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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/bpf_helpers.h>
10#include "bpf_misc.h"
11#include "bpf_compiler.h"
12
13#define FUNCTION_NAME_LEN 64
14#define FILE_NAME_LEN 128
15#define TASK_COMM_LEN 16
16
17typedef struct {
18 int PyThreadState_frame;
19 int PyThreadState_thread;
20 int PyFrameObject_back;
21 int PyFrameObject_code;
22 int PyFrameObject_lineno;
23 int PyCodeObject_filename;
24 int PyCodeObject_name;
25 int String_data;
26 int String_size;
27} OffsetConfig;
28
29typedef struct {
30 uintptr_t current_state_addr;
31 uintptr_t tls_key_addr;
32 OffsetConfig offsets;
33 bool use_tls;
34} PidData;
35
36typedef struct {
37 uint32_t success;
38} Stats;
39
40typedef struct {
41 char name[FUNCTION_NAME_LEN];
42 char file[FILE_NAME_LEN];
43} Symbol;
44
45typedef struct {
46 uint32_t pid;
47 uint32_t tid;
48 char comm[TASK_COMM_LEN];
49 int32_t kernel_stack_id;
50 int32_t user_stack_id;
51 bool thread_current;
52 bool pthread_match;
53 bool stack_complete;
54 int16_t stack_len;
55 int32_t stack[STACK_MAX_LEN];
56
57 int has_meta;
58 int metadata;
59 char dummy_safeguard;
60} Event;
61
62
63typedef int pid_t;
64
65typedef struct {
66 void* f_back; // PyFrameObject.f_back, previous frame
67 void* f_code; // PyFrameObject.f_code, pointer to PyCodeObject
68 void* co_filename; // PyCodeObject.co_filename
69 void* co_name; // PyCodeObject.co_name
70} FrameData;
71
72#ifdef SUBPROGS
73__noinline
74#else
75__always_inline
76#endif
77static void *get_thread_state(void *tls_base, PidData *pidData)
78{
79 void* thread_state;
80 int key;
81
82 bpf_probe_read_user(&key, sizeof(key), (void*)(long)pidData->tls_key_addr);
83 bpf_probe_read_user(&thread_state, sizeof(thread_state),
84 tls_base + 0x310 + key * 0x10 + 0x08);
85 return thread_state;
86}
87
88static __always_inline bool get_frame_data(void *frame_ptr, PidData *pidData,
89 FrameData *frame, Symbol *symbol)
90{
91 // read data from PyFrameObject
92 bpf_probe_read_user(&frame->f_back,
93 sizeof(frame->f_back),
94 frame_ptr + pidData->offsets.PyFrameObject_back);
95 bpf_probe_read_user(&frame->f_code,
96 sizeof(frame->f_code),
97 frame_ptr + pidData->offsets.PyFrameObject_code);
98
99 // read data from PyCodeObject
100 if (!frame->f_code)
101 return false;
102 bpf_probe_read_user(&frame->co_filename,
103 sizeof(frame->co_filename),
104 frame->f_code + pidData->offsets.PyCodeObject_filename);
105 bpf_probe_read_user(&frame->co_name,
106 sizeof(frame->co_name),
107 frame->f_code + pidData->offsets.PyCodeObject_name);
108 // read actual names into symbol
109 if (frame->co_filename)
110 bpf_probe_read_user_str(&symbol->file,
111 sizeof(symbol->file),
112 frame->co_filename +
113 pidData->offsets.String_data);
114 if (frame->co_name)
115 bpf_probe_read_user_str(&symbol->name,
116 sizeof(symbol->name),
117 frame->co_name +
118 pidData->offsets.String_data);
119 return true;
120}
121
122struct {
123 __uint(type, BPF_MAP_TYPE_HASH);
124 __uint(max_entries, 1);
125 __type(key, int);
126 __type(value, PidData);
127} pidmap SEC(".maps");
128
129struct {
130 __uint(type, BPF_MAP_TYPE_HASH);
131 __uint(max_entries, 1);
132 __type(key, int);
133 __type(value, Event);
134} eventmap SEC(".maps");
135
136struct {
137 __uint(type, BPF_MAP_TYPE_HASH);
138 __uint(max_entries, 1);
139 __type(key, Symbol);
140 __type(value, int);
141} symbolmap SEC(".maps");
142
143struct {
144 __uint(type, BPF_MAP_TYPE_ARRAY);
145 __uint(max_entries, 1);
146 __type(key, int);
147 __type(value, Stats);
148} statsmap SEC(".maps");
149
150struct {
151 __uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY);
152 __uint(max_entries, 32);
153 __uint(key_size, sizeof(int));
154 __uint(value_size, sizeof(int));
155} perfmap SEC(".maps");
156
157struct {
158 __uint(type, BPF_MAP_TYPE_STACK_TRACE);
159 __uint(max_entries, 1000);
160 __uint(key_size, sizeof(int));
161 __uint(value_size, sizeof(long long) * 127);
162} stackmap SEC(".maps");
163
164#ifdef USE_BPF_LOOP
165struct process_frame_ctx {
166 int cur_cpu;
167 int32_t *symbol_counter;
168 void *frame_ptr;
169 FrameData *frame;
170 PidData *pidData;
171 Symbol *sym;
172 Event *event;
173 bool done;
174};
175
176static int process_frame_callback(__u32 i, struct process_frame_ctx *ctx)
177{
178 int zero = 0;
179 void *frame_ptr = ctx->frame_ptr;
180 PidData *pidData = ctx->pidData;
181 FrameData *frame = ctx->frame;
182 int32_t *symbol_counter = ctx->symbol_counter;
183 int cur_cpu = ctx->cur_cpu;
184 Event *event = ctx->event;
185 Symbol *sym = ctx->sym;
186
187 if (frame_ptr && get_frame_data(frame_ptr, pidData, frame, sym)) {
188 int32_t new_symbol_id = *symbol_counter * 64 + cur_cpu;
189 int32_t *symbol_id = bpf_map_lookup_elem(&symbolmap, sym);
190
191 if (!symbol_id) {
192 bpf_map_update_elem(&symbolmap, sym, &zero, 0);
193 symbol_id = bpf_map_lookup_elem(&symbolmap, sym);
194 if (!symbol_id) {
195 ctx->done = true;
196 return 1;
197 }
198 }
199 if (*symbol_id == new_symbol_id)
200 (*symbol_counter)++;
201
202 barrier_var(i);
203 if (i >= STACK_MAX_LEN)
204 return 1;
205
206 event->stack[i] = *symbol_id;
207
208 event->stack_len = i + 1;
209 frame_ptr = frame->f_back;
210 }
211 return 0;
212}
213#endif /* USE_BPF_LOOP */
214
215#ifdef GLOBAL_FUNC
216__noinline
217#elif defined(SUBPROGS)
218static __noinline
219#else
220static __always_inline
221#endif
222int __on_event(struct bpf_raw_tracepoint_args *ctx)
223{
224 uint64_t pid_tgid = bpf_get_current_pid_tgid();
225 pid_t pid = (pid_t)(pid_tgid >> 32);
226 PidData* pidData = bpf_map_lookup_elem(&pidmap, &pid);
227 if (!pidData)
228 return 0;
229
230 int zero = 0;
231 Event* event = bpf_map_lookup_elem(&eventmap, &zero);
232 if (!event)
233 return 0;
234
235 event->pid = pid;
236
237 event->tid = (pid_t)pid_tgid;
238 bpf_get_current_comm(&event->comm, sizeof(event->comm));
239
240 event->user_stack_id = bpf_get_stackid(ctx, &stackmap, BPF_F_USER_STACK);
241 event->kernel_stack_id = bpf_get_stackid(ctx, &stackmap, 0);
242
243 void* thread_state_current = (void*)0;
244 bpf_probe_read_user(&thread_state_current,
245 sizeof(thread_state_current),
246 (void*)(long)pidData->current_state_addr);
247
248 struct task_struct* task = (struct task_struct*)bpf_get_current_task();
249 void* tls_base = (void*)task;
250
251 void* thread_state = pidData->use_tls ? get_thread_state(tls_base, pidData)
252 : thread_state_current;
253 event->thread_current = thread_state == thread_state_current;
254
255 if (pidData->use_tls) {
256 uint64_t pthread_created;
257 uint64_t pthread_self;
258 bpf_probe_read_user(&pthread_self, sizeof(pthread_self),
259 tls_base + 0x10);
260
261 bpf_probe_read_user(&pthread_created,
262 sizeof(pthread_created),
263 thread_state +
264 pidData->offsets.PyThreadState_thread);
265 event->pthread_match = pthread_created == pthread_self;
266 } else {
267 event->pthread_match = 1;
268 }
269
270 if (event->pthread_match || !pidData->use_tls) {
271 void* frame_ptr;
272 FrameData frame;
273 Symbol sym = {};
274 int cur_cpu = bpf_get_smp_processor_id();
275
276 bpf_probe_read_user(&frame_ptr,
277 sizeof(frame_ptr),
278 thread_state +
279 pidData->offsets.PyThreadState_frame);
280
281 int32_t* symbol_counter = bpf_map_lookup_elem(&symbolmap, &sym);
282 if (symbol_counter == NULL)
283 return 0;
284#ifdef USE_BPF_LOOP
285 struct process_frame_ctx ctx = {
286 .cur_cpu = cur_cpu,
287 .symbol_counter = symbol_counter,
288 .frame_ptr = frame_ptr,
289 .frame = &frame,
290 .pidData = pidData,
291 .sym = &sym,
292 .event = event,
293 };
294
295 bpf_loop(STACK_MAX_LEN, process_frame_callback, &ctx, 0);
296 if (ctx.done)
297 return 0;
298#else
299#if defined(USE_ITER)
300/* no for loop, no unrolling */
301#elif defined(NO_UNROLL)
302 __pragma_loop_no_unroll
303#elif defined(UNROLL_COUNT)
304 __pragma_loop_unroll_count(UNROLL_COUNT)
305#else
306 __pragma_loop_unroll_full
307#endif /* NO_UNROLL */
308 /* Unwind python stack */
309#ifdef USE_ITER
310 int i;
311 bpf_for(i, 0, STACK_MAX_LEN) {
312#else /* !USE_ITER */
313 for (int i = 0; i < STACK_MAX_LEN; ++i) {
314#endif
315 if (frame_ptr && get_frame_data(frame_ptr, pidData, &frame, &sym)) {
316 int32_t new_symbol_id = *symbol_counter * 64 + cur_cpu;
317 int32_t *symbol_id = bpf_map_lookup_elem(&symbolmap, &sym);
318 if (!symbol_id) {
319 bpf_map_update_elem(&symbolmap, &sym, &zero, 0);
320 symbol_id = bpf_map_lookup_elem(&symbolmap, &sym);
321 if (!symbol_id)
322 return 0;
323 }
324 if (*symbol_id == new_symbol_id)
325 (*symbol_counter)++;
326 event->stack[i] = *symbol_id;
327 event->stack_len = i + 1;
328 frame_ptr = frame.f_back;
329 }
330 }
331#endif /* USE_BPF_LOOP */
332 event->stack_complete = frame_ptr == NULL;
333 } else {
334 event->stack_complete = 1;
335 }
336
337 Stats* stats = bpf_map_lookup_elem(&statsmap, &zero);
338 if (stats)
339 stats->success++;
340
341 event->has_meta = 0;
342 bpf_perf_event_output(ctx, &perfmap, 0, event, offsetof(Event, metadata));
343 return 0;
344}
345
346SEC("raw_tracepoint/kfree_skb")
347int on_event(struct bpf_raw_tracepoint_args* ctx)
348{
349 int ret = 0;
350 ret |= __on_event(ctx);
351 ret |= __on_event(ctx);
352 ret |= __on_event(ctx);
353 ret |= __on_event(ctx);
354 ret |= __on_event(ctx);
355 return ret;
356}
357
358char _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_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";