selftests/bpf: Add tests for array map with local percpu kptr
Add non-sleepable and sleepable tests with percpu kptr. For non-sleepable test, four programs are executed in the order of: 1. allocate percpu data. 2. assign values to percpu data. 3. retrieve percpu data. 4. de-allocate percpu data. The sleepable prog tried to exercise all above 4 steps in a single prog. Also for sleepable prog, rcu_read_lock is needed to protect direct percpu ptr access (from map value) and following bpf_this_cpu_ptr() and bpf_per_cpu_ptr() helpers. Signed-off-by: Yonghong Song <yonghong.song@linux.dev> Link: https://lore.kernel.org/r/20230827152811.2000125-1-yonghong.song@linux.dev Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Yonghong Song
Alexei Starovoitov
parent
968c76cb3d
commit
6adf82a439
78
tools/testing/selftests/bpf/prog_tests/percpu_alloc.c
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78
tools/testing/selftests/bpf/prog_tests/percpu_alloc.c
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@ -0,0 +1,78 @@
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// SPDX-License-Identifier: GPL-2.0
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#include <test_progs.h>
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#include "percpu_alloc_array.skel.h"
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static void test_array(void)
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{
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struct percpu_alloc_array *skel;
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int err, prog_fd;
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LIBBPF_OPTS(bpf_test_run_opts, topts);
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skel = percpu_alloc_array__open();
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if (!ASSERT_OK_PTR(skel, "percpu_alloc_array__open"))
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return;
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bpf_program__set_autoload(skel->progs.test_array_map_1, true);
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bpf_program__set_autoload(skel->progs.test_array_map_2, true);
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bpf_program__set_autoload(skel->progs.test_array_map_3, true);
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bpf_program__set_autoload(skel->progs.test_array_map_4, true);
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skel->rodata->nr_cpus = libbpf_num_possible_cpus();
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err = percpu_alloc_array__load(skel);
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if (!ASSERT_OK(err, "percpu_alloc_array__load"))
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goto out;
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err = percpu_alloc_array__attach(skel);
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if (!ASSERT_OK(err, "percpu_alloc_array__attach"))
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goto out;
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prog_fd = bpf_program__fd(skel->progs.test_array_map_1);
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err = bpf_prog_test_run_opts(prog_fd, &topts);
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ASSERT_OK(err, "test_run array_map 1-4");
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ASSERT_EQ(topts.retval, 0, "test_run array_map 1-4");
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ASSERT_EQ(skel->bss->cpu0_field_d, 2, "cpu0_field_d");
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ASSERT_EQ(skel->bss->sum_field_c, 1, "sum_field_c");
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out:
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percpu_alloc_array__destroy(skel);
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}
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static void test_array_sleepable(void)
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{
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struct percpu_alloc_array *skel;
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int err, prog_fd;
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LIBBPF_OPTS(bpf_test_run_opts, topts);
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skel = percpu_alloc_array__open();
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if (!ASSERT_OK_PTR(skel, "percpu_alloc__open"))
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return;
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bpf_program__set_autoload(skel->progs.test_array_map_10, true);
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skel->rodata->nr_cpus = libbpf_num_possible_cpus();
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err = percpu_alloc_array__load(skel);
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if (!ASSERT_OK(err, "percpu_alloc_array__load"))
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goto out;
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err = percpu_alloc_array__attach(skel);
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if (!ASSERT_OK(err, "percpu_alloc_array__attach"))
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goto out;
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prog_fd = bpf_program__fd(skel->progs.test_array_map_10);
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err = bpf_prog_test_run_opts(prog_fd, &topts);
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ASSERT_OK(err, "test_run array_map_10");
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ASSERT_EQ(topts.retval, 0, "test_run array_map_10");
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ASSERT_EQ(skel->bss->cpu0_field_d, 2, "cpu0_field_d");
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ASSERT_EQ(skel->bss->sum_field_c, 1, "sum_field_c");
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out:
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percpu_alloc_array__destroy(skel);
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}
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void test_percpu_alloc(void)
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{
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if (test__start_subtest("array"))
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test_array();
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if (test__start_subtest("array_sleepable"))
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test_array_sleepable();
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}
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187
tools/testing/selftests/bpf/progs/percpu_alloc_array.c
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187
tools/testing/selftests/bpf/progs/percpu_alloc_array.c
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@ -0,0 +1,187 @@
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#include "bpf_experimental.h"
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struct val_t {
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long b, c, d;
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};
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struct elem {
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long sum;
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struct val_t __percpu_kptr *pc;
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};
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struct {
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__uint(type, BPF_MAP_TYPE_ARRAY);
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__uint(max_entries, 1);
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__type(key, int);
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__type(value, struct elem);
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} array SEC(".maps");
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void bpf_rcu_read_lock(void) __ksym;
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void bpf_rcu_read_unlock(void) __ksym;
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const volatile int nr_cpus;
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/* Initialize the percpu object */
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SEC("?fentry/bpf_fentry_test1")
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int BPF_PROG(test_array_map_1)
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{
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struct val_t __percpu_kptr *p;
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struct elem *e;
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int index = 0;
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e = bpf_map_lookup_elem(&array, &index);
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if (!e)
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return 0;
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p = bpf_percpu_obj_new(struct val_t);
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if (!p)
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return 0;
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p = bpf_kptr_xchg(&e->pc, p);
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if (p)
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bpf_percpu_obj_drop(p);
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return 0;
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}
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/* Update percpu data */
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SEC("?fentry/bpf_fentry_test2")
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int BPF_PROG(test_array_map_2)
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{
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struct val_t __percpu_kptr *p;
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struct val_t *v;
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struct elem *e;
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int index = 0;
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e = bpf_map_lookup_elem(&array, &index);
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if (!e)
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return 0;
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p = e->pc;
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if (!p)
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return 0;
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v = bpf_per_cpu_ptr(p, 0);
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if (!v)
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return 0;
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v->c = 1;
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v->d = 2;
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return 0;
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}
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int cpu0_field_d, sum_field_c;
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/* Summarize percpu data */
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SEC("?fentry/bpf_fentry_test3")
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int BPF_PROG(test_array_map_3)
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{
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struct val_t __percpu_kptr *p;
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int i, index = 0;
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struct val_t *v;
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struct elem *e;
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e = bpf_map_lookup_elem(&array, &index);
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if (!e)
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return 0;
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p = e->pc;
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if (!p)
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return 0;
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bpf_for(i, 0, nr_cpus) {
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v = bpf_per_cpu_ptr(p, i);
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if (v) {
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if (i == 0)
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cpu0_field_d = v->d;
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sum_field_c += v->c;
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}
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}
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return 0;
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}
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/* Explicitly free allocated percpu data */
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SEC("?fentry/bpf_fentry_test4")
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int BPF_PROG(test_array_map_4)
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{
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struct val_t __percpu_kptr *p;
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struct elem *e;
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int index = 0;
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e = bpf_map_lookup_elem(&array, &index);
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if (!e)
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return 0;
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/* delete */
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p = bpf_kptr_xchg(&e->pc, NULL);
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if (p) {
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bpf_percpu_obj_drop(p);
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}
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return 0;
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}
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SEC("?fentry.s/bpf_fentry_test1")
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int BPF_PROG(test_array_map_10)
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{
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struct val_t __percpu_kptr *p, *p1;
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int i, index = 0;
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struct val_t *v;
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struct elem *e;
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e = bpf_map_lookup_elem(&array, &index);
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if (!e)
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return 0;
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bpf_rcu_read_lock();
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p = e->pc;
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if (!p) {
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p = bpf_percpu_obj_new(struct val_t);
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if (!p)
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goto out;
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p1 = bpf_kptr_xchg(&e->pc, p);
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if (p1) {
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/* race condition */
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bpf_percpu_obj_drop(p1);
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}
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p = e->pc;
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if (!p)
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goto out;
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}
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v = bpf_this_cpu_ptr(p);
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v->c = 3;
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v = bpf_this_cpu_ptr(p);
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v->c = 0;
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v = bpf_per_cpu_ptr(p, 0);
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if (!v)
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goto out;
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v->c = 1;
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v->d = 2;
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/* delete */
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p1 = bpf_kptr_xchg(&e->pc, NULL);
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if (!p1)
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goto out;
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bpf_for(i, 0, nr_cpus) {
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v = bpf_per_cpu_ptr(p, i);
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if (v) {
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if (i == 0)
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cpu0_field_d = v->d;
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sum_field_c += v->c;
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}
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}
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/* finally release p */
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bpf_percpu_obj_drop(p1);
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out:
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bpf_rcu_read_unlock();
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return 0;
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}
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char _license[] SEC("license") = "GPL";
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