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2021-11-12kfence: default to dynamic branch instead of static keys modeMarco Elver1-4/+8
commit 4f612ed3f748962cbef1316ff3d323e2b9055b6e upstream. We have observed that on very large machines with newer CPUs, the static key/branch switching delay is on the order of milliseconds. This is due to the required broadcast IPIs, which simply does not scale well to hundreds of CPUs (cores). If done too frequently, this can adversely affect tail latencies of various workloads. One workaround is to increase the sample interval to several seconds, while decreasing sampled allocation coverage, but the problem still exists and could still increase tail latencies. As already noted in the Kconfig help text, there are trade-offs: at lower sample intervals the dynamic branch results in better performance; however, at very large sample intervals, the static keys mode can result in better performance -- careful benchmarking is recommended. Our initial benchmarking showed that with large enough sample intervals and workloads stressing the allocator, the static keys mode was slightly better. Evaluating and observing the possible system-wide side-effects of the static-key-switching induced broadcast IPIs, however, was a blind spot (in particular on large machines with 100s of cores). Therefore, a major downside of the static keys mode is, unfortunately, that it is hard to predict performance on new system architectures and topologies, but also making conclusions about performance of new workloads based on a limited set of benchmarks. Most distributions will simply select the defaults, while targeting a large variety of different workloads and system architectures. As such, the better default is CONFIG_KFENCE_STATIC_KEYS=n, and re-enabling it is only recommended after careful evaluation. For reference, on x86-64 the condition in kfence_alloc() generates exactly 2 instructions in the kmem_cache_alloc() fast-path: | ... | cmpl $0x0,0x1a8021c(%rip) # ffffffff82d560d0 <kfence_allocation_gate> | je ffffffff812d6003 <kmem_cache_alloc+0x243> | ... which, given kfence_allocation_gate is infrequently modified, should be well predicted by most CPUs. Link: https://lkml.kernel.org/r/20211019102524.2807208-2-elver@google.com Signed-off-by: Marco Elver <elver@google.com> Cc: Alexander Potapenko <glider@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Jann Horn <jannh@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-09-08Merge branch 'akpm' (patches from Andrew)Linus Torvalds1-45/+53
Merge more updates from Andrew Morton: "147 patches, based on 7d2a07b769330c34b4deabeed939325c77a7ec2f. Subsystems affected by this patch series: mm (memory-hotplug, rmap, ioremap, highmem, cleanups, secretmem, kfence, damon, and vmscan), alpha, percpu, procfs, misc, core-kernel, MAINTAINERS, lib, checkpatch, epoll, init, nilfs2, coredump, fork, pids, criu, kconfig, selftests, ipc, and scripts" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (94 commits) scripts: check_extable: fix typo in user error message mm/workingset: correct kernel-doc notations ipc: replace costly bailout check in sysvipc_find_ipc() selftests/memfd: remove unused variable Kconfig.debug: drop selecting non-existing HARDLOCKUP_DETECTOR_ARCH configs: remove the obsolete CONFIG_INPUT_POLLDEV prctl: allow to setup brk for et_dyn executables pid: cleanup the stale comment mentioning pidmap_init(). kernel/fork.c: unexport get_{mm,task}_exe_file coredump: fix memleak in dump_vma_snapshot() fs/coredump.c: log if a core dump is aborted due to changed file permissions nilfs2: use refcount_dec_and_lock() to fix potential UAF nilfs2: fix memory leak in nilfs_sysfs_delete_snapshot_group nilfs2: fix memory leak in nilfs_sysfs_create_snapshot_group nilfs2: fix memory leak in nilfs_sysfs_delete_##name##_group nilfs2: fix memory leak in nilfs_sysfs_create_##name##_group nilfs2: fix NULL pointer in nilfs_##name##_attr_release nilfs2: fix memory leak in nilfs_sysfs_create_device_group trap: cleanup trap_init() init: move usermodehelper_enable() to populate_rootfs() ...
2021-09-08kfence: show cpu and timestamp in alloc/free infoMarco Elver1-45/+53
Record cpu and timestamp on allocations and frees, and show them in reports. Upon an error, this can help correlate earlier messages in the kernel log via allocation and free timestamps. Link: https://lkml.kernel.org/r/20210714175312.2947941-1-elver@google.com Suggested-by: Joern Engel <joern@purestorage.com> Signed-off-by: Marco Elver <elver@google.com> Acked-by: Alexander Potapenko <glider@google.com> Acked-by: Joern Engel <joern@purestorage.com> Cc: Yuanyuan Zhong <yzhong@purestorage.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-09-03Merge branch 'akpm' (patches from Andrew)Linus Torvalds1-5/+8
Merge misc updates from Andrew Morton: "173 patches. Subsystems affected by this series: ia64, ocfs2, block, and mm (debug, pagecache, gup, swap, shmem, memcg, selftests, pagemap, mremap, bootmem, sparsemem, vmalloc, kasan, pagealloc, memory-failure, hugetlb, userfaultfd, vmscan, compaction, mempolicy, memblock, oom-kill, migration, ksm, percpu, vmstat, and madvise)" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (173 commits) mm/madvise: add MADV_WILLNEED to process_madvise() mm/vmstat: remove unneeded return value mm/vmstat: simplify the array size calculation mm/vmstat: correct some wrong comments mm/percpu,c: remove obsolete comments of pcpu_chunk_populated() selftests: vm: add COW time test for KSM pages selftests: vm: add KSM merging time test mm: KSM: fix data type selftests: vm: add KSM merging across nodes test selftests: vm: add KSM zero page merging test selftests: vm: add KSM unmerge test selftests: vm: add KSM merge test mm/migrate: correct kernel-doc notation mm: wire up syscall process_mrelease mm: introduce process_mrelease system call memblock: make memblock_find_in_range method private mm/mempolicy.c: use in_task() in mempolicy_slab_node() mm/mempolicy: unify the create() func for bind/interleave/prefer-many policies mm/mempolicy: advertise new MPOL_PREFERRED_MANY mm/hugetlb: add support for mempolicy MPOL_PREFERRED_MANY ...
2021-09-03mm/kasan: move kasan.fault to mm/kasan/report.cWoody Lin1-5/+8
Move the boot parameter 'kasan.fault' from hw_tags.c to report.c, so it can support all KASAN modes - generic, and both tag-based. Link: https://lkml.kernel.org/r/20210713010536.3161822-1-woodylin@google.com Signed-off-by: Woody Lin <woodylin@google.com> Reviewed-by: Marco Elver <elver@google.com> Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Alexander Potapenko <glider@google.com> Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-09-02Merge tag 'locking-debug-2021-09-01' of ↵Linus Torvalds1-0/+12
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull memory model updates from Ingo Molnar: "LKMM updates: - Update documentation and code example KCSAN updates: - Introduce CONFIG_KCSAN_STRICT (which RCU uses) - Optimize use of get_ctx() by kcsan_found_watchpoint() - Rework atomic.h into permissive.h - Add the ability to ignore writes that change only one bit of a given data-racy variable. - Improve comments" * tag 'locking-debug-2021-09-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: tools/memory-model: Document data_race(READ_ONCE()) tools/memory-model: Heuristics using data_race() must handle all values tools/memory-model: Add example for heuristic lockless reads tools/memory-model: Make read_foo_diagnostic() more clearly diagnostic kcsan: Make strict mode imply interruptible watchers kcsan: permissive: Ignore data-racy 1-bit value changes kcsan: Print if strict or non-strict during init kcsan: Rework atomic.h into permissive.h kcsan: Reduce get_ctx() uses in kcsan_found_watchpoint() kcsan: Introduce CONFIG_KCSAN_STRICT kcsan: Remove CONFIG_KCSAN_DEBUG kcsan: Improve some Kconfig comments
2021-08-13kunit: tool: make --raw_output support only showing kunit outputDaniel Latypov1-3/+6
--raw_output is nice, but it would be nicer if could show only output after KUnit tests have started. So change the flag to allow specifying a string ('kunit'). Make it so `--raw_output` alone will default to `--raw_output=all` and have the same original behavior. Drop the small kunit_parser.raw_output() function since it feels wrong to put it in "kunit_parser.py" when the point of it is to not parse anything. E.g. $ ./tools/testing/kunit/kunit.py run --raw_output=kunit ... [15:24:07] Starting KUnit Kernel ... TAP version 14 1..1 # Subtest: example 1..3 # example_simple_test: initializing ok 1 - example_simple_test # example_skip_test: initializing # example_skip_test: You should not see a line below. ok 2 - example_skip_test # SKIP this test should be skipped # example_mark_skipped_test: initializing # example_mark_skipped_test: You should see a line below. # example_mark_skipped_test: You should see this line. ok 3 - example_mark_skipped_test # SKIP this test should be skipped ok 1 - example [15:24:10] Elapsed time: 6.487s total, 0.001s configuring, 3.510s building, 0.000s running Signed-off-by: Daniel Latypov <dlatypov@google.com> Reviewed-by: David Gow <davidgow@google.com> Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
2021-08-13kunit: tool: add --kernel_args to allow setting module paramsDaniel Latypov1-0/+10
kunit.py currently does not make it possible for users to specify module parameters (/kernel arguments more generally) unless one directly tweaks the kunit.py code itself. This hasn't mattered much so far, but this would make it easier to port existing tests that expose module parameters over to KUnit and/or let current KUnit tests take advantage of them. Tested using an kunit internal parameter: $ ./tools/testing/kunit/kunit.py run --kunitconfig=lib/kunit \ --kernel_args=kunit.filter_glob=kunit_status ... Testing complete. 2 tests run. 0 failed. 0 crashed. 0 skipped. Signed-off-by: Daniel Latypov <dlatypov@google.com> Reviewed-by: David Gow <davidgow@google.com> Reviewed-by: Brendan Higgins <brendanhiggins@google.com> Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
2021-07-20kcsan: Rework atomic.h into permissive.hMarco Elver1-0/+8
Rework atomic.h into permissive.h to better reflect its purpose, and introduce kcsan_ignore_address() and kcsan_ignore_data_race(). Introduce CONFIG_KCSAN_PERMISSIVE and update the stub functions in preparation for subsequent changes. As before, developers who choose to use KCSAN in "strict" mode will see all data races and are not affected. Furthermore, by relying on the value-change filter logic for kcsan_ignore_data_race(), even if the permissive rules are enabled, the opt-outs in report.c:skip_report() override them (such as for RCU-related functions by default). The option CONFIG_KCSAN_PERMISSIVE is disabled by default, so that the documented default behaviour of KCSAN does not change. Instead, like CONFIG_KCSAN_IGNORE_ATOMICS, the option needs to be explicitly opted in. Signed-off-by: Marco Elver <elver@google.com> Acked-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2021-07-20kcsan: Introduce CONFIG_KCSAN_STRICTMarco Elver1-0/+4
Add a simpler Kconfig variable to configure KCSAN's "strict" mode. This makes it simpler in documentation or messages to suggest just a single configuration option to select the strictest checking mode (vs. currently having to list several options). Signed-off-by: Marco Elver <elver@google.com> Acked-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2021-07-12Documentation: kunit: drop obsolete note about uml_abort for coverageDaniel Latypov1-13/+1
Commit b6d5799b0b58 ("kunit: Add 'kunit_shutdown' option") changes KUnit to call kernel_halt() by default when done testing. This fixes the issue with not having .gcda files due to not calling atexit() handlers, and therefore we can stop recommending people manually tweak UML code. The need to use older versions of GCC (<=6) remains however, due to linktime issues, same as before. Note: There also might still be issues with .gcda files as well in newer versions. Signed-off-by: Daniel Latypov <dlatypov@google.com> Reviewed-by: David Gow <davidgow@google.com> Reviewed-by: Brendan Higgins <brendanhiggins@google.com> Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
2021-07-04Merge branch 'kcsan.2021.05.18a' of ↵Linus Torvalds1-54/+39
git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu Pull KCSAN updates from Paul McKenney. * 'kcsan.2021.05.18a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu: kcsan: Use URL link for pointing access-marking.txt kcsan: Document "value changed" line kcsan: Report observed value changes kcsan: Remove kcsan_report_type kcsan: Remove reporting indirection kcsan: Refactor access_info initialization kcsan: Fold panic() call into print_report() kcsan: Refactor passing watchpoint/other_info kcsan: Distinguish kcsan_report() calls kcsan: Simplify value change detection kcsan: Add pointer to access-marking.txt to data_race() bullet
2021-07-02Merge tag 'linux-kselftest-kunit-fixes-5.14-rc1' of ↵Linus Torvalds5-24/+485
git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest Pull KUnit update from Shuah Khan: "Fixes and features: - add support for skipped tests - introduce kunit_kmalloc_array/kunit_kcalloc() helpers - add gnu_printf specifiers - add kunit_shutdown - add unit test for filtering suites by names - convert lib/test_list_sort.c to use KUnit - code organization moving default config to tools/testing/kunit - refactor of internal parser input handling - cleanups and updates to documentation - code cleanup related to casts" * tag 'linux-kselftest-kunit-fixes-5.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest: (29 commits) kunit: add unit test for filtering suites by names kasan: test: make use of kunit_skip() kunit: test: Add example tests which are always skipped kunit: tool: Support skipped tests in kunit_tool kunit: Support skipped tests thunderbolt: test: Reinstate a few casts of bitfields kunit: tool: internal refactor of parser input handling lib/test: convert lib/test_list_sort.c to use KUnit kunit: introduce kunit_kmalloc_array/kunit_kcalloc() helpers kunit: Remove the unused all_tests.config kunit: Move default config from arch/um -> tools/testing/kunit kunit: arch/um/configs: Enable KUNIT_ALL_TESTS by default kunit: Add gnu_printf specifiers lib/cmdline_kunit: Remove a cast which are no-longer required kernel/sysctl-test: Remove some casts which are no-longer required thunderbolt: test: Remove some casts which are no longer required mmc: sdhci-of-aspeed: Remove some unnecessary casts from KUnit tests iio: Remove a cast in iio-test-format which is no longer required device property: Remove some casts in property-entry-test Documentation: kunit: Clean up some string casts in examples ...
2021-06-30Merge branch 'akpm' (patches from Andrew)Linus Torvalds1-5/+4
Merge misc updates from Andrew Morton: "191 patches. Subsystems affected by this patch series: kthread, ia64, scripts, ntfs, squashfs, ocfs2, kernel/watchdog, and mm (gup, pagealloc, slab, slub, kmemleak, dax, debug, pagecache, gup, swap, memcg, pagemap, mprotect, bootmem, dma, tracing, vmalloc, kasan, initialization, pagealloc, and memory-failure)" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (191 commits) mm,hwpoison: make get_hwpoison_page() call get_any_page() mm,hwpoison: send SIGBUS with error virutal address mm/page_alloc: split pcp->high across all online CPUs for cpuless nodes mm/page_alloc: allow high-order pages to be stored on the per-cpu lists mm: replace CONFIG_FLAT_NODE_MEM_MAP with CONFIG_FLATMEM mm: replace CONFIG_NEED_MULTIPLE_NODES with CONFIG_NUMA docs: remove description of DISCONTIGMEM arch, mm: remove stale mentions of DISCONIGMEM mm: remove CONFIG_DISCONTIGMEM m68k: remove support for DISCONTIGMEM arc: remove support for DISCONTIGMEM arc: update comment about HIGHMEM implementation alpha: remove DISCONTIGMEM and NUMA mm/page_alloc: move free_the_page mm/page_alloc: fix counting of managed_pages mm/page_alloc: improve memmap_pages dbg msg mm: drop SECTION_SHIFT in code comments mm/page_alloc: introduce vm.percpu_pagelist_high_fraction mm/page_alloc: limit the number of pages on PCP lists when reclaim is active mm/page_alloc: scale the number of pages that are batch freed ...
2021-06-29kasan: test: improve failure message in KUNIT_EXPECT_KASAN_FAIL()David Gow1-5/+4
The KUNIT_EXPECT_KASAN_FAIL() macro currently uses KUNIT_EXPECT_EQ() to compare fail_data.report_expected and fail_data.report_found. This always gave a somewhat useless error message on failure, but the addition of extra compile-time checking with READ_ONCE() has caused it to get much longer, and be truncated before anything useful is displayed. Instead, just check fail_data.report_found by hand (we've just set report_expected to 'true'), and print a better failure message with KUNIT_FAIL(). Because of this, report_expected is no longer used anywhere, and can be removed. Beforehand, a failure in: KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)area)[3100]); would have looked like: [22:00:34] [FAILED] vmalloc_oob [22:00:34] # vmalloc_oob: EXPECTATION FAILED at lib/test_kasan.c:991 [22:00:34] Expected ({ do { extern void __compiletime_assert_705(void) __attribute__((__error__("Unsupported access size for {READ,WRITE}_ONCE()."))); if (!((sizeof(fail_data.report_expected) == sizeof(char) || sizeof(fail_data.repp [22:00:34] not ok 45 - vmalloc_oob With this change, it instead looks like: [22:04:04] [FAILED] vmalloc_oob [22:04:04] # vmalloc_oob: EXPECTATION FAILED at lib/test_kasan.c:993 [22:04:04] KASAN failure expected in "((volatile char *)area)[3100]", but none occurred [22:04:04] not ok 45 - vmalloc_oob Also update the example failure in the documentation to reflect this. Link: https://lkml.kernel.org/r/20210606005531.165954-1-davidgow@google.com Signed-off-by: David Gow <davidgow@google.com> Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com> Reviewed-by: Marco Elver <elver@google.com> Acked-by: Brendan Higgins <brendanhiggins@google.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Daniel Axtens <dja@axtens.net> Cc: David Gow <davidgow@google.com> Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-24kunit: Move default config from arch/um -> tools/testing/kunitDavid Gow1-1/+1
The default .kunitconfig file is currently kept in arch/um/configs/kunit_defconfig, but -- with the impending QEMU patch -- will no-longer be exclusively used for UML-based kernels. Move it alongside the other KUnit configs in tools/testing/kunit/configs, and give it a name which matches the existing all_tests.config and broken_on_uml.config files. Also update the Getting Started documentation to point to the new file. Signed-off-by: David Gow <davidgow@google.com> Reviewed-by: Brendan Higgins <brendanhiggins@google.com> Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
2021-06-24Documentation: kunit: Clean up some string casts in examplesDavid Gow1-4/+3
As the type checking is no longer excessively strict, get rid of the unsightly (char*) casts -- and comment discussing them -- from the KUnit usage page. Signed-off-by: David Gow <davidgow@google.com> Reviewed-by: Daniel Latypov <dlatypov@google.com> Acked-by: Brendan Higgins <brendanhiggins@google.com> Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
2021-06-23docs: dev-tools: kunit: don't use a table for docs nameMauro Carvalho Chehab1-4/+4
We'll be replacing :doc:`foo` references to Documentation/foo.rst. Yet, here it happens inside a table. Doing a search-and-replace would break it. Yet, as there's no good reason to use a table there, let's just convert it into a list. Reviewed-by: David Gow <davidgow@google.com> Acked-by: Brendan Higgins <brendanhiggins@google.com> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
2021-06-17docs: dev-tools: kunit: avoid using ReST :doc:`foo` markupMauro Carvalho Chehab5-15/+18
The :doc:`foo` tag is auto-generated via automarkup.py. So, use the filename at the sources, instead of :doc:`foo`. Reviewed-by: David Gow <davidgow@google.com> Acked-by: Brendan Higgins <brendanhiggins@google.com> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Link: https://lore.kernel.org/r/6fde409079959a95b62b9b2692503608d7ff0dbd.1623824363.git.mchehab+huawei@kernel.org Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2021-06-17docs: dev-tools: testing-overview.rst: avoid using ReST :doc:`foo` markupMauro Carvalho Chehab1-9/+9
The :doc:`foo` tag is auto-generated via automarkup.py. So, use the filename at the sources, instead of :doc:`foo`. Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Link: https://lore.kernel.org/r/6bbecd4170ee08f36f8060b0719a46c64a21aefc.1623824363.git.mchehab+huawei@kernel.org Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2021-06-17docs: dev-tools: kunit: don't use a table for docs nameMauro Carvalho Chehab1-4/+4
We'll be replacing :doc:`foo` references to Documentation/foo.rst. Yet, here it happens inside a table. Doing a search-and-replace would break it. Yet, as there's no good reason to use a table there, let's just convert it into a list. Reviewed-by: David Gow <davidgow@google.com> Acked-by: Brendan Higgins <brendanhiggins@google.com> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Link: https://lore.kernel.org/r/07d3a8ccafbb6345d6e78fb090290859e84361a1.1623824363.git.mchehab+huawei@kernel.org Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2021-06-15docs: checkpatch: Document and segregate more checkpatch message typesDwaipayan Ray1-71/+328
Add and document more checkpatch message types. About 50% of all message types are documented now. In addition to this: - Create a new subsection 'Indentation and Line Breaks'. - Rename subsection 'Comment style' to simply 'Comments'. - Refactor some of the existing types to appropriate subsections. Reviewed-by: Lukas Bulwahn <lukas.bulwahn@gmail.com> Tested-by: Lukas Bulwahn <lukas.bulwahn@gmail.com> Signed-off-by: Dwaipayan Ray <dwaipayanray1@gmail.com> Link: https://lore.kernel.org/r/20210614141132.6881-1-dwaipayanray1@gmail.com Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2021-06-12Documentation: kunit: document support for QEMU in kunit_toolBrendan Higgins2-11/+87
Document QEMU support, what it does, and how to use it in kunit_tool. Signed-off-by: Brendan Higgins <brendanhiggins@google.com> Reviewed-by: David Gow <davidgow@google.com> Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
2021-05-21Documentation: kunit: Update kunit_tool pageDavid Gow1-8/+132
The kunit_tool documentation page was pretty minimal, and a bit outdated. Update it and flesh it out a bit. In particular, - Mention that .kunitconfig is now in the build directory - Describe the use of --kunitconfig to specify a different config framgent - Mention the split functionality (i.e., commands other than 'run') - Describe --raw_output and kunit.py parse - Mention the globbing support - Provide a quick overview of other options, including --build_dir and --alltests Note that this does overlap a little with the new running_tips page. I don't think it's a problem having both: this page is supposed to be a bit more of a reference, rather than a list of useful tips, so the fact that they both describe the same features isn't a problem. Signed-off-by: David Gow <davidgow@google.com> Reviewed-by: Daniel Latypov <dlatypov@google.com> Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
2021-05-21Documentation: kunit: add tips for running KUnitDaniel Latypov3-0/+262
This is long overdue. There are several things that aren't nailed down (in-tree .kunitconfig's), or partially broken (GCOV on UML), but having them documented, warts and all, is better than having nothing. This covers a bunch of the more recent features * kunit_filter_glob * kunit.py run --kunitconfig * slightly more detail on building tests as modules * CONFIG_KUNIT_DEBUGFS By my count, the only headline features now not mentioned are the KASAN integration and KernelCI json output support (kunit.py run --json). And then it also discusses how to get code coverage reports under UML and non-UML since this is a question people have repeatedly asked. Non-UML coverage collection is no different from normal, but we should probably explicitly call this out. As for UML, I was able to get it working again with two small hacks.* E.g. with CONFIG_KUNIT=y && CONFIG_KUNIT_ALL_TESTS=y Overall coverage rate: lines......: 15.1% (18294 of 120776 lines) functions..: 16.8% (1860 of 11050 functions) Note: this doesn't document --alltests since this is not stable yet. Hopefully being run more frequently as part of KernelCI will help... *Using gcc/gcov-6 and not using uml_abort() in os_dump_core(). I've documented these hacks in "Notes" but left TODOs for brendanhiggins@google.com who tracked down the runtime issue in GCC. To be clear: these are not issues specific to KUnit, but rather to UML. Signed-off-by: Daniel Latypov <dlatypov@google.com> Reviewed-by: David Gow <davidgow@google.com> Reviewed-by: Brendan Higgins <brendanhiggins@google.com> Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
2021-05-20Documentation: checkpatch: Tweak BIT() macro includeAndrew Jeffery1-1/+1
While include/linux/bitops.h brings in the BIT() macro, it was moved to include/linux/bits.h in commit 8bd9cb51daac ("locking/atomics, asm-generic: Move some macros from <linux/bitops.h> to a new <linux/bits.h> file"). Since that commit BIT() has moved again into include/vdso/bits.h via commit 3945ff37d2f4 ("linux/bits.h: Extract common header for vDSO"). I think the move to the vDSO header can be considered an implementation detail, so for now update the checkpatch documentation to recommend use of include/linux/bits.h. Signed-off-by: Andrew Jeffery <andrew@aj.id.au> Acked-by: Jiri Slaby <jirislaby@kernel.org> Acked-by: Lukas Bulwahn <lukas.bulwahn@gmail.com> Acked-by: Dwaipayan Ray <dwaipayanray1@gmail.com> Cc: Jiri Slaby <jirislaby@kernel.org> Link: https://lore.kernel.org/r/20210520093949.511471-1-andrew@aj.id.au Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2021-05-20docs: Add more message type documentations for checkpatchDwaipayan Ray1-7/+163
- Document a couple of more checkpatch message types. - Add a blank line before all `See:` lines to improve the rst output. - Create a new subsection `Permissions` and move a few types to it. Signed-off-by: Dwaipayan Ray <dwaipayanray1@gmail.com> Acked-by: Lukas Bulwahn <lukas.bulwahn@gmail.com> Link: https://lore.kernel.org/r/20210515132348.19082-1-dwaipayanray1@gmail.com Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2021-05-18kcsan: Use URL link for pointing access-marking.txtAkira Yokosawa1-2/+3
For consistency within kcsan.rst, use a URL link as the same as in section "Data Races". Acked-by: Marco Elver <elver@google.com> Signed-off-by: Akira Yokosawa <akiyks@gmail.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2021-05-18kcsan: Document "value changed" lineMarco Elver1-53/+35
Update the example reports based on the latest reports generated by kcsan_test module, which now include the "value changed" line. Add a brief description of the "value changed" line. Signed-off-by: Marco Elver <elver@google.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2021-05-18kcsan: Add pointer to access-marking.txt to data_race() bulletPaul E. McKenney1-1/+3
This commit references tools/memory-model/Documentation/access-marking.txt in the bullet introducing data_race(). The access-marking.txt file gives advice on when data_race() should and should not be used. Suggested-by: Akira Yokosawa <akiyks@gmail.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2021-05-07scripts/gdb: add lx_current support for arm64Barry Song1-1/+1
arm64 uses SP_EL0 to save the current task_struct address. While running in EL0, SP_EL0 is clobbered by userspace. So if the upper bit is not 1 (not TTBR1), the current address is invalid. This patch checks the upper bit of SP_EL0, if the upper bit is 1, lx_current() of arm64 will return the derefrence of current task. Otherwise, lx_current() will tell users they are running in userspace(EL0). While arm64 is running in EL0, it is actually pointless to print current task as the memory of kernel space is not accessible in EL0. Link: https://lkml.kernel.org/r/20210314203444.15188-3-song.bao.hua@hisilicon.com Signed-off-by: Barry Song <song.bao.hua@hisilicon.com> Cc: Jan Kiszka <jan.kiszka@siemens.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Kieran Bingham <kbingham@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-05-07scripts/gdb: document lx_current is only supported by x86Barry Song1-1/+1
Patch series "scripts/gdb: clarify the platforms supporting lx_current and add arm64 support", v2. lx_current depends on per_cpu current_task variable which exists on x86 only. so it actually works on x86 only. the 1st patch documents this clearly; the 2nd patch adds support for arm64. This patch (of 2): x86 is the only architecture which has per_cpu current_task: arch$ git grep current_task | grep -i per_cpu x86/include/asm/current.h:DECLARE_PER_CPU(struct task_struct *, current_task); x86/kernel/cpu/common.c:DEFINE_PER_CPU(struct task_struct *, current_task) ____cacheline_aligned = x86/kernel/cpu/common.c:EXPORT_PER_CPU_SYMBOL(current_task); x86/kernel/cpu/common.c:DEFINE_PER_CPU(struct task_struct *, current_task) = &init_task; x86/kernel/cpu/common.c:EXPORT_PER_CPU_SYMBOL(current_task); x86/kernel/smpboot.c: per_cpu(current_task, cpu) = idle; On other architectures, lx_current() will lead to a python exception: (gdb) p $lx_current().pid Python Exception <class 'gdb.error'> No symbol "current_task" in current context.: Error occurred in Python: No symbol "current_task" in current context. To avoid more people struggling and wasting time in other architectures, document it. Link: https://lkml.kernel.org/r/20210314203444.15188-1-song.bao.hua@hisilicon.com Link: https://lkml.kernel.org/r/20210314203444.15188-2-song.bao.hua@hisilicon.com Signed-off-by: Barry Song <song.bao.hua@hisilicon.com> Cc: Jan Kiszka <jan.kiszka@siemens.com> Cc: Kieran Bingham <kbingham@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-04-30kasan: docs: update tests sectionAndrey Konovalov1-17/+15
Update the "Tests" section in KASAN documentation: - Add an introductory sentence. - Add proper indentation for the list of ways to run KUnit tests. - Punctuation, readability, and other minor clean-ups. Link: https://lkml.kernel.org/r/fb08845e25c8847ffda271fa19cda2621c04a65b.1615559068.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Reviewed-by: Marco Elver <elver@google.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-04-30kasan: docs: update ignoring accesses sectionAndrey Konovalov1-4/+30
Update the "Ignoring accesses" section in KASAN documentation: - Mention __no_sanitize_address/noinstr. - Mention kasan_disable/enable_current(). - Mention kasan_reset_tag()/page_kasan_tag_reset(). - Readability and punctuation clean-ups. Link: https://lkml.kernel.org/r/4531ba5f3eca61f6aade863c136778cc8c807a64.1615559068.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Reviewed-by: Marco Elver <elver@google.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-04-30kasan: docs: update shadow memory sectionAndrey Konovalov1-17/+14
Update the "Shadow memory" section in KASAN documentation: - Rearrange the introduction paragraph do it doesn't give a "KASAN has an issue" impression. - Update the list of architectures with vmalloc support. - Punctuation, readability, and other minor clean-ups. Link: https://lkml.kernel.org/r/00f8c38b0fd5290a3f4dced04eaba41383e67e14.1615559068.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Reviewed-by: Marco Elver <elver@google.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-04-30kasan: docs: update HW_TAGS implementation details sectionAndrey Konovalov1-13/+13
Update the "Implementation details" section for HW_TAGS KASAN: - Punctuation, readability, and other minor clean-ups. Link: https://lkml.kernel.org/r/ee2caf4c138cc1fd239822c2abefd5af6c057744.1615559068.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Reviewed-by: Marco Elver <elver@google.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-04-30kasan: docs: update SW_TAGS implementation details sectionAndrey Konovalov1-20/+19
Update the "Implementation details" section for SW_TAGS KASAN: - Clarify the introduction sentence. - Punctuation, readability, and other minor clean-ups. Link: https://lkml.kernel.org/r/69b9b2e49d8cf789358fa24558be3fc0ce4ee32c.1615559068.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Reviewed-by: Marco Elver <elver@google.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-04-30kasan: docs: update GENERIC implementation details sectionAndrey Konovalov1-14/+13
Update the "Implementation details" section for generic KASAN: - Don't mention kmemcheck, it's not present in the kernel anymore. - Don't mention GCC as the only supported compiler. - Update kasan_mem_to_shadow() definition to match actual code. - Punctuation, readability, and other minor clean-ups. Link: https://lkml.kernel.org/r/f2f35fdab701f8c709f63d328f98aec2982c8acc.1615559068.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Reviewed-by: Marco Elver <elver@google.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-04-30kasan: docs: update boot parameters sectionAndrey Konovalov1-4/+10
Update the "Boot parameters" section in KASAN documentation: - Mention panic_on_warn. - Mention kasan_multi_shot and its interaction with panic_on_warn. - Clarify kasan.fault=panic interaction with panic_on_warn. - A readability clean-up. Link: https://lkml.kernel.org/r/01364952f15789948f0627d6733b5cdf5209f83a.1615559068.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Reviewed-by: Marco Elver <elver@google.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-04-30kasan: docs: update error reports sectionAndrey Konovalov1-20/+26
Update the "Error reports" section in KASAN documentation: - Mention that bug titles are best-effort. - Move and reword the part about auxiliary stacks from "Implementation details". - Punctuation, readability, and other minor clean-ups. Link: https://lkml.kernel.org/r/3531e8fe6972cf39d1954e3643237b19eb21227e.1615559068.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Reviewed-by: Marco Elver <elver@google.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-04-30kasan: docs: update usage sectionAndrey Konovalov1-12/+11
Update the "Usage" section in KASAN documentation: - Add inline code snippet markers. - Reword the part about stack traces for clarity. - Other minor clean-ups. Link: https://lkml.kernel.org/r/48427809cd4b8b5d6bc00926cbe87e2b5081df17.1615559068.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Reviewed-by: Marco Elver <elver@google.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-04-30kasan: docs: update overview sectionAndrey Konovalov1-8/+19
Update the "Overview" section in KASAN documentation: - Outline main use cases for each mode. - Mention that HW_TAGS mode need compiler support too. - Move the part about SLUB/SLAB support from "Usage" to "Overview". - Punctuation, readability, and other minor clean-ups. Link: https://lkml.kernel.org/r/1486fba8514de3d7db2f47df2192db59228b0a7b.1615559068.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Reviewed-by: Marco Elver <elver@google.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-04-30kasan: docs: clean up sectionsAndrey Konovalov1-27/+27
Update KASAN documentation: - Give some sections clearer names. - Remove unneeded subsections in the "Tests" section. - Move the "For developers" section and split into subsections. Link: https://lkml.kernel.org/r/c2bbb56eaea80ad484f0ee85bb71959a3a63f1d7.1615559068.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Reviewed-by: Marco Elver <elver@google.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-04-28Merge tag 'locking-core-2021-04-28' of ↵Linus Torvalds1-0/+3
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull locking updates from Ingo Molnar: - rtmutex cleanup & spring cleaning pass that removes ~400 lines of code - Futex simplifications & cleanups - Add debugging to the CSD code, to help track down a tenacious race (or hw problem) - Add lockdep_assert_not_held(), to allow code to require a lock to not be held, and propagate this into the ath10k driver - Misc LKMM documentation updates - Misc KCSAN updates: cleanups & documentation updates - Misc fixes and cleanups - Fix locktorture bugs with ww_mutexes * tag 'locking-core-2021-04-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (44 commits) kcsan: Fix printk format string static_call: Relax static_call_update() function argument type static_call: Fix unused variable warn w/o MODULE locking/rtmutex: Clean up signal handling in __rt_mutex_slowlock() locking/rtmutex: Restrict the trylock WARN_ON() to debug locking/rtmutex: Fix misleading comment in rt_mutex_postunlock() locking/rtmutex: Consolidate the fast/slowpath invocation locking/rtmutex: Make text section and inlining consistent locking/rtmutex: Move debug functions as inlines into common header locking/rtmutex: Decrapify __rt_mutex_init() locking/rtmutex: Remove pointless CONFIG_RT_MUTEXES=n stubs locking/rtmutex: Inline chainwalk depth check locking/rtmutex: Move rt_mutex_debug_task_free() to rtmutex.c locking/rtmutex: Remove empty and unused debug stubs locking/rtmutex: Consolidate rt_mutex_init() locking/rtmutex: Remove output from deadlock detector locking/rtmutex: Remove rtmutex deadlock tester leftovers locking/rtmutex: Remove rt_mutex_timed_lock() MAINTAINERS: Add myself as futex reviewer locking/mutex: Remove repeated declaration ...
2021-04-28Merge tag 'linux-kselftest-kunit-5.13-rc1' of ↵Linus Torvalds1-2/+76
git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest Pull KUnit updates from Shuah Khan: "Several fixes and a new feature to support failure from dynamic analysis tools such as UBSAN and fake ops for testing. - a fake ops struct for testing a "free" function to complain if it was called with an invalid argument, or caught a double-free. Most return void and have no normal means of signalling failure (e.g. super_operations, iommu_ops, etc.)" * tag 'linux-kselftest-kunit-5.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest: Documentation: kunit: add tips for using current->kunit_test kunit: fix -Wunused-function warning for __kunit_fail_current_test kunit: support failure from dynamic analysis tools kunit: tool: make --kunitconfig accept dirs, add lib/kunit fragment kunit: make KUNIT_EXPECT_STREQ() quote values, don't print literals kunit: Match parenthesis alignment to improve code readability
2021-04-28Merge tag 'linux-kselftest-next-5.13-rc1' of ↵Linus Torvalds1-2/+2
git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest Pull Kselftest updates from Shuah Khan: - fixes and updates to resctrl test from Fenghua Yu and Reinette Chatre - fixes to Kselftest documentation, framework - minor spelling correction in timers test * tag 'linux-kselftest-next-5.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest: (25 commits) selftests/resctrl: Change a few printed messages Documentation: kselftest: fix path to test module files selftests/resctrl: Create .gitignore to include resctrl_tests selftests/resctrl: Fix checking for < 0 for unsigned values selftests/resctrl: Fix incorrect parsing of iMC counters selftests/resctrl: Fix unmount resctrl FS selftests/resctrl: Skip the test if requested resctrl feature is not supported selftests/resctrl: Modularize resctrl test suite main() function selftests/resctrl: Don't hard code value of "no_of_bits" variable selftests/resctrl: Fix MBA/MBM results reporting format selftests/resctrl: Use resctrl/info for feature detection selftests/resctrl: Check for resctrl mount point only if resctrl FS is supported selftests/resctrl: Add config dependencies selftests/resctrl: Fix a printed message selftests/resctrl: Share show_cache_info() by CAT and CMT tests selftests/resctrl: Call kselftest APIs to log test results selftests/resctrl: Rename CQM test as CMT test selftests/resctrl: Fix missing options "-n" and "-p" selftests/resctrl: Ensure sibling CPU is not same as original CPU selftests/resctrl: Clean up resctrl features check ...
2021-04-26Merge tag 'docs-5.13' of git://git.lwn.net/linuxLinus Torvalds4-2/+883
Pull documentation updates from Jonathan Corbet: "It's been a relatively busy cycle in docsland, though more than usually well contained to Documentation/ itself. Highlights include: - The Chinese translators have been busy and show no signs of stopping anytime soon. Italian has also caught up. - Aditya Srivastava has been working on improvements to the kernel-doc script. - Thorsten continues his work on reporting-issues.rst and related documentation around regression reporting. - Lots of documentation updates, typo fixes, etc. as usual" * tag 'docs-5.13' of git://git.lwn.net/linux: (139 commits) docs/zh_CN: add openrisc translation to zh_CN index docs/zh_CN: add openrisc index.rst translation docs/zh_CN: add openrisc todo.rst translation docs/zh_CN: add openrisc openrisc_port.rst translation docs/zh_CN: add core api translation to zh_CN index docs/zh_CN: add core-api index.rst translation docs/zh_CN: add core-api irq index.rst translation docs/zh_CN: add core-api irq irqflags-tracing.rst translation docs/zh_CN: add core-api irq irq-domain.rst translation docs/zh_CN: add core-api irq irq-affinity.rst translation docs/zh_CN: add core-api irq concepts.rst translation docs: sphinx-pre-install: don't barf on beta Sphinx releases scripts: kernel-doc: improve parsing for kernel-doc comments syntax docs/zh_CN: two minor fixes in zh_CN/doc-guide/ Documentation: dev-tools: Add Testing Overview docs/zh_CN: add translations in zh_CN/dev-tools/gcov docs: reporting-issues: make people CC the regressions list MAINTAINERS: add regressions mailing list doc:it_IT: align Italian documentation docs/zh_CN: sync reporting-issues.rst ...
2021-04-15Documentation: dev-tools: Add Testing OverviewDavid Gow2-0/+121
The kernel now has a number of testing and debugging tools, and we've seen a bit of confusion about what the differences between them are. Add a basic documentation outlining the testing tools, when to use each, and how they interact. This is a pretty quick overview rather than the idealised "kernel testing guide" that'd probably be optimal, but given the number of times questions like "When do you use KUnit and when do you use Kselftest?" are being asked, it seemed worth at least having something. Hopefully this can form the basis for more detailed documentation later. Signed-off-by: David Gow <davidgow@google.com> Reviewed-by: Marco Elver <elver@google.com> Reviewed-by: Daniel Latypov <dlatypov@google.com> Link: https://lore.kernel.org/r/20210415054036.581117-1-davidgow@google.com Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2021-04-11kasan: Add KASAN mode kernel parameterVincenzo Frascino1-0/+9
Architectures supported by KASAN_HW_TAGS can provide a sync or async mode of execution. On an MTE enabled arm64 hw for example this can be identified with the synchronous or asynchronous tagging mode of execution. In synchronous mode, an exception is triggered if a tag check fault occurs. In asynchronous mode, if a tag check fault occurs, the TFSR_EL1 register is updated asynchronously. The kernel checks the corresponding bits periodically. KASAN requires a specific kernel command line parameter to make use of this hw features. Add KASAN HW execution mode kernel command line parameter. Note: This patch adds the kasan.mode kernel parameter and the sync/async kernel command line options to enable the described features. [ Add a new var instead of exposing kasan_arg_mode to be consistent with flags for other command line arguments. ] Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Konovalov <andreyknvl@google.com> Reviewed-by: Andrey Konovalov <andreyknvl@google.com> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Andrey Konovalov <andreyknvl@google.com> Tested-by: Andrey Konovalov <andreyknvl@google.com> Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Link: https://lore.kernel.org/r/20210315132019.33202-3-vincenzo.frascino@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2021-04-08docs/gcov: Convert two tags to ref in dev-tools/gov.rstWu XiangCheng1-2/+6
Htmldocs does not display the chapter number, convert the two manual chapter number tags to ref tags. Signed-off-by: Wu XiangCheng <bobwxc@email.cn> Acked-by: Peter Oberparleiter <oberpar@linux.ibm.com> Link: https://lore.kernel.org/r/20210403113752.GA32236@mipc Signed-off-by: Jonathan Corbet <corbet@lwn.net>
generated by cgit v1.2.3 (git 2.39.0) at 2024-07-21 09:47:04 +0300