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1// SPDX-License-Identifier: GPL-2.0
2// Copyright (c) 2019 Facebook
3#include <linux/sched.h>
4#include <linux/ptrace.h>
5#include <stdint.h>
6#include <stddef.h>
7#include <stdbool.h>
8#include <linux/bpf.h>
9#include "bpf_helpers.h"
10
11#define FUNCTION_NAME_LEN 64
12#define FILE_NAME_LEN 128
13#define TASK_COMM_LEN 16
14
15typedef struct {
16 int PyThreadState_frame;
17 int PyThreadState_thread;
18 int PyFrameObject_back;
19 int PyFrameObject_code;
20 int PyFrameObject_lineno;
21 int PyCodeObject_filename;
22 int PyCodeObject_name;
23 int String_data;
24 int String_size;
25} OffsetConfig;
26
27typedef struct {
28 uintptr_t current_state_addr;
29 uintptr_t tls_key_addr;
30 OffsetConfig offsets;
31 bool use_tls;
32} PidData;
33
34typedef struct {
35 uint32_t success;
36} Stats;
37
38typedef struct {
39 char name[FUNCTION_NAME_LEN];
40 char file[FILE_NAME_LEN];
41} Symbol;
42
43typedef struct {
44 uint32_t pid;
45 uint32_t tid;
46 char comm[TASK_COMM_LEN];
47 int32_t kernel_stack_id;
48 int32_t user_stack_id;
49 bool thread_current;
50 bool pthread_match;
51 bool stack_complete;
52 int16_t stack_len;
53 int32_t stack[STACK_MAX_LEN];
54
55 int has_meta;
56 int metadata;
57 char dummy_safeguard;
58} Event;
59
60
61typedef int pid_t;
62
63typedef struct {
64 void* f_back; // PyFrameObject.f_back, previous frame
65 void* f_code; // PyFrameObject.f_code, pointer to PyCodeObject
66 void* co_filename; // PyCodeObject.co_filename
67 void* co_name; // PyCodeObject.co_name
68} FrameData;
69
70static __always_inline void *get_thread_state(void *tls_base, PidData *pidData)
71{
72 void* thread_state;
73 int key;
74
75 bpf_probe_read(&key, sizeof(key), (void*)(long)pidData->tls_key_addr);
76 bpf_probe_read(&thread_state, sizeof(thread_state),
77 tls_base + 0x310 + key * 0x10 + 0x08);
78 return thread_state;
79}
80
81static __always_inline bool get_frame_data(void *frame_ptr, PidData *pidData,
82 FrameData *frame, Symbol *symbol)
83{
84 // read data from PyFrameObject
85 bpf_probe_read(&frame->f_back,
86 sizeof(frame->f_back),
87 frame_ptr + pidData->offsets.PyFrameObject_back);
88 bpf_probe_read(&frame->f_code,
89 sizeof(frame->f_code),
90 frame_ptr + pidData->offsets.PyFrameObject_code);
91
92 // read data from PyCodeObject
93 if (!frame->f_code)
94 return false;
95 bpf_probe_read(&frame->co_filename,
96 sizeof(frame->co_filename),
97 frame->f_code + pidData->offsets.PyCodeObject_filename);
98 bpf_probe_read(&frame->co_name,
99 sizeof(frame->co_name),
100 frame->f_code + pidData->offsets.PyCodeObject_name);
101 // read actual names into symbol
102 if (frame->co_filename)
103 bpf_probe_read_str(&symbol->file,
104 sizeof(symbol->file),
105 frame->co_filename + pidData->offsets.String_data);
106 if (frame->co_name)
107 bpf_probe_read_str(&symbol->name,
108 sizeof(symbol->name),
109 frame->co_name + pidData->offsets.String_data);
110 return true;
111}
112
113struct {
114 __uint(type, BPF_MAP_TYPE_HASH);
115 __uint(max_entries, 1);
116 __type(key, int);
117 __type(value, PidData);
118} pidmap SEC(".maps");
119
120struct {
121 __uint(type, BPF_MAP_TYPE_HASH);
122 __uint(max_entries, 1);
123 __type(key, int);
124 __type(value, Event);
125} eventmap SEC(".maps");
126
127struct {
128 __uint(type, BPF_MAP_TYPE_HASH);
129 __uint(max_entries, 1);
130 __type(key, Symbol);
131 __type(value, int);
132} symbolmap SEC(".maps");
133
134struct {
135 __uint(type, BPF_MAP_TYPE_ARRAY);
136 __uint(max_entries, 1);
137 __type(key, int);
138 __type(value, Stats);
139} statsmap SEC(".maps");
140
141struct {
142 __uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY);
143 __uint(max_entries, 32);
144 __uint(key_size, sizeof(int));
145 __uint(value_size, sizeof(int));
146} perfmap SEC(".maps");
147
148struct {
149 __uint(type, BPF_MAP_TYPE_STACK_TRACE);
150 __uint(max_entries, 1000);
151 __uint(key_size, sizeof(int));
152 __uint(value_size, sizeof(long long) * 127);
153} stackmap SEC(".maps");
154
155static __always_inline int __on_event(struct pt_regs *ctx)
156{
157 uint64_t pid_tgid = bpf_get_current_pid_tgid();
158 pid_t pid = (pid_t)(pid_tgid >> 32);
159 PidData* pidData = bpf_map_lookup_elem(&pidmap, &pid);
160 if (!pidData)
161 return 0;
162
163 int zero = 0;
164 Event* event = bpf_map_lookup_elem(&eventmap, &zero);
165 if (!event)
166 return 0;
167
168 event->pid = pid;
169
170 event->tid = (pid_t)pid_tgid;
171 bpf_get_current_comm(&event->comm, sizeof(event->comm));
172
173 event->user_stack_id = bpf_get_stackid(ctx, &stackmap, BPF_F_USER_STACK);
174 event->kernel_stack_id = bpf_get_stackid(ctx, &stackmap, 0);
175
176 void* thread_state_current = (void*)0;
177 bpf_probe_read(&thread_state_current,
178 sizeof(thread_state_current),
179 (void*)(long)pidData->current_state_addr);
180
181 struct task_struct* task = (struct task_struct*)bpf_get_current_task();
182 void* tls_base = (void*)task;
183
184 void* thread_state = pidData->use_tls ? get_thread_state(tls_base, pidData)
185 : thread_state_current;
186 event->thread_current = thread_state == thread_state_current;
187
188 if (pidData->use_tls) {
189 uint64_t pthread_created;
190 uint64_t pthread_self;
191 bpf_probe_read(&pthread_self, sizeof(pthread_self), tls_base + 0x10);
192
193 bpf_probe_read(&pthread_created,
194 sizeof(pthread_created),
195 thread_state + pidData->offsets.PyThreadState_thread);
196 event->pthread_match = pthread_created == pthread_self;
197 } else {
198 event->pthread_match = 1;
199 }
200
201 if (event->pthread_match || !pidData->use_tls) {
202 void* frame_ptr;
203 FrameData frame;
204 Symbol sym = {};
205 int cur_cpu = bpf_get_smp_processor_id();
206
207 bpf_probe_read(&frame_ptr,
208 sizeof(frame_ptr),
209 thread_state + pidData->offsets.PyThreadState_frame);
210
211 int32_t* symbol_counter = bpf_map_lookup_elem(&symbolmap, &sym);
212 if (symbol_counter == NULL)
213 return 0;
214#ifdef NO_UNROLL
215#pragma clang loop unroll(disable)
216#else
217#pragma clang loop unroll(full)
218#endif
219 /* Unwind python stack */
220 for (int i = 0; i < STACK_MAX_LEN; ++i) {
221 if (frame_ptr && get_frame_data(frame_ptr, pidData, &frame, &sym)) {
222 int32_t new_symbol_id = *symbol_counter * 64 + cur_cpu;
223 int32_t *symbol_id = bpf_map_lookup_elem(&symbolmap, &sym);
224 if (!symbol_id) {
225 bpf_map_update_elem(&symbolmap, &sym, &zero, 0);
226 symbol_id = bpf_map_lookup_elem(&symbolmap, &sym);
227 if (!symbol_id)
228 return 0;
229 }
230 if (*symbol_id == new_symbol_id)
231 (*symbol_counter)++;
232 event->stack[i] = *symbol_id;
233 event->stack_len = i + 1;
234 frame_ptr = frame.f_back;
235 }
236 }
237 event->stack_complete = frame_ptr == NULL;
238 } else {
239 event->stack_complete = 1;
240 }
241
242 Stats* stats = bpf_map_lookup_elem(&statsmap, &zero);
243 if (stats)
244 stats->success++;
245
246 event->has_meta = 0;
247 bpf_perf_event_output(ctx, &perfmap, 0, event, offsetof(Event, metadata));
248 return 0;
249}
250
251SEC("raw_tracepoint/kfree_skb")
252int on_event(struct pt_regs* ctx)
253{
254 int i, ret = 0;
255 ret |= __on_event(ctx);
256 ret |= __on_event(ctx);
257 ret |= __on_event(ctx);
258 ret |= __on_event(ctx);
259 ret |= __on_event(ctx);
260 return ret;
261}
262
263char _license[] SEC("license") = "GPL";
1// SPDX-License-Identifier: GPL-2.0
2// Copyright (c) 2019 Facebook
3#include <linux/sched.h>
4#include <linux/ptrace.h>
5#include <stdint.h>
6#include <stddef.h>
7#include <stdbool.h>
8#include <linux/bpf.h>
9#include <bpf/bpf_helpers.h>
10
11#define FUNCTION_NAME_LEN 64
12#define FILE_NAME_LEN 128
13#define TASK_COMM_LEN 16
14
15typedef struct {
16 int PyThreadState_frame;
17 int PyThreadState_thread;
18 int PyFrameObject_back;
19 int PyFrameObject_code;
20 int PyFrameObject_lineno;
21 int PyCodeObject_filename;
22 int PyCodeObject_name;
23 int String_data;
24 int String_size;
25} OffsetConfig;
26
27typedef struct {
28 uintptr_t current_state_addr;
29 uintptr_t tls_key_addr;
30 OffsetConfig offsets;
31 bool use_tls;
32} PidData;
33
34typedef struct {
35 uint32_t success;
36} Stats;
37
38typedef struct {
39 char name[FUNCTION_NAME_LEN];
40 char file[FILE_NAME_LEN];
41} Symbol;
42
43typedef struct {
44 uint32_t pid;
45 uint32_t tid;
46 char comm[TASK_COMM_LEN];
47 int32_t kernel_stack_id;
48 int32_t user_stack_id;
49 bool thread_current;
50 bool pthread_match;
51 bool stack_complete;
52 int16_t stack_len;
53 int32_t stack[STACK_MAX_LEN];
54
55 int has_meta;
56 int metadata;
57 char dummy_safeguard;
58} Event;
59
60
61typedef int pid_t;
62
63typedef struct {
64 void* f_back; // PyFrameObject.f_back, previous frame
65 void* f_code; // PyFrameObject.f_code, pointer to PyCodeObject
66 void* co_filename; // PyCodeObject.co_filename
67 void* co_name; // PyCodeObject.co_name
68} FrameData;
69
70#ifdef SUBPROGS
71__noinline
72#else
73__always_inline
74#endif
75static void *get_thread_state(void *tls_base, PidData *pidData)
76{
77 void* thread_state;
78 int key;
79
80 bpf_probe_read_user(&key, sizeof(key), (void*)(long)pidData->tls_key_addr);
81 bpf_probe_read_user(&thread_state, sizeof(thread_state),
82 tls_base + 0x310 + key * 0x10 + 0x08);
83 return thread_state;
84}
85
86static __always_inline bool get_frame_data(void *frame_ptr, PidData *pidData,
87 FrameData *frame, Symbol *symbol)
88{
89 // read data from PyFrameObject
90 bpf_probe_read_user(&frame->f_back,
91 sizeof(frame->f_back),
92 frame_ptr + pidData->offsets.PyFrameObject_back);
93 bpf_probe_read_user(&frame->f_code,
94 sizeof(frame->f_code),
95 frame_ptr + pidData->offsets.PyFrameObject_code);
96
97 // read data from PyCodeObject
98 if (!frame->f_code)
99 return false;
100 bpf_probe_read_user(&frame->co_filename,
101 sizeof(frame->co_filename),
102 frame->f_code + pidData->offsets.PyCodeObject_filename);
103 bpf_probe_read_user(&frame->co_name,
104 sizeof(frame->co_name),
105 frame->f_code + pidData->offsets.PyCodeObject_name);
106 // read actual names into symbol
107 if (frame->co_filename)
108 bpf_probe_read_user_str(&symbol->file,
109 sizeof(symbol->file),
110 frame->co_filename +
111 pidData->offsets.String_data);
112 if (frame->co_name)
113 bpf_probe_read_user_str(&symbol->name,
114 sizeof(symbol->name),
115 frame->co_name +
116 pidData->offsets.String_data);
117 return true;
118}
119
120struct {
121 __uint(type, BPF_MAP_TYPE_HASH);
122 __uint(max_entries, 1);
123 __type(key, int);
124 __type(value, PidData);
125} pidmap SEC(".maps");
126
127struct {
128 __uint(type, BPF_MAP_TYPE_HASH);
129 __uint(max_entries, 1);
130 __type(key, int);
131 __type(value, Event);
132} eventmap SEC(".maps");
133
134struct {
135 __uint(type, BPF_MAP_TYPE_HASH);
136 __uint(max_entries, 1);
137 __type(key, Symbol);
138 __type(value, int);
139} symbolmap SEC(".maps");
140
141struct {
142 __uint(type, BPF_MAP_TYPE_ARRAY);
143 __uint(max_entries, 1);
144 __type(key, int);
145 __type(value, Stats);
146} statsmap SEC(".maps");
147
148struct {
149 __uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY);
150 __uint(max_entries, 32);
151 __uint(key_size, sizeof(int));
152 __uint(value_size, sizeof(int));
153} perfmap SEC(".maps");
154
155struct {
156 __uint(type, BPF_MAP_TYPE_STACK_TRACE);
157 __uint(max_entries, 1000);
158 __uint(key_size, sizeof(int));
159 __uint(value_size, sizeof(long long) * 127);
160} stackmap SEC(".maps");
161
162#ifdef USE_BPF_LOOP
163struct process_frame_ctx {
164 int cur_cpu;
165 int32_t *symbol_counter;
166 void *frame_ptr;
167 FrameData *frame;
168 PidData *pidData;
169 Symbol *sym;
170 Event *event;
171 bool done;
172};
173
174static int process_frame_callback(__u32 i, struct process_frame_ctx *ctx)
175{
176 int zero = 0;
177 void *frame_ptr = ctx->frame_ptr;
178 PidData *pidData = ctx->pidData;
179 FrameData *frame = ctx->frame;
180 int32_t *symbol_counter = ctx->symbol_counter;
181 int cur_cpu = ctx->cur_cpu;
182 Event *event = ctx->event;
183 Symbol *sym = ctx->sym;
184
185 if (frame_ptr && get_frame_data(frame_ptr, pidData, frame, sym)) {
186 int32_t new_symbol_id = *symbol_counter * 64 + cur_cpu;
187 int32_t *symbol_id = bpf_map_lookup_elem(&symbolmap, sym);
188
189 if (!symbol_id) {
190 bpf_map_update_elem(&symbolmap, sym, &zero, 0);
191 symbol_id = bpf_map_lookup_elem(&symbolmap, sym);
192 if (!symbol_id) {
193 ctx->done = true;
194 return 1;
195 }
196 }
197 if (*symbol_id == new_symbol_id)
198 (*symbol_counter)++;
199
200 barrier_var(i);
201 if (i >= STACK_MAX_LEN)
202 return 1;
203
204 event->stack[i] = *symbol_id;
205
206 event->stack_len = i + 1;
207 frame_ptr = frame->f_back;
208 }
209 return 0;
210}
211#endif /* USE_BPF_LOOP */
212
213#ifdef GLOBAL_FUNC
214__noinline
215#elif defined(SUBPROGS)
216static __noinline
217#else
218static __always_inline
219#endif
220int __on_event(struct bpf_raw_tracepoint_args *ctx)
221{
222 uint64_t pid_tgid = bpf_get_current_pid_tgid();
223 pid_t pid = (pid_t)(pid_tgid >> 32);
224 PidData* pidData = bpf_map_lookup_elem(&pidmap, &pid);
225 if (!pidData)
226 return 0;
227
228 int zero = 0;
229 Event* event = bpf_map_lookup_elem(&eventmap, &zero);
230 if (!event)
231 return 0;
232
233 event->pid = pid;
234
235 event->tid = (pid_t)pid_tgid;
236 bpf_get_current_comm(&event->comm, sizeof(event->comm));
237
238 event->user_stack_id = bpf_get_stackid(ctx, &stackmap, BPF_F_USER_STACK);
239 event->kernel_stack_id = bpf_get_stackid(ctx, &stackmap, 0);
240
241 void* thread_state_current = (void*)0;
242 bpf_probe_read_user(&thread_state_current,
243 sizeof(thread_state_current),
244 (void*)(long)pidData->current_state_addr);
245
246 struct task_struct* task = (struct task_struct*)bpf_get_current_task();
247 void* tls_base = (void*)task;
248
249 void* thread_state = pidData->use_tls ? get_thread_state(tls_base, pidData)
250 : thread_state_current;
251 event->thread_current = thread_state == thread_state_current;
252
253 if (pidData->use_tls) {
254 uint64_t pthread_created;
255 uint64_t pthread_self;
256 bpf_probe_read_user(&pthread_self, sizeof(pthread_self),
257 tls_base + 0x10);
258
259 bpf_probe_read_user(&pthread_created,
260 sizeof(pthread_created),
261 thread_state +
262 pidData->offsets.PyThreadState_thread);
263 event->pthread_match = pthread_created == pthread_self;
264 } else {
265 event->pthread_match = 1;
266 }
267
268 if (event->pthread_match || !pidData->use_tls) {
269 void* frame_ptr;
270 FrameData frame;
271 Symbol sym = {};
272 int cur_cpu = bpf_get_smp_processor_id();
273
274 bpf_probe_read_user(&frame_ptr,
275 sizeof(frame_ptr),
276 thread_state +
277 pidData->offsets.PyThreadState_frame);
278
279 int32_t* symbol_counter = bpf_map_lookup_elem(&symbolmap, &sym);
280 if (symbol_counter == NULL)
281 return 0;
282#ifdef USE_BPF_LOOP
283 struct process_frame_ctx ctx = {
284 .cur_cpu = cur_cpu,
285 .symbol_counter = symbol_counter,
286 .frame_ptr = frame_ptr,
287 .frame = &frame,
288 .pidData = pidData,
289 .sym = &sym,
290 .event = event,
291 };
292
293 bpf_loop(STACK_MAX_LEN, process_frame_callback, &ctx, 0);
294 if (ctx.done)
295 return 0;
296#else
297#ifdef NO_UNROLL
298#pragma clang loop unroll(disable)
299#else
300#ifdef UNROLL_COUNT
301#pragma clang loop unroll_count(UNROLL_COUNT)
302#else
303#pragma clang loop unroll(full)
304#endif
305#endif /* NO_UNROLL */
306 /* Unwind python stack */
307 for (int i = 0; i < STACK_MAX_LEN; ++i) {
308 if (frame_ptr && get_frame_data(frame_ptr, pidData, &frame, &sym)) {
309 int32_t new_symbol_id = *symbol_counter * 64 + cur_cpu;
310 int32_t *symbol_id = bpf_map_lookup_elem(&symbolmap, &sym);
311 if (!symbol_id) {
312 bpf_map_update_elem(&symbolmap, &sym, &zero, 0);
313 symbol_id = bpf_map_lookup_elem(&symbolmap, &sym);
314 if (!symbol_id)
315 return 0;
316 }
317 if (*symbol_id == new_symbol_id)
318 (*symbol_counter)++;
319 event->stack[i] = *symbol_id;
320 event->stack_len = i + 1;
321 frame_ptr = frame.f_back;
322 }
323 }
324#endif /* USE_BPF_LOOP */
325 event->stack_complete = frame_ptr == NULL;
326 } else {
327 event->stack_complete = 1;
328 }
329
330 Stats* stats = bpf_map_lookup_elem(&statsmap, &zero);
331 if (stats)
332 stats->success++;
333
334 event->has_meta = 0;
335 bpf_perf_event_output(ctx, &perfmap, 0, event, offsetof(Event, metadata));
336 return 0;
337}
338
339SEC("raw_tracepoint/kfree_skb")
340int on_event(struct bpf_raw_tracepoint_args* ctx)
341{
342 int i, ret = 0;
343 ret |= __on_event(ctx);
344 ret |= __on_event(ctx);
345 ret |= __on_event(ctx);
346 ret |= __on_event(ctx);
347 ret |= __on_event(ctx);
348 return ret;
349}
350
351char _license[] SEC("license") = "GPL";