1 /*-
2 * Copyright (c) 1998 Berkeley Software Design, Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 * 3. Berkeley Software Design Inc's name may not be used to endorse or
13 * promote products derived from this software without specific prior
14 * written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY BERKELEY SOFTWARE DESIGN INC ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL BERKELEY SOFTWARE DESIGN INC BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 *
28 * from BSDI $Id: mutex_witness.c,v 1.1.2.20 2000/04/27 03:10:27 cp Exp $
29 * and BSDI $Id: synch_machdep.c,v 2.3.2.39 2000/04/27 03:10:25 cp Exp $
30 */
31
32 /*
33 * Implementation of the `witness' lock verifier. Originally implemented for
34 * mutexes in BSD/OS. Extended to handle generic lock objects and lock
35 * classes in FreeBSD.
36 */
37
38 /*
39 * Main Entry: witness
40 * Pronunciation: 'wit-n&s
41 * Function: noun
42 * Etymology: Middle English witnesse, from Old English witnes knowledge,
43 * testimony, witness, from 2wit
44 * Date: before 12th century
45 * 1 : attestation of a fact or event : TESTIMONY
46 * 2 : one that gives evidence; specifically : one who testifies in
47 * a cause or before a judicial tribunal
48 * 3 : one asked to be present at a transaction so as to be able to
49 * testify to its having taken place
50 * 4 : one who has personal knowledge of something
51 * 5 a : something serving as evidence or proof : SIGN
52 * b : public affirmation by word or example of usually
53 * religious faith or conviction <the heroic witness to divine
54 * life -- Pilot>
55 * 6 capitalized : a member of the Jehovah's Witnesses
56 */
57
58 /*
59 * Special rules concerning Giant and lock orders:
60 *
61 * 1) Giant must be acquired before any other mutexes. Stated another way,
62 * no other mutex may be held when Giant is acquired.
63 *
64 * 2) Giant must be released when blocking on a sleepable lock.
65 *
66 * This rule is less obvious, but is a result of Giant providing the same
67 * semantics as spl(). Basically, when a thread sleeps, it must release
68 * Giant. When a thread blocks on a sleepable lock, it sleeps. Hence rule
69 * 2).
70 *
71 * 3) Giant may be acquired before or after sleepable locks.
72 *
73 * This rule is also not quite as obvious. Giant may be acquired after
74 * a sleepable lock because it is a non-sleepable lock and non-sleepable
75 * locks may always be acquired while holding a sleepable lock. The second
76 * case, Giant before a sleepable lock, follows from rule 2) above. Suppose
77 * you have two threads T1 and T2 and a sleepable lock X. Suppose that T1
78 * acquires X and blocks on Giant. Then suppose that T2 acquires Giant and
79 * blocks on X. When T2 blocks on X, T2 will release Giant allowing T1 to
80 * execute. Thus, acquiring Giant both before and after a sleepable lock
81 * will not result in a lock order reversal.
82 */
83
84 #include <sys/cdefs.h>
85 __FBSDID("$FreeBSD$");
86
87 #include "opt_ddb.h"
88 #include "opt_hwpmc_hooks.h"
89 #include "opt_witness.h"
90
91 #include <sys/param.h>
92 #include <sys/bus.h>
93 #include <sys/kdb.h>
94 #include <sys/kernel.h>
95 #include <sys/ktr.h>
96 #include <sys/lock.h>
97 #include <sys/malloc.h>
98 #include <sys/mutex.h>
99 #include <sys/priv.h>
100 #include <sys/proc.h>
101 #include <sys/sysctl.h>
102 #include <sys/systm.h>
103
104 #include <ddb/ddb.h>
105
106 #include <machine/stdarg.h>
107
108 /* Note that these traces do not work with KTR_ALQ. */
109 #if 0
110 #define KTR_WITNESS KTR_SUBSYS
111 #else
112 #define KTR_WITNESS 0
113 #endif
114
115 /* Easier to stay with the old names. */
116 #define lo_list lo_witness_data.lod_list
117 #define lo_witness lo_witness_data.lod_witness
118
119 /* Define this to check for blessed mutexes */
120 #undef BLESSING
121
122 #define WITNESS_COUNT 1024
123 #define WITNESS_CHILDCOUNT (WITNESS_COUNT * 4)
124 /*
125 * XXX: This is somewhat bogus, as we assume here that at most 1024 threads
126 * will hold LOCK_NCHILDREN * 2 locks. We handle failure ok, and we should
127 * probably be safe for the most part, but it's still a SWAG.
128 */
129 #define LOCK_CHILDCOUNT (MAXCPU + 1024) * 2
130
131 #define WITNESS_NCHILDREN 6
132
133 struct witness_child_list_entry;
134
135 struct witness {
136 const char *w_name;
137 struct lock_class *w_class;
138 STAILQ_ENTRY(witness) w_list; /* List of all witnesses. */
139 STAILQ_ENTRY(witness) w_typelist; /* Witnesses of a type. */
140 struct witness_child_list_entry *w_children; /* Great evilness... */
141 const char *w_file;
142 int w_line;
143 u_int w_level;
144 u_int w_refcount;
145 u_char w_Giant_squawked:1;
146 u_char w_other_squawked:1;
147 u_char w_same_squawked:1;
148 u_char w_displayed:1;
149 };
150
151 struct witness_child_list_entry {
152 struct witness_child_list_entry *wcl_next;
153 struct witness *wcl_children[WITNESS_NCHILDREN];
154 u_int wcl_count;
155 };
156
157 STAILQ_HEAD(witness_list, witness);
158
159 #ifdef BLESSING
160 struct witness_blessed {
161 const char *b_lock1;
162 const char *b_lock2;
163 };
164 #endif
165
166 struct witness_order_list_entry {
167 const char *w_name;
168 struct lock_class *w_class;
169 };
170
171 #ifdef BLESSING
172 static int blessed(struct witness *, struct witness *);
173 #endif
174 static int depart(struct witness *w);
175 static struct witness *enroll(const char *description,
176 struct lock_class *lock_class);
177 static int insertchild(struct witness *parent, struct witness *child);
178 static int isitmychild(struct witness *parent, struct witness *child);
179 static int isitmydescendant(struct witness *parent, struct witness *child);
180 static int itismychild(struct witness *parent, struct witness *child);
181 static void removechild(struct witness *parent, struct witness *child);
182 static int sysctl_debug_witness_watch(SYSCTL_HANDLER_ARGS);
183 static const char *fixup_filename(const char *file);
184 static struct witness *witness_get(void);
185 static void witness_free(struct witness *m);
186 static struct witness_child_list_entry *witness_child_get(void);
187 static void witness_child_free(struct witness_child_list_entry *wcl);
188 static struct lock_list_entry *witness_lock_list_get(void);
189 static void witness_lock_list_free(struct lock_list_entry *lle);
190 static struct lock_instance *find_instance(struct lock_list_entry *lock_list,
191 struct lock_object *lock);
192 static void witness_list_lock(struct lock_instance *instance);
193 #ifdef DDB
194 static void witness_leveldescendents(struct witness *parent, int level);
195 static void witness_levelall(void);
196 static void witness_displaydescendants(void(*)(const char *fmt, ...),
197 struct witness *, int indent);
198 static void witness_display_list(void(*prnt)(const char *fmt, ...),
199 struct witness_list *list);
200 static void witness_display(void(*)(const char *fmt, ...));
201 static void witness_list(struct thread *td);
202 #endif
203
204 SYSCTL_NODE(_debug, OID_AUTO, witness, CTLFLAG_RW, 0, "Witness Locking");
205
206 /*
207 * If set to 0, witness is disabled. If set to a non-zero value, witness
208 * performs full lock order checking for all locks. At runtime, this
209 * value may be set to 0 to turn off witness. witness is not allowed be
210 * turned on once it is turned off, however.
211 */
212 static int witness_watch = 1;
213 TUNABLE_INT("debug.witness.watch", &witness_watch);
214 SYSCTL_PROC(_debug_witness, OID_AUTO, watch, CTLFLAG_RW | CTLTYPE_INT, NULL, 0,
215 sysctl_debug_witness_watch, "I", "witness is watching lock operations");
216
217 #ifdef KDB
218 /*
219 * When KDB is enabled and witness_kdb is set to 1, it will cause the system
220 * to drop into kdebug() when:
221 * - a lock hierarchy violation occurs
222 * - locks are held when going to sleep.
223 */
224 #ifdef WITNESS_KDB
225 int witness_kdb = 1;
226 #else
227 int witness_kdb = 0;
228 #endif
229 TUNABLE_INT("debug.witness.kdb", &witness_kdb);
230 SYSCTL_INT(_debug_witness, OID_AUTO, kdb, CTLFLAG_RW, &witness_kdb, 0, "");
231
232 /*
233 * When KDB is enabled and witness_trace is set to 1, it will cause the system
234 * to print a stack trace:
235 * - a lock hierarchy violation occurs
236 * - locks are held when going to sleep.
237 */
238 int witness_trace = 1;
239 TUNABLE_INT("debug.witness.trace", &witness_trace);
240 SYSCTL_INT(_debug_witness, OID_AUTO, trace, CTLFLAG_RW, &witness_trace, 0, "");
241 #endif /* KDB */
242
243 #ifdef WITNESS_SKIPSPIN
244 int witness_skipspin = 1;
245 #else
246 int witness_skipspin = 0;
247 #endif
248 TUNABLE_INT("debug.witness.skipspin", &witness_skipspin);
249 SYSCTL_INT(_debug_witness, OID_AUTO, skipspin, CTLFLAG_RDTUN,
250 &witness_skipspin, 0, "");
251
252 static struct mtx w_mtx;
253 static struct witness_list w_free = STAILQ_HEAD_INITIALIZER(w_free);
254 static struct witness_list w_all = STAILQ_HEAD_INITIALIZER(w_all);
255 static struct witness_list w_spin = STAILQ_HEAD_INITIALIZER(w_spin);
256 static struct witness_list w_sleep = STAILQ_HEAD_INITIALIZER(w_sleep);
257 static struct witness_child_list_entry *w_child_free = NULL;
258 static struct lock_list_entry *w_lock_list_free = NULL;
259
260 static int w_free_cnt, w_spin_cnt, w_sleep_cnt, w_child_free_cnt, w_child_cnt;
261 SYSCTL_INT(_debug_witness, OID_AUTO, free_cnt, CTLFLAG_RD, &w_free_cnt, 0, "");
262 SYSCTL_INT(_debug_witness, OID_AUTO, spin_cnt, CTLFLAG_RD, &w_spin_cnt, 0, "");
263 SYSCTL_INT(_debug_witness, OID_AUTO, sleep_cnt, CTLFLAG_RD, &w_sleep_cnt, 0,
264 "");
265 SYSCTL_INT(_debug_witness, OID_AUTO, child_free_cnt, CTLFLAG_RD,
266 &w_child_free_cnt, 0, "");
267 SYSCTL_INT(_debug_witness, OID_AUTO, child_cnt, CTLFLAG_RD, &w_child_cnt, 0,
268 "");
269
270 static struct witness w_data[WITNESS_COUNT];
271 static struct witness_child_list_entry w_childdata[WITNESS_CHILDCOUNT];
272 static struct lock_list_entry w_locklistdata[LOCK_CHILDCOUNT];
273
274 static struct witness_order_list_entry order_lists[] = {
275 /*
276 * sx locks
277 */
278 { "proctree", &lock_class_sx },
279 { "allproc", &lock_class_sx },
280 { "allprison", &lock_class_sx },
281 { NULL, NULL },
282 /*
283 * Various mutexes
284 */
285 { "Giant", &lock_class_mtx_sleep },
286 { "pipe mutex", &lock_class_mtx_sleep },
287 { "sigio lock", &lock_class_mtx_sleep },
288 { "process group", &lock_class_mtx_sleep },
289 { "process lock", &lock_class_mtx_sleep },
290 { "session", &lock_class_mtx_sleep },
291 { "uidinfo hash", &lock_class_mtx_sleep },
292 { "uidinfo struct", &lock_class_mtx_sleep },
293 #ifdef HWPMC_HOOKS
294 { "pmc-sleep", &lock_class_mtx_sleep },
295 #endif
296 { NULL, NULL },
297 /*
298 * Sockets
299 */
300 { "accept", &lock_class_mtx_sleep },
301 { "so_snd", &lock_class_mtx_sleep },
302 { "so_rcv", &lock_class_mtx_sleep },
303 { "sellck", &lock_class_mtx_sleep },
304 { NULL, NULL },
305 /*
306 * Routing
307 */
308 { "so_rcv", &lock_class_mtx_sleep },
309 { "radix node head", &lock_class_mtx_sleep },
310 { "rtentry", &lock_class_mtx_sleep },
311 { "ifaddr", &lock_class_mtx_sleep },
312 { NULL, NULL },
313 /*
314 * Multicast - protocol locks before interface locks, after UDP locks.
315 */
316 { "udpinp", &lock_class_mtx_sleep },
317 { "in_multi_mtx", &lock_class_mtx_sleep },
318 { "igmp_mtx", &lock_class_mtx_sleep },
319 { "if_addr_mtx", &lock_class_mtx_sleep },
320 { NULL, NULL },
321 /*
322 * UNIX Domain Sockets
323 */
324 { "unp", &lock_class_mtx_sleep },
325 { "so_snd", &lock_class_mtx_sleep },
326 { NULL, NULL },
327 /*
328 * UDP/IP
329 */
330 { "udp", &lock_class_mtx_sleep },
331 { "udpinp", &lock_class_mtx_sleep },
332 { "so_snd", &lock_class_mtx_sleep },
333 { NULL, NULL },
334 /*
335 * TCP/IP
336 */
337 { "tcp", &lock_class_mtx_sleep },
338 { "tcpinp", &lock_class_mtx_sleep },
339 { "so_snd", &lock_class_mtx_sleep },
340 { NULL, NULL },
341 /*
342 * SLIP
343 */
344 { "slip_mtx", &lock_class_mtx_sleep },
345 { "slip sc_mtx", &lock_class_mtx_sleep },
346 { NULL, NULL },
347 /*
348 * netatalk
349 */
350 { "ddp_list_mtx", &lock_class_mtx_sleep },
351 { "ddp_mtx", &lock_class_mtx_sleep },
352 { NULL, NULL },
353 /*
354 * BPF
355 */
356 { "bpf global lock", &lock_class_mtx_sleep },
357 { "bpf interface lock", &lock_class_mtx_sleep },
358 { "bpf cdev lock", &lock_class_mtx_sleep },
359 { NULL, NULL },
360 /*
361 * NFS server
362 */
363 { "nfsd_mtx", &lock_class_mtx_sleep },
364 { "so_snd", &lock_class_mtx_sleep },
365 { NULL, NULL },
366
367 /*
368 * IEEE 802.11
369 */
370 { "802.11 com lock", &lock_class_mtx_sleep},
371 { NULL, NULL },
372 /*
373 * Network drivers
374 */
375 { "network driver", &lock_class_mtx_sleep},
376 { NULL, NULL },
377
378 /*
379 * Netgraph
380 */
381 { "ng_node", &lock_class_mtx_sleep },
382 { "ng_worklist", &lock_class_mtx_sleep },
383 { NULL, NULL },
384 /*
385 * CDEV
386 */
387 { "system map", &lock_class_mtx_sleep },
388 { "vm page queue mutex", &lock_class_mtx_sleep },
389 { "vnode interlock", &lock_class_mtx_sleep },
390 { "cdev", &lock_class_mtx_sleep },
391 { NULL, NULL },
392 /*
393 * kqueue/VFS interaction
394 */
395 { "kqueue", &lock_class_mtx_sleep },
396 { "struct mount mtx", &lock_class_mtx_sleep },
397 { "vnode interlock", &lock_class_mtx_sleep },
398 { NULL, NULL },
399 /*
400 * spin locks
401 */
402 #ifdef SMP
403 { "ap boot", &lock_class_mtx_spin },
404 #endif
405 { "rm.mutex_mtx", &lock_class_mtx_spin },
406 { "sio", &lock_class_mtx_spin },
407 { "scrlock", &lock_class_mtx_spin },
408 #ifdef __i386__
409 { "cy", &lock_class_mtx_spin },
410 #endif
411 #ifdef __sparc64__
412 { "pcib_mtx", &lock_class_mtx_spin },
413 { "rtc_mtx", &lock_class_mtx_spin },
414 #endif
415 { "scc_hwmtx", &lock_class_mtx_spin },
416 { "uart_hwmtx", &lock_class_mtx_spin },
417 { "fast_taskqueue", &lock_class_mtx_spin },
418 { "intr table", &lock_class_mtx_spin },
419 #ifdef HWPMC_HOOKS
420 { "pmc-per-proc", &lock_class_mtx_spin },
421 #endif
422 { "process slock", &lock_class_mtx_spin },
423 { "sleepq chain", &lock_class_mtx_spin },
424 { "umtx lock", &lock_class_mtx_spin },
425 { "turnstile chain", &lock_class_mtx_spin },
426 { "turnstile lock", &lock_class_mtx_spin },
427 { "sched lock", &lock_class_mtx_spin },
428 { "td_contested", &lock_class_mtx_spin },
429 { "callout", &lock_class_mtx_spin },
430 { "entropy harvest mutex", &lock_class_mtx_spin },
431 { "syscons video lock", &lock_class_mtx_spin },
432 { "time lock", &lock_class_mtx_spin },
433 #ifdef SMP
434 { "smp rendezvous", &lock_class_mtx_spin },
435 #endif
436 /*
437 * leaf locks
438 */
439 { "icu", &lock_class_mtx_spin },
440 #if defined(SMP) && defined(__sparc64__)
441 { "ipi", &lock_class_mtx_spin },
442 #endif
443 #ifdef __i386__
444 { "allpmaps", &lock_class_mtx_spin },
445 { "descriptor tables", &lock_class_mtx_spin },
446 #endif
447 { "clk", &lock_class_mtx_spin },
448 { "mprof lock", &lock_class_mtx_spin },
449 { "kse lock", &lock_class_mtx_spin },
450 { "zombie lock", &lock_class_mtx_spin },
451 { "ALD Queue", &lock_class_mtx_spin },
452 #ifdef __ia64__
453 { "MCA spin lock", &lock_class_mtx_spin },
454 #endif
455 #if defined(__i386__) || defined(__amd64__)
456 { "pcicfg", &lock_class_mtx_spin },
457 { "NDIS thread lock", &lock_class_mtx_spin },
458 #endif
459 { "tw_osl_io_lock", &lock_class_mtx_spin },
460 { "tw_osl_q_lock", &lock_class_mtx_spin },
461 { "tw_cl_io_lock", &lock_class_mtx_spin },
462 { "tw_cl_intr_lock", &lock_class_mtx_spin },
463 { "tw_cl_gen_lock", &lock_class_mtx_spin },
464 #ifdef HWPMC_HOOKS
465 { "pmc-leaf", &lock_class_mtx_spin },
466 #endif
467 { "blocked lock", &lock_class_mtx_spin },
468 { NULL, NULL },
469 { NULL, NULL }
470 };
471
472 #ifdef BLESSING
473 /*
474 * Pairs of locks which have been blessed
475 * Don't complain about order problems with blessed locks
476 */
477 static struct witness_blessed blessed_list[] = {
478 };
479 static int blessed_count =
480 sizeof(blessed_list) / sizeof(struct witness_blessed);
481 #endif
482
483 /*
484 * List of locks initialized prior to witness being initialized whose
485 * enrollment is currently deferred.
486 */
487 STAILQ_HEAD(, lock_object) pending_locks =
488 STAILQ_HEAD_INITIALIZER(pending_locks);
489
490 /*
491 * This global is set to 0 once it becomes safe to use the witness code.
492 */
493 static int witness_cold = 1;
494
495 /*
496 * This global is set to 1 once the static lock orders have been enrolled
497 * so that a warning can be issued for any spin locks enrolled later.
498 */
499 static int witness_spin_warn = 0;
500
501 /*
502 * The WITNESS-enabled diagnostic code. Note that the witness code does
503 * assume that the early boot is single-threaded at least until after this
504 * routine is completed.
505 */
506 static void
507 witness_initialize(void *dummy __unused)
508 {
509 struct lock_object *lock;
510 struct witness_order_list_entry *order;
511 struct witness *w, *w1;
512 int i;
513
514 /*
515 * We have to release Giant before initializing its witness
516 * structure so that WITNESS doesn't get confused.
517 */
518 mtx_unlock(&Giant);
519 mtx_assert(&Giant, MA_NOTOWNED);
520
521 CTR1(KTR_WITNESS, "%s: initializing witness", __func__);
522 mtx_init(&w_mtx, "witness lock", NULL, MTX_SPIN | MTX_QUIET |
523 MTX_NOWITNESS | MTX_NOPROFILE);
524 for (i = 0; i < WITNESS_COUNT; i++)
525 witness_free(&w_data[i]);
526 for (i = 0; i < WITNESS_CHILDCOUNT; i++)
527 witness_child_free(&w_childdata[i]);
528 for (i = 0; i < LOCK_CHILDCOUNT; i++)
529 witness_lock_list_free(&w_locklistdata[i]);
530
531 /* First add in all the specified order lists. */
532 for (order = order_lists; order->w_name != NULL; order++) {
533 w = enroll(order->w_name, order->w_class);
534 if (w == NULL)
535 continue;
536 w->w_file = "order list";
537 for (order++; order->w_name != NULL; order++) {
538 w1 = enroll(order->w_name, order->w_class);
539 if (w1 == NULL)
540 continue;
541 w1->w_file = "order list";
542 if (!itismychild(w, w1))
543 panic("Not enough memory for static orders!");
544 w = w1;
545 }
546 }
547 witness_spin_warn = 1;
548
549 /* Iterate through all locks and add them to witness. */
550 while (!STAILQ_EMPTY(&pending_locks)) {
551 lock = STAILQ_FIRST(&pending_locks);
552 STAILQ_REMOVE_HEAD(&pending_locks, lo_list);
553 KASSERT(lock->lo_flags & LO_WITNESS,
554 ("%s: lock %s is on pending list but not LO_WITNESS",
555 __func__, lock->lo_name));
556 lock->lo_witness = enroll(lock->lo_type, LOCK_CLASS(lock));
557 }
558
559 /* Mark the witness code as being ready for use. */
560 witness_cold = 0;
561
562 mtx_lock(&Giant);
563 }
564 SYSINIT(witness_init, SI_SUB_WITNESS, SI_ORDER_FIRST, witness_initialize, NULL)
565
566 static int
567 sysctl_debug_witness_watch(SYSCTL_HANDLER_ARGS)
568 {
569 int error, value;
570
571 value = witness_watch;
572 error = sysctl_handle_int(oidp, &value, 0, req);
573 if (error != 0 || req->newptr == NULL)
574 return (error);
575 if (value == witness_watch)
576 return (0);
577 if (value != 0)
578 return (EINVAL);
579 witness_watch = 0;
580 return (0);
581 }
582
583 void
584 witness_init(struct lock_object *lock)
585 {
586 struct lock_class *class;
587
588 /* Various sanity checks. */
589 class = LOCK_CLASS(lock);
590 if ((lock->lo_flags & LO_RECURSABLE) != 0 &&
591 (class->lc_flags & LC_RECURSABLE) == 0)
592 panic("%s: lock (%s) %s can not be recursable", __func__,
593 class->lc_name, lock->lo_name);
594 if ((lock->lo_flags & LO_SLEEPABLE) != 0 &&
595 (class->lc_flags & LC_SLEEPABLE) == 0)
596 panic("%s: lock (%s) %s can not be sleepable", __func__,
597 class->lc_name, lock->lo_name);
598 if ((lock->lo_flags & LO_UPGRADABLE) != 0 &&
599 (class->lc_flags & LC_UPGRADABLE) == 0)
600 panic("%s: lock (%s) %s can not be upgradable", __func__,
601 class->lc_name, lock->lo_name);
602
603 /*
604 * If we shouldn't watch this lock, then just clear lo_witness.
605 * Otherwise, if witness_cold is set, then it is too early to
606 * enroll this lock, so defer it to witness_initialize() by adding
607 * it to the pending_locks list. If it is not too early, then enroll
608 * the lock now.
609 */
610 if (witness_watch == 0 || panicstr != NULL ||
611 (lock->lo_flags & LO_WITNESS) == 0)
612 lock->lo_witness = NULL;
613 else if (witness_cold) {
614 STAILQ_INSERT_TAIL(&pending_locks, lock, lo_list);
615 lock->lo_flags |= LO_ENROLLPEND;
616 } else
617 lock->lo_witness = enroll(lock->lo_type, class);
618 }
619
620 void
621 witness_destroy(struct lock_object *lock)
622 {
623 struct lock_class *class;
624 struct witness *w;
625
626 class = LOCK_CLASS(lock);
627 if (witness_cold)
628 panic("lock (%s) %s destroyed while witness_cold",
629 class->lc_name, lock->lo_name);
630
631 /* XXX: need to verify that no one holds the lock */
632 if ((lock->lo_flags & (LO_WITNESS | LO_ENROLLPEND)) == LO_WITNESS &&
633 lock->lo_witness != NULL) {
634 w = lock->lo_witness;
635 mtx_lock_spin(&w_mtx);
636 MPASS(w->w_refcount > 0);
637 w->w_refcount--;
638
639 /*
640 * Lock is already released if we have an allocation failure
641 * and depart() fails.
642 */
643 if (w->w_refcount != 0 || depart(w))
644 mtx_unlock_spin(&w_mtx);
645 }
646
647 /*
648 * If this lock is destroyed before witness is up and running,
649 * remove it from the pending list.
650 */
651 if (lock->lo_flags & LO_ENROLLPEND) {
652 STAILQ_REMOVE(&pending_locks, lock, lock_object, lo_list);
653 lock->lo_flags &= ~LO_ENROLLPEND;
654 }
655 }
656
657 #ifdef DDB
658 static void
659 witness_levelall (void)
660 {
661 struct witness_list *list;
662 struct witness *w, *w1;
663
664 /*
665 * First clear all levels.
666 */
667 STAILQ_FOREACH(w, &w_all, w_list) {
668 w->w_level = 0;
669 }
670
671 /*
672 * Look for locks with no parent and level all their descendants.
673 */
674 STAILQ_FOREACH(w, &w_all, w_list) {
675 /*
676 * This is just an optimization, technically we could get
677 * away just walking the all list each time.
678 */
679 if (w->w_class->lc_flags & LC_SLEEPLOCK)
680 list = &w_sleep;
681 else
682 list = &w_spin;
683 STAILQ_FOREACH(w1, list, w_typelist) {
684 if (isitmychild(w1, w))
685 goto skip;
686 }
687 witness_leveldescendents(w, 0);
688 skip:
689 ; /* silence GCC 3.x */
690 }
691 }
692
693 static void
694 witness_leveldescendents(struct witness *parent, int level)
695 {
696 struct witness_child_list_entry *wcl;
697 int i;
698
699 if (parent->w_level < level)
700 parent->w_level = level;
701 level++;
702 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next)
703 for (i = 0; i < wcl->wcl_count; i++)
704 witness_leveldescendents(wcl->wcl_children[i], level);
705 }
706
707 static void
708 witness_displaydescendants(void(*prnt)(const char *fmt, ...),
709 struct witness *parent, int indent)
710 {
711 struct witness_child_list_entry *wcl;
712 int i, level;
713
714 level = parent->w_level;
715 prnt("%-2d", level);
716 for (i = 0; i < indent; i++)
717 prnt(" ");
718 if (parent->w_refcount > 0)
719 prnt("%s", parent->w_name);
720 else
721 prnt("(dead)");
722 if (parent->w_displayed) {
723 prnt(" -- (already displayed)\n");
724 return;
725 }
726 parent->w_displayed = 1;
727 if (parent->w_refcount > 0) {
728 if (parent->w_file != NULL)
729 prnt(" -- last acquired @ %s:%d", parent->w_file,
730 parent->w_line);
731 }
732 prnt("\n");
733 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next)
734 for (i = 0; i < wcl->wcl_count; i++)
735 witness_displaydescendants(prnt,
736 wcl->wcl_children[i], indent + 1);
737 }
738
739 static void
740 witness_display_list(void(*prnt)(const char *fmt, ...),
741 struct witness_list *list)
742 {
743 struct witness *w;
744
745 STAILQ_FOREACH(w, list, w_typelist) {
746 if (w->w_file == NULL || w->w_level > 0)
747 continue;
748 /*
749 * This lock has no anscestors, display its descendants.
750 */
751 witness_displaydescendants(prnt, w, 0);
752 }
753 }
754
755 static void
756 witness_display(void(*prnt)(const char *fmt, ...))
757 {
758 struct witness *w;
759
760 KASSERT(!witness_cold, ("%s: witness_cold", __func__));
761 witness_levelall();
762
763 /* Clear all the displayed flags. */
764 STAILQ_FOREACH(w, &w_all, w_list) {
765 w->w_displayed = 0;
766 }
767
768 /*
769 * First, handle sleep locks which have been acquired at least
770 * once.
771 */
772 prnt("Sleep locks:\n");
773 witness_display_list(prnt, &w_sleep);
774
775 /*
776 * Now do spin locks which have been acquired at least once.
777 */
778 prnt("\nSpin locks:\n");
779 witness_display_list(prnt, &w_spin);
780
781 /*
782 * Finally, any locks which have not been acquired yet.
783 */
784 prnt("\nLocks which were never acquired:\n");
785 STAILQ_FOREACH(w, &w_all, w_list) {
786 if (w->w_file != NULL || w->w_refcount == 0)
787 continue;
788 prnt("%s\n", w->w_name);
789 }
790 }
791 #endif /* DDB */
792
793 /* Trim useless garbage from filenames. */
794 static const char *
795 fixup_filename(const char *file)
796 {
797
798 if (file == NULL)
799 return (NULL);
800 while (strncmp(file, "../", 3) == 0)
801 file += 3;
802 return (file);
803 }
804
805 int
806 witness_defineorder(struct lock_object *lock1, struct lock_object *lock2)
807 {
808
809 if (witness_watch == 0 || panicstr != NULL)
810 return (0);
811
812 /* Require locks that witness knows about. */
813 if (lock1 == NULL || lock1->lo_witness == NULL || lock2 == NULL ||
814 lock2->lo_witness == NULL)
815 return (EINVAL);
816
817 MPASS(!mtx_owned(&w_mtx));
818 mtx_lock_spin(&w_mtx);
819
820 /*
821 * If we already have either an explicit or implied lock order that
822 * is the other way around, then return an error.
823 */
824 if (isitmydescendant(lock2->lo_witness, lock1->lo_witness)) {
825 mtx_unlock_spin(&w_mtx);
826 return (EDOOFUS);
827 }
828
829 /* Try to add the new order. */
830 CTR3(KTR_WITNESS, "%s: adding %s as a child of %s", __func__,
831 lock2->lo_type, lock1->lo_type);
832 if (!itismychild(lock1->lo_witness, lock2->lo_witness))
833 return (ENOMEM);
834 mtx_unlock_spin(&w_mtx);
835 return (0);
836 }
837
838 void
839 witness_checkorder(struct lock_object *lock, int flags, const char *file,
840 int line)
841 {
842 struct lock_list_entry **lock_list, *lle;
843 struct lock_instance *lock1, *lock2;
844 struct lock_class *class;
845 struct witness *w, *w1;
846 struct thread *td;
847 int i, j;
848
849 if (witness_cold || witness_watch == 0 || lock->lo_witness == NULL ||
850 panicstr != NULL)
851 return;
852
853 /*
854 * Try locks do not block if they fail to acquire the lock, thus
855 * there is no danger of deadlocks or of switching while holding a
856 * spin lock if we acquire a lock via a try operation. This
857 * function shouldn't even be called for try locks, so panic if
858 * that happens.
859 */
860 if (flags & LOP_TRYLOCK)
861 panic("%s should not be called for try lock operations",
862 __func__);
863
864 w = lock->lo_witness;
865 class = LOCK_CLASS(lock);
866 td = curthread;
867 file = fixup_filename(file);
868
869 if (class->lc_flags & LC_SLEEPLOCK) {
870 /*
871 * Since spin locks include a critical section, this check
872 * implicitly enforces a lock order of all sleep locks before
873 * all spin locks.
874 */
875 if (td->td_critnest != 0 && !kdb_active)
876 panic("blockable sleep lock (%s) %s @ %s:%d",
877 class->lc_name, lock->lo_name, file, line);
878
879 /*
880 * If this is the first lock acquired then just return as
881 * no order checking is needed.
882 */
883 if (td->td_sleeplocks == NULL)
884 return;
885 lock_list = &td->td_sleeplocks;
886 } else {
887 /*
888 * If this is the first lock, just return as no order
889 * checking is needed. We check this in both if clauses
890 * here as unifying the check would require us to use a
891 * critical section to ensure we don't migrate while doing
892 * the check. Note that if this is not the first lock, we
893 * are already in a critical section and are safe for the
894 * rest of the check.
895 */
896 if (PCPU_GET(spinlocks) == NULL)
897 return;
898 lock_list = PCPU_PTR(spinlocks);
899 }
900
901 /*
902 * Check to see if we are recursing on a lock we already own. If
903 * so, make sure that we don't mismatch exclusive and shared lock
904 * acquires.
905 */
906 lock1 = find_instance(*lock_list, lock);
907 if (lock1 != NULL) {
908 if ((lock1->li_flags & LI_EXCLUSIVE) != 0 &&
909 (flags & LOP_EXCLUSIVE) == 0) {
910 printf("shared lock of (%s) %s @ %s:%d\n",
911 class->lc_name, lock->lo_name, file, line);
912 printf("while exclusively locked from %s:%d\n",
913 lock1->li_file, lock1->li_line);
914 panic("share->excl");
915 }
916 if ((lock1->li_flags & LI_EXCLUSIVE) == 0 &&
917 (flags & LOP_EXCLUSIVE) != 0) {
918 printf("exclusive lock of (%s) %s @ %s:%d\n",
919 class->lc_name, lock->lo_name, file, line);
920 printf("while share locked from %s:%d\n",
921 lock1->li_file, lock1->li_line);
922 panic("excl->share");
923 }
924 return;
925 }
926
927 /*
928 * Try locks do not block if they fail to acquire the lock, thus
929 * there is no danger of deadlocks or of switching while holding a
930 * spin lock if we acquire a lock via a try operation.
931 */
932 if (flags & LOP_TRYLOCK)
933 return;
934
935 /*
936 * Check for duplicate locks of the same type. Note that we only
937 * have to check for this on the last lock we just acquired. Any
938 * other cases will be caught as lock order violations.
939 */
940 lock1 = &(*lock_list)->ll_children[(*lock_list)->ll_count - 1];
941 w1 = lock1->li_lock->lo_witness;
942 if (w1 == w) {
943 if (w->w_same_squawked || (lock->lo_flags & LO_DUPOK) ||
944 (flags & LOP_DUPOK))
945 return;
946 w->w_same_squawked = 1;
947 printf("acquiring duplicate lock of same type: \"%s\"\n",
948 lock->lo_type);
949 printf(" 1st %s @ %s:%d\n", lock1->li_lock->lo_name,
950 lock1->li_file, lock1->li_line);
951 printf(" 2nd %s @ %s:%d\n", lock->lo_name, file, line);
952 #ifdef KDB
953 goto debugger;
954 #else
955 return;
956 #endif
957 }
958 MPASS(!mtx_owned(&w_mtx));
959 mtx_lock_spin(&w_mtx);
960 /*
961 * If we know that the the lock we are acquiring comes after
962 * the lock we most recently acquired in the lock order tree,
963 * then there is no need for any further checks.
964 */
965 if (isitmychild(w1, w)) {
966 mtx_unlock_spin(&w_mtx);
967 return;
968 }
969 for (j = 0, lle = *lock_list; lle != NULL; lle = lle->ll_next) {
970 for (i = lle->ll_count - 1; i >= 0; i--, j++) {
971
972 MPASS(j < WITNESS_COUNT);
973 lock1 = &lle->ll_children[i];
974 w1 = lock1->li_lock->lo_witness;
975
976 /*
977 * If this lock doesn't undergo witness checking,
978 * then skip it.
979 */
980 if (w1 == NULL) {
981 KASSERT((lock1->li_lock->lo_flags & LO_WITNESS) == 0,
982 ("lock missing witness structure"));
983 continue;
984 }
985 /*
986 * If we are locking Giant and this is a sleepable
987 * lock, then skip it.
988 */
989 if ((lock1->li_lock->lo_flags & LO_SLEEPABLE) != 0 &&
990 lock == &Giant.lock_object)
991 continue;
992 /*
993 * If we are locking a sleepable lock and this lock
994 * is Giant, then skip it.
995 */
996 if ((lock->lo_flags & LO_SLEEPABLE) != 0 &&
997 lock1->li_lock == &Giant.lock_object)
998 continue;
999 /*
1000 * If we are locking a sleepable lock and this lock
1001 * isn't sleepable, we want to treat it as a lock
1002 * order violation to enfore a general lock order of
1003 * sleepable locks before non-sleepable locks.
1004 */
1005 if (((lock->lo_flags & LO_SLEEPABLE) != 0 &&
1006 (lock1->li_lock->lo_flags & LO_SLEEPABLE) == 0))
1007 goto reversal;
1008 /*
1009 * If we are locking Giant and this is a non-sleepable
1010 * lock, then treat it as a reversal.
1011 */
1012 if ((lock1->li_lock->lo_flags & LO_SLEEPABLE) == 0 &&
1013 lock == &Giant.lock_object)
1014 goto reversal;
1015 /*
1016 * Check the lock order hierarchy for a reveresal.
1017 */
1018 if (!isitmydescendant(w, w1))
1019 continue;
1020 reversal:
1021 /*
1022 * We have a lock order violation, check to see if it
1023 * is allowed or has already been yelled about.
1024 */
1025 mtx_unlock_spin(&w_mtx);
1026 #ifdef BLESSING
1027 /*
1028 * If the lock order is blessed, just bail. We don't
1029 * look for other lock order violations though, which
1030 * may be a bug.
1031 */
1032 if (blessed(w, w1))
1033 return;
1034 #endif
1035 if (lock1->li_lock == &Giant.lock_object) {
1036 if (w1->w_Giant_squawked)
1037 return;
1038 else
1039 w1->w_Giant_squawked = 1;
1040 } else {
1041 if (w1->w_other_squawked)
1042 return;
1043 else
1044 w1->w_other_squawked = 1;
1045 }
1046 /*
1047 * Ok, yell about it.
1048 */
1049 if (((lock->lo_flags & LO_SLEEPABLE) != 0 &&
1050 (lock1->li_lock->lo_flags & LO_SLEEPABLE) == 0))
1051 printf(
1052 "lock order reversal: (sleepable after non-sleepable)\n");
1053 else if ((lock1->li_lock->lo_flags & LO_SLEEPABLE) == 0
1054 && lock == &Giant.lock_object)
1055 printf(
1056 "lock order reversal: (Giant after non-sleepable)\n");
1057 else
1058 printf("lock order reversal:\n");
1059 /*
1060 * Try to locate an earlier lock with
1061 * witness w in our list.
1062 */
1063 do {
1064 lock2 = &lle->ll_children[i];
1065 MPASS(lock2->li_lock != NULL);
1066 if (lock2->li_lock->lo_witness == w)
1067 break;
1068 if (i == 0 && lle->ll_next != NULL) {
1069 lle = lle->ll_next;
1070 i = lle->ll_count - 1;
1071 MPASS(i >= 0 && i < LOCK_NCHILDREN);
1072 } else
1073 i--;
1074 } while (i >= 0);
1075 if (i < 0) {
1076 printf(" 1st %p %s (%s) @ %s:%d\n",
1077 lock1->li_lock, lock1->li_lock->lo_name,
1078 lock1->li_lock->lo_type, lock1->li_file,
1079 lock1->li_line);
1080 printf(" 2nd %p %s (%s) @ %s:%d\n", lock,
1081 lock->lo_name, lock->lo_type, file, line);
1082 } else {
1083 printf(" 1st %p %s (%s) @ %s:%d\n",
1084 lock2->li_lock, lock2->li_lock->lo_name,
1085 lock2->li_lock->lo_type, lock2->li_file,
1086 lock2->li_line);
1087 printf(" 2nd %p %s (%s) @ %s:%d\n",
1088 lock1->li_lock, lock1->li_lock->lo_name,
1089 lock1->li_lock->lo_type, lock1->li_file,
1090 lock1->li_line);
1091 printf(" 3rd %p %s (%s) @ %s:%d\n", lock,
1092 lock->lo_name, lock->lo_type, file, line);
1093 }
1094 #ifdef KDB
1095 goto debugger;
1096 #else
1097 return;
1098 #endif
1099 }
1100 }
1101 lock1 = &(*lock_list)->ll_children[(*lock_list)->ll_count - 1];
1102 /*
1103 * If requested, build a new lock order. However, don't build a new
1104 * relationship between a sleepable lock and Giant if it is in the
1105 * wrong direction. The correct lock order is that sleepable locks
1106 * always come before Giant.
1107 */
1108 if (flags & LOP_NEWORDER &&
1109 !(lock1->li_lock == &Giant.lock_object &&
1110 (lock->lo_flags & LO_SLEEPABLE) != 0)) {
1111 CTR3(KTR_WITNESS, "%s: adding %s as a child of %s", __func__,
1112 lock->lo_type, lock1->li_lock->lo_type);
1113 if (!itismychild(lock1->li_lock->lo_witness, w))
1114 /* Witness is dead. */
1115 return;
1116 }
1117 mtx_unlock_spin(&w_mtx);
1118 return;
1119
1120 #ifdef KDB
1121 debugger:
1122 if (witness_trace)
1123 kdb_backtrace();
1124 if (witness_kdb)
1125 kdb_enter(__func__);
1126 #endif
1127 }
1128
1129 void
1130 witness_lock(struct lock_object *lock, int flags, const char *file, int line)
1131 {
1132 struct lock_list_entry **lock_list, *lle;
1133 struct lock_instance *instance;
1134 struct witness *w;
1135 struct thread *td;
1136
1137 if (witness_cold || witness_watch == 0 || lock->lo_witness == NULL ||
1138 panicstr != NULL)
1139 return;
1140 w = lock->lo_witness;
1141 td = curthread;
1142 file = fixup_filename(file);
1143
1144 /* Determine lock list for this lock. */
1145 if (LOCK_CLASS(lock)->lc_flags & LC_SLEEPLOCK)
1146 lock_list = &td->td_sleeplocks;
1147 else
1148 lock_list = PCPU_PTR(spinlocks);
1149
1150 /* Check to see if we are recursing on a lock we already own. */
1151 instance = find_instance(*lock_list, lock);
1152 if (instance != NULL) {
1153 instance->li_flags++;
1154 CTR4(KTR_WITNESS, "%s: pid %d recursed on %s r=%d", __func__,
1155 td->td_proc->p_pid, lock->lo_name,
1156 instance->li_flags & LI_RECURSEMASK);
1157 instance->li_file = file;
1158 instance->li_line = line;
1159 return;
1160 }
1161
1162 /* Update per-witness last file and line acquire. */
1163 w->w_file = file;
1164 w->w_line = line;
1165
1166 /* Find the next open lock instance in the list and fill it. */
1167 lle = *lock_list;
1168 if (lle == NULL || lle->ll_count == LOCK_NCHILDREN) {
1169 lle = witness_lock_list_get();
1170 if (lle == NULL)
1171 return;
1172 lle->ll_next = *lock_list;
1173 CTR3(KTR_WITNESS, "%s: pid %d added lle %p", __func__,
1174 td->td_proc->p_pid, lle);
1175 *lock_list = lle;
1176 }
1177 instance = &lle->ll_children[lle->ll_count++];
1178 instance->li_lock = lock;
1179 instance->li_line = line;
1180 instance->li_file = file;
1181 if ((flags & LOP_EXCLUSIVE) != 0)
1182 instance->li_flags = LI_EXCLUSIVE;
1183 else
1184 instance->li_flags = 0;
1185 CTR4(KTR_WITNESS, "%s: pid %d added %s as lle[%d]", __func__,
1186 td->td_proc->p_pid, lock->lo_name, lle->ll_count - 1);
1187 }
1188
1189 void
1190 witness_upgrade(struct lock_object *lock, int flags, const char *file, int line)
1191 {
1192 struct lock_instance *instance;
1193 struct lock_class *class;
1194
1195 KASSERT(!witness_cold, ("%s: witness_cold", __func__));
1196 if (lock->lo_witness == NULL || witness_watch == 0 || panicstr != NULL)
1197 return;
1198 class = LOCK_CLASS(lock);
1199 file = fixup_filename(file);
1200 if ((lock->lo_flags & LO_UPGRADABLE) == 0)
1201 panic("upgrade of non-upgradable lock (%s) %s @ %s:%d",
1202 class->lc_name, lock->lo_name, file, line);
1203 if ((flags & LOP_TRYLOCK) == 0)
1204 panic("non-try upgrade of lock (%s) %s @ %s:%d", class->lc_name,
1205 lock->lo_name, file, line);
1206 if ((class->lc_flags & LC_SLEEPLOCK) == 0)
1207 panic("upgrade of non-sleep lock (%s) %s @ %s:%d",
1208 class->lc_name, lock->lo_name, file, line);
1209 instance = find_instance(curthread->td_sleeplocks, lock);
1210 if (instance == NULL)
1211 panic("upgrade of unlocked lock (%s) %s @ %s:%d",
1212 class->lc_name, lock->lo_name, file, line);
1213 if ((instance->li_flags & LI_EXCLUSIVE) != 0)
1214 panic("upgrade of exclusive lock (%s) %s @ %s:%d",
1215 class->lc_name, lock->lo_name, file, line);
1216 if ((instance->li_flags & LI_RECURSEMASK) != 0)
1217 panic("upgrade of recursed lock (%s) %s r=%d @ %s:%d",
1218 class->lc_name, lock->lo_name,
1219 instance->li_flags & LI_RECURSEMASK, file, line);
1220 instance->li_flags |= LI_EXCLUSIVE;
1221 }
1222
1223 void
1224 witness_downgrade(struct lock_object *lock, int flags, const char *file,
1225 int line)
1226 {
1227 struct lock_instance *instance;
1228 struct lock_class *class;
1229
1230 KASSERT(!witness_cold, ("%s: witness_cold", __func__));
1231 if (lock->lo_witness == NULL || witness_watch == 0 || panicstr != NULL)
1232 return;
1233 class = LOCK_CLASS(lock);
1234 file = fixup_filename(file);
1235 if ((lock->lo_flags & LO_UPGRADABLE) == 0)
1236 panic("downgrade of non-upgradable lock (%s) %s @ %s:%d",
1237 class->lc_name, lock->lo_name, file, line);
1238 if ((class->lc_flags & LC_SLEEPLOCK) == 0)
1239 panic("downgrade of non-sleep lock (%s) %s @ %s:%d",
1240 class->lc_name, lock->lo_name, file, line);
1241 instance = find_instance(curthread->td_sleeplocks, lock);
1242 if (instance == NULL)
1243 panic("downgrade of unlocked lock (%s) %s @ %s:%d",
1244 class->lc_name, lock->lo_name, file, line);
1245 if ((instance->li_flags & LI_EXCLUSIVE) == 0)
1246 panic("downgrade of shared lock (%s) %s @ %s:%d",
1247 class->lc_name, lock->lo_name, file, line);
1248 if ((instance->li_flags & LI_RECURSEMASK) != 0)
1249 panic("downgrade of recursed lock (%s) %s r=%d @ %s:%d",
1250 class->lc_name, lock->lo_name,
1251 instance->li_flags & LI_RECURSEMASK, file, line);
1252 instance->li_flags &= ~LI_EXCLUSIVE;
1253 }
1254
1255 void
1256 witness_unlock(struct lock_object *lock, int flags, const char *file, int line)
1257 {
1258 struct lock_list_entry **lock_list, *lle;
1259 struct lock_instance *instance;
1260 struct lock_class *class;
1261 struct thread *td;
1262 register_t s;
1263 int i, j;
1264
1265 if (witness_cold || witness_watch == 0 || lock->lo_witness == NULL ||
1266 panicstr != NULL)
1267 return;
1268 td = curthread;
1269 class = LOCK_CLASS(lock);
1270 file = fixup_filename(file);
1271
1272 /* Find lock instance associated with this lock. */
1273 if (class->lc_flags & LC_SLEEPLOCK)
1274 lock_list = &td->td_sleeplocks;
1275 else
1276 lock_list = PCPU_PTR(spinlocks);
1277 for (; *lock_list != NULL; lock_list = &(*lock_list)->ll_next)
1278 for (i = 0; i < (*lock_list)->ll_count; i++) {
1279 instance = &(*lock_list)->ll_children[i];
1280 if (instance->li_lock == lock)
1281 goto found;
1282 }
1283 panic("lock (%s) %s not locked @ %s:%d", class->lc_name, lock->lo_name,
1284 file, line);
1285 found:
1286
1287 /* First, check for shared/exclusive mismatches. */
1288 if ((instance->li_flags & LI_EXCLUSIVE) != 0 &&
1289 (flags & LOP_EXCLUSIVE) == 0) {
1290 printf("shared unlock of (%s) %s @ %s:%d\n", class->lc_name,
1291 lock->lo_name, file, line);
1292 printf("while exclusively locked from %s:%d\n",
1293 instance->li_file, instance->li_line);
1294 panic("excl->ushare");
1295 }
1296 if ((instance->li_flags & LI_EXCLUSIVE) == 0 &&
1297 (flags & LOP_EXCLUSIVE) != 0) {
1298 printf("exclusive unlock of (%s) %s @ %s:%d\n", class->lc_name,
1299 lock->lo_name, file, line);
1300 printf("while share locked from %s:%d\n", instance->li_file,
1301 instance->li_line);
1302 panic("share->uexcl");
1303 }
1304
1305 /* If we are recursed, unrecurse. */
1306 if ((instance->li_flags & LI_RECURSEMASK) > 0) {
1307 CTR4(KTR_WITNESS, "%s: pid %d unrecursed on %s r=%d", __func__,
1308 td->td_proc->p_pid, instance->li_lock->lo_name,
1309 instance->li_flags);
1310 instance->li_flags--;
1311 return;
1312 }
1313
1314 /* Otherwise, remove this item from the list. */
1315 s = intr_disable();
1316 CTR4(KTR_WITNESS, "%s: pid %d removed %s from lle[%d]", __func__,
1317 td->td_proc->p_pid, instance->li_lock->lo_name,
1318 (*lock_list)->ll_count - 1);
1319 for (j = i; j < (*lock_list)->ll_count - 1; j++)
1320 (*lock_list)->ll_children[j] =
1321 (*lock_list)->ll_children[j + 1];
1322 (*lock_list)->ll_count--;
1323 intr_restore(s);
1324
1325 /* If this lock list entry is now empty, free it. */
1326 if ((*lock_list)->ll_count == 0) {
1327 lle = *lock_list;
1328 *lock_list = lle->ll_next;
1329 CTR3(KTR_WITNESS, "%s: pid %d removed lle %p", __func__,
1330 td->td_proc->p_pid, lle);
1331 witness_lock_list_free(lle);
1332 }
1333 }
1334
1335 /*
1336 * Warn if any locks other than 'lock' are held. Flags can be passed in to
1337 * exempt Giant and sleepable locks from the checks as well. If any
1338 * non-exempt locks are held, then a supplied message is printed to the
1339 * console along with a list of the offending locks. If indicated in the
1340 * flags then a failure results in a panic as well.
1341 */
1342 int
1343 witness_warn(int flags, struct lock_object *lock, const char *fmt, ...)
1344 {
1345 struct lock_list_entry *lle;
1346 struct lock_instance *lock1;
1347 struct thread *td;
1348 va_list ap;
1349 int i, n;
1350
1351 if (witness_cold || witness_watch == 0 || panicstr != NULL)
1352 return (0);
1353 n = 0;
1354 td = curthread;
1355 for (lle = td->td_sleeplocks; lle != NULL; lle = lle->ll_next)
1356 for (i = lle->ll_count - 1; i >= 0; i--) {
1357 lock1 = &lle->ll_children[i];
1358 if (lock1->li_lock == lock)
1359 continue;
1360 if (flags & WARN_GIANTOK &&
1361 lock1->li_lock == &Giant.lock_object)
1362 continue;
1363 if (flags & WARN_SLEEPOK &&
1364 (lock1->li_lock->lo_flags & LO_SLEEPABLE) != 0)
1365 continue;
1366 if (n == 0) {
1367 va_start(ap, fmt);
1368 vprintf(fmt, ap);
1369 va_end(ap);
1370 printf(" with the following");
1371 if (flags & WARN_SLEEPOK)
1372 printf(" non-sleepable");
1373 printf(" locks held:\n");
1374 }
1375 n++;
1376 witness_list_lock(lock1);
1377 }
1378 if (PCPU_GET(spinlocks) != NULL) {
1379 /*
1380 * Since we already hold a spinlock preemption is
1381 * already blocked.
1382 */
1383 if (n == 0) {
1384 va_start(ap, fmt);
1385 vprintf(fmt, ap);
1386 va_end(ap);
1387 printf(" with the following");
1388 if (flags & WARN_SLEEPOK)
1389 printf(" non-sleepable");
1390 printf(" locks held:\n");
1391 }
1392 n += witness_list_locks(PCPU_PTR(spinlocks));
1393 }
1394 if (flags & WARN_PANIC && n)
1395 panic("witness_warn");
1396 #ifdef KDB
1397 else if (witness_kdb && n)
1398 kdb_enter(__func__);
1399 else if (witness_trace && n)
1400 kdb_backtrace();
1401 #endif
1402 return (n);
1403 }
1404
1405 const char *
1406 witness_file(struct lock_object *lock)
1407 {
1408 struct witness *w;
1409
1410 if (witness_cold || witness_watch == 0 || lock->lo_witness == NULL)
1411 return ("?");
1412 w = lock->lo_witness;
1413 return (w->w_file);
1414 }
1415
1416 int
1417 witness_line(struct lock_object *lock)
1418 {
1419 struct witness *w;
1420
1421 if (witness_cold || witness_watch == 0 || lock->lo_witness == NULL)
1422 return (0);
1423 w = lock->lo_witness;
1424 return (w->w_line);
1425 }
1426
1427 static struct witness *
1428 enroll(const char *description, struct lock_class *lock_class)
1429 {
1430 struct witness *w;
1431
1432 if (witness_watch == 0 || panicstr != NULL)
1433 return (NULL);
1434 if ((lock_class->lc_flags & LC_SPINLOCK) && witness_skipspin)
1435 return (NULL);
1436 mtx_lock_spin(&w_mtx);
1437 STAILQ_FOREACH(w, &w_all, w_list) {
1438 if (w->w_name == description || (w->w_refcount > 0 &&
1439 strcmp(description, w->w_name) == 0)) {
1440 w->w_refcount++;
1441 mtx_unlock_spin(&w_mtx);
1442 if (lock_class != w->w_class)
1443 panic(
1444 "lock (%s) %s does not match earlier (%s) lock",
1445 description, lock_class->lc_name,
1446 w->w_class->lc_name);
1447 return (w);
1448 }
1449 }
1450 if ((w = witness_get()) == NULL)
1451 goto out;
1452 w->w_name = description;
1453 w->w_class = lock_class;
1454 w->w_refcount = 1;
1455 STAILQ_INSERT_HEAD(&w_all, w, w_list);
1456 if (lock_class->lc_flags & LC_SPINLOCK) {
1457 STAILQ_INSERT_HEAD(&w_spin, w, w_typelist);
1458 w_spin_cnt++;
1459 } else if (lock_class->lc_flags & LC_SLEEPLOCK) {
1460 STAILQ_INSERT_HEAD(&w_sleep, w, w_typelist);
1461 w_sleep_cnt++;
1462 } else {
1463 mtx_unlock_spin(&w_mtx);
1464 panic("lock class %s is not sleep or spin",
1465 lock_class->lc_name);
1466 }
1467 mtx_unlock_spin(&w_mtx);
1468 out:
1469 /*
1470 * We issue a warning for any spin locks not defined in the static
1471 * order list as a way to discourage their use (folks should really
1472 * be using non-spin mutexes most of the time). However, several
1473 * 3rd part device drivers use spin locks because that is all they
1474 * have available on Windows and Linux and they think that normal
1475 * mutexes are insufficient.
1476 */
1477 if ((lock_class->lc_flags & LC_SPINLOCK) && witness_spin_warn)
1478 printf("WITNESS: spin lock %s not in order list\n",
1479 description);
1480 return (w);
1481 }
1482
1483 /* Don't let the door bang you on the way out... */
1484 static int
1485 depart(struct witness *w)
1486 {
1487 struct witness_child_list_entry *wcl, *nwcl;
1488 struct witness_list *list;
1489 struct witness *parent;
1490
1491 MPASS(w->w_refcount == 0);
1492 if (w->w_class->lc_flags & LC_SLEEPLOCK) {
1493 list = &w_sleep;
1494 w_sleep_cnt--;
1495 } else {
1496 list = &w_spin;
1497 w_spin_cnt--;
1498 }
1499 /*
1500 * First, we run through the entire tree looking for any
1501 * witnesses that the outgoing witness is a child of. For
1502 * each parent that we find, we reparent all the direct
1503 * children of the outgoing witness to its parent.
1504 */
1505 STAILQ_FOREACH(parent, list, w_typelist) {
1506 if (!isitmychild(parent, w))
1507 continue;
1508 removechild(parent, w);
1509 }
1510
1511 /*
1512 * Now we go through and free up the child list of the
1513 * outgoing witness.
1514 */
1515 for (wcl = w->w_children; wcl != NULL; wcl = nwcl) {
1516 nwcl = wcl->wcl_next;
1517 w_child_cnt--;
1518 witness_child_free(wcl);
1519 }
1520
1521 /*
1522 * Detach from various lists and free.
1523 */
1524 STAILQ_REMOVE(list, w, witness, w_typelist);
1525 STAILQ_REMOVE(&w_all, w, witness, w_list);
1526 witness_free(w);
1527
1528 return (1);
1529 }
1530
1531 /*
1532 * Add "child" as a direct child of "parent". Returns false if
1533 * we fail due to out of memory.
1534 */
1535 static int
1536 insertchild(struct witness *parent, struct witness *child)
1537 {
1538 struct witness_child_list_entry **wcl;
1539
1540 MPASS(child != NULL && parent != NULL);
1541
1542 /*
1543 * Insert "child" after "parent"
1544 */
1545 wcl = &parent->w_children;
1546 while (*wcl != NULL && (*wcl)->wcl_count == WITNESS_NCHILDREN)
1547 wcl = &(*wcl)->wcl_next;
1548 if (*wcl == NULL) {
1549 *wcl = witness_child_get();
1550 if (*wcl == NULL)
1551 return (0);
1552 w_child_cnt++;
1553 }
1554 (*wcl)->wcl_children[(*wcl)->wcl_count++] = child;
1555
1556 return (1);
1557 }
1558
1559
1560 static int
1561 itismychild(struct witness *parent, struct witness *child)
1562 {
1563 struct witness_list *list;
1564
1565 MPASS(child != NULL && parent != NULL);
1566 if ((parent->w_class->lc_flags & (LC_SLEEPLOCK | LC_SPINLOCK)) !=
1567 (child->w_class->lc_flags & (LC_SLEEPLOCK | LC_SPINLOCK)))
1568 panic(
1569 "%s: parent (%s) and child (%s) are not the same lock type",
1570 __func__, parent->w_class->lc_name,
1571 child->w_class->lc_name);
1572
1573 if (!insertchild(parent, child))
1574 return (0);
1575
1576 if (parent->w_class->lc_flags & LC_SLEEPLOCK)
1577 list = &w_sleep;
1578 else
1579 list = &w_spin;
1580 return (1);
1581 }
1582
1583 static void
1584 removechild(struct witness *parent, struct witness *child)
1585 {
1586 struct witness_child_list_entry **wcl, *wcl1;
1587 int i;
1588
1589 for (wcl = &parent->w_children; *wcl != NULL; wcl = &(*wcl)->wcl_next)
1590 for (i = 0; i < (*wcl)->wcl_count; i++)
1591 if ((*wcl)->wcl_children[i] == child)
1592 goto found;
1593 return;
1594 found:
1595 (*wcl)->wcl_count--;
1596 if ((*wcl)->wcl_count > i)
1597 (*wcl)->wcl_children[i] =
1598 (*wcl)->wcl_children[(*wcl)->wcl_count];
1599 MPASS((*wcl)->wcl_children[i] != NULL);
1600 if ((*wcl)->wcl_count != 0)
1601 return;
1602 wcl1 = *wcl;
1603 *wcl = wcl1->wcl_next;
1604 w_child_cnt--;
1605 witness_child_free(wcl1);
1606 }
1607
1608 static int
1609 isitmychild(struct witness *parent, struct witness *child)
1610 {
1611 struct witness_child_list_entry *wcl;
1612 int i;
1613
1614 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) {
1615 for (i = 0; i < wcl->wcl_count; i++) {
1616 if (wcl->wcl_children[i] == child)
1617 return (1);
1618 }
1619 }
1620 return (0);
1621 }
1622
1623 static int
1624 isitmydescendant(struct witness *parent, struct witness *child)
1625 {
1626 struct witness_child_list_entry *wcl;
1627 int i, j;
1628
1629 if (isitmychild(parent, child))
1630 return (1);
1631 j = 0;
1632 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) {
1633 MPASS(j < 1000);
1634 for (i = 0; i < wcl->wcl_count; i++) {
1635 if (isitmydescendant(wcl->wcl_children[i], child))
1636 return (1);
1637 }
1638 j++;
1639 }
1640 return (0);
1641 }
1642
1643 #ifdef BLESSING
1644 static int
1645 blessed(struct witness *w1, struct witness *w2)
1646 {
1647 int i;
1648 struct witness_blessed *b;
1649
1650 for (i = 0; i < blessed_count; i++) {
1651 b = &blessed_list[i];
1652 if (strcmp(w1->w_name, b->b_lock1) == 0) {
1653 if (strcmp(w2->w_name, b->b_lock2) == 0)
1654 return (1);
1655 continue;
1656 }
1657 if (strcmp(w1->w_name, b->b_lock2) == 0)
1658 if (strcmp(w2->w_name, b->b_lock1) == 0)
1659 return (1);
1660 }
1661 return (0);
1662 }
1663 #endif
1664
1665 static struct witness *
1666 witness_get(void)
1667 {
1668 struct witness *w;
1669
1670 if (witness_watch == 0) {
1671 mtx_unlock_spin(&w_mtx);
1672 return (NULL);
1673 }
1674 if (STAILQ_EMPTY(&w_free)) {
1675 witness_watch = 0;
1676 mtx_unlock_spin(&w_mtx);
1677 printf("%s: witness exhausted\n", __func__);
1678 return (NULL);
1679 }
1680 w = STAILQ_FIRST(&w_free);
1681 STAILQ_REMOVE_HEAD(&w_free, w_list);
1682 w_free_cnt--;
1683 bzero(w, sizeof(*w));
1684 return (w);
1685 }
1686
1687 static void
1688 witness_free(struct witness *w)
1689 {
1690
1691 STAILQ_INSERT_HEAD(&w_free, w, w_list);
1692 w_free_cnt++;
1693 }
1694
1695 static struct witness_child_list_entry *
1696 witness_child_get(void)
1697 {
1698 struct witness_child_list_entry *wcl;
1699
1700 if (witness_watch == 0) {
1701 mtx_unlock_spin(&w_mtx);
1702 return (NULL);
1703 }
1704 wcl = w_child_free;
1705 if (wcl == NULL) {
1706 witness_watch = 0;
1707 mtx_unlock_spin(&w_mtx);
1708 printf("%s: witness exhausted\n", __func__);
1709 return (NULL);
1710 }
1711 w_child_free = wcl->wcl_next;
1712 w_child_free_cnt--;
1713 bzero(wcl, sizeof(*wcl));
1714 return (wcl);
1715 }
1716
1717 static void
1718 witness_child_free(struct witness_child_list_entry *wcl)
1719 {
1720
1721 wcl->wcl_next = w_child_free;
1722 w_child_free = wcl;
1723 w_child_free_cnt++;
1724 }
1725
1726 static struct lock_list_entry *
1727 witness_lock_list_get(void)
1728 {
1729 struct lock_list_entry *lle;
1730
1731 if (witness_watch == 0)
1732 return (NULL);
1733 mtx_lock_spin(&w_mtx);
1734 lle = w_lock_list_free;
1735 if (lle == NULL) {
1736 witness_watch = 0;
1737 mtx_unlock_spin(&w_mtx);
1738 printf("%s: witness exhausted\n", __func__);
1739 return (NULL);
1740 }
1741 w_lock_list_free = lle->ll_next;
1742 mtx_unlock_spin(&w_mtx);
1743 bzero(lle, sizeof(*lle));
1744 return (lle);
1745 }
1746
1747 static void
1748 witness_lock_list_free(struct lock_list_entry *lle)
1749 {
1750
1751 mtx_lock_spin(&w_mtx);
1752 lle->ll_next = w_lock_list_free;
1753 w_lock_list_free = lle;
1754 mtx_unlock_spin(&w_mtx);
1755 }
1756
1757 static struct lock_instance *
1758 find_instance(struct lock_list_entry *lock_list, struct lock_object *lock)
1759 {
1760 struct lock_list_entry *lle;
1761 struct lock_instance *instance;
1762 int i;
1763
1764 for (lle = lock_list; lle != NULL; lle = lle->ll_next)
1765 for (i = lle->ll_count - 1; i >= 0; i--) {
1766 instance = &lle->ll_children[i];
1767 if (instance->li_lock == lock)
1768 return (instance);
1769 }
1770 return (NULL);
1771 }
1772
1773 static void
1774 witness_list_lock(struct lock_instance *instance)
1775 {
1776 struct lock_object *lock;
1777
1778 lock = instance->li_lock;
1779 printf("%s %s %s", (instance->li_flags & LI_EXCLUSIVE) != 0 ?
1780 "exclusive" : "shared", LOCK_CLASS(lock)->lc_name, lock->lo_name);
1781 if (lock->lo_type != lock->lo_name)
1782 printf(" (%s)", lock->lo_type);
1783 printf(" r = %d (%p) locked @ %s:%d\n",
1784 instance->li_flags & LI_RECURSEMASK, lock, instance->li_file,
1785 instance->li_line);
1786 }
1787
1788 #ifdef DDB
1789 static int
1790 witness_thread_has_locks(struct thread *td)
1791 {
1792
1793 return (td->td_sleeplocks != NULL);
1794 }
1795
1796 static int
1797 witness_proc_has_locks(struct proc *p)
1798 {
1799 struct thread *td;
1800
1801 FOREACH_THREAD_IN_PROC(p, td) {
1802 if (witness_thread_has_locks(td))
1803 return (1);
1804 }
1805 return (0);
1806 }
1807 #endif
1808
1809 int
1810 witness_list_locks(struct lock_list_entry **lock_list)
1811 {
1812 struct lock_list_entry *lle;
1813 int i, nheld;
1814
1815 nheld = 0;
1816 for (lle = *lock_list; lle != NULL; lle = lle->ll_next)
1817 for (i = lle->ll_count - 1; i >= 0; i--) {
1818 witness_list_lock(&lle->ll_children[i]);
1819 nheld++;
1820 }
1821 return (nheld);
1822 }
1823
1824 /*
1825 * This is a bit risky at best. We call this function when we have timed
1826 * out acquiring a spin lock, and we assume that the other CPU is stuck
1827 * with this lock held. So, we go groveling around in the other CPU's
1828 * per-cpu data to try to find the lock instance for this spin lock to
1829 * see when it was last acquired.
1830 */
1831 void
1832 witness_display_spinlock(struct lock_object *lock, struct thread *owner)
1833 {
1834 struct lock_instance *instance;
1835 struct pcpu *pc;
1836
1837 if (owner->td_critnest == 0 || owner->td_oncpu == NOCPU)
1838 return;
1839 pc = pcpu_find(owner->td_oncpu);
1840 instance = find_instance(pc->pc_spinlocks, lock);
1841 if (instance != NULL)
1842 witness_list_lock(instance);
1843 }
1844
1845 void
1846 witness_save(struct lock_object *lock, const char **filep, int *linep)
1847 {
1848 struct lock_list_entry *lock_list;
1849 struct lock_instance *instance;
1850 struct lock_class *class;
1851
1852 KASSERT(!witness_cold, ("%s: witness_cold", __func__));
1853 if (lock->lo_witness == NULL || witness_watch == 0 || panicstr != NULL)
1854 return;
1855 class = LOCK_CLASS(lock);
1856 if (class->lc_flags & LC_SLEEPLOCK)
1857 lock_list = curthread->td_sleeplocks;
1858 else {
1859 if (witness_skipspin)
1860 return;
1861 lock_list = PCPU_GET(spinlocks);
1862 }
1863 instance = find_instance(lock_list, lock);
1864 if (instance == NULL)
1865 panic("%s: lock (%s) %s not locked", __func__,
1866 class->lc_name, lock->lo_name);
1867 *filep = instance->li_file;
1868 *linep = instance->li_line;
1869 }
1870
1871 void
1872 witness_restore(struct lock_object *lock, const char *file, int line)
1873 {
1874 struct lock_list_entry *lock_list;
1875 struct lock_instance *instance;
1876 struct lock_class *class;
1877
1878 KASSERT(!witness_cold, ("%s: witness_cold", __func__));
1879 if (lock->lo_witness == NULL || witness_watch == 0 || panicstr != NULL)
1880 return;
1881 class = LOCK_CLASS(lock);
1882 if (class->lc_flags & LC_SLEEPLOCK)
1883 lock_list = curthread->td_sleeplocks;
1884 else {
1885 if (witness_skipspin)
1886 return;
1887 lock_list = PCPU_GET(spinlocks);
1888 }
1889 instance = find_instance(lock_list, lock);
1890 if (instance == NULL)
1891 panic("%s: lock (%s) %s not locked", __func__,
1892 class->lc_name, lock->lo_name);
1893 lock->lo_witness->w_file = file;
1894 lock->lo_witness->w_line = line;
1895 instance->li_file = file;
1896 instance->li_line = line;
1897 }
1898
1899 void
1900 witness_assert(struct lock_object *lock, int flags, const char *file, int line)
1901 {
1902 #ifdef INVARIANT_SUPPORT
1903 struct lock_instance *instance;
1904 struct lock_class *class;
1905
1906 if (lock->lo_witness == NULL || witness_watch == 0 || panicstr != NULL)
1907 return;
1908 class = LOCK_CLASS(lock);
1909 if ((class->lc_flags & LC_SLEEPLOCK) != 0)
1910 instance = find_instance(curthread->td_sleeplocks, lock);
1911 else if ((class->lc_flags & LC_SPINLOCK) != 0)
1912 instance = find_instance(PCPU_GET(spinlocks), lock);
1913 else {
1914 panic("Lock (%s) %s is not sleep or spin!",
1915 class->lc_name, lock->lo_name);
1916 }
1917 file = fixup_filename(file);
1918 switch (flags) {
1919 case LA_UNLOCKED:
1920 if (instance != NULL)
1921 panic("Lock (%s) %s locked @ %s:%d.",
1922 class->lc_name, lock->lo_name, file, line);
1923 break;
1924 case LA_LOCKED:
1925 case LA_LOCKED | LA_RECURSED:
1926 case LA_LOCKED | LA_NOTRECURSED:
1927 case LA_SLOCKED:
1928 case LA_SLOCKED | LA_RECURSED:
1929 case LA_SLOCKED | LA_NOTRECURSED:
1930 case LA_XLOCKED:
1931 case LA_XLOCKED | LA_RECURSED:
1932 case LA_XLOCKED | LA_NOTRECURSED:
1933 if (instance == NULL) {
1934 panic("Lock (%s) %s not locked @ %s:%d.",
1935 class->lc_name, lock->lo_name, file, line);
1936 break;
1937 }
1938 if ((flags & LA_XLOCKED) != 0 &&
1939 (instance->li_flags & LI_EXCLUSIVE) == 0)
1940 panic("Lock (%s) %s not exclusively locked @ %s:%d.",
1941 class->lc_name, lock->lo_name, file, line);
1942 if ((flags & LA_SLOCKED) != 0 &&
1943 (instance->li_flags & LI_EXCLUSIVE) != 0)
1944 panic("Lock (%s) %s exclusively locked @ %s:%d.",
1945 class->lc_name, lock->lo_name, file, line);
1946 if ((flags & LA_RECURSED) != 0 &&
1947 (instance->li_flags & LI_RECURSEMASK) == 0)
1948 panic("Lock (%s) %s not recursed @ %s:%d.",
1949 class->lc_name, lock->lo_name, file, line);
1950 if ((flags & LA_NOTRECURSED) != 0 &&
1951 (instance->li_flags & LI_RECURSEMASK) != 0)
1952 panic("Lock (%s) %s recursed @ %s:%d.",
1953 class->lc_name, lock->lo_name, file, line);
1954 break;
1955 default:
1956 panic("Invalid lock assertion at %s:%d.", file, line);
1957
1958 }
1959 #endif /* INVARIANT_SUPPORT */
1960 }
1961
1962 #ifdef DDB
1963 static void
1964 witness_list(struct thread *td)
1965 {
1966
1967 KASSERT(!witness_cold, ("%s: witness_cold", __func__));
1968 KASSERT(kdb_active, ("%s: not in the debugger", __func__));
1969
1970 if (witness_watch == 0)
1971 return;
1972
1973 witness_list_locks(&td->td_sleeplocks);
1974
1975 /*
1976 * We only handle spinlocks if td == curthread. This is somewhat broken
1977 * if td is currently executing on some other CPU and holds spin locks
1978 * as we won't display those locks. If we had a MI way of getting
1979 * the per-cpu data for a given cpu then we could use
1980 * td->td_oncpu to get the list of spinlocks for this thread
1981 * and "fix" this.
1982 *
1983 * That still wouldn't really fix this unless we locked the scheduler
1984 * lock or stopped the other CPU to make sure it wasn't changing the
1985 * list out from under us. It is probably best to just not try to
1986 * handle threads on other CPU's for now.
1987 */
1988 if (td == curthread && PCPU_GET(spinlocks) != NULL)
1989 witness_list_locks(PCPU_PTR(spinlocks));
1990 }
1991
1992 DB_SHOW_COMMAND(locks, db_witness_list)
1993 {
1994 struct thread *td;
1995
1996 if (have_addr)
1997 td = db_lookup_thread(addr, TRUE);
1998 else
1999 td = kdb_thread;
2000 witness_list(td);
2001 }
2002
2003 DB_SHOW_COMMAND(alllocks, db_witness_list_all)
2004 {
2005 struct thread *td;
2006 struct proc *p;
2007
2008 /*
2009 * It would be nice to list only threads and processes that actually
2010 * held sleep locks, but that information is currently not exported
2011 * by WITNESS.
2012 */
2013 FOREACH_PROC_IN_SYSTEM(p) {
2014 if (!witness_proc_has_locks(p))
2015 continue;
2016 FOREACH_THREAD_IN_PROC(p, td) {
2017 if (!witness_thread_has_locks(td))
2018 continue;
2019 db_printf("Process %d (%s) thread %p (%d)\n", p->p_pid,
2020 p->p_comm, td, td->td_tid);
2021 witness_list(td);
2022 }
2023 }
2024 }
2025
2026 DB_SHOW_COMMAND(witness, db_witness_display)
2027 {
2028
2029 witness_display(db_printf);
2030 }
2031 #endif
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