64 lines
1.6 KiB
C
64 lines
1.6 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
/* Copyright (c) 2020 Facebook */
|
|
#include "bpf_iter.h"
|
|
#include <bpf/bpf_helpers.h>
|
|
|
|
char _license[] SEC("license") = "GPL";
|
|
|
|
#define MAX_STACK_TRACE_DEPTH 64
|
|
unsigned long entries[MAX_STACK_TRACE_DEPTH] = {};
|
|
#define SIZE_OF_ULONG (sizeof(unsigned long))
|
|
|
|
SEC("iter/task")
|
|
int dump_task_stack(struct bpf_iter__task *ctx)
|
|
{
|
|
struct seq_file *seq = ctx->meta->seq;
|
|
struct task_struct *task = ctx->task;
|
|
long i, retlen;
|
|
|
|
if (task == (void *)0)
|
|
return 0;
|
|
|
|
retlen = bpf_get_task_stack(task, entries,
|
|
MAX_STACK_TRACE_DEPTH * SIZE_OF_ULONG, 0);
|
|
if (retlen < 0)
|
|
return 0;
|
|
|
|
BPF_SEQ_PRINTF(seq, "pid: %8u num_entries: %8u\n", task->pid,
|
|
retlen / SIZE_OF_ULONG);
|
|
for (i = 0; i < MAX_STACK_TRACE_DEPTH; i++) {
|
|
if (retlen > i * SIZE_OF_ULONG)
|
|
BPF_SEQ_PRINTF(seq, "[<0>] %pB\n", (void *)entries[i]);
|
|
}
|
|
BPF_SEQ_PRINTF(seq, "\n");
|
|
|
|
return 0;
|
|
}
|
|
|
|
SEC("iter/task")
|
|
int get_task_user_stacks(struct bpf_iter__task *ctx)
|
|
{
|
|
struct seq_file *seq = ctx->meta->seq;
|
|
struct task_struct *task = ctx->task;
|
|
uint64_t buf_sz = 0;
|
|
int64_t res;
|
|
|
|
if (task == (void *)0)
|
|
return 0;
|
|
|
|
res = bpf_get_task_stack(task, entries,
|
|
MAX_STACK_TRACE_DEPTH * SIZE_OF_ULONG, BPF_F_USER_STACK);
|
|
if (res <= 0)
|
|
return 0;
|
|
|
|
buf_sz += res;
|
|
|
|
/* If the verifier doesn't refine bpf_get_task_stack res, and instead
|
|
* assumes res is entirely unknown, this program will fail to load as
|
|
* the verifier will believe that max buf_sz value allows reading
|
|
* past the end of entries in bpf_seq_write call
|
|
*/
|
|
bpf_seq_write(seq, &entries, buf_sz);
|
|
return 0;
|
|
}
|