1 // SPDX-License-Identifier: GPL-2.0 2 #include <vmlinux.h> 3 #include <bpf/bpf_helpers.h> 4 #include <bpf/bpf_tracing.h> 5 #include "bpf_misc.h" 6 #include "bpf_experimental.h" 7 8 SEC("?tc") 9 __failure __msg("1 bpf_preempt_enable is missing") 10 int preempt_lock_missing_1(struct __sk_buff *ctx) 11 { 12 bpf_preempt_disable(); 13 return 0; 14 } 15 16 SEC("?tc") 17 __failure __msg("2 bpf_preempt_enable(s) are missing") 18 int preempt_lock_missing_2(struct __sk_buff *ctx) 19 { 20 bpf_preempt_disable(); 21 bpf_preempt_disable(); 22 return 0; 23 } 24 25 SEC("?tc") 26 __failure __msg("3 bpf_preempt_enable(s) are missing") 27 int preempt_lock_missing_3(struct __sk_buff *ctx) 28 { 29 bpf_preempt_disable(); 30 bpf_preempt_disable(); 31 bpf_preempt_disable(); 32 return 0; 33 } 34 35 SEC("?tc") 36 __failure __msg("1 bpf_preempt_enable is missing") 37 int preempt_lock_missing_3_minus_2(struct __sk_buff *ctx) 38 { 39 bpf_preempt_disable(); 40 bpf_preempt_disable(); 41 bpf_preempt_disable(); 42 bpf_preempt_enable(); 43 bpf_preempt_enable(); 44 return 0; 45 } 46 47 static __noinline void preempt_disable(void) 48 { 49 bpf_preempt_disable(); 50 } 51 52 static __noinline void preempt_enable(void) 53 { 54 bpf_preempt_enable(); 55 } 56 57 SEC("?tc") 58 __failure __msg("1 bpf_preempt_enable is missing") 59 int preempt_lock_missing_1_subprog(struct __sk_buff *ctx) 60 { 61 preempt_disable(); 62 return 0; 63 } 64 65 SEC("?tc") 66 __failure __msg("2 bpf_preempt_enable(s) are missing") 67 int preempt_lock_missing_2_subprog(struct __sk_buff *ctx) 68 { 69 preempt_disable(); 70 preempt_disable(); 71 return 0; 72 } 73 74 SEC("?tc") 75 __failure __msg("1 bpf_preempt_enable is missing") 76 int preempt_lock_missing_2_minus_1_subprog(struct __sk_buff *ctx) 77 { 78 preempt_disable(); 79 preempt_disable(); 80 preempt_enable(); 81 return 0; 82 } 83 84 static __noinline void preempt_balance_subprog(void) 85 { 86 preempt_disable(); 87 preempt_enable(); 88 } 89 90 SEC("?tc") 91 __success int preempt_balance(struct __sk_buff *ctx) 92 { 93 bpf_guard_preempt(); 94 return 0; 95 } 96 97 SEC("?tc") 98 __success int preempt_balance_subprog_test(struct __sk_buff *ctx) 99 { 100 preempt_balance_subprog(); 101 return 0; 102 } 103 104 SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") 105 __failure __msg("sleepable helper bpf_copy_from_user#") 106 int preempt_sleepable_helper(void *ctx) 107 { 108 u32 data; 109 110 bpf_preempt_disable(); 111 bpf_copy_from_user(&data, sizeof(data), NULL); 112 bpf_preempt_enable(); 113 return 0; 114 } 115 116 int __noinline preempt_global_subprog(void) 117 { 118 preempt_balance_subprog(); 119 return 0; 120 } 121 122 SEC("?tc") 123 __failure __msg("global function calls are not allowed with preemption disabled") 124 int preempt_global_subprog_test(struct __sk_buff *ctx) 125 { 126 preempt_disable(); 127 preempt_global_subprog(); 128 preempt_enable(); 129 return 0; 130 } 131 132 char _license[] SEC("license") = "GPL"; 133