diff --git a/tools/testing/selftests/sched_ext/Makefile b/tools/testing/selftests/sched_ext/Makefile index 3cfe90e0f34f..49897727f535 100644 --- a/tools/testing/selftests/sched_ext/Makefile +++ b/tools/testing/selftests/sched_ext/Makefile @@ -164,6 +164,7 @@ all_test_bpfprogs := $(foreach prog,$(wildcard *.bpf.c),$(INCLUDE_DIR)/$(patsubs auto-test-targets := \ create_dsq \ dequeue \ + dequeue_iter \ enq_last_no_enq_fails \ ddsp_bogus_dsq_fail \ ddsp_vtimelocal_fail \ diff --git a/tools/testing/selftests/sched_ext/dequeue_iter.bpf.c b/tools/testing/selftests/sched_ext/dequeue_iter.bpf.c new file mode 100644 index 000000000000..76c2c71a90b6 --- /dev/null +++ b/tools/testing/selftests/sched_ext/dequeue_iter.bpf.c @@ -0,0 +1,73 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * ops.dequeue() of this scheduler iterates the user DSQ it consumes + * tasks from with bpf_iter_scx_dsq, which takes the DSQ lock. + * On a kernel that still runs ops.dequeue() with that lock held, the + * iteration self-deadlocks the CPU - this test wedges the system on + * unfixed kernels instead of failing cleanly. + * + * Copyright (c) 2026 fangqiurong + */ + +#include + +char _license[] SEC("license") = "GPL"; + +UEI_DEFINE(uei); + +#define TEST_DSQ_ID 1000 + +u64 dq_count; + +s32 BPF_STRUCT_OPS_SLEEPABLE(dequeue_iter_init) +{ + return scx_bpf_create_dsq(TEST_DSQ_ID, -1); +} + +s32 BPF_STRUCT_OPS(dequeue_iter_select_cpu, struct task_struct *p, + s32 prev_cpu, u64 wake_flags) +{ + return prev_cpu; +} + +void BPF_STRUCT_OPS(dequeue_iter_enqueue, struct task_struct *p, u64 enq_flags) +{ + scx_bpf_dsq_insert(p, TEST_DSQ_ID, SCX_SLICE_DFL, enq_flags); +} + +void BPF_STRUCT_OPS(dequeue_iter_dispatch, s32 cpu, struct task_struct *task) +{ + scx_bpf_dsq_move_to_local(TEST_DSQ_ID, 0); +} + +void BPF_STRUCT_OPS(dequeue_iter_dequeue, struct task_struct *p, u64 deq_flags) +{ + struct bpf_iter_scx_dsq it; + struct task_struct *t; + + if (!bpf_iter_scx_dsq_new(&it, TEST_DSQ_ID, 0)) { + while ((t = bpf_iter_scx_dsq_next(&it))) + ; + } + bpf_iter_scx_dsq_destroy(&it); + + __sync_fetch_and_add(&dq_count, 1); +} + +void BPF_STRUCT_OPS(dequeue_iter_exit, struct scx_exit_info *ei) +{ + UEI_RECORD(uei, ei); + scx_bpf_destroy_dsq(TEST_DSQ_ID); +} + +SEC(".struct_ops.link") +struct sched_ext_ops dequeue_iter_ops = { + .init = (void *)dequeue_iter_init, + .select_cpu = (void *)dequeue_iter_select_cpu, + .enqueue = (void *)dequeue_iter_enqueue, + .dispatch = (void *)dequeue_iter_dispatch, + .dequeue = (void *)dequeue_iter_dequeue, + .exit = (void *)dequeue_iter_exit, + .timeout_ms = 1000U, + .name = "dequeue_iter", +}; diff --git a/tools/testing/selftests/sched_ext/dequeue_iter.c b/tools/testing/selftests/sched_ext/dequeue_iter.c new file mode 100644 index 000000000000..f60711bf3b39 --- /dev/null +++ b/tools/testing/selftests/sched_ext/dequeue_iter.c @@ -0,0 +1,79 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (c) 2026 fangqiurong + */ +#include +#include +#include +#include +#include "dequeue_iter.bpf.skel.h" +#include "scx_test.h" + +#define DQ_TARGET 10 +#define DQ_DEADLINE_MS 3000 + +static unsigned long long now_ms(void) +{ + struct timespec ts; + + clock_gettime(CLOCK_MONOTONIC, &ts); + + return ts.tv_sec * 1000ULL + ts.tv_nsec / 1000000; +} + +static enum scx_test_status setup(void **ctx) +{ + struct dequeue_iter *skel; + + skel = dequeue_iter__open(); + SCX_FAIL_IF(!skel, "Failed to open"); + SCX_ENUM_INIT(skel); + SCX_FAIL_IF(dequeue_iter__load(skel), "Failed to load skel"); + + *ctx = skel; + + return SCX_TEST_PASS; +} + +static enum scx_test_status run(void *ctx) +{ + struct dequeue_iter *skel = ctx; + struct bpf_link *link; + unsigned long long end; + + link = bpf_map__attach_struct_ops(skel->maps.dequeue_iter_ops); + SCX_FAIL_IF(!link, "Failed to attach scheduler"); + + end = now_ms() + DQ_DEADLINE_MS; + while (skel->bss->dq_count < DQ_TARGET && !UEI_EXITED(skel, uei) && + now_ms() < end) + usleep(100); + + bpf_link__destroy(link); + + SCX_EQ(skel->data->uei.kind, EXIT_KIND(SCX_EXIT_UNREG)); + + if (skel->bss->dq_count < DQ_TARGET) { + SCX_ERR("ops.dequeue() fired only %llu times", + (unsigned long long)skel->bss->dq_count); + return SCX_TEST_FAIL; + } + + return SCX_TEST_PASS; +} + +static void cleanup(void *ctx) +{ + struct dequeue_iter *skel = ctx; + + dequeue_iter__destroy(skel); +} + +struct scx_test dequeue_iter = { + .name = "dequeue_iter", + .description = "Verify ops.dequeue() can iterate its source user DSQ", + .setup = setup, + .run = run, + .cleanup = cleanup, +}; +REGISTER_SCX_TEST(&dequeue_iter)