kernel/lib/Kconfig.debug

1 # SPDX-License-Identifier: GPL-2.0-only
19 	  parameter printk.time=1. See Documentation/admin-guide/kernel-parameters.rst
43 	int "Default console loglevel (1-15)"
53 	  Note: This does not affect the log level of un-prefixed printk()
58 	int "quiet console loglevel (1-15)"
69 	int "Default message log level (1-7)"
75 	  This was hard-coded to KERN_WARNING since at least 2.6.10 but folks
111 	  enabled/disabled based on various levels of scope - per source file,
151 		nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
155 		nullarbor:~ # echo -n 'file svcsock.c +p' >
159 		nullarbor:~ # echo -n 'module nfsd +p' >
163 		nullarbor:~ # echo -n 'func svc_process +p' >
167 		nullarbor:~ # echo -n 'func svc_process -p' >
170 	  See Documentation/admin-guide/dynamic-debug-howto.rst for additional
200 	  debugging but costs about 70-100K of memory.
204 menu "Compile-time checks and compiler options"
212 	  This adds debug symbols to the kernel and modules (gcc -g), and
235 	depends on $(cc-option,-gz=zlib)
236 	depends on $(ld-option,--compress-debug-sections=zlib)
241 	  Users of dpkg-deb via scripts/package/builddeb may find an increase in
250 	depends on $(cc-option,-gsplit-dwarf)
265 	depends on $(cc-option,-gdwarf-4)
288 	  instance. See Documentation/dev-tools/gdb-kernel-debugging.rst
316 	bool "Strip assembler-generated symbols during link"
319 	  Strip internal assembler-generated symbols during a link (symbols
336 	  This option will install uapi headers (headers exported to user-space)
339 	  user-space program samples. It is also needed by some features such
356 	  - Add the option -fno-inline-functions-called-once to gcc commands.
357 	    When inlining a function annotated with __init in a non-init
364 	bool "Make section mismatch errors non-fatal"
376 	  address alignment of other domains, and cause magic performance
381 	  It is mainly for debug and performance tuning use.
401 	bool "Compile-time stack metadata validation"
405 	  Add compile-time checks to validate stack metadata, including frame
413 	  tools/objtool/Documentation/stack-validation.txt.
421 	bool "Force weak per-cpu definitions"
450 	  keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
460 	  to a bitmask as described in Documentation/admin-guide/sysrq.rst.
501 	  debugfs=[on,no-mount,off]. The restrictions apply for API access
520 	  Access is off. Clients get -PERM when trying to create nodes in
522 	  Client can then back-off or continue without debugfs access.
571 	  properly. This can make kmalloc/kfree-intensive workloads
605 	int "debug_objects bootup default value (0-1)"
618 	  memory. This can make kmalloc/kfree-intensive workloads much slower.
631 	  "slub_debug=-".
635 	bool "Enable SLUB performance statistics"
644 	  Try running: slabinfo -DA
663 	  allocations. See Documentation/dev-tools/kmemleak.rst for more
720 	  task has ever had available in the sysrq-T and sysrq-P debug output.
746 	  Enable this to turn on extended checks in the virtual-memory system
747 	  that may impact performance.
756 	  can cause significant overhead, so only enable it in non-production
762 	bool "Debug VM red-black trees"
765 	  Enable VM red-black tree debugging information and extra validations.
770 	bool "Debug page-flags operations"
820 	  on the mminit_loglevel= command-line option.
830 	  debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
835 	  Example: Inject memory hotplug offline error (-12 == -ENOMEM)
837 	  # cd /sys/kernel/debug/notifier-error-inject/memory
838 	  # echo -12 > actions/MEM_GOING_OFFLINE/error
843 	  be called memory-notifier-error-inject.
854 	  and decreases performance.
877 	  These kinds of bugs usually occur when call-chains in the
958 	  high-availability systems that have uptime guarantees and
1050 	  to determine when a task has become non-responsive and should
1071 	  high-availability systems that have uptime guarantees and
1103 	  Also it could generate series of lockups with cooling-down periods.
1147 	  option may have a (very small) performance impact to some
1159 	  if kernel code uses it in a preemption-unsafe way. Also, the kernel
1196 	 participant CPUs, tasks and irq-contexts would be needed
1209 	 and rwsems - in which case all dependencies between these
1214 	 For more details, see Documentation/locking/lockdep-design.rst.
1217 	bool "Enable raw_spinlock - spinlock nesting checks"
1263 	bool "Spinlock and rw-lock debugging: basic checks"
1287 	 injecting additional -EDEADLK wound/backoff cases. Together with
1313 	 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1366 … Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1388 	bool "Locking API boot-time self-tests"
1391 	  Say Y here if you want the kernel to run a short self-test during
1392 	  bootup. The self-test checks whether common types of locking bugs
1407 	  Say Y here if you want kernel locking-primitive torture tests
1530 	  Enable this to turn on extended checks in the linked-list
1539 	  Enable this to turn on extended checks in the priority-ordered
1540 	  linked-list (plist) walking routines.  This checks the entire
1549 	  Enable this to turn on checks on scatter-gather tables. This can
1563 	  performance, say N.
1595 	bool "Force round-robin CPU selection for unbound work items"
1604 	  round-robin CPU selection to flush out usages which depend on the
1622 	  may introduce non-contiguous block device numbers.  This
1691 	  in charge of the OHCI-1394 controllers should be used instead.
1693 	  See Documentation/core-api/debugging-via-ohci1394.rst for more information.
1725 	  io-memory regardless of whether a driver is actively using that
1730 	  userspace access to *idle* io-memory ranges (see /proc/iomem) This
1764 	  interface /sys/kernel/debug/notifier-error-inject/pm
1769 	  Example: Inject PM suspend error (-12 = -ENOMEM)
1771 	  # cd /sys/kernel/debug/notifier-error-inject/pm/
1772 	  # echo -12 > actions/PM_SUSPEND_PREPARE/error
1777 	  be called pm-notifier-error-inject.
1788 	  /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1794 	  be called of-reconfig-notifier-error-inject.
1804 	  interface /sys/kernel/debug/notifier-error-inject/netdev
1809 	  Example: Inject netdevice mtu change error (-22 = -EINVAL)
1811 	  # cd /sys/kernel/debug/notifier-error-inject/netdev
1812 	  # echo -22 > actions/NETDEV_CHANGEMTU/error
1817 	  be called netdev-notifier-error-inject.
1822 	bool "Fault-injections of functions"
1832 	bool "Fault-injection framework"
1835 	  Provide fault-injection framework.
1836 	  For more details, see Documentation/fault-injection/.
1839 	bool "Fault-injection capability for kmalloc"
1843 	  Provide fault-injection capability for kmalloc.
1846 	bool "Fault-injection capability for alloc_pages()"
1849 	  Provide fault-injection capability for alloc_pages().
1855 	  Provides fault-injection capability to inject failures
1859 	bool "Fault-injection capability for disk IO"
1862 	  Provide fault-injection capability for disk IO.
1865 	bool "Fault-injection capability for faking disk interrupts"
1868 	  Provide fault-injection capability on end IO handling. This
1876 	bool "Fault-injection capability for futexes"
1880 	  Provide fault-injection capability for futexes.
1883 	bool "Debugfs entries for fault-injection capabilities"
1886 	  Enable configuration of fault-injection capabilities via debugfs.
1889 	bool "Fault-injection capability for functions"
1892 	  Provide function-based fault-injection capability.
1899 	bool "Fault-injection capability for MMC IO"
1902 	  Provide fault-injection capability for MMC IO.
1909 	bool "stacktrace filter for fault-injection capabilities"
1915 	  Provide stacktrace filter for fault-injection capabilities
1925 	def_bool $(cc-option,-fsanitize-coverage=trace-pc)
1937 	  for coverage-guided fuzzing (randomized testing).
1943 	  For more details, see Documentation/dev-tools/kcov.rst.
1948 	depends on $(cc-option,-fsanitize-coverage=trace-cmp)
1971 	  KCOV uses preallocated per-cpu areas to collect coverage from
1992 	Documentation/fault-injection/provoke-crashes.rst
2015 	tristate "Array-based sort test"
2018 	  This option enables the self-test function of 'sort()' at boot,
2049 	tristate "Red-Black tree test"
2052 	  A benchmark measuring the performance of the rbtree library.
2056 	tristate "Reed-Solomon library test"
2062 	  This option enables the self-test function of rslib at boot,
2072 	  A benchmark measuring the performance of the interval tree library
2078 	  Enable this option to build test module which validates per-cpu
2084 	tristate "Perform an atomic64_t self-test"
2096 	  This is a one-shot self test that permutes through the
2098 	  N-disk array.  Recovery is performed with the asynchronous
2149 	  This is intended to help people writing architecture-specific
2192 	  no compiler warnings from C=1 sparse checker or -Wextra
2199 	tristate "Test module for stress/performance analysis of vmalloc allocator"
2205 	  stress and performance analysis. So, any new change for vmalloc
2206 	  subsystem can be evaluated from performance and stability point
2249 	  functions performance.
2260 	  actual firmware-using device. The contents can be rechecked by
2270 	  proc sysctl interfaces available to drivers safely without affecting
2287 	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2299 	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2304 	tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
2318 	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2330 	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2341 	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2383 	  tools/testing/selftests/kmod/kmod.sh --help
2392 	  virt_to_phys() done against the non-linear part of the
2417 	  make -C tools/testing/selftests TARGETS=livepatch run_tests
2421 	  tools/testing/selftests/livepatch/test-callbacks.sh
2422 	  tools/testing/selftests/livepatch/test-livepatch.sh
2423 	  tools/testing/selftests/livepatch/test-shadow-vars.sh
2439 	  Test if the kernel is zero-initializing stack variables and
2449 	  Test if the kernel is zero-initializing heap and page allocations.
2463 	  Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
2482 	  for self-testing floating point control register setting in
2494 	        memtest=0, mean disabled; -- default
2503 	bool "Microsoft Hyper-V driver testing"
2507 	  Select this option to enable Hyper-V vmbus testing.