1 // SPDX-License-Identifier: GPL-2.0 2 /* Copyright (c) 2020 Facebook */ 3 #include "bpf_iter.h" 4 #include <bpf/bpf_helpers.h> 5 #include <bpf/bpf_tracing.h> 6 7 char _license[] SEC("license") = "GPL"; 8 9 #define MAX_STACK_TRACE_DEPTH 64 10 unsigned long entries[MAX_STACK_TRACE_DEPTH] = {}; 11 #define SIZE_OF_ULONG (sizeof(unsigned long)) 12 13 SEC("iter/task") 14 int dump_task_stack(struct bpf_iter__task *ctx) 15 { 16 struct seq_file *seq = ctx->meta->seq; 17 struct task_struct *task = ctx->task; 18 long i, retlen; 19 20 if (task == (void *)0) 21 return 0; 22 23 retlen = bpf_get_task_stack(task, entries, 24 MAX_STACK_TRACE_DEPTH * SIZE_OF_ULONG, 0); 25 if (retlen < 0) 26 return 0; 27 28 BPF_SEQ_PRINTF(seq, "pid: %8u num_entries: %8u\n", task->pid, 29 retlen / SIZE_OF_ULONG); 30 for (i = 0; i < MAX_STACK_TRACE_DEPTH; i++) { 31 if (retlen > i * SIZE_OF_ULONG) 32 BPF_SEQ_PRINTF(seq, "[<0>] %pB\n", (void *)entries[i]); 33 } 34 BPF_SEQ_PRINTF(seq, "\n"); 35 36 return 0; 37 } 38