to panic on "hung tasks", + which are bugs that cause the kernel to leave a task stuck + in uninterruptible "D" state. + + The panic can be used in combination with panic_timeout, + to cause the system to reboot automatically after a + hung task has been detected. This feature is useful for + high-availability systems that have uptime guarantees and + where a hung tasks must be resolved ASAP. + + Say N if unsure. + +config BOOTPARAM_HUNG_TASK_PANIC_VALUE + int + depends on DETECT_HUNG_TASK + range 0 1 + default 0 if !BOOTPARAM_HUNG_TASK_PANIC + default 1 if BOOTPARAM_HUNG_TASK_PANIC + +config WQ_WATCHDOG + bool "Detect Workqueue Stalls" + depends on DEBUG_KERNEL + help + Say Y here to enable stall detection on workqueues. If a + worker pool doesn't make forward progress on a pending work + item for over a given amount of time, 30s by default, a + warning message is printed along with dump of workqueue + state. This can be configured through kernel parameter + "workqueue.watchdog_thresh" and its sysfs counterpart. + +endmenu # "Debug lockups and hangs" + +config PANIC_ON_OOPS + bool "Panic on Oops" + help + Say Y here to enable the kernel to panic when it oopses. This + has the same effect as setting oops=panic on the kernel command + line. + + This feature is useful to ensure that the kernel does not do + anything erroneous after an oops which could result in data + corruption or other issues. + + Say N if unsure. + +config PANIC_ON_OOPS_VALUE + int + range 0 1 + default 0 if !PANIC_ON_OOPS + default 1 if PANIC_ON_OOPS + +config PANIC_TIMEOUT + int "panic timeout" + default 0 + help + Set the timeout value (in seconds) until a reboot occurs when the + the kernel panics. If n = 0, then we wait forever. A timeout + value n > 0 will wait n seconds before rebooting, while a timeout + value n < 0 will reboot immediately. + +config SCHED_DEBUG + bool "Collect scheduler debugging info" + depends on DEBUG_KERNEL && PROC_FS + default y + help + If you say Y here, the /proc/sched_debug file will be provided + that can help debug the scheduler. The runtime overhead of this + option is minimal. + +config SCHED_INFO + bool + default n + +config SCHEDSTATS + bool "Collect scheduler statistics" + depends on DEBUG_KERNEL && PROC_FS + select SCHED_INFO + help + If you say Y here, additional code will be inserted into the + scheduler and related routines to collect statistics about + scheduler behavior and provide them in /proc/schedstat. These + stats may be useful for both tuning and debugging the scheduler + If you aren't debugging the scheduler or trying to tune a specific + application, you can say N to avoid the very slight overhead + this adds. + +config SCHED_STACK_END_CHECK + bool "Detect stack corruption on calls to schedule()" + depends on DEBUG_KERNEL + default n + help + This option checks for a stack overrun on calls to schedule(). + If the stack end location is found to be over written always panic as + the content of the corrupted region can no longer be trusted. + This is to ensure no erroneous behaviour occurs which could result in + data corruption or a sporadic crash at a later stage once the region + is examined. The runtime overhead introduced is minimal. + +config DEBUG_TIMEKEEPING + bool "Enable extra timekeeping sanity checking" + help + This option will enable additional timekeeping sanity checks + which may be helpful when diagnosing issues where timekeeping + problems are suspected. + + This may include checks in the timekeeping hotpaths, so this + option may have a (very small) performance impact to some + workloads. + + If unsure, say N. + +config DEBUG_PREEMPT + bool "Debug preemptible kernel" + depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT + default y + help + If you say Y here then the kernel will use a debug variant of the + commonly used smp_processor_id() function and will print warnings + if kernel code uses it in a preemption-unsafe way. Also, the kernel + will detect preemption count underflows. + +menu "Lock Debugging (spinlocks, mutexes, etc...)" + +config LOCK_DEBUGGING_SUPPORT + bool + depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT + default y + +config PROVE_LOCKING + bool "Lock debugging: prove locking correctness" + depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT + select LOCKDEP + select DEBUG_SPINLOCK + select DEBUG_MUTEXES + select DEBUG_RT_MUTEXES if RT_MUTEXES + select DEBUG_RWSEMS if RWSEM_SPIN_ON_OWNER + select DEBUG_WW_MUTEX_SLOWPATH + select DEBUG_LOCK_ALLOC + select TRACE_IRQFLAGS + default n + help + This feature enables the kernel to prove that all locking + that occurs in the kernel runtime is mathematically + correct: that under no circumstance could an arbitrary (and + not yet triggered) combination of observed locking + sequences (on an arbitrary number of CPUs, running an + arbitrary number of tasks and interrupt contexts) cause a + deadlock. + + In short, this feature enables the kernel to report locking + related deadlocks before they actually occur. + + The proof does not depend on how hard and complex a + deadlock scenario would be to trigger: how many + participant CPUs, tasks and irq-contexts would be needed + for it to trigger. The proof also does not depend on + timing: if a race and a resulting deadlock is possible + theoretically (no matter how unlikely the race scenario + is), it will be proven so and will immediately be + reported by the kernel (once the event is observed that + makes the deadlock theoretically possible). + + If a deadlock is impossible (i.e. the locking rules, as + observed by the kernel, are mathematically correct), the + kernel reports nothing. + + NOTE: this feature can also be enabled for rwlocks, mutexes + and rwsems - in which case all dependencies between these + different locking variants are observed and mapped too, and + the proof of observed correctness is also maintained for an + arbitrary combination of these separate locking variants. + + For more details, see Documentation/locking/lockdep-design.txt. + +config LOCK_STAT + bool "Lock usage statistics" + depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT + select LOCKDEP + select DEBUG_SPINLOCK + select DEBUG_MUTEXES + select DEBUG_RT_MUTEXES if RT_MUTEXES + select DEBUG_LOCK_ALLOC + default n + help + This feature enables tracking lock contention points + + For more details, see Documentation/locking/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_RT_MUTEXES + bool "RT Mutex debugging, deadlock detection" + depends on DEBUG_KERNEL && RT_MUTEXES + help + This allows rt mutex semantics violations and rt mutex related + deadlocks (lockups) to be detected and reported automatically. + +config DEBUG_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 + best used in conjunction with the NMI watchdog so that spinlock + deadlocks are also debuggable. + +config DEBUG_MUTEXES + bool "Mutex debugging: basic checks" + depends on DEBUG_KERNEL + help + This feature allows mutex semantics violations to be detected and + reported. + +config DEBUG_WW_MUTEX_SLOWPATH + bool "Wait/wound mutex debugging: Slowpath testing" + depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT + select DEBUG_LOCK_ALLOC + select DEBUG_SPINLOCK + select DEBUG_MUTEXES + help + This feature enables slowpath testing for w/w mutex users by + injecting additional -EDEADLK wound/backoff cases. Together with + the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this + will test all possible w/w mutex interface abuse with the + exception of simply not acquiring all the required locks. + Note that this feature can introduce significant overhead, so + it really should not be enabled in a production or distro kernel, + even a debug kernel. If you are a driver writer, enable it. If + you are a distro, do not. + +config DEBUG_RWSEMS + bool "RW Semaphore debugging: basic checks" + depends on DEBUG_KERNEL && RWSEM_SPIN_ON_OWNER + help + This debugging feature allows mismatched rw semaphore locks and unlocks + to be detected and reported. + +config DEBUG_LOCK_ALLOC + bool "Lock debugging: detect incorrect freeing of live locks" + depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT + select DEBUG_SPINLOCK + select DEBUG_MUTEXES + select DEBUG_RT_MUTEXES if RT_MUTEXES + select LOCKDEP + help + This feature will check whether any held lock (spinlock, rwlock, + mutex or rwsem) is incorrectly freed by the kernel, via any of the + memory-freeing routines (kfree(), kmem_cache_free(), free_pages(), + vfree(), etc.), whether a live lock is incorrectly reinitialized via + spin_lock_init()/mutex_init()/etc., or whether there is any lock + held during task exit. + +config LOCKDEP + bool + depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT + select STACKTRACE + select FRAME_POINTER if !MIPS && !PPC && !ARM && !S390 && !MICROBLAZE && !ARC && !X86 + select KALLSYMS + select KALLSYMS_ALL + +config LOCKDEP_SMALL + bool + +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 DEBUG_ATOMIC_SLEEP + bool "Sleep inside atomic section checking" + select PREEMPT_COUNT + depends on DEBUG_KERNEL + depends on !ARCH_NO_PREEMPT + help + If you say Y here, various routines which may sleep will become very + 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" + 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 LOCK_TORTURE_TEST + tristate "torture tests for locking" + depends on DEBUG_KERNEL + select TORTURE_TEST + help + This option provides a kernel module that runs torture tests + on kernel locking primitives. The kernel module may be built + after the fact on the running kernel to be tested, if desired. + + Say Y here if you want kernel locking-primitive torture tests + to be built into the kernel. + Say M if you want these torture tests to build as a module. + Say N if you are unsure. + +config WW_MUTEX_SELFTEST + tristate "Wait/wound mutex selftests" + help + This option provides a kernel module that runs tests on the + on the struct ww_mutex locking API. + + It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction + with this test harness. + + Say M if you want these self tests to build as a module. + Say N if you are unsure. + +endmenu # lock debugging + +config TRACE_IRQFLAGS + bool + help + Enables hooks to interrupt enabling and disabling for + either tracing or lock debugging. + +config STACKTRACE + bool "Stack backtrace support" + depends on STACKTRACE_SUPPORT + help + This option causes the kernel to create a /proc/pid/stack for + every process, showing its current stack trace. + It is also used by various kernel debugging features that require + stack trace generation. + +config WARN_ALL_UNSEEDED_RANDOM + bool "Warn for all uses of unseeded randomness" + default n + help + Some parts of the kernel contain bugs relating to their use of + cryptographically secure random numbers before it's actually possible + to generate those numbers securely. This setting ensures that these + flaws don't go unnoticed, by enabling a message, should this ever + occur. This will allow people with obscure setups to know when things + are going wrong, so that they might contact developers about fixing + it. + + Unfortunately, on some models of some architectures getting + a fully seeded CRNG is extremely difficult, and so this can + result in dmesg getting spammed for a surprisingly long + time. This is really bad from a security perspective, and + so architecture maintainers really need to do what they can + to get the CRNG seeded sooner after the system is booted. + However, since users cannot do anything actionable to + address this, by default this option is disabled. + + Say Y here if you want to receive warnings for all uses of + unseeded randomness. This will be of use primarily for + those developers interested in improving the security of + Linux kernels running on their architecture (or + subarchitecture). + +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_KOBJECT_RELEASE + bool "kobject release debugging" + depends on DEBUG_OBJECTS_TIMERS + help + kobjects are reference counted objects. This means that their + last reference count put is not predictable, and the kobject can + live on past the point at which a driver decides to drop it's + initial reference to the kobject gained on allocation. An + example of this would be a struct device which has just been + unregistered. + + However, some buggy drivers assume that after such an operation, + the memory backing the kobject can be immediately freed. This + goes completely against the principles of a refcounted object. + + If you say Y here, the kernel will delay the release of kobjects + on the last reference count to improve the visibility of this + kind of kobject release bug. + +config HAVE_DEBUG_BUGVERBOSE + bool + +config DEBUG_BUGVERBOSE + bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT + depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE) + 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_LIST + bool "Debug linked list manipulation" + depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION + help + Enable this to turn on extended checks in the linked-list + walking routines. + + If unsure, say N. + +config DEBUG_PI_LIST + bool "Debug priority linked list manipulation" + depends on DEBUG_KERNEL + help + Enable this to turn on extended checks in the priority-ordered + linked-list (plist) walking routines. This checks the entire + list multiple times during each manipulation. + + 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. + +source "kernel/rcu/Kconfig.debug" + +config DEBUG_WQ_FORCE_RR_CPU + bool "Force round-robin CPU selection for unbound work items" + depends on DEBUG_KERNEL + default n + help + Workqueue used to implicitly guarantee that work items queued + without explicit CPU specified are put on the local CPU. This + guarantee is no longer true and while local CPU is still + preferred work items may be put on foreign CPUs. Kernel + parameter "workqueue.debug_force_rr_cpu" is added to force + round-robin CPU selection to flush out usages which depend on the + now broken guarantee. This config option enables the debug + feature by default. When enabled, memory and cache locality will + be impacted. + +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 CPU_HOTPLUG_STATE_CONTROL + bool "Enable CPU hotplug state control" + depends on DEBUG_KERNEL + depends on HOTPLUG_CPU + default n + help + Allows to write steps between "offline" and "online" to the CPUs + sysfs target file so states can be stepped granular. This is a debug + option for now as the hotplug machinery cannot be stopped and + restarted at arbitrary points yet. + + Say N if your are unsure. + +config NOTIFIER_ERROR_INJECTION + tristate "Notifier error injection" + depends on DEBUG_KERNEL + select DEBUG_FS + help + This option provides the ability to inject artificial errors to + specified notifier chain callbacks. It is useful to test the error + handling of notifier call chain failures. + + Say N if unsure. + +config PM_NOTIFIER_ERROR_INJECT + tristate "PM notifier error injection module" + depends on PM && NOTIFIER_ERROR_INJECTION + default m if PM_DEBUG + help + This option provides the ability to inject artificial errors to + PM notifier chain callbacks. It is controlled through debugfs + interface /sys/kernel/debug/notifier-error-inject/pm + + If the notifier call chain should be failed with some events + notified, write the error code to "actions/<notifier event>/error". + + Example: Inject PM suspend error (-12 = -ENOMEM) + + # cd /sys/kernel/debug/notifier-error-inject/pm/ + # echo -12 > actions/PM_SUSPEND_PREPARE/error + # echo mem > /sys/power/state + bash: echo: write error: Cannot allocate memory + + To compile this code as a module, choose M here: the module will + be called pm-notifier-error-inject. + + If unsure, say N. + +config OF_RECONFIG_NOTIFIER_ERROR_INJECT + tristate "OF reconfig notifier error injection module" + depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION + help + This option provides the ability to inject artificial errors to + OF reconfig notifier chain callbacks. It is controlled + through debugfs interface under + /sys/kernel/debug/notifier-error-inject/OF-reconfig/ + + If the notifier call chain should be failed with some events + notified, write the error code to "actions/<notifier event>/error". + + To compile this code as a module, choose M here: the module will + be called of-reconfig-notifier-error-inject. + + If unsure, say N. + +config NETDEV_NOTIFIER_ERROR_INJECT + tristate "Netdev notifier error injection module" + depends on NET && NOTIFIER_ERROR_INJECTION + help + This option provides the ability to inject artificial errors to + netdevice notifier chain callbacks. It is controlled through debugfs + interface /sys/kernel/debug/notifier-error-inject/netdev + + If the notifier call chain should be failed with some events + notified, write the error code to "actions/<notifier event>/error". + + Example: Inject netdevice mtu change error (-22 = -EINVAL) + + # cd /sys/kernel/debug/notifier-error-inject/netdev + # echo -22 > actions/NETDEV_CHANGEMTU/error + # ip link set eth0 mtu 1024 + RTNETLINK answers: Invalid argument + + To compile this code as a module, choose M here: the module will + be called netdev-notifier-error-inject. + + If unsure, say N. + +config FUNCTION_ERROR_INJECTION + def_bool y + depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES + +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 FAIL_FUTEX + bool "Fault-injection capability for futexes" + select DEBUG_FS + depends on FAULT_INJECTION && FUTEX + help + Provide fault-injection capability for futexes. + +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 FAIL_FUNCTION + bool "Fault-injection capability for functions" + depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION + help + Provide function-based fault-injection capability. + This will allow you to override a specific function with a return + with given return value. As a result, function caller will see + an error value and have to handle it. This is useful to test the + error handling in various subsystems. + +config FAIL_MMC_REQUEST + bool "Fault-injection capability for MMC IO" + depends on FAULT_INJECTION_DEBUG_FS && 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_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 !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM && !ARC && !X86 + help + Provide stacktrace filter for fault-injection capabilities + +config LATENCYTOP + bool "Latency measuring infrastructure" + depends on DEBUG_KERNEL + depends on STACKTRACE_SUPPORT + depends on PROC_FS + select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM && !ARC && !X86 + 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. + +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 DMA_API_DEBUG + bool "Enable debugging of DMA-API usage" + select NEED_DMA_MAP_STATE + 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 also attempts to catch cases where a page owned by DMA is + accessed by the cpu in a way that could cause data corruption. For + example, this enables cow_user_page() to check that the source page is + not undergoing DMA. + + This option causes a performance degradation. Use only if you want to + debug device drivers and dma interactions. + + If unsure, say N. + +config DMA_API_DEBUG_SG + bool "Debug DMA scatter-gather usage" + default y + depends on DMA_API_DEBUG + help + Perform extra checking that callers of dma_map_sg() have respected the + appropriate segment length/boundary limits for the given device when + preparing DMA scatterlists. + + This is particularly likely to have been overlooked in cases where the + dma_map_sg() API is used for general bulk mapping of pages rather than + preparing literal scatter-gather descriptors, where there is a risk of + unexpected behaviour from DMA API implementations if the scatterlist + is technically out-of-spec. + + If unsure, say N. + +menuconfig RUNTIME_TESTING_MENU + bool "Runtime Testing" + def_bool y + +if RUNTIME_TESTING_MENU + +config LKDTM + tristate "Linux Kernel Dump Test Tool Module" + depends on DEBUG_FS + depends on BLOCK + 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 TEST_LIST_SORT + tristate "Linked list sorting test" + depends on DEBUG_KERNEL || m + help + Enable this to turn on 'list_sort()' function test. This test is + executed only once during system boot (so affects only boot time), + or at module load time. + + If unsure, say N. + +config TEST_SORT + tristate "Array-based sort test" + depends on DEBUG_KERNEL || m + help + This option enables the self-test function of 'sort()' at boot, + or at module load time. + + If unsure, say N. + +config KPROBES_SANITY_TEST + bool "Kprobes sanity tests" + depends on DEBUG_KERNEL + depends on KPROBES + help + This option provides for testing basic kprobes functionality on + boot. Samples of kprobe 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 + 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 RBTREE_TEST + tristate "Red-Black tree test" + depends on DEBUG_KERNEL + help + A benchmark measuring the performance of the rbtree library. + Also includes rbtree invariant checks. + +config INTERVAL_TREE_TEST + tristate "Interval tree test" + depends on DEBUG_KERNEL + select INTERVAL_TREE + help + A benchmark measuring the performance of the interval tree library + +config PERCPU_TEST + tristate "Per cpu operations test" + depends on m && DEBUG_KERNEL + help + Enable this option to build test module which validates per-cpu + operations. + + If unsure, say N. + +config ATOMIC64_SELFTEST + tristate "Perform an atomic64_t self-test" + help + Enable this option to test the atomic64_t functions at boot or + at module load time. + + 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. + +config TEST_HEXDUMP + tristate "Test functions located in the hexdump module at runtime" + +config TEST_STRING_HELPERS + tristate "Test functions located in the string_helpers module at runtime" + +config TEST_KSTRTOX + tristate "Test kstrto*() family of functions at runtime" + +config TEST_PRINTF + tristate "Test printf() family of functions at runtime" + +config TEST_BITMAP + tristate "Test bitmap_*() family of functions at runtime" + help + Enable this option to test the bitmap functions at boot. + + If unsure, say N. + +config TEST_BITFIELD + tristate "Test bitfield functions at runtime" + help + Enable this option to test the bitfield functions at boot. + + If unsure, say N. + +config TEST_UUID + tristate "Test functions located in the uuid module at runtime" + +config TEST_OVERFLOW + tristate "Test check_*_overflow() functions at runtime" + +config TEST_RHASHTABLE + tristate "Perform selftest on resizable hash table" + help + Enable this option to test the rhashtable functions at boot. + + If unsure, say N. + +config TEST_HASH + tristate "Perform selftest on hash functions" + help + Enable this option to test the kernel's integer (<linux/hash.h>), + string (<linux/stringhash.h>), and siphash (<linux/siphash.h>) + hash functions on boot (or module load). + + This is intended to help people writing architecture-specific + optimized versions. If unsure, say N. + +config TEST_IDA + tristate "Perform selftest on IDA functions" + +config TEST_PARMAN + tristate "Perform selftest on priority array manager" + depends on PARMAN + help + Enable this option to test priority array manager on boot + (or module load). + + If unsure, say N. + +config TEST_LKM + tristate "Test module loading with 'hello world' module" + depends on m + help + This builds the "test_module" module that emits "Hello, world" + on printk when loaded. It is designed to be used for basic + evaluation of the module loading subsystem (for example when + validating module verification). It lacks any extra dependencies, + and will not normally be loaded by the system unless explicitly + requested by name. + + If unsure, say N. + +config TEST_USER_COPY + tristate "Test user/kernel boundary protections" + depends on m + help + This builds the "test_user_copy" module that runs sanity checks + on the copy_to/from_user infrastructure, making sure basic + user/kernel boundary testing is working. If it fails to load, + a regression has been detected in the user/kernel memory boundary + protections. + + If unsure, say N. + +config TEST_BPF + tristate "Test BPF filter functionality" + depends on m && NET + help + This builds the "test_bpf" module that runs various test vectors + against the BPF interpreter or BPF JIT compiler depending on the + current setting. This is in particular useful for BPF JIT compiler + development, but also to run regression tests against changes in + the interpreter code. It also enables test stubs for eBPF maps and + verifier used by user space verifier testsuite. + + If unsure, say N. + +config FIND_BIT_BENCHMARK + tristate "Test find_bit functions" + help + This builds the "test_find_bit" module that measure find_*_bit() + functions performance. + + If unsure, say N. + +config TEST_FIRMWARE + tristate "Test firmware loading via userspace interface" + depends on FW_LOADER + help + This builds the "test_firmware" module that creates a userspace + interface for testing firmware loading. This can be used to + control the triggering of firmware loading without needing an + actual firmware-using device. The contents can be rechecked by + userspace. + + If unsure, say N. + +config TEST_SYSCTL + tristate "sysctl test driver" + depends on PROC_SYSCTL + help + This builds the "test_sysctl" module. This driver enables to test the + proc sysctl interfaces available to drivers safely without affecting + production knobs which might alter system functionality. + + If unsure, say N. + +config TEST_UDELAY + tristate "udelay test driver" + help + This builds the "udelay_test" module that helps to make sure + that udelay() is working properly. + + If unsure, say N. + +config TEST_STATIC_KEYS + tristate "Test static keys" + depends on m + help + Test the static key interfaces. + + If unsure, say N. + +config TEST_KMOD + tristate "kmod stress tester" + depends on m + depends on BLOCK && (64BIT || LBDAF) # for XFS, BTRFS + depends on NETDEVICES && NET_CORE && INET # for TUN + depends on BLOCK + select TEST_LKM + select XFS_FS + select TUN + select BTRFS_FS + help + Test the kernel's module loading mechanism: kmod. kmod implements + support to load modules using the Linux kernel's usermode helper. + This test provides a series of tests against kmod. + + Although technically you can either build test_kmod as a module or + into the kernel we disallow building it into the kernel since + it stress tests request_module() and this will very likely cause + some issues by taking over precious threads available from other + module load requests, ultimately this could be fatal. + + To run tests run: + + tools/testing/selftests/kmod/kmod.sh --help + + If unsure, say N. + +config TEST_DEBUG_VIRTUAL + tristate "Test CONFIG_DEBUG_VIRTUAL feature" + depends on DEBUG_VIRTUAL + help + Test the kernel's ability to detect incorrect calls to + virt_to_phys() done against the non-linear part of the + kernel's virtual address map. + + If unsure, say N. + +endif # RUNTIME_TESTING_MENU + +config MEMTEST + bool "Memtest" + depends on HAVE_MEMBLOCK + ---help--- + This option adds a kernel parameter 'memtest', which allows memtest + to be set. + memtest=0, mean disabled; -- default + memtest=1, mean do 1 test pattern; + ... + memtest=17, mean do 17 test patterns. + If you are unsure how to answer this question, answer N. + +config BUG_ON_DATA_CORRUPTION + bool "Trigger a BUG when data corruption is detected" + select DEBUG_LIST + help + Select this option if the kernel should BUG when it encounters + data corruption in kernel memory structures when they get checked + for validity. + + If unsure, say N. + +source "samples/Kconfig" + +source "lib/Kconfig.kgdb" + +source "lib/Kconfig.ubsan" + +config ARCH_HAS_DEVMEM_IS_ALLOWED + bool + +config STRICT_DEVMEM + bool "Filter access to /dev/mem" + depends on MMU && DEVMEM + depends on ARCH_HAS_DEVMEM_IS_ALLOWED + default y if PPC || X86 || ARM64 + ---help--- + If this option is disabled, you allow userspace (root) access to all + of memory, including kernel and userspace memory. Accidental + access to this is obviously disastrous, but specific access can + be used by people debugging the kernel. Note that with PAT support + enabled, even in this case there are restrictions on /dev/mem + use due to the cache aliasing requirements. + + If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem + file only allows userspace access to PCI space and the BIOS code and + data regions. This is sufficient for dosemu and X and all common + users of /dev/mem. + + If in doubt, say Y. + +config IO_STRICT_DEVMEM + bool "Filter I/O access to /dev/mem" + depends on STRICT_DEVMEM + ---help--- + If this option is disabled, you allow userspace (root) access to all + io-memory regardless of whether a driver is actively using that + range. Accidental access to this is obviously disastrous, but + specific access can be used by people debugging kernel drivers. + + If this option is switched on, the /dev/mem file only allows + userspace access to *idle* io-memory ranges (see /proc/iomem) This + may break traditional users of /dev/mem (dosemu, legacy X, etc...) + if the driver using a given range cannot be disabled. + + If in doubt, say Y. + +source "arch/$(SRCARCH)/Kconfig.debug" + +endmenu # Kernel hacking |