linux/lib/Kconfig.debug

1 # SPDX-License-Identifier: GPL-2.0-only
18 	  The behavior is also controlled by the kernel command line
19 	  parameter printk.time=1. See Documentation/admin-guide/kernel-parameters.rst
50 	int "Default console loglevel (1-15)"
60 	  Note: This does not affect the log level of un-prefixed printk()
61 	  usage in the kernel. That is controlled by the MESSAGE_LOGLEVEL_DEFAULT
65 	int "quiet console loglevel (1-15)"
76 	int "Default message log level (1-7)"
82 	  This was hard-coded to KERN_WARNING since at least 2.6.10 but folks
118 	  enabled/disabled based on various levels of scope - per source file,
130 	  Dynamic debugging is controlled via the 'dynamic_debug/control' file,
158 		nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
162 		nullarbor:~ # echo -n 'file svcsock.c +p' >
166 		nullarbor:~ # echo -n 'module nfsd +p' >
170 		nullarbor:~ # echo -n 'func svc_process +p' >
174 		nullarbor:~ # echo -n 'func svc_process -p' >
177 	  See Documentation/admin-guide/dynamic-debug-howto.rst for additional
207 	  debugging but costs about 70-100K of memory.
225 menu "Compile-time checks and compiler options"
237 	def_bool $(as-instr,.uleb128 .Lexpr_end4 - .Lexpr_start3\n.Lexpr_start3:\n.Lexpr_end4:)
245 	  This adds debug symbols to the kernel and modules (gcc -g), and
288 	  5.0+ accepts the -gdwarf-5 flag but only had partial support for some
292 	  15-18% savings in resulting image and debug info section sizes as
330 	depends on $(cc-option,-gz=zlib)
331 	depends on $(ld-option,--compress-debug-sections=zlib)
336 	  Users of dpkg-deb via scripts/package/builddeb may find an increase in
345 	depends on $(cc-option,-gz=zstd)
346 	depends on $(ld-option,--compress-debug-sections=zstd)
357 	depends on $(cc-option,-gsplit-dwarf)
358 	# RISC-V linker relaxation + -gsplit-dwarf has issues with LLVM and GCC
360 	# https://github.com/llvm/llvm-project/issues/56642
400 	  Support for the --lang_exclude flag which makes pahole exclude
414 	bool "Allow loading modules with non-matching BTF type info"
430 	  instance. See Documentation/dev-tools/gdb-kernel-debugging.rst
451 	bool "Strip assembler-generated symbols during link"
454 	  Strip internal assembler-generated symbols during a link (symbols
472 	  This option will install uapi headers (headers exported to user-space)
475 	  user-space program samples. It is also needed by some features such
493 	  - Add the option -fno-inline-functions-called-once to gcc commands.
494 	    When inlining a function annotated with __init in a non-init
501 	bool "Make section mismatch errors non-fatal"
543 	bool "Compile-time stack metadata validation"
548 	  Validate frame pointer rules at compile-time.  This helps ensure that
564 	  Selecting this option will pass "-Map=vmlinux.map" to ld
571 	bool "Force weak per-cpu definitions"
600 	  keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
610 	  to a bitmask as described in Documentation/admin-guide/sysrq.rst.
651 	  debugfs=[on,no-mount,off]. The restrictions apply for API access
670 	  Access is off. Clients get -PERM when trying to create nodes in
672 	  Client can then back-off or continue without debugfs access.
712 	  properly. This can make kmalloc/kfree-intensive workloads
746 	int "debug_objects bootup default value (0-1)"
766 	  task has ever had available in the sysrq-T and sysrq-P debug output.
795 	  Enable this to turn on extended checks in the virtual-memory system
820 	bool "Debug VM red-black trees"
823 	  Enable VM red-black tree debugging information and extra validations.
828 	bool "Debug page-flags operations"
878 	  on the mminit_loglevel= command-line option.
887 	  memory hotplug notifier chain callbacks.  It is controlled through
888 	  debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
893 	  Example: Inject memory hotplug offline error (-12 == -ENOMEM)
895 	  # cd /sys/kernel/debug/notifier-error-inject/memory
896 	  # echo -12 > actions/MEM_GOING_OFFLINE/error
901 	  be called memory-notifier-error-inject.
933 	  mechanism for non-highmem pages and on non-highmem systems.
957 	  These kinds of bugs usually occur when call-chains in the
1039 	  high-availability systems that have uptime guarantees and
1078 # Note that arch-specific variants are always preferred.
1093 	  an arch-specific hardlockup detector or if resources needed
1116 	  The arch-specific implementation of the hardlockup detector will
1166 	  to determine when a task has become non-responsive and should
1187 	  high-availability systems that have uptime guarantees and
1204 	bool "Report per-cpu work items which hog CPU for too long"
1207 	  Say Y here to enable reporting of concurrency-managed per-cpu work
1211 	  them from stalling other per-cpu work items. Occassional
1225 	  Also it could generate series of lockups with cooling-down periods.
1280 	  if kernel code uses it in a preemption-unsafe way. Also, the kernel
1321 	 participant CPUs, tasks and irq-contexts would be needed
1334 	 and rwsems - in which case all dependencies between these
1339 	 For more details, see Documentation/locking/lockdep-design.rst.
1342 	bool "Enable raw_spinlock - spinlock nesting checks"
1388 	bool "Spinlock and rw-lock debugging: basic checks"
1413 	 injecting additional -EDEADLK wound/backoff cases. Together with
1439 	 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1492 … Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1515 	bool "Locking API boot-time self-tests"
1518 	  Say Y here if you want the kernel to run a short self-test during
1519 	  bootup. The self-test checks whether common types of locking bugs
1534 	  Say Y here if you want kernel locking-primitive torture tests
1685 	  Enable this to turn on extended checks in the linked-list walking
1698 	  Enable this to turn on extended checks in the priority-ordered
1699 	  linked-list (plist) walking routines.  This checks the entire
1708 	  Enable this to turn on checks on scatter-gather tables. This can
1737 	bool "Force round-robin CPU selection for unbound work items"
1746 	  round-robin CPU selection to flush out usages which depend on the
1796 	  this feature to remotely access the memory of the crashed machine
1800 	  With remote DMA, you can monitor the printk buffer remotely using
1815 	  in charge of the OHCI-1394 controllers should be used instead.
1817 	  See Documentation/core-api/debugging-via-ohci1394.rst for more information.
1849 	  io-memory regardless of whether a driver is actively using that
1854 	  userspace access to *idle* io-memory ranges (see /proc/iomem) This
1887 	  PM notifier chain callbacks.  It is controlled through debugfs
1888 	  interface /sys/kernel/debug/notifier-error-inject/pm
1893 	  Example: Inject PM suspend error (-12 = -ENOMEM)
1895 	  # cd /sys/kernel/debug/notifier-error-inject/pm/
1896 	  # echo -12 > actions/PM_SUSPEND_PREPARE/error
1901 	  be called pm-notifier-error-inject.
1910 	  OF reconfig notifier chain callbacks.  It is controlled
1912 	  /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1918 	  be called of-reconfig-notifier-error-inject.
1927 	  netdevice notifier chain callbacks.  It is controlled through debugfs
1928 	  interface /sys/kernel/debug/notifier-error-inject/netdev
1933 	  Example: Inject netdevice mtu change error (-22 = -EINVAL)
1935 	  # cd /sys/kernel/debug/notifier-error-inject/netdev
1936 	  # echo -22 > actions/NETDEV_CHANGEMTU/error
1941 	  be called netdev-notifier-error-inject.
1946 	bool "Fault-injections of functions"
1956 	bool "Fault-injection framework"
1959 	  Provide fault-injection framework.
1960 	  For more details, see Documentation/fault-injection/.
1963 	bool "Fault-injection capability for kmalloc"
1967 	  Provide fault-injection capability for kmalloc.
1970 	bool "Fault-injection capability for alloc_pages()"
1973 	  Provide fault-injection capability for alloc_pages().
1979 	  Provides fault-injection capability to inject failures
1983 	bool "Fault-injection capability for disk IO"
1986 	  Provide fault-injection capability for disk IO.
1989 	bool "Fault-injection capability for faking disk interrupts"
1992 	  Provide fault-injection capability on end IO handling. This
2000 	bool "Fault-injection capability for futexes"
2004 	  Provide fault-injection capability for futexes.
2007 	bool "Debugfs entries for fault-injection capabilities"
2010 	  Enable configuration of fault-injection capabilities via debugfs.
2013 	bool "Fault-injection capability for functions"
2016 	  Provide function-based fault-injection capability.
2023 	bool "Fault-injection capability for MMC IO"
2026 	  Provide fault-injection capability for MMC IO.
2033 	bool "Fault-injection capability for SunRPC"
2036 	  Provide fault-injection capability for SunRPC and
2040 	bool "Configfs interface for fault-injection capabilities"
2044 	  This option allows configfs-based drivers to dynamically configure
2045 	  fault-injection via configfs.  Each parameter for driver-specific
2046 	  fault-injection can be made visible as a configfs attribute in a
2051 	bool "stacktrace filter for fault-injection capabilities"
2057 	  Provide stacktrace filter for fault-injection capabilities
2067 	def_bool $(cc-option,-fsanitize-coverage=trace-pc)
2081 	  for coverage-guided fuzzing (randomized testing).
2087 	  For more details, see Documentation/dev-tools/kcov.rst.
2092 	depends on $(cc-option,-fsanitize-coverage=trace-cmp)
2115 	  KCOV uses preallocated per-cpu areas to collect coverage from
2135 	  the kernel command line (when built-in), or from userspace (when
2136 	  built-in or modular.
2171 	Documentation/fault-injection/provoke-crashes.rst
2181 	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2207 	tristate "Array-based sort test" if !KUNIT_ALL_TESTS
2211 	  This option enables the self-test function of 'sort()' at boot,
2289 	tristate "Red-Black tree test"
2296 	tristate "Reed-Solomon library test"
2302 	  This option enables the self-test function of rslib at boot,
2318 	  Enable this option to build test module which validates per-cpu
2324 	tristate "Perform an atomic64_t self-test"
2336 	  This is a one-shot self test that permutes through the
2338 	  N-disk array.  Recovery is performed with the asynchronous
2431 	  no compiler warnings from C=1 sparse checker or -Wextra
2499 	  actual firmware-using device. The contents can be rechecked by
2527 	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2544 	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2562 	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2564 	  This is intended to help people writing architecture-specific
2575 	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2587 	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2592 	tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
2606 	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2619 	  in Documentation/dev-tools/kunit/.
2631 	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2643 	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2655 	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2667 	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2678 	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2689 	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2713 	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2726 	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2735 	  Test if the kernel is zero-initializing stack variables and
2736 	  padding. Coverage is controlled by compiler flags,
2778 	  This is intended to help people writing architecture-specific
2830 	  tools/testing/selftests/kmod/kmod.sh --help
2839 	  virt_to_phys() done against the non-linear part of the
2864 	  make -C tools/testing/selftests TARGETS=livepatch run_tests
2868 	  tools/testing/selftests/livepatch/test-callbacks.sh
2869 	  tools/testing/selftests/livepatch/test-livepatch.sh
2870 	  tools/testing/selftests/livepatch/test-shadow-vars.sh
2885 	  Test if the kernel is zero-initializing heap and page allocations.
2899 	  Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
2918 	  for self-testing floating point control register setting in
2949 	        memtest=0, mean disabled; -- default
2958 	bool "Microsoft Hyper-V driver testing"
2962 	  Select this option to enable Hyper-V vmbus testing.
2972 	  Enables rustc's `-Cdebug-assertions` codegen option.
2988 	  Enables rustc's `-Coverflow-checks` codegen option.
2991 	  overflow. When overflow-checks are enabled, a Rust panic will occur
2999 	bool "Allow unoptimized build-time assertions"
3023 	  please refer to the KUnit documentation in Documentation/dev-tools/kunit/.