9ff79af333
BPF selftests show a compilation error as follows:
libbpf: invalid relo for 'entries' in special section 0xfff2; forgot to
initialize global var?..
Fix it by initializing 'entries' to zeros.
Fixes: c7568114bc56 ("selftests/bpf: Add bpf_iter test with bpf_get_task_stack()")
Reported-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200703181719.3747072-1-songliubraving@fb.com
38 lines
933 B
C
38 lines
933 B
C
// SPDX-License-Identifier: GPL-2.0
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/* Copyright (c) 2020 Facebook */
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#include "bpf_iter.h"
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#include <bpf/bpf_helpers.h>
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#include <bpf/bpf_tracing.h>
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char _license[] SEC("license") = "GPL";
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#define MAX_STACK_TRACE_DEPTH 64
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unsigned long entries[MAX_STACK_TRACE_DEPTH] = {};
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#define SIZE_OF_ULONG (sizeof(unsigned long))
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SEC("iter/task")
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int dump_task_stack(struct bpf_iter__task *ctx)
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{
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struct seq_file *seq = ctx->meta->seq;
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struct task_struct *task = ctx->task;
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long i, retlen;
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if (task == (void *)0)
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return 0;
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retlen = bpf_get_task_stack(task, entries,
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MAX_STACK_TRACE_DEPTH * SIZE_OF_ULONG, 0);
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if (retlen < 0)
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return 0;
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BPF_SEQ_PRINTF(seq, "pid: %8u num_entries: %8u\n", task->pid,
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retlen / SIZE_OF_ULONG);
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for (i = 0; i < MAX_STACK_TRACE_DEPTH; i++) {
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if (retlen > i * SIZE_OF_ULONG)
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BPF_SEQ_PRINTF(seq, "[<0>] %pB\n", (void *)entries[i]);
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}
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BPF_SEQ_PRINTF(seq, "\n");
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return 0;
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}
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