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2022-10-03kasan: dynamically allocate stack ring entriesAndrey Konovalov
Instead of using a large static array, allocate the stack ring dynamically via memblock_alloc(). The size of the stack ring is controlled by a new kasan.stack_ring_size command-line parameter. When kasan.stack_ring_size is not provided, the default value of 32 << 10 is used. When the stack trace collection is disabled via kasan.stacktrace=off, the stack ring is not allocated. Link: https://lkml.kernel.org/r/03b82ab60db53427e9818e0b0c1971baa10c3cbc.1662411800.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Acked-by: Marco Elver <elver@google.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Evgenii Stepanov <eugenis@google.com> Cc: Peter Collingbourne <pcc@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-10-03kasan: support kasan.stacktrace for SW_TAGSAndrey Konovalov
Add support for the kasan.stacktrace command-line argument for Software Tag-Based KASAN. The following patch adds a command-line argument for selecting the stack ring size, and, as the stack ring is supported by both the Software and the Hardware Tag-Based KASAN modes, it is natural that both of them have support for kasan.stacktrace too. Link: https://lkml.kernel.org/r/3b43059103faa7f8796017847b7d674b658f11b5.1662411799.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 <ryabinin.a.a@gmail.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Evgenii Stepanov <eugenis@google.com> Cc: Peter Collingbourne <pcc@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-05-13kasan: move boot parameters section in documentationAndrey Konovalov
Move the "Boot parameters" section in KASAN documentation next to the section that describes KASAN build options. No content changes. Link: https://lkml.kernel.org/r/870628e1293b4f44edf7cbcb92374ff9eb7503d7.1652203271.git.andreyknvl@google.com Link: https://lkml.kernel.org/r/ec9c923f35e7c5312836c4624a7f317dc1ee2c1c.1652123204.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 <ryabinin.a.a@gmail.com> Cc: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-05-13kasan: update documentationAndrey Konovalov
Do assorted clean-ups and improvements to KASAN documentation, including: - Describe each mode in a dedicated paragraph. - Split out a Support section that describes in details which compilers, architectures and memory types each mode requires/supports. - Capitalize the first letter in the names of each KASAN mode. [andreyknvl@google.com: rewording, per Marco] Link: https://lkml.kernel.org/r/896b2d914d6b50d677fd7b38f76967cc705c01ba.1652203271.git.andreyknvl@google.com Link: https://lkml.kernel.org/r/5bd58ebebf066593ce0e1d265d60278b5f5a1874.1652123204.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 <ryabinin.a.a@gmail.com> Cc: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-03-24kasan: documentation updatesAndrey Konovalov
Update KASAN documentation: - Bump Clang version requirement for HW_TAGS as ARM64_MTE depends on AS_HAS_LSE_ATOMICS as of commit 2decad92f4731 ("arm64: mte: Ensure TIF_MTE_ASYNC_FAULT is set atomically"), which requires Clang 12. - Add description of the new kasan.vmalloc command line flag. - Mention that SW_TAGS and HW_TAGS modes now support vmalloc tagging. - Explicitly say that the "Shadow memory" section is only applicable to software KASAN modes. - Mention that shadow-based KASAN_VMALLOC is supported on arm64. Link: https://lkml.kernel.org/r/a61189128fa3f9fbcfd9884ff653d401864b8e74.1643047180.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Acked-by: Marco Elver <elver@google.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Evgenii Stepanov <eugenis@google.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Peter Collingbourne <pcc@google.com> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-10-07kasan: Extend KASAN mode kernel parameterVincenzo Frascino
Architectures supported by KASAN_HW_TAGS can provide an asymmetric mode of execution. On an MTE enabled arm64 hw for example this can be identified with the asymmetric tagging mode of execution. In particular, when such a mode is present, the CPU triggers a fault on a tag mismatch during a load operation and asynchronously updates a register when a tag mismatch is detected during a store operation. Extend the KASAN HW execution mode kernel command line parameter to support asymmetric mode. Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Konovalov <andreyknvl@gmail.com> Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com> Link: https://lore.kernel.org/r/20211006154751.4463-6-vincenzo.frascino@arm.com Signed-off-by: Will Deacon <will@kernel.org>
2021-09-03mm/kasan: move kasan.fault to mm/kasan/report.cWoody Lin
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>
2021-06-29kasan: test: improve failure message in KUNIT_EXPECT_KASAN_FAIL()David Gow
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>
2021-04-30kasan: docs: update tests sectionAndrey Konovalov
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 Konovalov
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 Konovalov
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 Konovalov
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 Konovalov
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 Konovalov
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 Konovalov
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 Konovalov
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 Konovalov
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 Konovalov
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 Konovalov
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>
2021-04-11kasan: Add KASAN mode kernel parameterVincenzo Frascino
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>
2021-02-26kasan: clarify that only first bug is reported in HW_TAGSAndrey Konovalov
Hwardware tag-based KASAN only reports the first found bug. After that MTE tag checking gets disabled. Clarify this in comments and documentation. Link: https://lkml.kernel.org/r/00383ba88a47c3f8342d12263c24bdf95527b07d.1612546384.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: Branislav Rankov <Branislav.Rankov@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Evgenii Stepanov <eugenis@google.com> Cc: Kevin Brodsky <kevin.brodsky@arm.com> Cc: Peter Collingbourne <pcc@google.com> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-02-24kasan: rename CONFIG_TEST_KASAN_MODULEAndrey Konovalov
Rename CONFIG_TEST_KASAN_MODULE to CONFIG_KASAN_MODULE_TEST. This naming is more consistent with the existing CONFIG_KASAN_KUNIT_TEST. Link: https://linux-review.googlesource.com/id/Id347dfa5fe8788b7a1a189863e039f409da0ae5f Link: https://lkml.kernel.org/r/f08250246683981bcf8a094fbba7c361995624d2.1610733117.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Reviewed-by: Marco Elver <elver@google.com> Reviewed-by: Alexander Potapenko <glider@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Branislav Rankov <Branislav.Rankov@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Evgenii Stepanov <eugenis@google.com> Cc: Kevin Brodsky <kevin.brodsky@arm.com> Cc: Peter Collingbourne <pcc@google.com> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-02-24kasan: clarify HW_TAGS impact on TBIAndrey Konovalov
Mention in the documentation that enabling CONFIG_KASAN_HW_TAGS always results in in-kernel TBI (Top Byte Ignore) being enabled. Also do a few minor documentation cleanups. Link: https://linux-review.googlesource.com/id/Iba2a6697e3c6304cb53f89ec61dedc77fa29e3ae Link: https://lkml.kernel.org/r/3b4ea6875bb14d312092ad14ac55cb456c83c08e.1610733117.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Reviewed-by: Marco Elver <elver@google.com> Reviewed-by: Alexander Potapenko <glider@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Branislav Rankov <Branislav.Rankov@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Evgenii Stepanov <eugenis@google.com> Cc: Kevin Brodsky <kevin.brodsky@arm.com> Cc: Peter Collingbourne <pcc@google.com> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-02-09kasan: fix stack traces dependency for HW_TAGSAndrey Konovalov
Currently, whether the alloc/free stack traces collection is enabled by default for hardware tag-based KASAN depends on CONFIG_DEBUG_KERNEL. The intention for this dependency was to only enable collection on slow debug kernels due to a significant perf and memory impact. As it turns out, CONFIG_DEBUG_KERNEL is not considered a debug option and is enabled on many productions kernels including Android and Ubuntu. As the result, this dependency is pointless and only complicates the code and documentation. Having stack traces collection disabled by default would make the hardware mode work differently to to the software ones, which is confusing. This change removes the dependency and enables stack traces collection by default. Looking into the future, this default might makes sense for production kernels, assuming we implement a fast stack trace collection approach. Link: https://lkml.kernel.org/r/6678d77ceffb71f1cff2cf61560e2ffe7bb6bfe9.1612808820.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Reviewed-by: Marco Elver <elver@google.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Alexander Potapenko <glider@google.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Peter Collingbourne <pcc@google.com> Cc: Evgenii Stepanov <eugenis@google.com> Cc: Branislav Rankov <Branislav.Rankov@arm.com> Cc: Kevin Brodsky <kevin.brodsky@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-01-24kasan: fix HW_TAGS boot parametersAndrey Konovalov
The initially proposed KASAN command line parameters are redundant. This change drops the complex "kasan.mode=off/prod/full" parameter and adds a simpler kill switch "kasan=off/on" instead. The new parameter together with the already existing ones provides a cleaner way to express the same set of features. The full set of parameters with this change: kasan=off/on - whether KASAN is enabled kasan.fault=report/panic - whether to only print a report or also panic kasan.stacktrace=off/on - whether to collect alloc/free stack traces Default values: kasan=on kasan.fault=report kasan.stacktrace=on (if CONFIG_DEBUG_KERNEL=y) kasan.stacktrace=off (otherwise) Link: https://linux-review.googlesource.com/id/Ib3694ed90b1e8ccac6cf77dfd301847af4aba7b8 Link: https://lkml.kernel.org/r/4e9c4a4bdcadc168317deb2419144582a9be6e61.1610736745.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Reviewed-by: Marco Elver <elver@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Alexander Potapenko <glider@google.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Peter Collingbourne <pcc@google.com> Cc: Evgenii Stepanov <eugenis@google.com> Cc: Branislav Rankov <Branislav.Rankov@arm.com> Cc: Kevin Brodsky <kevin.brodsky@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-12-22Merge branch 'akpm' (patches from Andrew)Linus Torvalds
Merge KASAN updates from Andrew Morton. This adds a new hardware tag-based mode to KASAN. The new mode is similar to the existing software tag-based KASAN, but relies on arm64 Memory Tagging Extension (MTE) to perform memory and pointer tagging (instead of shadow memory and compiler instrumentation). By Andrey Konovalov and Vincenzo Frascino. * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (60 commits) kasan: update documentation kasan, mm: allow cache merging with no metadata kasan: sanitize objects when metadata doesn't fit kasan: clarify comment in __kasan_kfree_large kasan: simplify assign_tag and set_tag calls kasan: don't round_up too much kasan, mm: rename kasan_poison_kfree kasan, mm: check kasan_enabled in annotations kasan: add and integrate kasan boot parameters kasan: inline (un)poison_range and check_invalid_free kasan: open-code kasan_unpoison_slab kasan: inline random_tag for HW_TAGS kasan: inline kasan_reset_tag for tag-based modes kasan: remove __kasan_unpoison_stack kasan: allow VMAP_STACK for HW_TAGS mode kasan, arm64: unpoison stack only with CONFIG_KASAN_STACK kasan: introduce set_alloc_info kasan: rename get_alloc/free_info kasan: simplify quarantine_put call site kselftest/arm64: check GCR_EL1 after context switch ...
2020-12-22Merge tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linuxLinus Torvalds
Pull ARM updates from Russell King: - Rework phys/virt translation - Add KASan support - Move DT out of linear map region - Use more PC-relative addressing in assembly - Remove FP emulation handling while in kernel mode - Link with '-z norelro' - remove old check for GCC <= 4.2 in ARM unwinder code - disable big endian if using clang's linker * tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm: (46 commits) ARM: 9027/1: head.S: explicitly map DT even if it lives in the first physical section ARM: 9038/1: Link with '-z norelro' ARM: 9037/1: uncompress: Add OF_DT_MAGIC macro ARM: 9036/1: uncompress: Fix dbgadtb size parameter name ARM: 9035/1: uncompress: Add be32tocpu macro ARM: 9033/1: arm/smp: Drop the macro S(x,s) ARM: 9032/1: arm/mm: Convert PUD level pgtable helper macros into functions ARM: 9031/1: hyp-stub: remove unused .L__boot_cpu_mode_offset symbol ARM: 9044/1: vfp: use undef hook for VFP support detection ARM: 9034/1: __div64_32(): straighten up inline asm constraints ARM: 9030/1: entry: omit FP emulation for UND exceptions taken in kernel mode ARM: 9029/1: Make iwmmxt.S support Clang's integrated assembler ARM: 9028/1: disable KASAN in call stack capturing routines ARM: 9026/1: unwind: remove old check for GCC <= 4.2 ARM: 9025/1: Kconfig: CPU_BIG_ENDIAN depends on !LD_IS_LLD ARM: 9024/1: Drop useless cast of "u64" to "long long" ARM: 9023/1: Spelling s/mmeory/memory/ ARM: 9022/1: Change arch/arm/lib/mem*.S to use WEAK instead of .weak ARM: kvm: replace open coded VA->PA calculations with adr_l call ARM: head.S: use PC relative insn sequence to calculate PHYS_OFFSET ...
2020-12-22kasan: update documentationAndrey Konovalov
This change updates KASAN documentation to reflect the addition of boot parameters and also reworks and clarifies some of the existing sections, in particular: defines what a memory granule is, mentions quarantine, makes Kunit section more readable. Link: https://lkml.kernel.org/r/748daf013e17d925b0fe00c1c3b5dce726dd2430.1606162397.git.andreyknvl@google.com Link: https://linux-review.googlesource.com/id/Ib1f83e91be273264b25f42b04448ac96b858849f Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Reviewed-by: Dmitry Vyukov <dvyukov@google.com> Reviewed-by: Marco Elver <elver@google.com> Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Branislav Rankov <Branislav.Rankov@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Evgenii Stepanov <eugenis@google.com> Cc: Kevin Brodsky <kevin.brodsky@arm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-12-22kasan: add documentation for hardware tag-based modeAndrey Konovalov
Add documentation for hardware tag-based KASAN mode and also add some clarifications for software tag-based mode. Link: https://lkml.kernel.org/r/20ed1d387685e89fc31be068f890f070ef9fd5d5.1606161801.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Reviewed-by: Marco Elver <elver@google.com> Reviewed-by: Alexander Potapenko <glider@google.com> Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Branislav Rankov <Branislav.Rankov@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Evgenii Stepanov <eugenis@google.com> Cc: Kevin Brodsky <kevin.brodsky@arm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-12-22kasan: rename KASAN_SHADOW_* to KASAN_GRANULE_*Andrey Konovalov
This is a preparatory commit for the upcoming addition of a new hardware tag-based (MTE-based) KASAN mode. The new mode won't be using shadow memory, but will still use the concept of memory granules. Each memory granule maps to a single metadata entry: 8 bytes per one shadow byte for generic mode, 16 bytes per one shadow byte for software tag-based mode, and 16 bytes per one allocation tag for hardware tag-based mode. Rename KASAN_SHADOW_SCALE_SIZE to KASAN_GRANULE_SIZE, and KASAN_SHADOW_MASK to KASAN_GRANULE_MASK. Also use MASK when used as a mask, otherwise use SIZE. No functional changes. Link: https://lkml.kernel.org/r/939b5754e47f528a6e6a6f28ffc5815d8d128033.1606161801.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Reviewed-by: Marco Elver <elver@google.com> Reviewed-by: Alexander Potapenko <glider@google.com> Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Branislav Rankov <Branislav.Rankov@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Evgenii Stepanov <eugenis@google.com> Cc: Kevin Brodsky <kevin.brodsky@arm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-12-15Merge branch 'akpm' (patches from Andrew)Linus Torvalds
Merge misc updates from Andrew Morton: - a few random little subsystems - almost all of the MM patches which are staged ahead of linux-next material. I'll trickle to post-linux-next work in as the dependents get merged up. Subsystems affected by this patch series: kthread, kbuild, ide, ntfs, ocfs2, arch, and mm (slab-generic, slab, slub, dax, debug, pagecache, gup, swap, shmem, memcg, pagemap, mremap, hmm, vmalloc, documentation, kasan, pagealloc, memory-failure, hugetlb, vmscan, z3fold, compaction, oom-kill, migration, cma, page-poison, userfaultfd, zswap, zsmalloc, uaccess, zram, and cleanups). * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (200 commits) mm: cleanup kstrto*() usage mm: fix fall-through warnings for Clang mm: slub: convert sysfs sprintf family to sysfs_emit/sysfs_emit_at mm: shmem: convert shmem_enabled_show to use sysfs_emit_at mm:backing-dev: use sysfs_emit in macro defining functions mm: huge_memory: convert remaining use of sprintf to sysfs_emit and neatening mm: use sysfs_emit for struct kobject * uses mm: fix kernel-doc markups zram: break the strict dependency from lzo zram: add stat to gather incompressible pages since zram set up zram: support page writeback mm/process_vm_access: remove redundant initialization of iov_r mm/zsmalloc.c: rework the list_add code in insert_zspage() mm/zswap: move to use crypto_acomp API for hardware acceleration mm/zswap: fix passing zero to 'PTR_ERR' warning mm/zswap: make struct kernel_param_ops definitions const userfaultfd/selftests: hint the test runner on required privilege userfaultfd/selftests: fix retval check for userfaultfd_open() userfaultfd/selftests: always dump something in modes userfaultfd: selftests: make __{s,u}64 format specifiers portable ...
2020-12-15kasan: update documentation for generic kasanWalter Wu
Generic KASAN also supports to record the last two workqueue stacks and print them in KASAN report. So that need to update documentation. Link: https://lkml.kernel.org/r/20201203023037.30792-1-walter-zh.wu@mediatek.com Signed-off-by: Walter Wu <walter-zh.wu@mediatek.com> Suggested-by: Marco Elver <elver@google.com> Acked-by: Marco Elver <elver@google.com> Reviewed-by: Dmitry Vyukov <dvyukov@google.com> Reviewed-by: Andrey Konovalov <andreyknvl@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Alexander Potapenko <glider@google.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Lai Jiangshan <jiangshanlai@gmail.com> Cc: Matthias Brugger <matthias.bgg@gmail.com> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-11-30Documentation: fix typos in dev-tools/kasan.rstAndrew Klychkov
Documentation: dev-tools: kasan.rst: fix typos Signed-off-by: Andrew Klychkov <andrew.a.klyckov@gmail.com> Link: https://lore.kernel.org/r/20201129192928.GA5692@ak-VirtualBox Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-10-28docs: kasan.rst: add two missing blank linesMauro Carvalho Chehab
literal blocks should start and end with a blank line, as otherwise the parser complains and may do the wrong thing, as warned by Sphinx: Documentation/dev-tools/kasan.rst:298: WARNING: Literal block ends without a blank line; unexpected unindent. Documentation/dev-tools/kasan.rst:303: WARNING: Literal block ends without a blank line; unexpected unindent. Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Reviewed-by: Andrey Konovalov <andreyknvl@google.com> Link: https://lore.kernel.org/r/cd6c4280fe26b07f2c5e5ed2918e17e88bb03419.1603791716.git.mchehab+huawei@kernel.org Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-10-27ARM: 9017/2: Enable KASan for ARMLinus Walleij
This patch enables the kernel address sanitizer for ARM. XIP_KERNEL has not been tested and is therefore not allowed for now. Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Alexander Potapenko <glider@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: kasan-dev@googlegroups.com Acked-by: Dmitry Vyukov <dvyukov@google.com> Reviewed-by: Ard Biesheuvel <ardb@kernel.org> Tested-by: Ard Biesheuvel <ardb@kernel.org> # QEMU/KVM/mach-virt/LPAE/8G Tested-by: Florian Fainelli <f.fainelli@gmail.com> # Brahma SoCs Tested-by: Ahmad Fatoum <a.fatoum@pengutronix.de> # i.MX6Q Signed-off-by: Abbott Liu <liuwenliang@huawei.com> Signed-off-by: Florian Fainelli <f.fainelli@gmail.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
2020-10-13KASAN: Testing DocumentationPatricia Alfonso
Include documentation on how to test KASAN using CONFIG_TEST_KASAN_KUNIT and CONFIG_TEST_KASAN_MODULE. Signed-off-by: Patricia Alfonso <trishalfonso@google.com> Signed-off-by: David Gow <davidgow@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Tested-by: Andrey Konovalov <andreyknvl@google.com> Reviewed-by: Andrey Konovalov <andreyknvl@google.com> Reviewed-by: Dmitry Vyukov <dvyukov@google.com> Acked-by: Brendan Higgins <brendanhiggins@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Shuah Khan <shuah@kernel.org> Cc: Vincent Guittot <vincent.guittot@linaro.org> Link: https://lkml.kernel.org/r/20200915035828.570483-5-davidgow@google.com Link: https://lkml.kernel.org/r/20200910070331.3358048-5-davidgow@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-13kasan: remove mentions of unsupported Clang versionsMarco Elver
Since the kernel now requires at least Clang 10.0.1, remove any mention of old Clang versions and simplify the documentation. Signed-off-by: Marco Elver <elver@google.com> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrey Konovalov <andreyknvl@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Cc: Fangrui Song <maskray@google.com> Cc: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com> Cc: Sedat Dilek <sedat.dilek@gmail.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: Will Deacon <will@kernel.org> Link: https://lkml.kernel.org/r/20200902225911.209899-7-ndesaulniers@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-07kasan: update documentation for generic kasanWalter Wu
Generic KASAN will support to record the last two call_rcu() call stacks and print them in KASAN report. So that need to update documentation. Signed-off-by: Walter Wu <walter-zh.wu@mediatek.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Tested-by: Dmitry Vyukov <dvyukov@google.com> Reviewed-by: Dmitry Vyukov <dvyukov@google.com> Reviewed-by: Andrey Konovalov <andreyknvl@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Alexander Potapenko <glider@google.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Matthias Brugger <matthias.bgg@gmail.com> Cc: "Paul E . McKenney" <paulmck@kernel.org> Cc: Josh Triplett <josh@joshtriplett.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Lai Jiangshan <jiangshanlai@gmail.com> Cc: Joel Fernandes <joel@joelfernandes.org> Link: http://lkml.kernel.org/r/20200601051111.1359-1-walter-zh.wu@mediatek.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-07kasan: update required compiler versions in documentationMarco Elver
Updates the recently changed compiler requirements for KASAN. In particular, we require GCC >= 8.3.0, and add a note that Clang 11 supports OOB detection of globals. Fixes: 7b861a53e46b ("kasan: Bump required compiler version") Fixes: acf7b0bf7dcf ("kasan: Fix required compiler version") Signed-off-by: Marco Elver <elver@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrey Konovalov <andreyknvl@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Walter Wu <walter-zh.wu@mediatek.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Daniel Axtens <dja@axtens.net> Link: http://lkml.kernel.org/r/20200629104157.3242503-2-elver@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-01-22kasan: Add riscv to KASAN documentation.Nick Hu
Add riscv to the KASAN documentation to mention that riscv is supporting generic kasan now. Signed-off-by: Nick Hu <nickhu@andestech.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2019-12-01kasan: support backing vmalloc space with real shadow memoryDaniel Axtens
Patch series "kasan: support backing vmalloc space with real shadow memory", v11. Currently, vmalloc space is backed by the early shadow page. This means that kasan is incompatible with VMAP_STACK. This series provides a mechanism to back vmalloc space with real, dynamically allocated memory. I have only wired up x86, because that's the only currently supported arch I can work with easily, but it's very easy to wire up other architectures, and it appears that there is some work-in-progress code to do this on arm64 and s390. This has been discussed before in the context of VMAP_STACK: - https://bugzilla.kernel.org/show_bug.cgi?id=202009 - https://lkml.org/lkml/2018/7/22/198 - https://lkml.org/lkml/2019/7/19/822 In terms of implementation details: Most mappings in vmalloc space are small, requiring less than a full page of shadow space. Allocating a full shadow page per mapping would therefore be wasteful. Furthermore, to ensure that different mappings use different shadow pages, mappings would have to be aligned to KASAN_SHADOW_SCALE_SIZE * PAGE_SIZE. Instead, share backing space across multiple mappings. Allocate a backing page when a mapping in vmalloc space uses a particular page of the shadow region. This page can be shared by other vmalloc mappings later on. We hook in to the vmap infrastructure to lazily clean up unused shadow memory. Testing with test_vmalloc.sh on an x86 VM with 2 vCPUs shows that: - Turning on KASAN, inline instrumentation, without vmalloc, introuduces a 4.1x-4.2x slowdown in vmalloc operations. - Turning this on introduces the following slowdowns over KASAN: * ~1.76x slower single-threaded (test_vmalloc.sh performance) * ~2.18x slower when both cpus are performing operations simultaneously (test_vmalloc.sh sequential_test_order=1) This is unfortunate but given that this is a debug feature only, not the end of the world. The benchmarks are also a stress-test for the vmalloc subsystem: they're not indicative of an overall 2x slowdown! This patch (of 4): Hook into vmalloc and vmap, and dynamically allocate real shadow memory to back the mappings. Most mappings in vmalloc space are small, requiring less than a full page of shadow space. Allocating a full shadow page per mapping would therefore be wasteful. Furthermore, to ensure that different mappings use different shadow pages, mappings would have to be aligned to KASAN_SHADOW_SCALE_SIZE * PAGE_SIZE. Instead, share backing space across multiple mappings. Allocate a backing page when a mapping in vmalloc space uses a particular page of the shadow region. This page can be shared by other vmalloc mappings later on. We hook in to the vmap infrastructure to lazily clean up unused shadow memory. To avoid the difficulties around swapping mappings around, this code expects that the part of the shadow region that covers the vmalloc space will not be covered by the early shadow page, but will be left unmapped. This will require changes in arch-specific code. This allows KASAN with VMAP_STACK, and may be helpful for architectures that do not have a separate module space (e.g. powerpc64, which I am currently working on). It also allows relaxing the module alignment back to PAGE_SIZE. Testing with test_vmalloc.sh on an x86 VM with 2 vCPUs shows that: - Turning on KASAN, inline instrumentation, without vmalloc, introuduces a 4.1x-4.2x slowdown in vmalloc operations. - Turning this on introduces the following slowdowns over KASAN: * ~1.76x slower single-threaded (test_vmalloc.sh performance) * ~2.18x slower when both cpus are performing operations simultaneously (test_vmalloc.sh sequential_test_order=3D1) This is unfortunate but given that this is a debug feature only, not the end of the world. The full benchmark results are: Performance No KASAN KASAN original x baseline KASAN vmalloc x baseline x KASAN fix_size_alloc_test 662004 11404956 17.23 19144610 28.92 1.68 full_fit_alloc_test 710950 12029752 16.92 13184651 18.55 1.10 long_busy_list_alloc_test 9431875 43990172 4.66 82970178 8.80 1.89 random_size_alloc_test 5033626 23061762 4.58 47158834 9.37 2.04 fix_align_alloc_test 1252514 15276910 12.20 31266116 24.96 2.05 random_size_align_alloc_te 1648501 14578321 8.84 25560052 15.51 1.75 align_shift_alloc_test 147 830 5.65 5692 38.72 6.86 pcpu_alloc_test 80732 125520 1.55 140864 1.74 1.12 Total Cycles 119240774314 763211341128 6.40 1390338696894 11.66 1.82 Sequential, 2 cpus No KASAN KASAN original x baseline KASAN vmalloc x baseline x KASAN fix_size_alloc_test 1423150 14276550 10.03 27733022 19.49 1.94 full_fit_alloc_test 1754219 14722640 8.39 15030786 8.57 1.02 long_busy_list_alloc_test 11451858 52154973 4.55 107016027 9.34 2.05 random_size_alloc_test 5989020 26735276 4.46 68885923 11.50 2.58 fix_align_alloc_test 2050976 20166900 9.83 50491675 24.62 2.50 random_size_align_alloc_te 2858229 17971700 6.29 38730225 13.55 2.16 align_shift_alloc_test 405 6428 15.87 26253 64.82 4.08 pcpu_alloc_test 127183 151464 1.19 216263 1.70 1.43 Total Cycles 54181269392 308723699764 5.70 650772566394 12.01 2.11 fix_size_alloc_test 1420404 14289308 10.06 27790035 19.56 1.94 full_fit_alloc_test 1736145 14806234 8.53 15274301 8.80 1.03 long_busy_list_alloc_test 11404638 52270785 4.58 107550254 9.43 2.06 random_size_alloc_test 6017006 26650625 4.43 68696127 11.42 2.58 fix_align_alloc_test 2045504 20280985 9.91 50414862 24.65 2.49 random_size_align_alloc_te 2845338 17931018 6.30 38510276 13.53 2.15 align_shift_alloc_test 472 3760 7.97 9656 20.46 2.57 pcpu_alloc_test 118643 132732 1.12 146504 1.23 1.10 Total Cycles 54040011688 309102805492 5.72 651325675652 12.05 2.11 [dja@axtens.net: fixups] Link: http://lkml.kernel.org/r/20191120052719.7201-1-dja@axtens.net Link: https://bugzilla.kernel.org/show_bug.cgi?id=3D202009 Link: http://lkml.kernel.org/r/20191031093909.9228-2-dja@axtens.net Signed-off-by: Mark Rutland <mark.rutland@arm.com> [shadow rework] Signed-off-by: Daniel Axtens <dja@axtens.net> Co-developed-by: Mark Rutland <mark.rutland@arm.com> Acked-by: Vasily Gorbik <gor@linux.ibm.com> Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Alexander Potapenko <glider@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Christophe Leroy <christophe.leroy@c-s.fr> Cc: Qian Cai <cai@lca.pw> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-10-14mm, page_owner: decouple freeing stack trace from debug_pageallocVlastimil Babka
Commit 8974558f49a6 ("mm, page_owner, debug_pagealloc: save and dump freeing stack trace") enhanced page_owner to also store freeing stack trace, when debug_pagealloc is also enabled. KASAN would also like to do this [1] to improve error reports to debug e.g. UAF issues. Kirill has suggested that the freeing stack trace saving should be also possible to be enabled separately from KASAN or debug_pagealloc, i.e. with an extra boot option. Qian argued that we have enough options already, and avoiding the extra overhead is not worth the complications in the case of a debugging option. Kirill noted that the extra stack handle in struct page_owner requires 0.1% of memory. This patch therefore enables free stack saving whenever page_owner is enabled, regardless of whether debug_pagealloc or KASAN is also enabled. KASAN kernels booted with page_owner=on will thus benefit from the improved error reports. [1] https://bugzilla.kernel.org/show_bug.cgi?id=203967 [vbabka@suse.cz: v3] Link: http://lkml.kernel.org/r/20191007091808.7096-3-vbabka@suse.cz Link: http://lkml.kernel.org/r/20190930122916.14969-3-vbabka@suse.cz Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Qian Cai <cai@lca.pw> Suggested-by: Dmitry Vyukov <dvyukov@google.com> Suggested-by: Walter Wu <walter-zh.wu@mediatek.com> Suggested-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Suggested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Suggested-by: Qian Cai <cai@lca.pw> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-12-28kasan: update documentationAndrey Konovalov
This patch updates KASAN documentation to reflect the addition of the new tag-based mode. Link: http://lkml.kernel.org/r/aabef9de317c54b8a3919a4946ce534c6576726a.1544099024.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Reviewed-by: Dmitry Vyukov <dvyukov@google.com> Cc: Christoph Lameter <cl@linux.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-04-16docs/vm: rename documentation files to .rstMike Rapoport
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2016-08-19Merge branch 'dev-tools' into doc/4.9Jonathan Corbet
Coalesce development-tool documents into a single directory and sphinxify them.
2016-08-18docs: sphinxify kasan.txt and move to dev-toolsJonathan Corbet
No textual changes beyond formatting. Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Acked-by: Alexander Potapenko <glider@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Jonathan Corbet <corbet@lwn.net>