tools/testing/selftests/bpf/progs/task_storage_nodeadlock.c

   1 // SPDX-License-Identifier: GPL-2.0
   2
   3 #include "vmlinux.h"
   4 #include <bpf/bpf_helpers.h>
   5 #include <bpf/bpf_tracing.h>
   6
   7 char _license[] SEC("license") = "GPL";
   8
   9 #ifndef EBUSY
  10 #define EBUSY 16
  11 #endif
  12
  13 extern bool CONFIG_PREEMPT __kconfig __weak;
  14 int nr_get_errs = 0;
  15 int nr_del_errs = 0;
  16
  17 struct {
  18         __uint(type, BPF_MAP_TYPE_TASK_STORAGE);
  19         __uint(map_flags, BPF_F_NO_PREALLOC);
  20         __type(key, int);
  21         __type(value, int);
  22 } task_storage SEC(".maps");
  23
  24 SEC("lsm.s/socket_post_create")
  25 int BPF_PROG(socket_post_create, struct socket *sock, int family, int type,
  26              int protocol, int kern)
  27 {
  28         struct task_struct *task;
  29         int ret, zero = 0;
  30         int *value;
  31
  32         if (!CONFIG_PREEMPT)
  33                 return 0;
  34
  35         task = bpf_get_current_task_btf();
  36         value = bpf_task_storage_get(&task_storage, task, &zero,
  37                                      BPF_LOCAL_STORAGE_GET_F_CREATE);
  38         if (!value)
  39                 __sync_fetch_and_add(&nr_get_errs, 1);
  40
  41         ret = bpf_task_storage_delete(&task_storage,
  42                                       bpf_get_current_task_btf());
  43         if (ret == -EBUSY)
  44                 __sync_fetch_and_add(&nr_del_errs, 1);
  45
  46         return 0;
  47 }