Linux-kselftest-mirror February 2025

linux-kselftest-mirror@lists.linaro.org

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334 discussions

[PATCH bpf-next v7 0/5] Support eliding map lookup nullness

by Daniel Xu

This patch allows progs to elide a null check on statically known map lookup keys. In other words, if the verifier can statically prove that the lookup will be in-bounds, allow the prog to drop the null check. This is useful for two reasons: 1. Large numbers of nullness checks (especially when they cannot fail) unnecessarily pushes prog towards BPF_COMPLEXITY_LIMIT_JMP_SEQ. 2. It forms a tighter contract between programmer and verifier. For (1), bpftrace is starting to make heavier use of percpu scratch maps. As a result, for user scripts with large number of unrolled loops, we are starting to hit jump complexity verification errors. These percpu lookups cannot fail anyways, as we only use static key values. Eliding nullness probably results in less work for verifier as well. For (2), percpu scratch maps are often used as a larger stack, as the currrent stack is limited to 512 bytes. In these situations, it is desirable for the programmer to express: "this lookup should never fail, and if it does, it means I messed up the code". By omitting the null check, the programmer can "ask" the verifier to double check the logic. === Changelog === Changes in v7: * Use more accurate frame number when marking precise * Add test for non-stack key * Test for marking stack slot precise Changes in v6: * Use is_spilled_scalar_reg() helper and remove unnecessary comment * Add back deleted selftest with different helper to dirty dst buffer * Check size of spill is exactly key_size and update selftests * Read slot_type from correct offset into the spi * Rewrite selftests in C where possible * Mark constant map keys as precise Changes in v5: * Dropped all acks * Use s64 instead of long for const_map_key * Ensure stack slot contains spilled reg before accessing spilled_ptr * Ensure spilled reg is a scalar before accessing tnum const value * Fix verifier selftest for 32-bit write to write at 8 byte alignment to ensure spill is tracked * Introduce more precise tracking of helper stack accesses * Do constant map key extraction as part of helper argument processing and then remove duplicated stack checks * Use ret_flag instead of regs[BPF_REG_0].type * Handle STACK_ZERO * Fix bug in bpf_load_hdr_opt() arg annotation Changes in v4: * Only allow for CAP_BPF * Add test for stack growing upwards * Improve comment about stack growing upwards Changes in v3: * Check if stack is (erroneously) growing upwards * Mention in commit message why existing tests needed change Changes in v2: * Added a check for when R2 is not a ptr to stack * Added a check for when stack is uninitialized (no stack slot yet) * Updated existing tests to account for null elision * Added test case for when R2 can be both const and non-const Daniel Xu (5): bpf: verifier: Add missing newline on verbose() call bpf: tcp: Mark bpf_load_hdr_opt() arg2 as read-write bpf: verifier: Refactor helper access type tracking bpf: verifier: Support eliding map lookup nullness bpf: selftests: verifier: Add nullness elision tests kernel/bpf/verifier.c | 139 ++++++++++--- net/core/filter.c | 2 +- .../testing/selftests/bpf/progs/dynptr_fail.c | 6 +- tools/testing/selftests/bpf/progs/iters.c | 14 +- .../selftests/bpf/progs/map_kptr_fail.c | 2 +- .../selftests/bpf/progs/test_global_func10.c | 2 +- .../selftests/bpf/progs/uninit_stack.c | 5 +- .../bpf/progs/verifier_array_access.c | 188 ++++++++++++++++++ .../bpf/progs/verifier_basic_stack.c | 2 +- .../selftests/bpf/progs/verifier_const_or.c | 4 +- .../progs/verifier_helper_access_var_len.c | 12 +- .../selftests/bpf/progs/verifier_int_ptr.c | 2 +- .../selftests/bpf/progs/verifier_map_in_map.c | 2 +- .../selftests/bpf/progs/verifier_mtu.c | 2 +- .../selftests/bpf/progs/verifier_raw_stack.c | 4 +- .../selftests/bpf/progs/verifier_unpriv.c | 2 +- .../selftests/bpf/progs/verifier_var_off.c | 8 +- tools/testing/selftests/bpf/verifier/calls.c | 2 +- .../testing/selftests/bpf/verifier/map_kptr.c | 2 +- 19 files changed, 331 insertions(+), 69 deletions(-) -- 2.47.1

1 month

[PATCH] selftests/vDSO: Fix undefined CLONE_NEWTIME by including

by Purva Yeshi

Fix the build failure caused by the undefined `CLONE_NEWTIME`. Include the `linux/sched.h` header file where the function is defined to ensure successful compilation of the selftests. Signed-off-by: Purva Yeshi <purvayeshi550(a)gmail.com> --- tools/testing/selftests/vDSO/vdso_test_getrandom.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/tools/testing/selftests/vDSO/vdso_test_getrandom.c b/tools/testing/selftests/vDSO/vdso_test_getrandom.c index 95057f7567db..b2c9cf15878b 100644 --- a/tools/testing/selftests/vDSO/vdso_test_getrandom.c +++ b/tools/testing/selftests/vDSO/vdso_test_getrandom.c @@ -29,6 +29,8 @@ #include "vdso_config.h" #include "vdso_call.h" +#include <linux/sched.h> + #ifndef timespecsub #define timespecsub(tsp, usp, vsp) \ do { \ -- 2.34.1

1 month

[PATCH v2 0/5] selftests/nolibc: test kernel configuration cleanups

by Thomas Weißschuh

A few cleanups and optimizations for the management of the kernel configuration. Signed-off-by: Thomas Weißschuh <linux(a)weissschuh.net> --- Changes in v2: - Rebase on current torvalds/master - Call "make defconfig" separately - Link to v1: https://lore.kernel.org/r/20250122-nolibc-config-v1-0-a697db968b49@weisssch… --- Thomas Weißschuh (5): selftests/nolibc: drop custom EXTRACONFIG functionality selftests/nolibc: drop call to prepare target selftests/nolibc: drop call to mrproper target selftests/nolibc: execute defconfig before other targets selftests/nolibc: always keep test kernel configuration up to date tools/testing/selftests/nolibc/Makefile | 17 +++++------------ tools/testing/selftests/nolibc/run-tests.sh | 7 +++---- 2 files changed, 8 insertions(+), 16 deletions(-) --- base-commit: 21266b8df5224c4f677acf9f353eecc9094731f0 change-id: 20250122-nolibc-config-d639e1612c93 Best regards, -- Thomas Weißschuh <linux(a)weissschuh.net>

1 month

[PATCH 00/16] selftest/mm: Remove warnings found by adding compiler flags

by Muhammad Usama Anjum

Recently, I reviewed a patch on the mm/kselftest mailing list about a test which had obvious type mismatch fix in it. It was strange why that wasn't caught during development and when patch was accepted. This led me to discover that those extra compiler options to catch these warnings aren't being used. When I added them, I found tens of warnings in just mm suite. In this series, I'm fixing those warnings. The last check adds the compiler flags with which the warnings have been caught. Muhammad Usama Anjum (16): selftests/mm: remove argc and argv unused parameters selftests/mm: Fix unused parameter warnings selftests/mm: Fix unused parameter warnings selftests/mm: Fix type mismatch warnings selftests/mm: kselftest_harness: Fix warnings selftests/mm: cow: remove unused variables and fix type mismatch errors selftests/mm: hmm-tests: Remove always false expressions selftests/mm: guard-pages: Fix type mismatch warnings selftests/mm: hugetlb-madvise: fix type mismatch issues selftests/mm: hugepage-vmemmap: fix type mismatch warnings selftests/mm: hugetlb-read-hwpoison: Fix type mismatch warnings selftests/mm: khugepaged: Fix type mismatch warnings selftests/mm: protection_keys: Fix variables types mismatch warnings selftests/mm: thuge-gen: Fix type mismatch warnings selftests/mm: uffd-*: Fix all type mismatch warnings selftests/mm: Makefile: Add the compiler flags tools/testing/selftests/kselftest_harness.h | 6 +- tools/testing/selftests/mm/Makefile | 1 + tools/testing/selftests/mm/compaction_test.c | 4 +- tools/testing/selftests/mm/cow.c | 48 ++++++++------- tools/testing/selftests/mm/droppable.c | 2 +- tools/testing/selftests/mm/guard-pages.c | 4 +- tools/testing/selftests/mm/gup_longterm.c | 5 +- tools/testing/selftests/mm/hmm-tests.c | 4 +- tools/testing/selftests/mm/hugepage-vmemmap.c | 5 +- tools/testing/selftests/mm/hugetlb-madvise.c | 4 +- .../selftests/mm/hugetlb-read-hwpoison.c | 6 +- .../selftests/mm/hugetlb-soft-offline.c | 2 +- tools/testing/selftests/mm/hugetlb_dio.c | 2 +- .../selftests/mm/hugetlb_fault_after_madv.c | 6 +- .../selftests/mm/hugetlb_madv_vs_map.c | 8 +-- tools/testing/selftests/mm/khugepaged.c | 16 ++--- .../selftests/mm/ksm_functional_tests.c | 6 +- tools/testing/selftests/mm/ksm_tests.c | 17 +++--- tools/testing/selftests/mm/madv_populate.c | 2 +- tools/testing/selftests/mm/map_populate.c | 2 +- tools/testing/selftests/mm/memfd_secret.c | 6 +- .../testing/selftests/mm/mlock-random-test.c | 6 +- tools/testing/selftests/mm/mlock2-tests.c | 2 +- tools/testing/selftests/mm/on-fault-limit.c | 2 +- tools/testing/selftests/mm/pkey-x86.h | 4 +- .../selftests/mm/pkey_sighandler_tests.c | 21 ++++--- tools/testing/selftests/mm/protection_keys.c | 34 ++++++----- tools/testing/selftests/mm/soft-dirty.c | 8 +-- .../selftests/mm/split_huge_page_test.c | 4 +- tools/testing/selftests/mm/thuge-gen.c | 10 ++-- tools/testing/selftests/mm/uffd-common.c | 24 ++++---- tools/testing/selftests/mm/uffd-common.h | 2 +- tools/testing/selftests/mm/uffd-stress.c | 4 +- tools/testing/selftests/mm/uffd-unit-tests.c | 58 +++++++++---------- tools/testing/selftests/mm/uffd-wp-mremap.c | 2 +- .../selftests/mm/virtual_address_range.c | 2 +- 36 files changed, 180 insertions(+), 159 deletions(-) -- 2.39.5

1 month

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Linux-kselftest-mirror February 2025