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subr_lockdebug.c revision 1.5.2.7 
      1 /*	$NetBSD: subr_lockdebug.c,v 1.5.2.7 2007/08/20 23:04:50 ad Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2006, 2007 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Andrew Doran.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  * 3. All advertising materials mentioning features or use of this software
     19  *    must display the following acknowledgement:
     20  *	This product includes software developed by the NetBSD
     21  *	Foundation, Inc. and its contributors.
     22  * 4. Neither the name of The NetBSD Foundation nor the names of its
     23  *    contributors may be used to endorse or promote products derived
     24  *    from this software without specific prior written permission.
     25  *
     26  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     27  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     28  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     29  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     30  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     31  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     34  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     36  * POSSIBILITY OF SUCH DAMAGE.
     37  */
     38 
     39 /*
     40  * Basic lock debugging code shared among lock primatives.
     41  */
     42 
     43 #include "opt_multiprocessor.h"
     44 #include "opt_ddb.h"
     45 
     46 #include <sys/cdefs.h>
     47 __KERNEL_RCSID(0, "$NetBSD: subr_lockdebug.c,v 1.5.2.7 2007/08/20 23:04:50 ad Exp $");
     48 
     49 #include <sys/param.h>
     50 #include <sys/proc.h>
     51 #include <sys/systm.h>
     52 #include <sys/kernel.h>
     53 #include <sys/kmem.h>
     54 #include <sys/lock.h>
     55 #include <sys/lockdebug.h>
     56 #include <sys/sleepq.h>
     57 #include <sys/cpu.h>
     58 
     59 #ifdef LOCKDEBUG
     60 
     61 #define	LD_BATCH_SHIFT	9
     62 #define	LD_BATCH	(1 << LD_BATCH_SHIFT)
     63 #define	LD_BATCH_MASK	(LD_BATCH - 1)
     64 #define	LD_MAX_LOCKS	1048576
     65 #define	LD_SLOP		16
     66 
     67 #define	LD_LOCKED	0x01
     68 #define	LD_SLEEPER	0x02
     69 #define	LD_MLOCKS	8
     70 #define	LD_MLISTS	8192
     71 
     72 #define	LD_NOID		(LD_MAX_LOCKS + 1)
     73 
     74 typedef union lockdebuglk {
     75 	struct {
     76 		__cpu_simple_lock_t	lku_lock;
     77 		int			lku_oldspl;
     78 	} ul;
     79 	uint8_t	lk_pad[64];
     80 } volatile __aligned(64) lockdebuglk_t;
     81 
     82 #define	lk_lock		ul.lku_lock
     83 #define	lk_oldspl	ul.lku_oldspl
     84 
     85 typedef struct lockdebug {
     86 	_TAILQ_ENTRY(struct lockdebug, volatile) ld_chain;
     87 	_TAILQ_ENTRY(struct lockdebug, volatile) ld_achain;
     88 	_TAILQ_ENTRY(struct lockdebug, volatile) ld_mchain;
     89 	volatile void	*ld_lock;
     90 	lockops_t	*ld_lockops;
     91 	struct lwp	*ld_lwp;
     92 	uintptr_t	ld_locked;
     93 	uintptr_t	ld_unlocked;
     94 	uintptr_t	ld_initaddr;
     95 	u_int		ld_id;
     96 	uint16_t	ld_shares;
     97 	uint16_t	ld_cpu;
     98 	uint8_t		ld_flags;
     99 	uint8_t		ld_shwant;	/* advisory */
    100 	uint8_t		ld_exwant;	/* advisory */
    101 	uint8_t		ld_unused;
    102 } volatile lockdebug_t;
    103 
    104 typedef _TAILQ_HEAD(lockdebuglist, struct lockdebug, volatile) lockdebuglist_t;
    105 
    106 lockdebuglk_t		ld_sleeper_lk;
    107 lockdebuglk_t		ld_spinner_lk;
    108 lockdebuglk_t		ld_free_lk;
    109 lockdebuglk_t		ld_mem_lk[LD_MLOCKS];
    110 
    111 lockdebuglist_t		ld_mem_list[LD_MLISTS];
    112 lockdebuglist_t		ld_sleepers;
    113 lockdebuglist_t		ld_spinners;
    114 lockdebuglist_t		ld_free;
    115 lockdebuglist_t		ld_all;
    116 int			ld_nfree;
    117 int			ld_freeptr;
    118 int			ld_recurse;
    119 bool			ld_nomore;
    120 lockdebug_t		*ld_table[LD_MAX_LOCKS / LD_BATCH];
    121 
    122 lockdebug_t		ld_prime[LD_BATCH];
    123 
    124 static void	lockdebug_abort1(lockdebug_t *, lockdebuglk_t *lk,
    125 				 const char *, const char *, bool);
    126 static void	lockdebug_more(void);
    127 static void	lockdebug_init(void);
    128 
    129 static inline void
    130 lockdebug_lock(lockdebuglk_t *lk)
    131 {
    132 	int s;
    133 
    134 	s = splhigh();
    135 	__cpu_simple_lock(&lk->lk_lock);
    136 	lk->lk_oldspl = s;
    137 }
    138 
    139 static inline void
    140 lockdebug_unlock(lockdebuglk_t *lk)
    141 {
    142 	int s;
    143 
    144 	s = lk->lk_oldspl;
    145 	__cpu_simple_unlock(&(lk->lk_lock));
    146 	splx(s);
    147 }
    148 
    149 static inline void
    150 lockdebug_mhash(volatile void *addr, lockdebuglk_t **lk, lockdebuglist_t **head)
    151 {
    152 	u_int hash;
    153 
    154 	hash = (uintptr_t)addr >> PGSHIFT;
    155 	*lk = &ld_mem_lk[hash & (LD_MLOCKS - 1)];
    156 	*head = &ld_mem_list[hash & (LD_MLISTS - 1)];
    157 	lockdebug_lock(*lk);
    158 }
    159 
    160 /*
    161  * lockdebug_lookup:
    162  *
    163  *	Find a lockdebug structure by ID and return it locked.
    164  */
    165 static inline lockdebug_t *
    166 lockdebug_lookup(u_int id, lockdebuglk_t **lk)
    167 {
    168 	lockdebug_t *base, *ld;
    169 
    170 	if (id == LD_NOID)
    171 		return NULL;
    172 
    173 	if (id == 0 || id >= LD_MAX_LOCKS)
    174 		panic("lockdebug_lookup: uninitialized lock (1, id=%d)", id);
    175 
    176 	base = ld_table[id >> LD_BATCH_SHIFT];
    177 	ld = base + (id & LD_BATCH_MASK);
    178 
    179 	if (base == NULL || ld->ld_lock == NULL || ld->ld_id != id)
    180 		panic("lockdebug_lookup: uninitialized lock (2, id=%d)", id);
    181 
    182 	if ((ld->ld_flags & LD_SLEEPER) != 0)
    183 		*lk = &ld_sleeper_lk;
    184 	else
    185 		*lk = &ld_spinner_lk;
    186 
    187 	lockdebug_lock(*lk);
    188 	return ld;
    189 }
    190 
    191 /*
    192  * lockdebug_init:
    193  *
    194  *	Initialize the lockdebug system.  Allocate an initial pool of
    195  *	lockdebug structures before the VM system is up and running.
    196  */
    197 static void
    198 lockdebug_init(void)
    199 {
    200 	lockdebug_t *ld;
    201 	int i;
    202 
    203 	__cpu_simple_lock_init(&ld_sleeper_lk.lk_lock);
    204 	__cpu_simple_lock_init(&ld_spinner_lk.lk_lock);
    205 	__cpu_simple_lock_init(&ld_free_lk.lk_lock);
    206 
    207 	TAILQ_INIT(&ld_free);
    208 	TAILQ_INIT(&ld_all);
    209 	TAILQ_INIT(&ld_sleepers);
    210 	TAILQ_INIT(&ld_spinners);
    211 
    212 	ld = ld_prime;
    213 	ld_table[0] = ld;
    214 	for (i = 1, ld++; i < LD_BATCH; i++, ld++) {
    215 		ld->ld_id = i;
    216 		TAILQ_INSERT_TAIL(&ld_free, ld, ld_chain);
    217 		TAILQ_INSERT_TAIL(&ld_all, ld, ld_achain);
    218 	}
    219 	ld_freeptr = 1;
    220 	ld_nfree = LD_BATCH - 1;
    221 
    222 	for (i = 0; i < LD_MLOCKS; i++)
    223 		__cpu_simple_lock_init(&ld_mem_lk[i].lk_lock);
    224 	for (i = 0; i < LD_MLISTS; i++)
    225 		TAILQ_INIT(&ld_mem_list[i]);
    226 }
    227 
    228 /*
    229  * lockdebug_alloc:
    230  *
    231  *	A lock is being initialized, so allocate an associated debug
    232  *	structure.
    233  */
    234 u_int
    235 lockdebug_alloc(volatile void *lock, lockops_t *lo, uintptr_t initaddr)
    236 {
    237 #if 0
    238 	lockdebuglist_t *head;
    239 	lockdebuglk_t *lk;
    240 #endif
    241 	struct cpu_info *ci;
    242 	lockdebug_t *ld;
    243 
    244 	if (lo == NULL || panicstr != NULL)
    245 		return LD_NOID;
    246 	if (ld_freeptr == 0)
    247 		lockdebug_init();
    248 
    249 	ci = curcpu();
    250 
    251 	/*
    252 	 * Pinch a new debug structure.  We may recurse because we call
    253 	 * kmem_alloc(), which may need to initialize new locks somewhere
    254 	 * down the path.  If not recursing, we try to maintain at least
    255 	 * LD_SLOP structures free, which should hopefully be enough to
    256 	 * satisfy kmem_alloc().  If we can't provide a structure, not to
    257 	 * worry: we'll just mark the lock as not having an ID.
    258 	 */
    259 	lockdebug_lock(&ld_free_lk);
    260 	ci->ci_lkdebug_recurse++;
    261 
    262 	if (TAILQ_EMPTY(&ld_free)) {
    263 		if (ci->ci_lkdebug_recurse > 1 || ld_nomore) {
    264 			ci->ci_lkdebug_recurse--;
    265 			lockdebug_unlock(&ld_free_lk);
    266 			return LD_NOID;
    267 		}
    268 		lockdebug_more();
    269 	} else if (ci->ci_lkdebug_recurse == 1 && ld_nfree < LD_SLOP)
    270 		lockdebug_more();
    271 
    272 	if ((ld = TAILQ_FIRST(&ld_free)) == NULL) {
    273 		lockdebug_unlock(&ld_free_lk);
    274 		return LD_NOID;
    275 	}
    276 
    277 	TAILQ_REMOVE(&ld_free, ld, ld_chain);
    278 	ld_nfree--;
    279 
    280 	ci->ci_lkdebug_recurse--;
    281 	lockdebug_unlock(&ld_free_lk);
    282 
    283 	if (ld->ld_lock != NULL)
    284 		panic("lockdebug_alloc: corrupt table");
    285 
    286 	if (lo->lo_sleeplock)
    287 		lockdebug_lock(&ld_sleeper_lk);
    288 	else
    289 		lockdebug_lock(&ld_spinner_lk);
    290 
    291 	/* Initialise the structure. */
    292 	ld->ld_lock = lock;
    293 	ld->ld_lockops = lo;
    294 	ld->ld_locked = 0;
    295 	ld->ld_unlocked = 0;
    296 	ld->ld_lwp = NULL;
    297 	ld->ld_initaddr = initaddr;
    298 
    299 	if (lo->lo_sleeplock) {
    300 		ld->ld_flags = LD_SLEEPER;
    301 		lockdebug_unlock(&ld_sleeper_lk);
    302 	} else {
    303 		ld->ld_flags = 0;
    304 		lockdebug_unlock(&ld_spinner_lk);
    305 	}
    306 
    307 #if 0
    308 	/* Insert into address hash. */
    309 	lockdebug_mhash(lock, &lk, &head);
    310 	TAILQ_INSERT_HEAD(head, ld, ld_mchain);
    311 	lockdebug_unlock(lk);
    312 #endif
    313 
    314 	return ld->ld_id;
    315 }
    316 
    317 /*
    318  * lockdebug_free:
    319  *
    320  *	A lock is being destroyed, so release debugging resources.
    321  */
    322 void
    323 lockdebug_free(volatile void *lock, u_int id)
    324 {
    325 #if 0
    326 	lockdebuglist_t *head;
    327 #endif
    328 	lockdebug_t *ld;
    329 	lockdebuglk_t *lk;
    330 
    331 	if (panicstr != NULL)
    332 		return;
    333 
    334 	if ((ld = lockdebug_lookup(id, &lk)) == NULL)
    335 		return;
    336 
    337 	if (ld->ld_lock != lock) {
    338 		panic("lockdebug_free: destroying uninitialized lock %p"
    339 		    "(ld_id=%d ld_lock=%p)", lock, id, ld->ld_lock);
    340 		lockdebug_abort1(ld, lk, __func__, "lock record follows",
    341 		    true);
    342 	}
    343 	if ((ld->ld_flags & LD_LOCKED) != 0 || ld->ld_shares != 0)
    344 		lockdebug_abort1(ld, lk, __func__, "is locked", true);
    345 
    346 	ld->ld_lock = NULL;
    347 
    348 	lockdebug_unlock(lk);
    349 
    350 	lockdebug_lock(&ld_free_lk);
    351 	TAILQ_INSERT_TAIL(&ld_free, ld, ld_chain);
    352 	ld_nfree++;
    353 	lockdebug_unlock(&ld_free_lk);
    354 
    355 #if 0
    356 	/* Remove from address hash. */
    357 	lockdebug_mhash(lock, &lk, &head);
    358 	TAILQ_REMOVE(head, ld, ld_mchain);
    359 	lockdebug_unlock(lk);
    360 #endif
    361 }
    362 
    363 /*
    364  * lockdebug_more:
    365  *
    366  *	Allocate a batch of debug structures and add to the free list.
    367  *	Must be called with ld_free_lk held.
    368  */
    369 static void
    370 lockdebug_more(void)
    371 {
    372 	lockdebug_t *ld;
    373 	void *block;
    374 	int i, base, m;
    375 
    376 	while (ld_nfree < LD_SLOP) {
    377 		lockdebug_unlock(&ld_free_lk);
    378 		block = kmem_zalloc(LD_BATCH * sizeof(lockdebug_t), KM_SLEEP);
    379 		lockdebug_lock(&ld_free_lk);
    380 
    381 		if (block == NULL)
    382 			return;
    383 
    384 		if (ld_nfree > LD_SLOP) {
    385 			/* Somebody beat us to it. */
    386 			lockdebug_unlock(&ld_free_lk);
    387 			kmem_free(block, LD_BATCH * sizeof(lockdebug_t));
    388 			lockdebug_lock(&ld_free_lk);
    389 			continue;
    390 		}
    391 
    392 		base = ld_freeptr;
    393 		ld_nfree += LD_BATCH;
    394 		ld = block;
    395 		base <<= LD_BATCH_SHIFT;
    396 		m = min(LD_MAX_LOCKS, base + LD_BATCH);
    397 
    398 		if (m == LD_MAX_LOCKS)
    399 			ld_nomore = true;
    400 
    401 		for (i = base; i < m; i++, ld++) {
    402 			ld->ld_id = i;
    403 			TAILQ_INSERT_TAIL(&ld_free, ld, ld_chain);
    404 			TAILQ_INSERT_TAIL(&ld_all, ld, ld_achain);
    405 		}
    406 
    407 		mb_write();
    408 		ld_table[ld_freeptr++] = block;
    409 	}
    410 }
    411 
    412 /*
    413  * lockdebug_wantlock:
    414  *
    415  *	Process the preamble to a lock acquire.
    416  */
    417 void
    418 lockdebug_wantlock(u_int id, uintptr_t where, int shared)
    419 {
    420 	struct lwp *l = curlwp;
    421 	lockdebuglk_t *lk;
    422 	lockdebug_t *ld;
    423 	bool recurse;
    424 
    425 	(void)shared;
    426 	recurse = false;
    427 
    428 	if (panicstr != NULL)
    429 		return;
    430 
    431 	if ((ld = lockdebug_lookup(id, &lk)) == NULL)
    432 		return;
    433 
    434 	if ((ld->ld_flags & LD_LOCKED) != 0) {
    435 		if ((ld->ld_flags & LD_SLEEPER) != 0) {
    436 			if (ld->ld_lwp == l)
    437 				recurse = true;
    438 		} else if (ld->ld_cpu == (uint16_t)cpu_number())
    439 			recurse = true;
    440 	}
    441 
    442 	if (cpu_intr_p()) {
    443 		if ((ld->ld_flags & LD_SLEEPER) != 0)
    444 			lockdebug_abort1(ld, lk, __func__,
    445 			    "acquiring sleep lock from interrupt context",
    446 			    true);
    447 	}
    448 
    449 	if (shared)
    450 		ld->ld_shwant++;
    451 	else
    452 		ld->ld_exwant++;
    453 
    454 	if (recurse)
    455 		lockdebug_abort1(ld, lk, __func__, "locking against myself",
    456 		    true);
    457 
    458 	lockdebug_unlock(lk);
    459 }
    460 
    461 /*
    462  * lockdebug_locked:
    463  *
    464  *	Process a lock acquire operation.
    465  */
    466 void
    467 lockdebug_locked(u_int id, uintptr_t where, int shared)
    468 {
    469 	struct lwp *l = curlwp;
    470 	lockdebuglk_t *lk;
    471 	lockdebug_t *ld;
    472 
    473 	if (panicstr != NULL)
    474 		return;
    475 
    476 	if ((ld = lockdebug_lookup(id, &lk)) == NULL)
    477 		return;
    478 
    479 	if (shared) {
    480 		l->l_shlocks++;
    481 		ld->ld_shares++;
    482 		ld->ld_shwant--;
    483 	} else {
    484 		if ((ld->ld_flags & LD_LOCKED) != 0)
    485 			lockdebug_abort1(ld, lk, __func__,
    486 			    "already locked", true);
    487 
    488 		ld->ld_flags |= LD_LOCKED;
    489 		ld->ld_locked = where;
    490 		ld->ld_cpu = (uint16_t)cpu_number();
    491 		ld->ld_lwp = l;
    492 		ld->ld_exwant--;
    493 
    494 		if ((ld->ld_flags & LD_SLEEPER) != 0) {
    495 			l->l_exlocks++;
    496 			TAILQ_INSERT_TAIL(&ld_sleepers, ld, ld_chain);
    497 		} else {
    498 			curcpu()->ci_spin_locks2++;
    499 			TAILQ_INSERT_TAIL(&ld_spinners, ld, ld_chain);
    500 		}
    501 	}
    502 
    503 	lockdebug_unlock(lk);
    504 }
    505 
    506 /*
    507  * lockdebug_unlocked:
    508  *
    509  *	Process a lock release operation.
    510  */
    511 void
    512 lockdebug_unlocked(u_int id, uintptr_t where, int shared)
    513 {
    514 	struct lwp *l = curlwp;
    515 	lockdebuglk_t *lk;
    516 	lockdebug_t *ld;
    517 
    518 	if (panicstr != NULL)
    519 		return;
    520 
    521 	if ((ld = lockdebug_lookup(id, &lk)) == NULL)
    522 		return;
    523 
    524 	if (shared) {
    525 		if (l->l_shlocks == 0)
    526 			lockdebug_abort1(ld, lk, __func__,
    527 			    "no shared locks held by LWP", true);
    528 		if (ld->ld_shares == 0)
    529 			lockdebug_abort1(ld, lk, __func__,
    530 			    "no shared holds on this lock", true);
    531 		l->l_shlocks--;
    532 		ld->ld_shares--;
    533 	} else {
    534 		if ((ld->ld_flags & LD_LOCKED) == 0)
    535 			lockdebug_abort1(ld, lk, __func__, "not locked",
    536 			    true);
    537 
    538 		if ((ld->ld_flags & LD_SLEEPER) != 0) {
    539 			if (ld->ld_lwp != curlwp)
    540 				lockdebug_abort1(ld, lk, __func__,
    541 				    "not held by current LWP", true);
    542 			ld->ld_flags &= ~LD_LOCKED;
    543 			ld->ld_unlocked = where;
    544 			ld->ld_lwp = NULL;
    545 			curlwp->l_exlocks--;
    546 			TAILQ_REMOVE(&ld_sleepers, ld, ld_chain);
    547 		} else {
    548 			if (ld->ld_cpu != (uint16_t)cpu_number())
    549 				lockdebug_abort1(ld, lk, __func__,
    550 				    "not held by current CPU", true);
    551 			ld->ld_flags &= ~LD_LOCKED;
    552 			ld->ld_unlocked = where;
    553 			ld->ld_lwp = NULL;
    554 			curcpu()->ci_spin_locks2--;
    555 			TAILQ_REMOVE(&ld_spinners, ld, ld_chain);
    556 		}
    557 	}
    558 
    559 	lockdebug_unlock(lk);
    560 }
    561 
    562 /*
    563  * lockdebug_barrier:
    564  *
    565  *	Panic if we hold more than one specified spin lock, and optionally,
    566  *	if we hold sleep locks.
    567  */
    568 void
    569 lockdebug_barrier(volatile void *spinlock, int slplocks)
    570 {
    571 	struct lwp *l = curlwp;
    572 	lockdebug_t *ld;
    573 	uint16_t cpuno;
    574 
    575 	if (panicstr != NULL)
    576 		return;
    577 
    578 	if (curcpu()->ci_spin_locks2 != 0) {
    579 		cpuno = (uint16_t)cpu_number();
    580 
    581 		lockdebug_lock(&ld_spinner_lk);
    582 		TAILQ_FOREACH(ld, &ld_spinners, ld_chain) {
    583 			if (ld->ld_lock == spinlock) {
    584 				if (ld->ld_cpu != cpuno)
    585 					lockdebug_abort1(ld, &ld_spinner_lk,
    586 					    __func__,
    587 					    "not held by current CPU", true);
    588 				continue;
    589 			}
    590 			if (ld->ld_cpu == cpuno && (l->l_flag & LW_INTR) == 0)
    591 				lockdebug_abort1(ld, &ld_spinner_lk,
    592 				    __func__, "spin lock held", true);
    593 		}
    594 		lockdebug_unlock(&ld_spinner_lk);
    595 	}
    596 
    597 	if (!slplocks) {
    598 		if (l->l_exlocks != 0) {
    599 			lockdebug_lock(&ld_sleeper_lk);
    600 			TAILQ_FOREACH(ld, &ld_sleepers, ld_chain) {
    601 				if (ld->ld_lwp == l)
    602 					lockdebug_abort1(ld, &ld_sleeper_lk,
    603 					    __func__, "sleep lock held", true);
    604 			}
    605 			lockdebug_unlock(&ld_sleeper_lk);
    606 		}
    607 		if (l->l_shlocks != 0)
    608 			panic("lockdebug_barrier: holding %d shared locks",
    609 			    l->l_shlocks);
    610 	}
    611 }
    612 
    613 /*
    614  * lockdebug_mem_check:
    615  *
    616  *	Check for in-use locks within a memory region that is
    617  *	being freed.  We only check for active locks within the
    618  *	first page of the allocation.
    619  */
    620 void
    621 lockdebug_mem_check(const char *func, void *base, size_t sz)
    622 {
    623 #if 0
    624 	lockdebuglist_t *head;
    625 	lockdebuglk_t *lk;
    626 	lockdebug_t *ld;
    627 	uintptr_t sa, ea, la;
    628 
    629 	sa = (uintptr_t)base;
    630 	ea = sa + sz;
    631 
    632 	lockdebug_mhash(base, &lk, &head);
    633 	TAILQ_FOREACH(ld, head, ld_mchain) {
    634 		la = (uintptr_t)ld->ld_lock;
    635 		if (la >= sa && la < ea) {
    636 			lockdebug_abort1(ld, lk, func,
    637 			    "allocation contains active lock", !cold);
    638 			return;
    639 		}
    640 	}
    641 	lockdebug_unlock(lk);
    642 #endif
    643 }
    644 
    645 /*
    646  * lockdebug_dump:
    647  *
    648  *	Dump information about a lock on panic, or for DDB.
    649  */
    650 static void
    651 lockdebug_dump(lockdebug_t *ld, void (*pr)(const char *, ...))
    652 {
    653 	int sleeper = (ld->ld_flags & LD_SLEEPER);
    654 
    655 	(*pr)(
    656 	    "lock address : %#018lx type     : %18s\n"
    657 	    "shared holds : %18u exclusive: %18u\n"
    658 	    "shares wanted: %18u exclusive: %18u\n"
    659 	    "current cpu  : %18u last held: %18u\n"
    660 	    "current lwp  : %#018lx last held: %#018lx\n"
    661 	    "last locked  : %#018lx unlocked : %#018lx\n"
    662 	    "initialized  : %#018lx\n",
    663 	    (long)ld->ld_lock, (sleeper ? "sleep/adaptive" : "spin"),
    664 	    (unsigned)ld->ld_shares, ((ld->ld_flags & LD_LOCKED) != 0),
    665 	    (unsigned)ld->ld_shwant, (unsigned)ld->ld_exwant,
    666 	    (unsigned)cpu_number(), (unsigned)ld->ld_cpu,
    667 	    (long)curlwp, (long)ld->ld_lwp,
    668 	    (long)ld->ld_locked, (long)ld->ld_unlocked,
    669 	    (long)ld->ld_initaddr);
    670 
    671 	if (ld->ld_lockops->lo_dump != NULL)
    672 		(*ld->ld_lockops->lo_dump)(ld->ld_lock);
    673 
    674 	if (sleeper) {
    675 		(*pr)("\n");
    676 		turnstile_print(ld->ld_lock, pr);
    677 	}
    678 }
    679 
    680 /*
    681  * lockdebug_dump:
    682  *
    683  *	Dump information about a known lock.
    684  */
    685 static void
    686 lockdebug_abort1(lockdebug_t *ld, lockdebuglk_t *lk, const char *func,
    687 		 const char *msg, bool dopanic)
    688 {
    689 
    690 	printf_nolog("%s error: %s: %s\n\n", ld->ld_lockops->lo_name,
    691 	    func, msg);
    692 	lockdebug_dump(ld, printf_nolog);
    693 	lockdebug_unlock(lk);
    694 	printf_nolog("\n");
    695 	if (dopanic)
    696 		panic("LOCKDEBUG");
    697 }
    698 
    699 #endif	/* LOCKDEBUG */
    700 
    701 /*
    702  * lockdebug_lock_print:
    703  *
    704  *	Handle the DDB 'show lock' command.
    705  */
    706 #ifdef DDB
    707 void
    708 lockdebug_lock_print(void *addr, void (*pr)(const char *, ...))
    709 {
    710 #ifdef LOCKDEBUG
    711 	lockdebug_t *ld;
    712 
    713 	TAILQ_FOREACH(ld, &ld_all, ld_achain) {
    714 		if (ld->ld_lock == addr) {
    715 			lockdebug_dump(ld, pr);
    716 			return;
    717 		}
    718 	}
    719 	(*pr)("Sorry, no record of a lock with address %p found.\n", addr);
    720 #else
    721 	(*pr)("Sorry, kernel not built with the LOCKDEBUG option.\n");
    722 #endif	/* LOCKDEBUG */
    723 }
    724 #endif	/* DDB */
    725 
    726 /*
    727  * lockdebug_abort:
    728  *
    729  *	An error has been trapped - dump lock info and call panic().
    730  */
    731 void
    732 lockdebug_abort(u_int id, volatile void *lock, lockops_t *ops,
    733 		const char *func, const char *msg)
    734 {
    735 #ifdef LOCKDEBUG
    736 	lockdebug_t *ld;
    737 	lockdebuglk_t *lk;
    738 
    739 	if ((ld = lockdebug_lookup(id, &lk)) != NULL) {
    740 		lockdebug_abort1(ld, lk, func, msg, true);
    741 		/* NOTREACHED */
    742 	}
    743 #endif	/* LOCKDEBUG */
    744 
    745 	printf_nolog("%s error: %s: %s\n\n"
    746 	    "lock address : %#018lx\n"
    747 	    "current cpu  : %18d\n"
    748 	    "current lwp  : %#018lx\n",
    749 	    ops->lo_name, func, msg, (long)lock, (int)cpu_number(),
    750 	    (long)curlwp);
    751 
    752 	(*ops->lo_dump)(lock);
    753 
    754 	printf_nolog("\n");
    755 	panic("lock error");
    756 }
    757