August 2025 - Linux-kselftest-mirror

[PATCH v3 00/13] stackleak: Support Clang stack depth tracking

by Kees Cook

v3: - split up and drop __init vs inline patches that went via arch trees - apply feedback about preferring __init to __always_inline - incorporate Ritesh Harjani's patch for __init cleanups in powerpc - wider build testing on older compilers v2: https://lore.kernel.org/lkml/20250523043251.it.550-kees@kernel.org/ v1: https://lore.kernel.org/lkml/20250507180852.work.231-kees@kernel.org/ Hi, As part of looking at what GCC plugins could be replaced with Clang implementations, this series uses the recently landed stack depth tracking callback in Clang[1] to implement the stackleak feature. Since the Clang feature is now landed, I'm moving this out of RFC to a v1. Since this touches a lot of arch-specific Makefiles, I tried to trim the CC list down to just mailing lists in those cases, otherwise the CC was giant. Thanks! -Kees [1] https://clang.llvm.org/docs/SanitizerCoverage.html#tracing-stack-depth Kees Cook (12): stackleak: Rename STACKLEAK to KSTACK_ERASE stackleak: Rename stackleak_track_stack to __sanitizer_cov_stack_depth stackleak: Split KSTACK_ERASE_CFLAGS from GCC_PLUGINS_CFLAGS x86: Handle KCOV __init vs inline mismatches arm: Handle KCOV __init vs inline mismatches arm64: Handle KCOV __init vs inline mismatches s390: Handle KCOV __init vs inline mismatches mips: Handle KCOV __init vs inline mismatch init.h: Disable sanitizer coverage for __init and __head kstack_erase: Support Clang stack depth tracking configs/hardening: Enable CONFIG_KSTACK_ERASE configs/hardening: Enable CONFIG_INIT_ON_FREE_DEFAULT_ON Ritesh Harjani (IBM) (1): powerpc/mm/book3s64: Move kfence and debug_pagealloc related calls to __init section arch/Kconfig | 4 +- arch/arm/Kconfig | 2 +- arch/arm64/Kconfig | 2 +- arch/riscv/Kconfig | 2 +- arch/s390/Kconfig | 2 +- arch/x86/Kconfig | 2 +- security/Kconfig.hardening | 45 +++++++++------- Makefile | 1 + arch/arm/boot/compressed/Makefile | 2 +- arch/arm/vdso/Makefile | 2 +- arch/arm64/kernel/pi/Makefile | 2 +- arch/arm64/kernel/vdso/Makefile | 3 +- arch/arm64/kvm/hyp/nvhe/Makefile | 2 +- arch/riscv/kernel/pi/Makefile | 2 +- arch/riscv/purgatory/Makefile | 2 +- arch/sparc/vdso/Makefile | 3 +- arch/x86/entry/vdso/Makefile | 3 +- arch/x86/purgatory/Makefile | 2 +- drivers/firmware/efi/libstub/Makefile | 8 +-- drivers/misc/lkdtm/Makefile | 2 +- kernel/Makefile | 10 ++-- lib/Makefile | 2 +- scripts/Makefile.gcc-plugins | 16 +----- scripts/Makefile.kstack_erase | 21 ++++++++ scripts/gcc-plugins/stackleak_plugin.c | 52 +++++++++---------- Documentation/admin-guide/sysctl/kernel.rst | 4 +- Documentation/arch/x86/x86_64/mm.rst | 2 +- Documentation/security/self-protection.rst | 2 +- .../zh_CN/security/self-protection.rst | 2 +- arch/arm64/include/asm/acpi.h | 2 +- arch/mips/include/asm/time.h | 2 +- arch/s390/hypfs/hypfs.h | 2 +- arch/s390/hypfs/hypfs_diag.h | 2 +- arch/x86/entry/calling.h | 4 +- arch/x86/include/asm/acpi.h | 4 +- arch/x86/include/asm/init.h | 2 +- arch/x86/include/asm/realmode.h | 2 +- include/linux/acpi.h | 4 +- include/linux/bootconfig.h | 2 +- include/linux/efi.h | 2 +- include/linux/init.h | 4 +- include/linux/{stackleak.h => kstack_erase.h} | 20 +++---- include/linux/memblock.h | 2 +- include/linux/mfd/dbx500-prcmu.h | 2 +- include/linux/sched.h | 4 +- include/linux/smp.h | 2 +- arch/arm/kernel/entry-common.S | 2 +- arch/arm64/kernel/entry.S | 2 +- arch/riscv/kernel/entry.S | 2 +- arch/s390/kernel/entry.S | 2 +- arch/arm/mm/cache-feroceon-l2.c | 2 +- arch/arm/mm/cache-tauros2.c | 2 +- arch/powerpc/mm/book3s64/hash_utils.c | 6 +-- arch/powerpc/mm/book3s64/radix_pgtable.c | 4 +- arch/s390/mm/init.c | 2 +- arch/x86/kernel/kvm.c | 2 +- arch/x86/mm/init_64.c | 2 +- drivers/clocksource/timer-orion.c | 2 +- .../lkdtm/{stackleak.c => kstack_erase.c} | 26 +++++----- drivers/soc/ti/pm33xx.c | 2 +- fs/proc/base.c | 6 +-- kernel/fork.c | 2 +- kernel/kexec_handover.c | 4 +- kernel/{stackleak.c => kstack_erase.c} | 22 ++++---- tools/objtool/check.c | 4 +- tools/testing/selftests/lkdtm/config | 2 +- MAINTAINERS | 6 ++- kernel/configs/hardening.config | 6 +++ 68 files changed, 204 insertions(+), 172 deletions(-) create mode 100644 scripts/Makefile.kstack_erase rename include/linux/{stackleak.h => kstack_erase.h} (81%) rename drivers/misc/lkdtm/{stackleak.c => kstack_erase.c} (89%) rename kernel/{stackleak.c => kstack_erase.c} (87%) -- 2.34.1

2 weeks, 6 days

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[PATCH v8 00/14] riscv: add SBI FWFT misaligned exception delegation support

by Clément Léger

The SBI Firmware Feature extension allows the S-mode to request some specific features (either hardware or software) to be enabled. This series uses this extension to request misaligned access exception delegation to S-mode in order to let the kernel handle it. It also adds support for the KVM FWFT SBI extension based on the misaligned access handling infrastructure. FWFT SBI extension is part of the SBI V3.0 specifications [1]. It can be tested using the qemu provided at [2] which contains the series from [3]. Upstream kvm-unit-tests can be used inside kvm to tests the correct delegation of misaligned exceptions. Upstream OpenSBI can be used. Note: Since SBI V3.0 is not yet ratified, FWFT extension API is split between interface only and implementation, allowing to pick only the interface which do not have hard dependencies on SBI. The tests can be run using the kselftest from series [4]. $ qemu-system-riscv64 \ -cpu rv64,trap-misaligned-access=true,v=true \ -M virt \ -m 1024M \ -bios fw_dynamic.bin \ -kernel Image ... # ./misaligned TAP version 13 1..23 # Starting 23 tests from 1 test cases. # RUN global.gp_load_lh ... # OK global.gp_load_lh ok 1 global.gp_load_lh # RUN global.gp_load_lhu ... # OK global.gp_load_lhu ok 2 global.gp_load_lhu # RUN global.gp_load_lw ... # OK global.gp_load_lw ok 3 global.gp_load_lw # RUN global.gp_load_lwu ... # OK global.gp_load_lwu ok 4 global.gp_load_lwu # RUN global.gp_load_ld ... # OK global.gp_load_ld ok 5 global.gp_load_ld # RUN global.gp_load_c_lw ... # OK global.gp_load_c_lw ok 6 global.gp_load_c_lw # RUN global.gp_load_c_ld ... # OK global.gp_load_c_ld ok 7 global.gp_load_c_ld # RUN global.gp_load_c_ldsp ... # OK global.gp_load_c_ldsp ok 8 global.gp_load_c_ldsp # RUN global.gp_load_sh ... # OK global.gp_load_sh ok 9 global.gp_load_sh # RUN global.gp_load_sw ... # OK global.gp_load_sw ok 10 global.gp_load_sw # RUN global.gp_load_sd ... # OK global.gp_load_sd ok 11 global.gp_load_sd # RUN global.gp_load_c_sw ... # OK global.gp_load_c_sw ok 12 global.gp_load_c_sw # RUN global.gp_load_c_sd ... # OK global.gp_load_c_sd ok 13 global.gp_load_c_sd # RUN global.gp_load_c_sdsp ... # OK global.gp_load_c_sdsp ok 14 global.gp_load_c_sdsp # RUN global.fpu_load_flw ... # OK global.fpu_load_flw ok 15 global.fpu_load_flw # RUN global.fpu_load_fld ... # OK global.fpu_load_fld ok 16 global.fpu_load_fld # RUN global.fpu_load_c_fld ... # OK global.fpu_load_c_fld ok 17 global.fpu_load_c_fld # RUN global.fpu_load_c_fldsp ... # OK global.fpu_load_c_fldsp ok 18 global.fpu_load_c_fldsp # RUN global.fpu_store_fsw ... # OK global.fpu_store_fsw ok 19 global.fpu_store_fsw # RUN global.fpu_store_fsd ... # OK global.fpu_store_fsd ok 20 global.fpu_store_fsd # RUN global.fpu_store_c_fsd ... # OK global.fpu_store_c_fsd ok 21 global.fpu_store_c_fsd # RUN global.fpu_store_c_fsdsp ... # OK global.fpu_store_c_fsdsp ok 22 global.fpu_store_c_fsdsp # RUN global.gen_sigbus ... [12797.988647] misaligned[618]: unhandled signal 7 code 0x1 at 0x0000000000014dc0 in misaligned[4dc0,10000+76000] [12797.988990] CPU: 0 UID: 0 PID: 618 Comm: misaligned Not tainted 6.13.0-rc6-00008-g4ec4468967c9-dirty #51 [12797.989169] Hardware name: riscv-virtio,qemu (DT) [12797.989264] epc : 0000000000014dc0 ra : 0000000000014d00 sp : 00007fffe165d100 [12797.989407] gp : 000000000008f6e8 tp : 0000000000095760 t0 : 0000000000000008 [12797.989544] t1 : 00000000000965d8 t2 : 000000000008e830 s0 : 00007fffe165d160 [12797.989692] s1 : 000000000000001a a0 : 0000000000000000 a1 : 0000000000000002 [12797.989831] a2 : 0000000000000000 a3 : 0000000000000000 a4 : ffffffffdeadbeef [12797.989964] a5 : 000000000008ef61 a6 : 626769735f6e0000 a7 : fffffffffffff000 [12797.990094] s2 : 0000000000000001 s3 : 00007fffe165d838 s4 : 00007fffe165d848 [12797.990238] s5 : 000000000000001a s6 : 0000000000010442 s7 : 0000000000010200 [12797.990391] s8 : 000000000000003a s9 : 0000000000094508 s10: 0000000000000000 [12797.990526] s11: 0000555567460668 t3 : 00007fffe165d070 t4 : 00000000000965d0 [12797.990656] t5 : fefefefefefefeff t6 : 0000000000000073 [12797.990756] status: 0000000200004020 badaddr: 000000000008ef61 cause: 0000000000000006 [12797.990911] Code: 8793 8791 3423 fcf4 3783 fc84 c737 dead 0713 eef7 (c398) 0001 # OK global.gen_sigbus ok 23 global.gen_sigbus # PASSED: 23 / 23 tests passed. # Totals: pass:23 fail:0 xfail:0 xpass:0 skip:0 error:0 With kvm-tools: # lkvm run -k sbi.flat -m 128 Info: # lkvm run -k sbi.flat -m 128 -c 1 --name guest-97 Info: Removed ghost socket file "/root/.lkvm//guest-97.sock". ########################################################################## # kvm-unit-tests ########################################################################## ... [test messages elided] PASS: sbi: fwft: FWFT extension probing no error PASS: sbi: fwft: get/set reserved feature 0x6 error == SBI_ERR_DENIED PASS: sbi: fwft: get/set reserved feature 0x3fffffff error == SBI_ERR_DENIED PASS: sbi: fwft: get/set reserved feature 0x80000000 error == SBI_ERR_DENIED PASS: sbi: fwft: get/set reserved feature 0xbfffffff error == SBI_ERR_DENIED PASS: sbi: fwft: misaligned_deleg: Get misaligned deleg feature no error PASS: sbi: fwft: misaligned_deleg: Set misaligned deleg feature invalid value error PASS: sbi: fwft: misaligned_deleg: Set misaligned deleg feature invalid value error PASS: sbi: fwft: misaligned_deleg: Set misaligned deleg feature value no error PASS: sbi: fwft: misaligned_deleg: Set misaligned deleg feature value 0 PASS: sbi: fwft: misaligned_deleg: Set misaligned deleg feature value no error PASS: sbi: fwft: misaligned_deleg: Set misaligned deleg feature value 1 PASS: sbi: fwft: misaligned_deleg: Verify misaligned load exception trap in supervisor SUMMARY: 50 tests, 2 unexpected failures, 12 skipped This series is available at [5]. Link: https://github.com/riscv-non-isa/riscv-sbi-doc/releases/download/vv3.0-rc2/… [1] Link: https://github.com/rivosinc/qemu/tree/dev/cleger/misaligned [2] Link: https://lore.kernel.org/all/20241211211933.198792-3-fkonrad@amd.com/T/ [3] Link: https://lore.kernel.org/linux-riscv/20250414123543.1615478-1-cleger@rivosin… [4] Link: https://github.com/rivosinc/linux/tree/dev/cleger/fwft [5] --- V8: - Move misaligned_access_speed under CONFIG_RISCV_MISALIGNED and add a separate commit for that. V7: - Fix ifdefery build problems - Move sbi_fwft_is_supported with fwft_set_req struct - Added Atish Reviewed-by - Updated KVM vcpu cfg hedeleg value in set_delegation - Changed SBI ETIME error mapping to ETIMEDOUT - Fixed a few typo reported by Alok V6: - Rename FWFT interface to remove "_local" - Fix test for MEDELEG values in KVM FWFT support - Add __init for unaligned_access_init() - Rebased on master V5: - Return ERANGE as mapping for SBI_ERR_BAD_RANGE - Removed unused sbi_fwft_get() - Fix kernel for sbi_fwft_local_set_cpumask() - Fix indentation for sbi_fwft_local_set() - Remove spurious space in kvm_sbi_fwft_ops. - Rebased on origin/master - Remove fixes commits and sent them as a separate series [4] V4: - Check SBI version 3.0 instead of 2.0 for FWFT presence - Use long for kvm_sbi_fwft operation return value - Init KVM sbi extension even if default_disabled - Remove revert_on_fail parameter for sbi_fwft_feature_set(). - Fix comments for sbi_fwft_set/get() - Only handle local features (there are no globals yet in the spec) - Add new SBI errors to sbi_err_map_linux_errno() V3: - Added comment about kvm sbi fwft supported/set/get callback requirements - Move struct kvm_sbi_fwft_feature in kvm_sbi_fwft.c - Add a FWFT interface V2: - Added Kselftest for misaligned testing - Added get_user() usage instead of __get_user() - Reenable interrupt when possible in misaligned access handling - Document that riscv supports unaligned-traps - Fix KVM extension state when an init function is present - Rework SBI misaligned accesses trap delegation code - Added support for CPU hotplugging - Added KVM SBI reset callback - Added reset for KVM SBI FWFT lock - Return SBI_ERR_DENIED_LOCKED when LOCK flag is set Clément Léger (14): riscv: sbi: add Firmware Feature (FWFT) SBI extensions definitions riscv: sbi: remove useless parenthesis riscv: sbi: add new SBI error mappings riscv: sbi: add FWFT extension interface riscv: sbi: add SBI FWFT extension calls riscv: misaligned: request misaligned exception from SBI riscv: misaligned: use on_each_cpu() for scalar misaligned access probing riscv: misaligned: declare misaligned_access_speed under CONFIG_RISCV_MISALIGNED riscv: misaligned: move emulated access uniformity check in a function riscv: misaligned: add a function to check misalign trap delegability RISC-V: KVM: add SBI extension init()/deinit() functions RISC-V: KVM: add SBI extension reset callback RISC-V: KVM: add support for FWFT SBI extension RISC-V: KVM: add support for SBI_FWFT_MISALIGNED_DELEG arch/riscv/include/asm/cpufeature.h | 14 +- arch/riscv/include/asm/kvm_host.h | 5 +- arch/riscv/include/asm/kvm_vcpu_sbi.h | 12 + arch/riscv/include/asm/kvm_vcpu_sbi_fwft.h | 29 +++ arch/riscv/include/asm/sbi.h | 60 +++++ arch/riscv/include/uapi/asm/kvm.h | 1 + arch/riscv/kernel/sbi.c | 81 ++++++- arch/riscv/kernel/traps_misaligned.c | 112 ++++++++- arch/riscv/kernel/unaligned_access_speed.c | 8 +- arch/riscv/kvm/Makefile | 1 + arch/riscv/kvm/vcpu.c | 4 +- arch/riscv/kvm/vcpu_sbi.c | 54 +++++ arch/riscv/kvm/vcpu_sbi_fwft.c | 257 +++++++++++++++++++++ arch/riscv/kvm/vcpu_sbi_sta.c | 3 +- 14 files changed, 620 insertions(+), 21 deletions(-) create mode 100644 arch/riscv/include/asm/kvm_vcpu_sbi_fwft.h create mode 100644 arch/riscv/kvm/vcpu_sbi_fwft.c -- 2.49.0

2 weeks, 6 days

9
38
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[PATCH -rebased 15/15] selftests/sched_ext: Add test for DL server total_bw consistency

by Joel Fernandes

Add a new kselftest to verify that the total_bw value in /sys/kernel/debug/sched/debug remains consistent across all CPUs under different sched_ext BPF program states: 1. Before a BPF scheduler is loaded 2. While a BPF scheduler is loaded and active 3. After a BPF scheduler is unloaded The test runs CPU stress threads to ensure DL server bandwidth values stabilize before checking consistency. This helps catch potential issues with DL server bandwidth accounting during sched_ext transitions. Signed-off-by: Joel Fernandes <joelagnelf(a)nvidia.com> --- tools/testing/selftests/sched_ext/Makefile | 1 + tools/testing/selftests/sched_ext/total_bw.c | 282 +++++++++++++++++++ 2 files changed, 283 insertions(+) create mode 100644 tools/testing/selftests/sched_ext/total_bw.c diff --git a/tools/testing/selftests/sched_ext/Makefile b/tools/testing/selftests/sched_ext/Makefile index f0a8cba3a99f..d48be158b0a1 100644 --- a/tools/testing/selftests/sched_ext/Makefile +++ b/tools/testing/selftests/sched_ext/Makefile @@ -184,6 +184,7 @@ auto-test-targets := \ select_cpu_vtime \ rt_stall \ test_example \ + total_bw \ testcase-targets := $(addsuffix .o,$(addprefix $(SCXOBJ_DIR)/,$(auto-test-targets))) diff --git a/tools/testing/selftests/sched_ext/total_bw.c b/tools/testing/selftests/sched_ext/total_bw.c new file mode 100644 index 000000000000..d70852cee358 --- /dev/null +++ b/tools/testing/selftests/sched_ext/total_bw.c @@ -0,0 +1,282 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Test to verify that total_bw value remains consistent across all CPUs + * in different BPF program states. + * + * Copyright (C) 2025 Nvidia Corporation. + */ +#include <bpf/bpf.h> +#include <errno.h> +#include <pthread.h> +#include <scx/common.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <sys/wait.h> +#include <unistd.h> +#include "minimal.bpf.skel.h" +#include "scx_test.h" + +#define MAX_CPUS 512 +#define STRESS_DURATION_SEC 5 + +struct total_bw_ctx { + struct minimal *skel; + long baseline_bw[MAX_CPUS]; + int nr_cpus; +}; + +static void *cpu_stress_thread(void *arg) +{ + volatile int i; + time_t end_time = time(NULL) + STRESS_DURATION_SEC; + + while (time(NULL) < end_time) { + for (i = 0; i < 1000000; i++); + } + + return NULL; +} + +/* + * The first enqueue on a CPU causes the DL server to start, for that + * reason run stressor threads in the hopes it schedules on all CPUs. + */ +static int run_cpu_stress(int nr_cpus) +{ + pthread_t *threads; + int i, ret = 0; + + threads = calloc(nr_cpus, sizeof(pthread_t)); + if (!threads) + return -ENOMEM; + + /* Create threads to run on each CPU */ + for (i = 0; i < nr_cpus; i++) { + if (pthread_create(&threads[i], NULL, cpu_stress_thread, NULL)) { + ret = -errno; + fprintf(stderr, "Failed to create thread %d: %s\n", i, strerror(-ret)); + break; + } + } + + /* Wait for all threads to complete */ + for (i = 0; i < nr_cpus; i++) { + if (threads[i]) + pthread_join(threads[i], NULL); + } + + free(threads); + return ret; +} + +static int read_total_bw_values(long *bw_values, int max_cpus) +{ + FILE *fp; + char line[256]; + int cpu_count = 0; + + fp = fopen("/sys/kernel/debug/sched/debug", "r"); + if (!fp) { + SCX_ERR("Failed to open debug file"); + return -1; + } + + while (fgets(line, sizeof(line), fp)) { + char *bw_str = strstr(line, "total_bw"); + if (bw_str) { + bw_str = strchr(bw_str, ':'); + if (bw_str) { + /* Only store up to max_cpus values */ + if (cpu_count < max_cpus) { + bw_values[cpu_count] = atol(bw_str + 1); + } + cpu_count++; + } + } + } + + fclose(fp); + return cpu_count; +} + +static bool verify_total_bw_consistency(long *bw_values, int count) +{ + int i; + long first_value; + + if (count <= 0) + return false; + + first_value = bw_values[0]; + + for (i = 1; i < count; i++) { + if (bw_values[i] != first_value) { + SCX_ERR("Inconsistent total_bw: CPU0=%ld, CPU%d=%ld", + first_value, i, bw_values[i]); + return false; + } + } + + return true; +} + +static int fetch_verify_total_bw(long *bw_values, int nr_cpus) +{ + int attempts = 0; + int max_attempts = 10; + int count; + + /* + * The first enqueue on a CPU causes the DL server to start, for that + * reason run stressor threads in the hopes it schedules on all CPUs. + */ + if (run_cpu_stress(nr_cpus) < 0) { + SCX_ERR("Failed to run CPU stress"); + return -1; + } + + /* Try multiple times to get stable values */ + while (attempts < max_attempts) { + count = read_total_bw_values(bw_values, nr_cpus); + fprintf(stderr, "Read %d total_bw values (testing %d CPUs)\n", count, nr_cpus); + /* If system has more CPUs than we're testing, that's OK */ + if (count < nr_cpus) { + SCX_ERR("Expected at least %d CPUs, got %d", nr_cpus, count); + attempts++; + sleep(1); + continue; + } + + /* Only verify the CPUs we're testing */ + if (verify_total_bw_consistency(bw_values, nr_cpus)) { + fprintf(stderr, "Values are consistent: %ld\n", bw_values[0]); + return 0; + } + + attempts++; + sleep(1); + } + + return -1; +} + +static enum scx_test_status setup(void **ctx) +{ + struct total_bw_ctx *test_ctx; + + if (access("/sys/kernel/debug/sched/debug", R_OK) != 0) { + fprintf(stderr, "Skipping test: debugfs sched/debug not accessible\n"); + return SCX_TEST_SKIP; + } + + test_ctx = calloc(1, sizeof(*test_ctx)); + if (!test_ctx) + return SCX_TEST_FAIL; + + test_ctx->nr_cpus = sysconf(_SC_NPROCESSORS_ONLN); + if (test_ctx->nr_cpus <= 0) { + free(test_ctx); + return SCX_TEST_FAIL; + } + + /* If system has more CPUs than MAX_CPUS, just test the first MAX_CPUS */ + if (test_ctx->nr_cpus > MAX_CPUS) { + test_ctx->nr_cpus = MAX_CPUS; + } + + /* Test scenario 1: BPF program not loaded */ + /* Read and verify baseline total_bw before loading BPF program */ + fprintf(stderr, "BPF prog initially not loaded, reading total_bw values\n"); + if (fetch_verify_total_bw(test_ctx->baseline_bw, test_ctx->nr_cpus) < 0) { + SCX_ERR("Failed to get stable baseline values"); + free(test_ctx); + return SCX_TEST_FAIL; + } + + /* Load the BPF skeleton */ + test_ctx->skel = minimal__open(); + if (!test_ctx->skel) { + free(test_ctx); + return SCX_TEST_FAIL; + } + + SCX_ENUM_INIT(test_ctx->skel); + if (minimal__load(test_ctx->skel)) { + minimal__destroy(test_ctx->skel); + free(test_ctx); + return SCX_TEST_FAIL; + } + + *ctx = test_ctx; + return SCX_TEST_PASS; +} + +static enum scx_test_status run(void *ctx) +{ + struct total_bw_ctx *test_ctx = ctx; + struct bpf_link *link; + long loaded_bw[MAX_CPUS]; + long unloaded_bw[MAX_CPUS]; + int i; + + /* Test scenario 2: BPF program loaded */ + link = bpf_map__attach_struct_ops(test_ctx->skel->maps.minimal_ops); + if (!link) { + SCX_ERR("Failed to attach scheduler"); + return SCX_TEST_FAIL; + } + + fprintf(stderr, "BPF program loaded, reading total_bw values\n"); + if (fetch_verify_total_bw(loaded_bw, test_ctx->nr_cpus) < 0) { + SCX_ERR("Failed to get stable values with BPF loaded"); + bpf_link__destroy(link); + return SCX_TEST_FAIL; + } + bpf_link__destroy(link); + + /* Test scenario 3: BPF program unloaded */ + fprintf(stderr, "BPF program unloaded, reading total_bw values\n"); + if (fetch_verify_total_bw(unloaded_bw, test_ctx->nr_cpus) < 0) { + SCX_ERR("Failed to get stable values after BPF unload"); + return SCX_TEST_FAIL; + } + + /* Verify all three scenarios have the same total_bw values */ + for (i = 0; i < test_ctx->nr_cpus; i++) { + if (test_ctx->baseline_bw[i] != loaded_bw[i]) { + SCX_ERR("CPU%d: baseline_bw=%ld != loaded_bw=%ld", + i, test_ctx->baseline_bw[i], loaded_bw[i]); + return SCX_TEST_FAIL; + } + + if (test_ctx->baseline_bw[i] != unloaded_bw[i]) { + SCX_ERR("CPU%d: baseline_bw=%ld != unloaded_bw=%ld", + i, test_ctx->baseline_bw[i], unloaded_bw[i]); + return SCX_TEST_FAIL; + } + } + + fprintf(stderr, "All total_bw values are consistent across all scenarios\n"); + return SCX_TEST_PASS; +} + +static void cleanup(void *ctx) +{ + struct total_bw_ctx *test_ctx = ctx; + + if (test_ctx) { + if (test_ctx->skel) + minimal__destroy(test_ctx->skel); + free(test_ctx); + } +} + +struct scx_test total_bw = { + .name = "total_bw", + .description = "Verify total_bw consistency across BPF program states", + .setup = setup, + .run = run, + .cleanup = cleanup, +}; +REGISTER_SCX_TEST(&total_bw) -- 2.34.1

3 weeks

1
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[PATCH -rebased 14/15] selftests/sched_ext: Add test for sched_ext dl_server

by Joel Fernandes

From: Andrea Righi <arighi(a)nvidia.com> Add a selftest to validate the correct behavior of the deadline server for the ext_sched_class. [ Joel: Replaced occurences of CFS in the test with EXT. ] Signed-off-by: Joel Fernandes <joelagnelf(a)nvidia.com> Signed-off-by: Andrea Righi <arighi(a)nvidia.com> --- tools/testing/selftests/sched_ext/Makefile | 1 + .../selftests/sched_ext/rt_stall.bpf.c | 23 ++ tools/testing/selftests/sched_ext/rt_stall.c | 213 ++++++++++++++++++ 3 files changed, 237 insertions(+) create mode 100644 tools/testing/selftests/sched_ext/rt_stall.bpf.c create mode 100644 tools/testing/selftests/sched_ext/rt_stall.c diff --git a/tools/testing/selftests/sched_ext/Makefile b/tools/testing/selftests/sched_ext/Makefile index 9d9d6b4c38b0..f0a8cba3a99f 100644 --- a/tools/testing/selftests/sched_ext/Makefile +++ b/tools/testing/selftests/sched_ext/Makefile @@ -182,6 +182,7 @@ auto-test-targets := \ select_cpu_dispatch_bad_dsq \ select_cpu_dispatch_dbl_dsp \ select_cpu_vtime \ + rt_stall \ test_example \ testcase-targets := $(addsuffix .o,$(addprefix $(SCXOBJ_DIR)/,$(auto-test-targets))) diff --git a/tools/testing/selftests/sched_ext/rt_stall.bpf.c b/tools/testing/selftests/sched_ext/rt_stall.bpf.c new file mode 100644 index 000000000000..80086779dd1e --- /dev/null +++ b/tools/testing/selftests/sched_ext/rt_stall.bpf.c @@ -0,0 +1,23 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * A scheduler that verified if RT tasks can stall SCHED_EXT tasks. + * + * Copyright (c) 2025 NVIDIA Corporation. + */ + +#include <scx/common.bpf.h> + +char _license[] SEC("license") = "GPL"; + +UEI_DEFINE(uei); + +void BPF_STRUCT_OPS(rt_stall_exit, struct scx_exit_info *ei) +{ + UEI_RECORD(uei, ei); +} + +SEC(".struct_ops.link") +struct sched_ext_ops rt_stall_ops = { + .exit = (void *)rt_stall_exit, + .name = "rt_stall", +}; diff --git a/tools/testing/selftests/sched_ext/rt_stall.c b/tools/testing/selftests/sched_ext/rt_stall.c new file mode 100644 index 000000000000..d4cb545ebfd8 --- /dev/null +++ b/tools/testing/selftests/sched_ext/rt_stall.c @@ -0,0 +1,213 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (c) 2025 NVIDIA Corporation. + */ +#define _GNU_SOURCE +#include <stdio.h> +#include <stdlib.h> +#include <unistd.h> +#include <sched.h> +#include <sys/prctl.h> +#include <sys/types.h> +#include <sys/wait.h> +#include <time.h> +#include <linux/sched.h> +#include <signal.h> +#include <bpf/bpf.h> +#include <scx/common.h> +#include <sys/wait.h> +#include <unistd.h> +#include "rt_stall.bpf.skel.h" +#include "scx_test.h" +#include "../kselftest.h" + +#define CORE_ID 0 /* CPU to pin tasks to */ +#define RUN_TIME 5 /* How long to run the test in seconds */ + +/* Simple busy-wait function for test tasks */ +static void process_func(void) +{ + while (1) { + /* Busy wait */ + for (volatile unsigned long i = 0; i < 10000000UL; i++); + } +} + +/* Set CPU affinity to a specific core */ +static void set_affinity(int cpu) +{ + cpu_set_t mask; + + CPU_ZERO(&mask); + CPU_SET(cpu, &mask); + if (sched_setaffinity(0, sizeof(mask), &mask) != 0) { + perror("sched_setaffinity"); + exit(EXIT_FAILURE); + } +} + +/* Set task scheduling policy and priority */ +static void set_sched(int policy, int priority) +{ + struct sched_param param; + + param.sched_priority = priority; + if (sched_setscheduler(0, policy, &param) != 0) { + perror("sched_setscheduler"); + exit(EXIT_FAILURE); + } +} + +/* Get process runtime from /proc/<pid>/stat */ +static float get_process_runtime(int pid) +{ + char path[256]; + FILE *file; + long utime, stime; + int fields; + + snprintf(path, sizeof(path), "/proc/%d/stat", pid); + file = fopen(path, "r"); + if (file == NULL) { + perror("Failed to open stat file"); + return -1; + } + + /* Skip the first 13 fields and read the 14th and 15th */ + fields = fscanf(file, + "%*d %*s %*c %*d %*d %*d %*d %*d %*u %*u %*u %*u %*u %lu %lu", + &utime, &stime); + fclose(file); + + if (fields != 2) { + fprintf(stderr, "Failed to read stat file\n"); + return -1; + } + + /* Calculate the total time spent in the process */ + long total_time = utime + stime; + long ticks_per_second = sysconf(_SC_CLK_TCK); + float runtime_seconds = total_time * 1.0 / ticks_per_second; + + return runtime_seconds; +} + +static enum scx_test_status setup(void **ctx) +{ + struct rt_stall *skel; + + skel = rt_stall__open(); + SCX_FAIL_IF(!skel, "Failed to open"); + SCX_ENUM_INIT(skel); + SCX_FAIL_IF(rt_stall__load(skel), "Failed to load skel"); + + *ctx = skel; + + return SCX_TEST_PASS; +} + +static bool sched_stress_test(void) +{ + float cfs_runtime, rt_runtime; + int cfs_pid, rt_pid; + float expected_min_ratio = 0.04; /* 4% */ + + ksft_print_header(); + ksft_set_plan(1); + + /* Create and set up a EXT task */ + cfs_pid = fork(); + if (cfs_pid == 0) { + set_affinity(CORE_ID); + process_func(); + exit(0); + } else if (cfs_pid < 0) { + perror("fork for EXT task"); + ksft_exit_fail(); + } + + /* Create an RT task */ + rt_pid = fork(); + if (rt_pid == 0) { + set_affinity(CORE_ID); + set_sched(SCHED_FIFO, 50); + process_func(); + exit(0); + } else if (rt_pid < 0) { + perror("fork for RT task"); + ksft_exit_fail(); + } + + /* Let the processes run for the specified time */ + sleep(RUN_TIME); + + /* Get runtime for the EXT task */ + cfs_runtime = get_process_runtime(cfs_pid); + if (cfs_runtime != -1) + ksft_print_msg("Runtime of EXT task (PID %d) is %f seconds\n", cfs_pid, cfs_runtime); + else + ksft_exit_fail_msg("Error getting runtime for EXT task (PID %d)\n", cfs_pid); + + /* Get runtime for the RT task */ + rt_runtime = get_process_runtime(rt_pid); + if (rt_runtime != -1) + ksft_print_msg("Runtime of RT task (PID %d) is %f seconds\n", rt_pid, rt_runtime); + else + ksft_exit_fail_msg("Error getting runtime for RT task (PID %d)\n", rt_pid); + + /* Kill the processes */ + kill(cfs_pid, SIGKILL); + kill(rt_pid, SIGKILL); + waitpid(cfs_pid, NULL, 0); + waitpid(rt_pid, NULL, 0); + + /* Verify that the scx task got enough runtime */ + float actual_ratio = cfs_runtime / (cfs_runtime + rt_runtime); + ksft_print_msg("EXT task got %.2f%% of total runtime\n", actual_ratio * 100); + + if (actual_ratio >= expected_min_ratio) { + ksft_test_result_pass("PASS: EXT task got more than %.2f%% of runtime\n", + expected_min_ratio * 100); + return true; + } else { + ksft_test_result_fail("FAIL: EXT task got less than %.2f%% of runtime\n", + expected_min_ratio * 100); + return false; + } +} + +static enum scx_test_status run(void *ctx) +{ + struct rt_stall *skel = ctx; + struct bpf_link *link; + bool res; + + link = bpf_map__attach_struct_ops(skel->maps.rt_stall_ops); + SCX_FAIL_IF(!link, "Failed to attach scheduler"); + + res = sched_stress_test(); + + SCX_EQ(skel->data->uei.kind, EXIT_KIND(SCX_EXIT_NONE)); + bpf_link__destroy(link); + + if (!res) + ksft_exit_fail(); + + return SCX_TEST_PASS; +} + +static void cleanup(void *ctx) +{ + struct rt_stall *skel = ctx; + + rt_stall__destroy(skel); +} + +struct scx_test rt_stall = { + .name = "rt_stall", + .description = "Verify that RT tasks cannot stall SCHED_EXT tasks", + .setup = setup, + .run = run, + .cleanup = cleanup, +}; +REGISTER_SCX_TEST(&rt_stall) -- 2.34.1

3 weeks

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[PATCH v3 0/7] selftests/mm: Fix false positives and skip unsupported tests

by Aboorva Devarajan

Hi all, This patch series addresses false positives in the generic mm selftests and skips tests that cannot run correctly due to missing features or system limitations. v2: https://lore.kernel.org/all/20250703060656.54345-1-aboorvad@linux.ibm.com/ Changes in v3: - Rebased onto the latest mm-new branch, top commit of the base is commit 0709ddf8951f ("mm: add zblock allocator"). - Minor refactor based on the review comments. - Included the tags from the previous version. --- v1: https://lore.kernel.org/all/20250616160632.35250-1-aboorvad@linux.ibm.com/ Changes in v2: - Rebased onto the mm-new branch, top commit of the base is commit 3b4a8ad89f7e ("mm: add zblock allocator"). - Split some patches for clarity. - Updated virtual_address_range test to support testing 4PB VA on PPC64. - Added proper Fixes: tags. - Included a patch to skip a failing userfaultfd test when unsupported, instead of reporting a failure. --- Please let us know if you have any further comments. Thanks, Aboorva Aboorva Devarajan (3): selftests/mm: Fix child process exit codes in ksm_functional_tests selftests/mm: Skip thuge-gen test if system is not setup properly selftests/mm: Skip hugepage-mremap test if userfaultfd unavailable Donet Tom (4): mm/selftests: Fix incorrect pointer being passed to mark_range() selftests/mm: Add support to test 4PB VA on PPC64 selftest/mm: Fix ksm_funtional_test failures mm/selftests: Fix split_huge_page_test failure on systems with 64KB page size tools/testing/selftests/mm/hugepage-mremap.c | 16 +++++++++-- .../selftests/mm/ksm_functional_tests.c | 28 +++++++++++++------ .../selftests/mm/split_huge_page_test.c | 23 +++++++++------ tools/testing/selftests/mm/thuge-gen.c | 11 +++++--- .../selftests/mm/virtual_address_range.c | 13 ++++++++- 5 files changed, 67 insertions(+), 24 deletions(-) -- 2.47.1

3 weeks

4
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[PATCH v2 0/1] selftests/futex: Check for shmget support at runtime

by Wake Liu

Changes in v2: - Restore RET_FAIL assignments in error paths to ensure the test's exit code accurately reflects the failure status. Wake Liu (1): selftests/futex: Check for shmget support at runtime .../selftests/futex/functional/futex_wait.c | 49 +++++++------ .../selftests/futex/functional/futex_waitv.c | 73 ++++++++++++------- 2 files changed, 73 insertions(+), 49 deletions(-) -- 2.50.1.703.g449372360f-goog

3 weeks, 1 day

2
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[PATCH] selftests/filesystems/binderfs: Skip tests if user namespaces are unavailable

by Wake Liu

The binderfs selftests, specifically `binderfs_stress` and `binderfs_test_unprivileged`, depend on user namespaces to run. On kernels built without user namespace support (CONFIG_USER_NS=n), these tests will fail. To prevent these failures, add a check for the availability of user namespaces by testing for the existence of "/proc/self/ns/user". If the check fails, skip the tests and print an informative message. Signed-off-by: Wake Liu <wakel(a)google.com> --- .../selftests/filesystems/binderfs/binderfs_test.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/tools/testing/selftests/filesystems/binderfs/binderfs_test.c b/tools/testing/selftests/filesystems/binderfs/binderfs_test.c index 81db85a5cc16..e77ed34ebd06 100644 --- a/tools/testing/selftests/filesystems/binderfs/binderfs_test.c +++ b/tools/testing/selftests/filesystems/binderfs/binderfs_test.c @@ -291,6 +291,11 @@ static int write_id_mapping(enum idmap_type type, pid_t pid, const char *buf, return 0; } +static bool has_userns(void) +{ + return (access("/proc/self/ns/user", F_OK) == 0); +} + static void change_userns(struct __test_metadata *_metadata, int syncfds[2]) { int ret; @@ -378,6 +383,9 @@ static void *binder_version_thread(void *data) */ TEST(binderfs_stress) { + if (!has_userns()) + SKIP(return, "%s: user namespace not supported\n", __func__); + int fds[1000]; int syncfds[2]; pid_t pid; @@ -502,6 +510,8 @@ TEST(binderfs_test_privileged) TEST(binderfs_test_unprivileged) { + if (!has_userns()) + SKIP(return, "%s: user namespace not supported\n", __func__); int ret; int syncfds[2]; pid_t pid; -- 2.50.1.703.g449372360f-goog

3 weeks, 1 day

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[PATCH] selftests/futex: Skip futex_waitv tests if ENOSYS

by Wake Liu

The futex_waitv() syscall was introduced in Linux 5.16. The existing test in futex_wait_timeout.c will fail on kernels older than 5.16 due to the syscall not being implemented. Modify the test_timeout() function to check if the error returned is ENOSYS. If it is, skip the test and report it as such, rather than failing. This ensures the selftests can be run on a wider range of kernel versions without false negatives. Signed-off-by: Wake Liu <wakel(a)google.com> --- .../selftests/futex/functional/futex_wait_timeout.c | 11 ++++++++--- .../testing/selftests/futex/functional/futex_waitv.c | 8 ++++++++ 2 files changed, 16 insertions(+), 3 deletions(-) diff --git a/tools/testing/selftests/futex/functional/futex_wait_timeout.c b/tools/testing/selftests/futex/functional/futex_wait_timeout.c index d183f878360b..323cab339814 100644 --- a/tools/testing/selftests/futex/functional/futex_wait_timeout.c +++ b/tools/testing/selftests/futex/functional/futex_wait_timeout.c @@ -64,9 +64,14 @@ void *get_pi_lock(void *arg) static void test_timeout(int res, int *ret, char *test_name, int err) { if (!res || errno != err) { - ksft_test_result_fail("%s returned %d\n", test_name, - res < 0 ? errno : res); - *ret = RET_FAIL; + if (errno == ENOSYS) { + ksft_test_result_skip("%s: %s\n", + test_name, strerror(errno)); + } else { + ksft_test_result_fail("%s returned %d\n", test_name, + res < 0 ? errno : res); + *ret = RET_FAIL; + } } else { ksft_test_result_pass("%s succeeds\n", test_name); } diff --git a/tools/testing/selftests/futex/functional/futex_waitv.c b/tools/testing/selftests/futex/functional/futex_waitv.c index 034dbfef40cb..2a86fd3ea657 100644 --- a/tools/testing/selftests/futex/functional/futex_waitv.c +++ b/tools/testing/selftests/futex/functional/futex_waitv.c @@ -59,6 +59,14 @@ void *waiterfn(void *arg) int main(int argc, char *argv[]) { + if (!ksft_min_kernel_version(5, 16)) { + ksft_print_header(); + ksft_set_plan(0); + ksft_print_msg("%s: FUTEX_WAITV not implemented until 5.16\n", + basename(argv[0])); + ksft_print_cnts(); + return KSFT_SKIP; + } pthread_t waiter; int res, ret = RET_PASS; struct timespec to; -- 2.50.1.703.g449372360f-goog

3 weeks, 1 day

2
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[PATCH v3] selftests/futex: Check for shmget support at runtime

by Wake Liu

The futex tests `futex_wait.c` and `futex_waitv.c` rely on the `shmget()` syscall, which may not be available if the kernel is built without System V IPC support (CONFIG_SYSVIPC=n). This can lead to test failures on such systems. This patch modifies the tests to check for `shmget()` support at runtime by calling it and checking for an `ENOSYS` error. If `shmget()` is not supported, the tests are skipped with a clear message, improving the user experience and preventing false negatives. This approach is more robust than relying on compile-time checks and ensures that the tests run only when the required kernel features are present. Signed-off-by: Wake Liu <wakel(a)google.com> --- .../selftests/futex/functional/futex_wait.c | 57 ++++++++------- .../selftests/futex/functional/futex_waitv.c | 73 ++++++++++++------- 2 files changed, 78 insertions(+), 52 deletions(-) diff --git a/tools/testing/selftests/futex/functional/futex_wait.c b/tools/testing/selftests/futex/functional/futex_wait.c index 685140d9b93d..2a834f074959 100644 --- a/tools/testing/selftests/futex/functional/futex_wait.c +++ b/tools/testing/selftests/futex/functional/futex_wait.c @@ -48,7 +48,7 @@ static void *waiterfn(void *arg) int main(int argc, char *argv[]) { int res, ret = RET_PASS, fd, c, shm_id; - u_int32_t f_private = 0, *shared_data; + u_int32_t f_private = 0, *shared_data = NULL; unsigned int flags = FUTEX_PRIVATE_FLAG; pthread_t waiter; void *shm; @@ -96,32 +96,37 @@ int main(int argc, char *argv[]) /* Testing an anon page shared memory */ shm_id = shmget(IPC_PRIVATE, 4096, IPC_CREAT | 0666); if (shm_id < 0) { - perror("shmget"); - exit(1); - } - - shared_data = shmat(shm_id, NULL, 0); - - *shared_data = 0; - futex = shared_data; - - info("Calling shared (page anon) futex_wait on futex: %p\n", futex); - if (pthread_create(&waiter, NULL, waiterfn, NULL)) - error("pthread_create failed\n", errno); - - usleep(WAKE_WAIT_US); - - info("Calling shared (page anon) futex_wake on futex: %p\n", futex); - res = futex_wake(futex, 1, 0); - if (res != 1) { - ksft_test_result_fail("futex_wake shared (page anon) returned: %d %s\n", - errno, strerror(errno)); - ret = RET_FAIL; + if (errno == ENOSYS) { + ksft_test_result_skip("Kernel does not support System V shared memory\n"); + } else { + ksft_test_result_fail("shmget() failed with error: %s\n", strerror(errno)); + ret = RET_FAIL; + } } else { - ksft_test_result_pass("futex_wake shared (page anon) succeeds\n"); + shared_data = shmat(shm_id, NULL, 0); + + *shared_data = 0; + futex = shared_data; + + info("Calling shared (page anon) futex_wait on futex: %p\n", futex); + if (pthread_create(&waiter, NULL, waiterfn, NULL)) + error("pthread_create failed\n", errno); + + usleep(WAKE_WAIT_US); + + info("Calling shared (page anon) futex_wake on futex: %p\n", futex); + res = futex_wake(futex, 1, 0); + if (res != 1) { + if (res < 0) + ksft_test_result_fail("futex_wake shared (page anon) failed with res=%d: %m\n", res); + else + ksft_test_result_fail("futex_wake shared (page anon) returned %d, expected 1\n", res); + ret = RET_FAIL; + } else { + ksft_test_result_pass("futex_wake shared (page anon) succeeds\n"); + } } - /* Testing a file backed shared memory */ fd = open(SHM_PATH, O_RDWR | O_CREAT, S_IRUSR | S_IWUSR); if (fd < 0) { @@ -161,7 +166,8 @@ int main(int argc, char *argv[]) } /* Freeing resources */ - shmdt(shared_data); + if (shared_data) + shmdt(shared_data); munmap(shm, sizeof(f_private)); remove(SHM_PATH); close(fd); @@ -169,3 +175,4 @@ int main(int argc, char *argv[]) ksft_print_cnts(); return ret; } + diff --git a/tools/testing/selftests/futex/functional/futex_waitv.c b/tools/testing/selftests/futex/functional/futex_waitv.c index a94337f677e1..034dbfef40cb 100644 --- a/tools/testing/selftests/futex/functional/futex_waitv.c +++ b/tools/testing/selftests/futex/functional/futex_waitv.c @@ -110,40 +110,58 @@ int main(int argc, char *argv[]) } /* Shared waitv */ - for (i = 0; i < NR_FUTEXES; i++) { - int shm_id = shmget(IPC_PRIVATE, 4096, IPC_CREAT | 0666); - - if (shm_id < 0) { - perror("shmget"); - exit(1); + bool shm_supported = true; + int shm_id = shmget(IPC_PRIVATE, 4096, IPC_CREAT | 0666); + + if (shm_id < 0) { + if (errno == ENOSYS) { + shm_supported = false; + ksft_test_result_skip("Kernel does not support System V shared memory\n"); + } else { + ksft_test_result_fail("shmget() failed with error: %s\n", strerror(errno)); + ret = RET_FAIL; + shm_supported = false; } + } else { + shmctl(shm_id, IPC_RMID, NULL); + } - unsigned int *shared_data = shmat(shm_id, NULL, 0); + if (shm_supported) { + for (i = 0; i < NR_FUTEXES; i++) { + int shm_id = shmget(IPC_PRIVATE, 4096, IPC_CREAT | 0666); - *shared_data = 0; - waitv[i].uaddr = (uintptr_t)shared_data; - waitv[i].flags = FUTEX_32; - waitv[i].val = 0; - waitv[i].__reserved = 0; - } + if (shm_id < 0) { + perror("shmget"); + exit(1); + } - if (pthread_create(&waiter, NULL, waiterfn, NULL)) - error("pthread_create failed\n", errno); + unsigned int *shared_data = shmat(shm_id, NULL, 0); - usleep(WAKE_WAIT_US); + *shared_data = 0; + waitv[i].uaddr = (uintptr_t)shared_data; + waitv[i].flags = FUTEX_32; + waitv[i].val = 0; + waitv[i].__reserved = 0; + } - res = futex_wake(u64_to_ptr(waitv[NR_FUTEXES - 1].uaddr), 1, 0); - if (res != 1) { - ksft_test_result_fail("futex_wake shared returned: %d %s\n", - res ? errno : res, - res ? strerror(errno) : ""); - ret = RET_FAIL; - } else { - ksft_test_result_pass("futex_waitv shared\n"); - } + if (pthread_create(&waiter, NULL, waiterfn, NULL)) + error("pthread_create failed\n", errno); - for (i = 0; i < NR_FUTEXES; i++) - shmdt(u64_to_ptr(waitv[i].uaddr)); + usleep(WAKE_WAIT_US); + + res = futex_wake(u64_to_ptr(waitv[NR_FUTEXES - 1].uaddr), 1, 0); + if (res != 1) { + ksft_test_result_fail("futex_wake shared returned: %d %s\n", + res ? errno : res, + res ? strerror(errno) : ""); + ret = RET_FAIL; + } else { + ksft_test_result_pass("futex_waitv shared\n"); + } + + for (i = 0; i < NR_FUTEXES; i++) + shmdt(u64_to_ptr(waitv[i].uaddr)); + } /* Testing a waiter without FUTEX_32 flag */ waitv[0].flags = FUTEX_PRIVATE_FLAG; @@ -235,3 +253,4 @@ int main(int argc, char *argv[]) ksft_print_cnts(); return ret; } + -- 2.50.1.703.g449372360f-goog

3 weeks, 1 day

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[PATCH RFC v2 0/2] KVM: arm64: PMU: Use multiple host PMUs

by Akihiko Odaki

On heterogeneous arm64 systems, KVM's PMU emulation is based on the features of a single host PMU instance. When a vCPU is migrated to a pCPU with an incompatible PMU, counters such as PMCCNTR_EL0 stop incrementing. Although this behavior is permitted by the architecture, Windows does not handle it gracefully and may crash with a division-by-zero error. The current workaround requires VMMs to pin vCPUs to a set of pCPUs that share a compatible PMU. This is difficult to implement correctly in QEMU/libvirt, where pinning occurs after vCPU initialization, and it also restricts the guest to a subset of available pCPUs. This patch introduces the KVM_ARM_VCPU_PMU_V3_COMPOSITION attribute to create a "composite" PMU. When set, KVM exposes a PMU that is compatible with all pCPUs by advertising only a single cycle counter, a feature common to all PMUs. This allows Windows guests to run reliably on heterogeneous systems without crashing, even without vCPU pinning, and enables VMMs to schedule vCPUs across all available pCPUs, making full use of the host hardware. A QEMU patch that demonstrates the usage of the new attribute is available at: https://lore.kernel.org/qemu-devel/20250806-kvm-v1-1-d1d50b7058cd@rsg.ci.i.… ("[PATCH RFC] target/arm/kvm: Choose PMU backend") Signed-off-by: Akihiko Odaki <odaki(a)rsg.ci.i.u-tokyo.ac.jp> --- Changes in v2: - Added the KVM_ARM_VCPU_PMU_V3_COMPOSITION attribute to opt in the feature. - Added code to handle overflow. - Link to v1: https://lore.kernel.org/r/20250319-hybrid-v1-1-4d1ada10e705@daynix.com --- Akihiko Odaki (2): KVM: arm64: PMU: Introduce KVM_ARM_VCPU_PMU_V3_COMPOSITION KVM: arm64: selftests: Test guest PMUv3 composition Documentation/virt/kvm/devices/vcpu.rst | 30 ++ arch/arm64/include/asm/kvm_host.h | 2 + arch/arm64/include/uapi/asm/kvm.h | 1 + arch/arm64/kvm/arm.c | 5 +- arch/arm64/kvm/pmu-emul.c | 495 +++++++++++++-------- arch/arm64/kvm/sys_regs.c | 2 +- include/kvm/arm_pmu.h | 12 +- .../selftests/kvm/arm64/vpmu_counter_access.c | 148 ++++-- 8 files changed, 461 insertions(+), 234 deletions(-) --- base-commit: 8ec6d99a41e3d1dbdff2bdb3aa42951681e1e76c change-id: 20250224-hybrid-01d5ff47edd2 Best regards, -- Akihiko Odaki <odaki(a)rsg.ci.i.u-tokyo.ac.jp>

3 weeks, 1 day

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