| 1 | /* $NetBSD: subr_lockdebug.c,v 1.54 2015/09/29 01:44:57 ozaki-r Exp $ */ |
| 2 | |
| 3 | /*- |
| 4 | * Copyright (c) 2006, 2007, 2008 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 | * |
| 19 | * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS |
| 20 | * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED |
| 21 | * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
| 22 | * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS |
| 23 | * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
| 24 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
| 25 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
| 26 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
| 27 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
| 28 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
| 29 | * POSSIBILITY OF SUCH DAMAGE. |
| 30 | */ |
| 31 | |
| 32 | /* |
| 33 | * Basic lock debugging code shared among lock primitives. |
| 34 | */ |
| 35 | |
| 36 | #include <sys/cdefs.h> |
| 37 | __KERNEL_RCSID(0, "$NetBSD: subr_lockdebug.c,v 1.54 2015/09/29 01:44:57 ozaki-r Exp $" ); |
| 38 | |
| 39 | #ifdef _KERNEL_OPT |
| 40 | #include "opt_ddb.h" |
| 41 | #endif |
| 42 | |
| 43 | #include <sys/param.h> |
| 44 | #include <sys/proc.h> |
| 45 | #include <sys/systm.h> |
| 46 | #include <sys/kernel.h> |
| 47 | #include <sys/kmem.h> |
| 48 | #include <sys/lockdebug.h> |
| 49 | #include <sys/sleepq.h> |
| 50 | #include <sys/cpu.h> |
| 51 | #include <sys/atomic.h> |
| 52 | #include <sys/lock.h> |
| 53 | #include <sys/rbtree.h> |
| 54 | |
| 55 | #include <machine/lock.h> |
| 56 | |
| 57 | unsigned int ld_panic; |
| 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 | |
| 70 | #define LD_WRITE_LOCK 0x80000000 |
| 71 | |
| 72 | typedef struct lockdebug { |
| 73 | struct rb_node ld_rb_node; |
| 74 | __cpu_simple_lock_t ld_spinlock; |
| 75 | _TAILQ_ENTRY(struct lockdebug, volatile) ld_chain; |
| 76 | _TAILQ_ENTRY(struct lockdebug, volatile) ld_achain; |
| 77 | volatile void *ld_lock; |
| 78 | lockops_t *ld_lockops; |
| 79 | struct lwp *ld_lwp; |
| 80 | uintptr_t ld_locked; |
| 81 | uintptr_t ld_unlocked; |
| 82 | uintptr_t ld_initaddr; |
| 83 | uint16_t ld_shares; |
| 84 | uint16_t ld_cpu; |
| 85 | uint8_t ld_flags; |
| 86 | uint8_t ld_shwant; /* advisory */ |
| 87 | uint8_t ld_exwant; /* advisory */ |
| 88 | uint8_t ld_unused; |
| 89 | } volatile lockdebug_t; |
| 90 | |
| 91 | typedef _TAILQ_HEAD(lockdebuglist, struct lockdebug, volatile) lockdebuglist_t; |
| 92 | |
| 93 | __cpu_simple_lock_t ld_mod_lk; |
| 94 | lockdebuglist_t ld_free = TAILQ_HEAD_INITIALIZER(ld_free); |
| 95 | lockdebuglist_t ld_all = TAILQ_HEAD_INITIALIZER(ld_all); |
| 96 | int ld_nfree; |
| 97 | int ld_freeptr; |
| 98 | int ld_recurse; |
| 99 | bool ld_nomore; |
| 100 | lockdebug_t ld_prime[LD_BATCH]; |
| 101 | |
| 102 | static void lockdebug_abort1(lockdebug_t *, int, const char *, |
| 103 | const char *, bool); |
| 104 | static int lockdebug_more(int); |
| 105 | static void lockdebug_init(void); |
| 106 | static void lockdebug_dump(lockdebug_t *, void (*)(const char *, ...) |
| 107 | __printflike(1, 2)); |
| 108 | |
| 109 | static signed int |
| 110 | ld_rbto_compare_nodes(void *ctx, const void *n1, const void *n2) |
| 111 | { |
| 112 | const lockdebug_t *ld1 = n1; |
| 113 | const lockdebug_t *ld2 = n2; |
| 114 | const uintptr_t a = (uintptr_t)ld1->ld_lock; |
| 115 | const uintptr_t b = (uintptr_t)ld2->ld_lock; |
| 116 | |
| 117 | if (a < b) |
| 118 | return -1; |
| 119 | if (a > b) |
| 120 | return 1; |
| 121 | return 0; |
| 122 | } |
| 123 | |
| 124 | static signed int |
| 125 | ld_rbto_compare_key(void *ctx, const void *n, const void *key) |
| 126 | { |
| 127 | const lockdebug_t *ld = n; |
| 128 | const uintptr_t a = (uintptr_t)ld->ld_lock; |
| 129 | const uintptr_t b = (uintptr_t)key; |
| 130 | |
| 131 | if (a < b) |
| 132 | return -1; |
| 133 | if (a > b) |
| 134 | return 1; |
| 135 | return 0; |
| 136 | } |
| 137 | |
| 138 | static rb_tree_t ld_rb_tree; |
| 139 | |
| 140 | static const rb_tree_ops_t ld_rb_tree_ops = { |
| 141 | .rbto_compare_nodes = ld_rbto_compare_nodes, |
| 142 | .rbto_compare_key = ld_rbto_compare_key, |
| 143 | .rbto_node_offset = offsetof(lockdebug_t, ld_rb_node), |
| 144 | .rbto_context = NULL |
| 145 | }; |
| 146 | |
| 147 | static inline lockdebug_t * |
| 148 | lockdebug_lookup1(volatile void *lock) |
| 149 | { |
| 150 | lockdebug_t *ld; |
| 151 | struct cpu_info *ci; |
| 152 | |
| 153 | ci = curcpu(); |
| 154 | __cpu_simple_lock(&ci->ci_data.cpu_ld_lock); |
| 155 | ld = (lockdebug_t *)rb_tree_find_node(&ld_rb_tree, __UNVOLATILE(lock)); |
| 156 | __cpu_simple_unlock(&ci->ci_data.cpu_ld_lock); |
| 157 | if (ld == NULL) { |
| 158 | return NULL; |
| 159 | } |
| 160 | __cpu_simple_lock(&ld->ld_spinlock); |
| 161 | |
| 162 | return ld; |
| 163 | } |
| 164 | |
| 165 | static void |
| 166 | lockdebug_lock_cpus(void) |
| 167 | { |
| 168 | CPU_INFO_ITERATOR cii; |
| 169 | struct cpu_info *ci; |
| 170 | |
| 171 | for (CPU_INFO_FOREACH(cii, ci)) { |
| 172 | __cpu_simple_lock(&ci->ci_data.cpu_ld_lock); |
| 173 | } |
| 174 | } |
| 175 | |
| 176 | static void |
| 177 | lockdebug_unlock_cpus(void) |
| 178 | { |
| 179 | CPU_INFO_ITERATOR cii; |
| 180 | struct cpu_info *ci; |
| 181 | |
| 182 | for (CPU_INFO_FOREACH(cii, ci)) { |
| 183 | __cpu_simple_unlock(&ci->ci_data.cpu_ld_lock); |
| 184 | } |
| 185 | } |
| 186 | |
| 187 | /* |
| 188 | * lockdebug_lookup: |
| 189 | * |
| 190 | * Find a lockdebug structure by a pointer to a lock and return it locked. |
| 191 | */ |
| 192 | static inline lockdebug_t * |
| 193 | lockdebug_lookup(volatile void *lock, uintptr_t where) |
| 194 | { |
| 195 | lockdebug_t *ld; |
| 196 | |
| 197 | ld = lockdebug_lookup1(lock); |
| 198 | if (ld == NULL) { |
| 199 | panic("lockdebug_lookup: uninitialized lock " |
| 200 | "(lock=%p, from=%08" PRIxPTR")" , lock, where); |
| 201 | } |
| 202 | return ld; |
| 203 | } |
| 204 | |
| 205 | /* |
| 206 | * lockdebug_init: |
| 207 | * |
| 208 | * Initialize the lockdebug system. Allocate an initial pool of |
| 209 | * lockdebug structures before the VM system is up and running. |
| 210 | */ |
| 211 | static void |
| 212 | lockdebug_init(void) |
| 213 | { |
| 214 | lockdebug_t *ld; |
| 215 | int i; |
| 216 | |
| 217 | TAILQ_INIT(&curcpu()->ci_data.cpu_ld_locks); |
| 218 | TAILQ_INIT(&curlwp->l_ld_locks); |
| 219 | __cpu_simple_lock_init(&curcpu()->ci_data.cpu_ld_lock); |
| 220 | __cpu_simple_lock_init(&ld_mod_lk); |
| 221 | |
| 222 | rb_tree_init(&ld_rb_tree, &ld_rb_tree_ops); |
| 223 | |
| 224 | ld = ld_prime; |
| 225 | for (i = 1, ld++; i < LD_BATCH; i++, ld++) { |
| 226 | __cpu_simple_lock_init(&ld->ld_spinlock); |
| 227 | TAILQ_INSERT_TAIL(&ld_free, ld, ld_chain); |
| 228 | TAILQ_INSERT_TAIL(&ld_all, ld, ld_achain); |
| 229 | } |
| 230 | ld_freeptr = 1; |
| 231 | ld_nfree = LD_BATCH - 1; |
| 232 | } |
| 233 | |
| 234 | /* |
| 235 | * lockdebug_alloc: |
| 236 | * |
| 237 | * A lock is being initialized, so allocate an associated debug |
| 238 | * structure. |
| 239 | */ |
| 240 | bool |
| 241 | lockdebug_alloc(volatile void *lock, lockops_t *lo, uintptr_t initaddr) |
| 242 | { |
| 243 | struct cpu_info *ci; |
| 244 | lockdebug_t *ld; |
| 245 | int s; |
| 246 | |
| 247 | if (lo == NULL || panicstr != NULL || ld_panic) |
| 248 | return false; |
| 249 | if (ld_freeptr == 0) |
| 250 | lockdebug_init(); |
| 251 | |
| 252 | s = splhigh(); |
| 253 | __cpu_simple_lock(&ld_mod_lk); |
| 254 | if ((ld = lockdebug_lookup1(lock)) != NULL) { |
| 255 | __cpu_simple_unlock(&ld_mod_lk); |
| 256 | lockdebug_abort1(ld, s, __func__, "already initialized" , true); |
| 257 | return false; |
| 258 | } |
| 259 | |
| 260 | /* |
| 261 | * Pinch a new debug structure. We may recurse because we call |
| 262 | * kmem_alloc(), which may need to initialize new locks somewhere |
| 263 | * down the path. If not recursing, we try to maintain at least |
| 264 | * LD_SLOP structures free, which should hopefully be enough to |
| 265 | * satisfy kmem_alloc(). If we can't provide a structure, not to |
| 266 | * worry: we'll just mark the lock as not having an ID. |
| 267 | */ |
| 268 | ci = curcpu(); |
| 269 | ci->ci_lkdebug_recurse++; |
| 270 | if (TAILQ_EMPTY(&ld_free)) { |
| 271 | if (ci->ci_lkdebug_recurse > 1 || ld_nomore) { |
| 272 | ci->ci_lkdebug_recurse--; |
| 273 | __cpu_simple_unlock(&ld_mod_lk); |
| 274 | splx(s); |
| 275 | return false; |
| 276 | } |
| 277 | s = lockdebug_more(s); |
| 278 | } else if (ci->ci_lkdebug_recurse == 1 && ld_nfree < LD_SLOP) { |
| 279 | s = lockdebug_more(s); |
| 280 | } |
| 281 | if ((ld = TAILQ_FIRST(&ld_free)) == NULL) { |
| 282 | __cpu_simple_unlock(&ld_mod_lk); |
| 283 | splx(s); |
| 284 | return false; |
| 285 | } |
| 286 | TAILQ_REMOVE(&ld_free, ld, ld_chain); |
| 287 | ld_nfree--; |
| 288 | ci->ci_lkdebug_recurse--; |
| 289 | |
| 290 | if (ld->ld_lock != NULL) { |
| 291 | panic("lockdebug_alloc: corrupt table ld %p" , ld); |
| 292 | } |
| 293 | |
| 294 | /* Initialise the structure. */ |
| 295 | ld->ld_lock = lock; |
| 296 | ld->ld_lockops = lo; |
| 297 | ld->ld_locked = 0; |
| 298 | ld->ld_unlocked = 0; |
| 299 | ld->ld_lwp = NULL; |
| 300 | ld->ld_initaddr = initaddr; |
| 301 | ld->ld_flags = (lo->lo_type == LOCKOPS_SLEEP ? LD_SLEEPER : 0); |
| 302 | lockdebug_lock_cpus(); |
| 303 | (void)rb_tree_insert_node(&ld_rb_tree, __UNVOLATILE(ld)); |
| 304 | lockdebug_unlock_cpus(); |
| 305 | __cpu_simple_unlock(&ld_mod_lk); |
| 306 | |
| 307 | splx(s); |
| 308 | return true; |
| 309 | } |
| 310 | |
| 311 | /* |
| 312 | * lockdebug_free: |
| 313 | * |
| 314 | * A lock is being destroyed, so release debugging resources. |
| 315 | */ |
| 316 | void |
| 317 | lockdebug_free(volatile void *lock) |
| 318 | { |
| 319 | lockdebug_t *ld; |
| 320 | int s; |
| 321 | |
| 322 | if (panicstr != NULL || ld_panic) |
| 323 | return; |
| 324 | |
| 325 | s = splhigh(); |
| 326 | __cpu_simple_lock(&ld_mod_lk); |
| 327 | ld = lockdebug_lookup(lock, (uintptr_t) __builtin_return_address(0)); |
| 328 | if (ld == NULL) { |
| 329 | __cpu_simple_unlock(&ld_mod_lk); |
| 330 | panic("lockdebug_free: destroying uninitialized object %p" |
| 331 | "(ld_lock=%p)" , lock, ld->ld_lock); |
| 332 | return; |
| 333 | } |
| 334 | if ((ld->ld_flags & LD_LOCKED) != 0 || ld->ld_shares != 0) { |
| 335 | __cpu_simple_unlock(&ld_mod_lk); |
| 336 | lockdebug_abort1(ld, s, __func__, "is locked or in use" , true); |
| 337 | return; |
| 338 | } |
| 339 | lockdebug_lock_cpus(); |
| 340 | rb_tree_remove_node(&ld_rb_tree, __UNVOLATILE(ld)); |
| 341 | lockdebug_unlock_cpus(); |
| 342 | ld->ld_lock = NULL; |
| 343 | TAILQ_INSERT_TAIL(&ld_free, ld, ld_chain); |
| 344 | ld_nfree++; |
| 345 | __cpu_simple_unlock(&ld->ld_spinlock); |
| 346 | __cpu_simple_unlock(&ld_mod_lk); |
| 347 | splx(s); |
| 348 | } |
| 349 | |
| 350 | /* |
| 351 | * lockdebug_more: |
| 352 | * |
| 353 | * Allocate a batch of debug structures and add to the free list. |
| 354 | * Must be called with ld_mod_lk held. |
| 355 | */ |
| 356 | static int |
| 357 | lockdebug_more(int s) |
| 358 | { |
| 359 | lockdebug_t *ld; |
| 360 | void *block; |
| 361 | int i, base, m; |
| 362 | |
| 363 | /* |
| 364 | * Can't call kmem_alloc() if in interrupt context. XXX We could |
| 365 | * deadlock, because we don't know which locks the caller holds. |
| 366 | */ |
| 367 | if (cpu_intr_p() || (curlwp->l_pflag & LP_INTR) != 0) { |
| 368 | return s; |
| 369 | } |
| 370 | |
| 371 | while (ld_nfree < LD_SLOP) { |
| 372 | __cpu_simple_unlock(&ld_mod_lk); |
| 373 | splx(s); |
| 374 | block = kmem_zalloc(LD_BATCH * sizeof(lockdebug_t), KM_SLEEP); |
| 375 | s = splhigh(); |
| 376 | __cpu_simple_lock(&ld_mod_lk); |
| 377 | |
| 378 | if (block == NULL) |
| 379 | return s; |
| 380 | |
| 381 | if (ld_nfree > LD_SLOP) { |
| 382 | /* Somebody beat us to it. */ |
| 383 | __cpu_simple_unlock(&ld_mod_lk); |
| 384 | splx(s); |
| 385 | kmem_free(block, LD_BATCH * sizeof(lockdebug_t)); |
| 386 | s = splhigh(); |
| 387 | __cpu_simple_lock(&ld_mod_lk); |
| 388 | continue; |
| 389 | } |
| 390 | |
| 391 | base = ld_freeptr; |
| 392 | ld_nfree += LD_BATCH; |
| 393 | ld = block; |
| 394 | base <<= LD_BATCH_SHIFT; |
| 395 | m = min(LD_MAX_LOCKS, base + LD_BATCH); |
| 396 | |
| 397 | if (m == LD_MAX_LOCKS) |
| 398 | ld_nomore = true; |
| 399 | |
| 400 | for (i = base; i < m; i++, ld++) { |
| 401 | __cpu_simple_lock_init(&ld->ld_spinlock); |
| 402 | TAILQ_INSERT_TAIL(&ld_free, ld, ld_chain); |
| 403 | TAILQ_INSERT_TAIL(&ld_all, ld, ld_achain); |
| 404 | } |
| 405 | |
| 406 | membar_producer(); |
| 407 | } |
| 408 | |
| 409 | return s; |
| 410 | } |
| 411 | |
| 412 | /* |
| 413 | * lockdebug_wantlock: |
| 414 | * |
| 415 | * Process the preamble to a lock acquire. |
| 416 | */ |
| 417 | void |
| 418 | lockdebug_wantlock(volatile void *lock, uintptr_t where, int shared) |
| 419 | { |
| 420 | struct lwp *l = curlwp; |
| 421 | lockdebug_t *ld; |
| 422 | bool recurse; |
| 423 | int s; |
| 424 | |
| 425 | (void)shared; |
| 426 | recurse = false; |
| 427 | |
| 428 | if (panicstr != NULL || ld_panic) |
| 429 | return; |
| 430 | |
| 431 | s = splhigh(); |
| 432 | if ((ld = lockdebug_lookup(lock, where)) == NULL) { |
| 433 | splx(s); |
| 434 | return; |
| 435 | } |
| 436 | if ((ld->ld_flags & LD_LOCKED) != 0 || ld->ld_shares != 0) { |
| 437 | if ((ld->ld_flags & LD_SLEEPER) != 0) { |
| 438 | if (ld->ld_lwp == l) |
| 439 | recurse = true; |
| 440 | } else if (ld->ld_cpu == (uint16_t)cpu_index(curcpu())) |
| 441 | recurse = true; |
| 442 | } |
| 443 | if (cpu_intr_p()) { |
| 444 | if ((ld->ld_flags & LD_SLEEPER) != 0) { |
| 445 | lockdebug_abort1(ld, s, __func__, |
| 446 | "acquiring sleep lock from interrupt context" , |
| 447 | true); |
| 448 | return; |
| 449 | } |
| 450 | } |
| 451 | if (shared) |
| 452 | ld->ld_shwant++; |
| 453 | else |
| 454 | ld->ld_exwant++; |
| 455 | if (recurse) { |
| 456 | lockdebug_abort1(ld, s, __func__, "locking against myself" , |
| 457 | true); |
| 458 | return; |
| 459 | } |
| 460 | __cpu_simple_unlock(&ld->ld_spinlock); |
| 461 | splx(s); |
| 462 | } |
| 463 | |
| 464 | /* |
| 465 | * lockdebug_locked: |
| 466 | * |
| 467 | * Process a lock acquire operation. |
| 468 | */ |
| 469 | void |
| 470 | lockdebug_locked(volatile void *lock, void *cvlock, uintptr_t where, |
| 471 | int shared) |
| 472 | { |
| 473 | struct lwp *l = curlwp; |
| 474 | lockdebug_t *ld; |
| 475 | int s; |
| 476 | |
| 477 | if (panicstr != NULL || ld_panic) |
| 478 | return; |
| 479 | |
| 480 | s = splhigh(); |
| 481 | if ((ld = lockdebug_lookup(lock, where)) == NULL) { |
| 482 | splx(s); |
| 483 | return; |
| 484 | } |
| 485 | if (cvlock) { |
| 486 | KASSERT(ld->ld_lockops->lo_type == LOCKOPS_CV); |
| 487 | if (lock == (void *)&lbolt) { |
| 488 | /* nothing */ |
| 489 | } else if (ld->ld_shares++ == 0) { |
| 490 | ld->ld_locked = (uintptr_t)cvlock; |
| 491 | } else if (cvlock != (void *)ld->ld_locked) { |
| 492 | lockdebug_abort1(ld, s, __func__, "multiple locks used" |
| 493 | " with condition variable" , true); |
| 494 | return; |
| 495 | } |
| 496 | } else if (shared) { |
| 497 | l->l_shlocks++; |
| 498 | ld->ld_locked = where; |
| 499 | ld->ld_shares++; |
| 500 | ld->ld_shwant--; |
| 501 | } else { |
| 502 | if ((ld->ld_flags & LD_LOCKED) != 0) { |
| 503 | lockdebug_abort1(ld, s, __func__, "already locked" , |
| 504 | true); |
| 505 | return; |
| 506 | } |
| 507 | ld->ld_flags |= LD_LOCKED; |
| 508 | ld->ld_locked = where; |
| 509 | ld->ld_exwant--; |
| 510 | if ((ld->ld_flags & LD_SLEEPER) != 0) { |
| 511 | TAILQ_INSERT_TAIL(&l->l_ld_locks, ld, ld_chain); |
| 512 | } else { |
| 513 | TAILQ_INSERT_TAIL(&curcpu()->ci_data.cpu_ld_locks, |
| 514 | ld, ld_chain); |
| 515 | } |
| 516 | } |
| 517 | ld->ld_cpu = (uint16_t)cpu_index(curcpu()); |
| 518 | ld->ld_lwp = l; |
| 519 | __cpu_simple_unlock(&ld->ld_spinlock); |
| 520 | splx(s); |
| 521 | } |
| 522 | |
| 523 | /* |
| 524 | * lockdebug_unlocked: |
| 525 | * |
| 526 | * Process a lock release operation. |
| 527 | */ |
| 528 | void |
| 529 | lockdebug_unlocked(volatile void *lock, uintptr_t where, int shared) |
| 530 | { |
| 531 | struct lwp *l = curlwp; |
| 532 | lockdebug_t *ld; |
| 533 | int s; |
| 534 | |
| 535 | if (panicstr != NULL || ld_panic) |
| 536 | return; |
| 537 | |
| 538 | s = splhigh(); |
| 539 | if ((ld = lockdebug_lookup(lock, where)) == NULL) { |
| 540 | splx(s); |
| 541 | return; |
| 542 | } |
| 543 | if (ld->ld_lockops->lo_type == LOCKOPS_CV) { |
| 544 | if (lock == (void *)&lbolt) { |
| 545 | /* nothing */ |
| 546 | } else { |
| 547 | ld->ld_shares--; |
| 548 | } |
| 549 | } else if (shared) { |
| 550 | if (l->l_shlocks == 0) { |
| 551 | lockdebug_abort1(ld, s, __func__, |
| 552 | "no shared locks held by LWP" , true); |
| 553 | return; |
| 554 | } |
| 555 | if (ld->ld_shares == 0) { |
| 556 | lockdebug_abort1(ld, s, __func__, |
| 557 | "no shared holds on this lock" , true); |
| 558 | return; |
| 559 | } |
| 560 | l->l_shlocks--; |
| 561 | ld->ld_shares--; |
| 562 | if (ld->ld_lwp == l) { |
| 563 | ld->ld_unlocked = where; |
| 564 | ld->ld_lwp = NULL; |
| 565 | } |
| 566 | if (ld->ld_cpu == (uint16_t)cpu_index(curcpu())) |
| 567 | ld->ld_cpu = (uint16_t)-1; |
| 568 | } else { |
| 569 | if ((ld->ld_flags & LD_LOCKED) == 0) { |
| 570 | lockdebug_abort1(ld, s, __func__, "not locked" , true); |
| 571 | return; |
| 572 | } |
| 573 | |
| 574 | if ((ld->ld_flags & LD_SLEEPER) != 0) { |
| 575 | if (ld->ld_lwp != curlwp) { |
| 576 | lockdebug_abort1(ld, s, __func__, |
| 577 | "not held by current LWP" , true); |
| 578 | return; |
| 579 | } |
| 580 | TAILQ_REMOVE(&l->l_ld_locks, ld, ld_chain); |
| 581 | } else { |
| 582 | if (ld->ld_cpu != (uint16_t)cpu_index(curcpu())) { |
| 583 | lockdebug_abort1(ld, s, __func__, |
| 584 | "not held by current CPU" , true); |
| 585 | return; |
| 586 | } |
| 587 | TAILQ_REMOVE(&curcpu()->ci_data.cpu_ld_locks, ld, |
| 588 | ld_chain); |
| 589 | } |
| 590 | ld->ld_flags &= ~LD_LOCKED; |
| 591 | ld->ld_unlocked = where; |
| 592 | ld->ld_lwp = NULL; |
| 593 | } |
| 594 | __cpu_simple_unlock(&ld->ld_spinlock); |
| 595 | splx(s); |
| 596 | } |
| 597 | |
| 598 | /* |
| 599 | * lockdebug_wakeup: |
| 600 | * |
| 601 | * Process a wakeup on a condition variable. |
| 602 | */ |
| 603 | void |
| 604 | lockdebug_wakeup(volatile void *lock, uintptr_t where) |
| 605 | { |
| 606 | lockdebug_t *ld; |
| 607 | int s; |
| 608 | |
| 609 | if (panicstr != NULL || ld_panic || lock == (void *)&lbolt) |
| 610 | return; |
| 611 | |
| 612 | s = splhigh(); |
| 613 | /* Find the CV... */ |
| 614 | if ((ld = lockdebug_lookup(lock, where)) == NULL) { |
| 615 | splx(s); |
| 616 | return; |
| 617 | } |
| 618 | /* |
| 619 | * If it has any waiters, ensure that they are using the |
| 620 | * same interlock. |
| 621 | */ |
| 622 | if (ld->ld_shares != 0 && !mutex_owned((kmutex_t *)ld->ld_locked)) { |
| 623 | lockdebug_abort1(ld, s, __func__, "interlocking mutex not " |
| 624 | "held during wakeup" , true); |
| 625 | return; |
| 626 | } |
| 627 | __cpu_simple_unlock(&ld->ld_spinlock); |
| 628 | splx(s); |
| 629 | } |
| 630 | |
| 631 | /* |
| 632 | * lockdebug_barrier: |
| 633 | * |
| 634 | * Panic if we hold more than one specified spin lock, and optionally, |
| 635 | * if we hold sleep locks. |
| 636 | */ |
| 637 | void |
| 638 | lockdebug_barrier(volatile void *spinlock, int slplocks) |
| 639 | { |
| 640 | struct lwp *l = curlwp; |
| 641 | lockdebug_t *ld; |
| 642 | int s; |
| 643 | |
| 644 | if (panicstr != NULL || ld_panic) |
| 645 | return; |
| 646 | |
| 647 | s = splhigh(); |
| 648 | if ((l->l_pflag & LP_INTR) == 0) { |
| 649 | TAILQ_FOREACH(ld, &curcpu()->ci_data.cpu_ld_locks, ld_chain) { |
| 650 | if (ld->ld_lock == spinlock) { |
| 651 | continue; |
| 652 | } |
| 653 | __cpu_simple_lock(&ld->ld_spinlock); |
| 654 | lockdebug_abort1(ld, s, __func__, |
| 655 | "spin lock held" , true); |
| 656 | return; |
| 657 | } |
| 658 | } |
| 659 | if (slplocks) { |
| 660 | splx(s); |
| 661 | return; |
| 662 | } |
| 663 | if ((ld = TAILQ_FIRST(&l->l_ld_locks)) != NULL) { |
| 664 | __cpu_simple_lock(&ld->ld_spinlock); |
| 665 | lockdebug_abort1(ld, s, __func__, "sleep lock held" , true); |
| 666 | return; |
| 667 | } |
| 668 | splx(s); |
| 669 | if (l->l_shlocks != 0) { |
| 670 | TAILQ_FOREACH(ld, &ld_all, ld_achain) { |
| 671 | if (ld->ld_lockops->lo_type == LOCKOPS_CV) |
| 672 | continue; |
| 673 | if (ld->ld_lwp == l) |
| 674 | lockdebug_dump(ld, printf); |
| 675 | } |
| 676 | panic("%s: holding %d shared locks" , __func__, l->l_shlocks); |
| 677 | } |
| 678 | } |
| 679 | |
| 680 | /* |
| 681 | * lockdebug_mem_check: |
| 682 | * |
| 683 | * Check for in-use locks within a memory region that is |
| 684 | * being freed. |
| 685 | */ |
| 686 | void |
| 687 | lockdebug_mem_check(const char *func, void *base, size_t sz) |
| 688 | { |
| 689 | lockdebug_t *ld; |
| 690 | struct cpu_info *ci; |
| 691 | int s; |
| 692 | |
| 693 | if (panicstr != NULL || ld_panic) |
| 694 | return; |
| 695 | |
| 696 | s = splhigh(); |
| 697 | ci = curcpu(); |
| 698 | __cpu_simple_lock(&ci->ci_data.cpu_ld_lock); |
| 699 | ld = (lockdebug_t *)rb_tree_find_node_geq(&ld_rb_tree, base); |
| 700 | if (ld != NULL) { |
| 701 | const uintptr_t lock = (uintptr_t)ld->ld_lock; |
| 702 | |
| 703 | if ((uintptr_t)base > lock) |
| 704 | panic("%s: corrupt tree ld=%p, base=%p, sz=%zu" , |
| 705 | __func__, ld, base, sz); |
| 706 | if (lock >= (uintptr_t)base + sz) |
| 707 | ld = NULL; |
| 708 | } |
| 709 | __cpu_simple_unlock(&ci->ci_data.cpu_ld_lock); |
| 710 | if (ld != NULL) { |
| 711 | __cpu_simple_lock(&ld->ld_spinlock); |
| 712 | lockdebug_abort1(ld, s, func, |
| 713 | "allocation contains active lock" , !cold); |
| 714 | return; |
| 715 | } |
| 716 | splx(s); |
| 717 | } |
| 718 | |
| 719 | /* |
| 720 | * lockdebug_dump: |
| 721 | * |
| 722 | * Dump information about a lock on panic, or for DDB. |
| 723 | */ |
| 724 | static void |
| 725 | lockdebug_dump(lockdebug_t *ld, void (*pr)(const char *, ...) |
| 726 | __printflike(1, 2)) |
| 727 | { |
| 728 | int sleeper = (ld->ld_flags & LD_SLEEPER); |
| 729 | |
| 730 | (*pr)( |
| 731 | "lock address : %#018lx type : %18s\n" |
| 732 | "initialized : %#018lx" , |
| 733 | (long)ld->ld_lock, (sleeper ? "sleep/adaptive" : "spin" ), |
| 734 | (long)ld->ld_initaddr); |
| 735 | |
| 736 | if (ld->ld_lockops->lo_type == LOCKOPS_CV) { |
| 737 | (*pr)(" interlock: %#018lx\n" , (long)ld->ld_locked); |
| 738 | } else { |
| 739 | (*pr)("\n" |
| 740 | "shared holds : %18u exclusive: %18u\n" |
| 741 | "shares wanted: %18u exclusive: %18u\n" |
| 742 | "current cpu : %18u last held: %18u\n" |
| 743 | "current lwp : %#018lx last held: %#018lx\n" |
| 744 | "last locked%c : %#018lx unlocked%c: %#018lx\n" , |
| 745 | (unsigned)ld->ld_shares, ((ld->ld_flags & LD_LOCKED) != 0), |
| 746 | (unsigned)ld->ld_shwant, (unsigned)ld->ld_exwant, |
| 747 | (unsigned)cpu_index(curcpu()), (unsigned)ld->ld_cpu, |
| 748 | (long)curlwp, (long)ld->ld_lwp, |
| 749 | ((ld->ld_flags & LD_LOCKED) ? '*' : ' '), |
| 750 | (long)ld->ld_locked, |
| 751 | ((ld->ld_flags & LD_LOCKED) ? ' ' : '*'), |
| 752 | (long)ld->ld_unlocked); |
| 753 | } |
| 754 | |
| 755 | if (ld->ld_lockops->lo_dump != NULL) |
| 756 | (*ld->ld_lockops->lo_dump)(ld->ld_lock); |
| 757 | |
| 758 | if (sleeper) { |
| 759 | (*pr)("\n" ); |
| 760 | turnstile_print(ld->ld_lock, pr); |
| 761 | } |
| 762 | } |
| 763 | |
| 764 | /* |
| 765 | * lockdebug_abort1: |
| 766 | * |
| 767 | * An error has been trapped - dump lock info and panic. |
| 768 | */ |
| 769 | static void |
| 770 | lockdebug_abort1(lockdebug_t *ld, int s, const char *func, |
| 771 | const char *msg, bool dopanic) |
| 772 | { |
| 773 | |
| 774 | /* |
| 775 | * Don't make the situation worse if the system is already going |
| 776 | * down in flames. Once a panic is triggered, lockdebug state |
| 777 | * becomes stale and cannot be trusted. |
| 778 | */ |
| 779 | if (atomic_inc_uint_nv(&ld_panic) != 1) { |
| 780 | __cpu_simple_unlock(&ld->ld_spinlock); |
| 781 | splx(s); |
| 782 | return; |
| 783 | } |
| 784 | |
| 785 | printf_nolog("%s error: %s: %s\n\n" , ld->ld_lockops->lo_name, |
| 786 | func, msg); |
| 787 | lockdebug_dump(ld, printf_nolog); |
| 788 | __cpu_simple_unlock(&ld->ld_spinlock); |
| 789 | splx(s); |
| 790 | printf_nolog("\n" ); |
| 791 | if (dopanic) |
| 792 | panic("LOCKDEBUG: %s error: %s: %s" , ld->ld_lockops->lo_name, |
| 793 | func, msg); |
| 794 | } |
| 795 | |
| 796 | #endif /* LOCKDEBUG */ |
| 797 | |
| 798 | /* |
| 799 | * lockdebug_lock_print: |
| 800 | * |
| 801 | * Handle the DDB 'show lock' command. |
| 802 | */ |
| 803 | #ifdef DDB |
| 804 | void |
| 805 | lockdebug_lock_print(void *addr, void (*pr)(const char *, ...)) |
| 806 | { |
| 807 | #ifdef LOCKDEBUG |
| 808 | lockdebug_t *ld; |
| 809 | |
| 810 | TAILQ_FOREACH(ld, &ld_all, ld_achain) { |
| 811 | if (ld->ld_lock == NULL) |
| 812 | continue; |
| 813 | if (addr == NULL || ld->ld_lock == addr) { |
| 814 | lockdebug_dump(ld, pr); |
| 815 | if (addr != NULL) |
| 816 | return; |
| 817 | } |
| 818 | } |
| 819 | if (addr != NULL) { |
| 820 | (*pr)("Sorry, no record of a lock with address %p found.\n" , |
| 821 | addr); |
| 822 | } |
| 823 | #else |
| 824 | (*pr)("Sorry, kernel not built with the LOCKDEBUG option.\n" ); |
| 825 | #endif /* LOCKDEBUG */ |
| 826 | } |
| 827 | #endif /* DDB */ |
| 828 | |
| 829 | /* |
| 830 | * lockdebug_abort: |
| 831 | * |
| 832 | * An error has been trapped - dump lock info and call panic(). |
| 833 | */ |
| 834 | void |
| 835 | lockdebug_abort(volatile void *lock, lockops_t *ops, const char *func, |
| 836 | const char *msg) |
| 837 | { |
| 838 | #ifdef LOCKDEBUG |
| 839 | lockdebug_t *ld; |
| 840 | int s; |
| 841 | |
| 842 | s = splhigh(); |
| 843 | if ((ld = lockdebug_lookup(lock, |
| 844 | (uintptr_t) __builtin_return_address(0))) != NULL) { |
| 845 | lockdebug_abort1(ld, s, func, msg, true); |
| 846 | return; |
| 847 | } |
| 848 | splx(s); |
| 849 | #endif /* LOCKDEBUG */ |
| 850 | |
| 851 | /* |
| 852 | * Complain first on the occurrance only. Otherwise proceeed to |
| 853 | * panic where we will `rendezvous' with other CPUs if the machine |
| 854 | * is going down in flames. |
| 855 | */ |
| 856 | if (atomic_inc_uint_nv(&ld_panic) == 1) { |
| 857 | printf_nolog("%s error: %s: %s\n\n" |
| 858 | "lock address : %#018lx\n" |
| 859 | "current cpu : %18d\n" |
| 860 | "current lwp : %#018lx\n" , |
| 861 | ops->lo_name, func, msg, (long)lock, |
| 862 | (int)cpu_index(curcpu()), (long)curlwp); |
| 863 | (*ops->lo_dump)(lock); |
| 864 | printf_nolog("\n" ); |
| 865 | } |
| 866 | |
| 867 | panic("lock error: %s: %s: %s: lock %p cpu %d lwp %p" , |
| 868 | ops->lo_name, func, msg, lock, cpu_index(curcpu()), curlwp); |
| 869 | } |
| 870 | |