1 /*
2 * Copyright (c) 2018, 2020, Red Hat, Inc. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26
27 #include "gc/shenandoah/shenandoahAsserts.hpp"
28 #include "gc/shenandoah/shenandoahForwarding.hpp"
29 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
30 #include "gc/shenandoah/shenandoahHeapRegionSet.inline.hpp"
31 #include "gc/shenandoah/shenandoahMarkingContext.inline.hpp"
32 #include "gc/shenandoah/shenandoahUtils.hpp"
33 #include "memory/resourceArea.hpp"
34
35 void print_raw_memory(ShenandoahMessageBuffer &msg, void* loc) {
36 // Be extra safe. Only access data that is guaranteed to be safe:
37 // should be in heap, in known committed region, within that region.
38
39 ShenandoahHeap* heap = ShenandoahHeap::heap();
40 if (!heap->is_in(loc)) return;
41
42 ShenandoahHeapRegion* r = heap->heap_region_containing(loc);
43 if (r != nullptr && r->is_committed()) {
44 address start = MAX2((address) r->bottom(), (address) loc - 32);
45 address end = MIN2((address) r->end(), (address) loc + 128);
46 if (start >= end) return;
47
48 stringStream ss;
49 os::print_hex_dump(&ss, start, end, 4);
50 msg.append("\n");
51 msg.append("Raw heap memory:\n%s", ss.freeze());
52 }
53 }
54
55 void ShenandoahAsserts::print_obj(ShenandoahMessageBuffer& msg, oop obj) {
56 ShenandoahHeap* heap = ShenandoahHeap::heap();
57 ShenandoahHeapRegion *r = heap->heap_region_containing(obj);
58
59 ResourceMark rm;
60 stringStream ss;
61 r->print_on(&ss);
62
63 stringStream mw_ss;
64 obj->mark().print_on(&mw_ss);
65
66 ShenandoahMarkingContext* const ctx = heap->marking_context();
67
68 msg.append(" " PTR_FORMAT " - klass " PTR_FORMAT " %s\n", p2i(obj), p2i(obj->klass()), obj->klass()->external_name());
69 msg.append(" %3s allocated after mark start\n", ctx->allocated_after_mark_start(obj) ? "" : "not");
70 msg.append(" %3s after update watermark\n", cast_from_oop<HeapWord*>(obj) >= r->get_update_watermark() ? "" : "not");
71 msg.append(" %3s marked strong\n", ctx->is_marked_strong(obj) ? "" : "not");
72 msg.append(" %3s marked weak\n", ctx->is_marked_weak(obj) ? "" : "not");
73 msg.append(" %3s in collection set\n", heap->in_collection_set(obj) ? "" : "not");
74 if (heap->mode()->is_generational() && !obj->is_forwarded()) {
75 msg.append(" age: %d\n", obj->age());
76 }
77 msg.append(" mark:%s\n", mw_ss.freeze());
78 msg.append(" region: %s", ss.freeze());
79 }
80
81 void ShenandoahAsserts::print_non_obj(ShenandoahMessageBuffer& msg, void* loc) {
82 ShenandoahHeap* heap = ShenandoahHeap::heap();
83 if (heap->is_in(loc)) {
84 msg.append(" inside Java heap\n");
85 ShenandoahHeapRegion *r = heap->heap_region_containing(loc);
86 stringStream ss;
87 r->print_on(&ss);
88
89 msg.append(" %3s in collection set\n", heap->in_collection_set_loc(loc) ? "" : "not");
90 msg.append(" region: %s", ss.freeze());
91 } else {
92 msg.append(" outside of Java heap\n");
93 stringStream ss;
94 os::print_location(&ss, (intptr_t) loc, false);
95 msg.append(" %s", ss.freeze());
96 }
97 }
98
99 void ShenandoahAsserts::print_obj_safe(ShenandoahMessageBuffer& msg, void* loc) {
100 ShenandoahHeap* heap = ShenandoahHeap::heap();
101 msg.append(" " PTR_FORMAT " - safe print, no details\n", p2i(loc));
102 if (heap->is_in(loc)) {
103 ShenandoahHeapRegion* r = heap->heap_region_containing(loc);
104 if (r != nullptr) {
105 stringStream ss;
106 r->print_on(&ss);
107 msg.append(" region: %s", ss.freeze());
108 print_raw_memory(msg, loc);
109 }
110 }
111 }
112
113 void ShenandoahAsserts::print_failure(SafeLevel level, oop obj, void* interior_loc, oop loc,
114 const char* phase, const char* label,
115 const char* file, int line) {
116 ShenandoahHeap* heap = ShenandoahHeap::heap();
117 ResourceMark rm;
118
119 bool loc_in_heap = (loc != nullptr && heap->is_in(loc));
120
121 ShenandoahMessageBuffer msg("%s; %s\n\n", phase, label);
122
123 msg.append("Referenced from:\n");
124 if (interior_loc != nullptr) {
125 msg.append(" interior location: " PTR_FORMAT "\n", p2i(interior_loc));
126 if (loc_in_heap) {
127 print_obj(msg, loc);
128 } else {
129 print_non_obj(msg, interior_loc);
130 }
131 } else {
132 msg.append(" no interior location recorded (probably a plain heap scan, or detached oop)\n");
133 }
134 msg.append("\n");
135
136 msg.append("Object:\n");
137 if (level >= _safe_oop) {
138 print_obj(msg, obj);
139 } else {
140 print_obj_safe(msg, obj);
141 }
142 msg.append("\n");
143
144 if (level >= _safe_oop) {
145 oop fwd = ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
146 msg.append("Forwardee:\n");
147 if (obj != fwd) {
148 if (level >= _safe_oop_fwd) {
149 print_obj(msg, fwd);
150 } else {
151 print_obj_safe(msg, fwd);
152 }
153 } else {
154 msg.append(" (the object itself)");
155 }
156 msg.append("\n");
157 }
158
159 if (level >= _safe_oop_fwd) {
160 oop fwd = ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
161 oop fwd2 = ShenandoahForwarding::get_forwardee_raw_unchecked(fwd);
162 if (fwd != fwd2) {
163 msg.append("Second forwardee:\n");
164 print_obj_safe(msg, fwd2);
165 msg.append("\n");
166 }
167 }
168
169 report_vm_error(file, line, msg.buffer());
170 }
171
172 void ShenandoahAsserts::assert_in_heap(void* interior_loc, oop obj, const char *file, int line) {
173 ShenandoahHeap* heap = ShenandoahHeap::heap();
174
175 if (!heap->is_in(obj)) {
176 print_failure(_safe_unknown, obj, interior_loc, nullptr, "Shenandoah assert_in_heap failed",
177 "oop must point to a heap address",
178 file, line);
179 }
180 }
181
182 void ShenandoahAsserts::assert_in_heap_or_null(void* interior_loc, oop obj, const char *file, int line) {
183 ShenandoahHeap* heap = ShenandoahHeap::heap();
184
185 if (obj != nullptr && !heap->is_in(obj)) {
186 print_failure(_safe_unknown, obj, interior_loc, nullptr, "Shenandoah assert_in_heap_or_null failed",
187 "oop must point to a heap address",
188 file, line);
189 }
190 }
191
192 void ShenandoahAsserts::assert_correct(void* interior_loc, oop obj, const char* file, int line) {
193 ShenandoahHeap* heap = ShenandoahHeap::heap();
194
195 // Step 1. Check that obj is correct.
196 // After this step, it is safe to call heap_region_containing().
197 if (!heap->is_in(obj)) {
198 print_failure(_safe_unknown, obj, interior_loc, nullptr, "Shenandoah assert_correct failed",
199 "oop must point to a heap address",
200 file, line);
201 }
202
203 Klass* obj_klass = obj->klass_or_null();
204 if (obj_klass == nullptr) {
205 print_failure(_safe_unknown, obj, interior_loc, nullptr, "Shenandoah assert_correct failed",
206 "Object klass pointer should not be null",
207 file,line);
208 }
209
210 if (!Metaspace::contains(obj_klass)) {
211 print_failure(_safe_unknown, obj, interior_loc, nullptr, "Shenandoah assert_correct failed",
212 "Object klass pointer must go to metaspace",
213 file,line);
214 }
215
216 oop fwd = ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
217
218 if (obj != fwd) {
219 // When Full GC moves the objects, we cannot trust fwdptrs. If we got here, it means something
220 // tries fwdptr manipulation when Full GC is running. The only exception is using the fwdptr
221 // that still points to the object itself.
222 if (heap->is_full_gc_move_in_progress()) {
223 print_failure(_safe_oop, obj, interior_loc, nullptr, "Shenandoah assert_correct failed",
224 "Non-trivial forwarding pointer during Full GC moves, probable bug.",
225 file, line);
226 }
227
228 // Step 2. Check that forwardee is correct
229 if (!heap->is_in(fwd)) {
230 print_failure(_safe_oop, obj, interior_loc, nullptr, "Shenandoah assert_correct failed",
231 "Forwardee must point to a heap address",
232 file, line);
233 }
234
235 if (obj_klass != fwd->klass()) {
236 print_failure(_safe_oop, obj, interior_loc, nullptr, "Shenandoah assert_correct failed",
237 "Forwardee klass disagrees with object class",
238 file, line);
239 }
240
241 // Step 3. Check that forwardee points to correct region
242 if (heap->heap_region_index_containing(fwd) == heap->heap_region_index_containing(obj)) {
243 print_failure(_safe_all, obj, interior_loc, nullptr, "Shenandoah assert_correct failed",
244 "Non-trivial forwardee should in another region",
245 file, line);
246 }
247
248 // Step 4. Check for multiple forwardings
249 oop fwd2 = ShenandoahForwarding::get_forwardee_raw_unchecked(fwd);
250 if (fwd != fwd2) {
251 print_failure(_safe_all, obj, interior_loc, nullptr, "Shenandoah assert_correct failed",
252 "Multiple forwardings",
253 file, line);
254 }
255 }
256
257 // Do additional checks for special objects: their fields can hold metadata as well.
258 // We want to check class loading/unloading did not corrupt them.
259
260 if (obj_klass == vmClasses::Class_klass()) {
261 Metadata* klass = obj->metadata_field(java_lang_Class::klass_offset());
262 if (klass != nullptr && !Metaspace::contains(klass)) {
263 print_failure(_safe_all, obj, interior_loc, nullptr, "Shenandoah assert_correct failed",
264 "Instance class mirror should point to Metaspace",
265 file, line);
266 }
267
268 Metadata* array_klass = obj->metadata_field(java_lang_Class::array_klass_offset());
269 if (array_klass != nullptr && !Metaspace::contains(array_klass)) {
270 print_failure(_safe_all, obj, interior_loc, nullptr, "Shenandoah assert_correct failed",
271 "Array class mirror should point to Metaspace",
272 file, line);
273 }
274 }
275 }
276
277 void ShenandoahAsserts::assert_in_correct_region(void* interior_loc, oop obj, const char* file, int line) {
278 assert_correct(interior_loc, obj, file, line);
279
280 ShenandoahHeap* heap = ShenandoahHeap::heap();
281 ShenandoahHeapRegion* r = heap->heap_region_containing(obj);
282 if (!r->is_active()) {
283 print_failure(_safe_unknown, obj, interior_loc, nullptr, "Shenandoah assert_in_correct_region failed",
284 "Object must reside in active region",
285 file, line);
286 }
287
288 size_t alloc_size = obj->size();
289 if (ShenandoahHeapRegion::requires_humongous(alloc_size)) {
290 size_t idx = r->index();
291 size_t num_regions = ShenandoahHeapRegion::required_regions(alloc_size * HeapWordSize);
292 for (size_t i = idx; i < idx + num_regions; i++) {
293 ShenandoahHeapRegion* chain_reg = heap->get_region(i);
294 if (i == idx && !chain_reg->is_humongous_start()) {
295 print_failure(_safe_unknown, obj, interior_loc, nullptr, "Shenandoah assert_in_correct_region failed",
296 "Object must reside in humongous start",
297 file, line);
298 }
299 if (i != idx && !chain_reg->is_humongous_continuation()) {
300 print_failure(_safe_oop, obj, interior_loc, nullptr, "Shenandoah assert_in_correct_region failed",
301 "Humongous continuation should be of proper size",
302 file, line);
303 }
304 }
305 }
306 }
307
308 void ShenandoahAsserts::assert_forwarded(void* interior_loc, oop obj, const char* file, int line) {
309 assert_correct(interior_loc, obj, file, line);
310 oop fwd = ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
311
312 if (obj == fwd) {
313 print_failure(_safe_all, obj, interior_loc, nullptr, "Shenandoah assert_forwarded failed",
314 "Object should be forwarded",
315 file, line);
316 }
317 }
318
319 void ShenandoahAsserts::assert_not_forwarded(void* interior_loc, oop obj, const char* file, int line) {
320 assert_correct(interior_loc, obj, file, line);
321 oop fwd = ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
322
323 if (obj != fwd) {
324 print_failure(_safe_all, obj, interior_loc, nullptr, "Shenandoah assert_not_forwarded failed",
325 "Object should not be forwarded",
326 file, line);
327 }
328 }
329
330 void ShenandoahAsserts::assert_marked(void *interior_loc, oop obj, const char *file, int line) {
331 assert_correct(interior_loc, obj, file, line);
332
333 ShenandoahHeap* heap = ShenandoahHeap::heap();
334 if (!heap->marking_context()->is_marked(obj)) {
335 print_failure(_safe_all, obj, interior_loc, nullptr, "Shenandoah assert_marked failed",
336 "Object should be marked",
337 file, line);
338 }
339 }
340
341 void ShenandoahAsserts::assert_marked_weak(void *interior_loc, oop obj, const char *file, int line) {
342 assert_correct(interior_loc, obj, file, line);
343
344 ShenandoahHeap* heap = ShenandoahHeap::heap();
345 if (!heap->marking_context()->is_marked_weak(obj)) {
346 print_failure(_safe_all, obj, interior_loc, nullptr, "Shenandoah assert_marked_weak failed",
347 "Object should be marked weakly",
348 file, line);
349 }
350 }
351
352 void ShenandoahAsserts::assert_marked_strong(void *interior_loc, oop obj, const char *file, int line) {
353 assert_correct(interior_loc, obj, file, line);
354
355 ShenandoahHeap* heap = ShenandoahHeap::heap();
356 if (!heap->marking_context()->is_marked_strong(obj)) {
357 print_failure(_safe_all, obj, interior_loc, nullptr, "Shenandoah assert_marked_strong failed",
358 "Object should be marked strongly",
359 file, line);
360 }
361 }
362
363 void ShenandoahAsserts::assert_in_cset(void* interior_loc, oop obj, const char* file, int line) {
364 assert_correct(interior_loc, obj, file, line);
365
366 ShenandoahHeap* heap = ShenandoahHeap::heap();
367 if (!heap->in_collection_set(obj)) {
368 print_failure(_safe_all, obj, interior_loc, nullptr, "Shenandoah assert_in_cset failed",
369 "Object should be in collection set",
370 file, line);
371 }
372 }
373
374 void ShenandoahAsserts::assert_not_in_cset(void* interior_loc, oop obj, const char* file, int line) {
375 assert_correct(interior_loc, obj, file, line);
376
377 ShenandoahHeap* heap = ShenandoahHeap::heap();
378 if (heap->in_collection_set(obj)) {
379 print_failure(_safe_all, obj, interior_loc, nullptr, "Shenandoah assert_not_in_cset failed",
380 "Object should not be in collection set",
381 file, line);
382 }
383 }
384
385 void ShenandoahAsserts::assert_not_in_cset_loc(void* interior_loc, const char* file, int line) {
386 ShenandoahHeap* heap = ShenandoahHeap::heap();
387 if (heap->in_collection_set_loc(interior_loc)) {
388 print_failure(_safe_unknown, nullptr, interior_loc, nullptr, "Shenandoah assert_not_in_cset_loc failed",
389 "Interior location should not be in collection set",
390 file, line);
391 }
392 }
393
394 void ShenandoahAsserts::print_rp_failure(const char *label, BoolObjectClosure* actual,
395 const char *file, int line) {
396 ShenandoahMessageBuffer msg("%s\n", label);
397 msg.append(" Actual: " PTR_FORMAT "\n", p2i(actual));
398 report_vm_error(file, line, msg.buffer());
399 }
400
401 void ShenandoahAsserts::assert_locked_or_shenandoah_safepoint(Mutex* lock, const char* file, int line) {
402 if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) {
403 return;
404 }
405
406 if (lock->owned_by_self()) {
407 return;
408 }
409
410 ShenandoahMessageBuffer msg("Must be at a Shenandoah safepoint or held %s lock", lock->name());
411 report_vm_error(file, line, msg.buffer());
412 }
413
414 void ShenandoahAsserts::assert_heaplocked(const char* file, int line) {
415 ShenandoahHeap* heap = ShenandoahHeap::heap();
416
417 if (heap->lock()->owned_by_self()) {
418 return;
419 }
420
421 ShenandoahMessageBuffer msg("Heap lock must be owned by current thread");
422 report_vm_error(file, line, msg.buffer());
423 }
424
425 void ShenandoahAsserts::assert_not_heaplocked(const char* file, int line) {
426 ShenandoahHeap* heap = ShenandoahHeap::heap();
427
428 if (!heap->lock()->owned_by_self()) {
429 return;
430 }
431
432 ShenandoahMessageBuffer msg("Heap lock must not be owned by current thread");
433 report_vm_error(file, line, msg.buffer());
434 }
435
436 void ShenandoahAsserts::assert_heaplocked_or_safepoint(const char* file, int line) {
437 ShenandoahHeap* heap = ShenandoahHeap::heap();
438
439 if (heap->lock()->owned_by_self()) {
440 return;
441 }
442
443 if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) {
444 return;
445 }
446
447 ShenandoahMessageBuffer msg("Heap lock must be owned by current thread, or be at safepoint");
448 report_vm_error(file, line, msg.buffer());
449 }
450
451 void ShenandoahAsserts::assert_generational(const char* file, int line) {
452 if (ShenandoahHeap::heap()->mode()->is_generational()) {
453 return;
454 }
455
456 ShenandoahMessageBuffer msg("Must be in generational mode");
457 report_vm_error(file, line, msg.buffer());
458 }
459
460 void ShenandoahAsserts::assert_control_or_vm_thread_at_safepoint(bool at_safepoint, const char* file, int line) {
461 Thread* thr = Thread::current();
462 if (thr == ShenandoahHeap::heap()->control_thread()) {
463 return;
464 }
465 if (thr->is_VM_thread()) {
466 if (!at_safepoint) {
467 return;
468 } else if (SafepointSynchronize::is_at_safepoint()) {
469 return;
470 }
471 }
472
473 ShenandoahMessageBuffer msg("Must be either control thread, or vm thread");
474 if (at_safepoint) {
475 msg.append(" at a safepoint");
476 }
477 report_vm_error(file, line, msg.buffer());
478 }
479
480 void ShenandoahAsserts::assert_generations_reconciled(const char* file, int line) {
481 if (!SafepointSynchronize::is_at_safepoint()) {
482 return;
483 }
484
485 ShenandoahHeap* heap = ShenandoahHeap::heap();
486 ShenandoahGeneration* ggen = heap->gc_generation();
487 ShenandoahGeneration* agen = heap->active_generation();
488 if (agen == ggen) {
489 return;
490 }
491
492 ShenandoahMessageBuffer msg("Active(%d) & GC(%d) Generations aren't reconciled", agen->type(), ggen->type());
493 report_vm_error(file, line, msg.buffer());
494 }