1 // SPDX-License-Identifier: GPL-2.0 2 /* Copyright (c) 2021 Facebook */ 3 4 #include "vmlinux.h" 5 #include <bpf/bpf_helpers.h> 6 #include <bpf/bpf_tracing.h> 7 8 #ifndef EBUSY 9 #define EBUSY 16 10 #endif 11 12 char _license[] SEC("license") = "GPL"; 13 int nr_del_errs = 0; 14 int test_pid = 0; 15 16 struct { 17 __uint(type, BPF_MAP_TYPE_TASK_STORAGE); 18 __uint(map_flags, BPF_F_NO_PREALLOC); 19 __type(key, int); 20 __type(value, long); 21 } map_a SEC(".maps"); 22 23 struct { 24 __uint(type, BPF_MAP_TYPE_TASK_STORAGE); 25 __uint(map_flags, BPF_F_NO_PREALLOC); 26 __type(key, int); 27 __type(value, long); 28 } map_b SEC(".maps"); 29 30 SEC("fentry/bpf_local_storage_update") 31 int BPF_PROG(on_update) 32 { 33 struct task_struct *task = bpf_get_current_task_btf(); 34 long *ptr; 35 36 if (!test_pid || task->pid != test_pid) 37 return 0; 38 39 /* This will succeed as there is no real deadlock */ 40 ptr = bpf_task_storage_get(&map_a, task, 0, 41 BPF_LOCAL_STORAGE_GET_F_CREATE); 42 if (ptr) { 43 int err; 44 45 *ptr += 1; 46 err = bpf_task_storage_delete(&map_a, task); 47 if (err == -EBUSY) 48 nr_del_errs++; 49 } 50 51 /* This will succeed as there is no real deadlock */ 52 ptr = bpf_task_storage_get(&map_b, task, 0, 53 BPF_LOCAL_STORAGE_GET_F_CREATE); 54 if (ptr) 55 *ptr += 1; 56 57 return 0; 58 } 59 60 SEC("tp_btf/sys_enter") 61 int BPF_PROG(on_enter, struct pt_regs *regs, long id) 62 { 63 struct task_struct *task; 64 long *ptr; 65 66 task = bpf_get_current_task_btf(); 67 if (!test_pid || task->pid != test_pid) 68 return 0; 69 70 ptr = bpf_task_storage_get(&map_a, task, 0, 71 BPF_LOCAL_STORAGE_GET_F_CREATE); 72 if (ptr && !*ptr) 73 *ptr = 200; 74 75 ptr = bpf_task_storage_get(&map_b, task, 0, 76 BPF_LOCAL_STORAGE_GET_F_CREATE); 77 if (ptr && !*ptr) 78 *ptr = 100; 79 return 0; 80 } 81