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8c8c5e3c85
The ringbuf max_entries must be PAGE_ALIGNED. See kernel function ringbuf_map_alloc(). So for arm64 64KB page size, adjust max_entries and other related metrics properly. Signed-off-by: Yonghong Song <yonghong.song@linux.dev> Link: https://lore.kernel.org/r/20250607013621.1552332-1-yonghong.song@linux.dev Signed-off-by: Alexei Starovoitov <ast@kernel.org>
46 lines
941 B
C
46 lines
941 B
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/bpf.h>
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#include <bpf/bpf_helpers.h>
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#include "bpf_misc.h"
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char _license[] SEC("license") = "GPL";
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struct {
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__uint(type, BPF_MAP_TYPE_RINGBUF);
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} ringbuf SEC(".maps");
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/* inputs */
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int pid = 0;
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/* outputs */
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long passed = 0;
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long discarded = 0;
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SEC("fentry/" SYS_PREFIX "sys_getpgid")
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int test_ringbuf_write(void *ctx)
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{
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int *foo, cur_pid = bpf_get_current_pid_tgid() >> 32;
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void *sample1, *sample2;
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if (cur_pid != pid)
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return 0;
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sample1 = bpf_ringbuf_reserve(&ringbuf, 0x30000, 0);
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if (!sample1)
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return 0;
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/* first one can pass */
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sample2 = bpf_ringbuf_reserve(&ringbuf, 0x30000, 0);
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if (!sample2) {
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bpf_ringbuf_discard(sample1, 0);
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__sync_fetch_and_add(&discarded, 1);
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return 0;
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}
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/* second one must not */
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__sync_fetch_and_add(&passed, 1);
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foo = sample2 + 4084;
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*foo = 256;
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bpf_ringbuf_discard(sample1, 0);
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bpf_ringbuf_discard(sample2, 0);
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return 0;
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}
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