The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


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FreeBSD/Linux Kernel Cross Reference
sys/vm/uma_dbg.c

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    1 /*-
    2  * Copyright (c) 2002, 2003, 2004, 2005 Jeffrey Roberson <jeff@FreeBSD.org>
    3  * Copyright (c) 2004, 2005 Bosko Milekic <bmilekic@FreeBSD.org>
    4  * All rights reserved.
    5  *
    6  * Redistribution and use in source and binary forms, with or without
    7  * modification, are permitted provided that the following conditions
    8  * are met:
    9  * 1. Redistributions of source code must retain the above copyright
   10  *    notice unmodified, this list of conditions, and the following
   11  *    disclaimer.
   12  * 2. Redistributions in binary form must reproduce the above copyright
   13  *    notice, this list of conditions and the following disclaimer in the
   14  *    documentation and/or other materials provided with the distribution.
   15  *
   16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
   17  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   18  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
   19  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
   20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
   21  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   22  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   23  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   24  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
   25  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   26  */
   27 
   28 /*
   29  * uma_dbg.c    Debugging features for UMA users
   30  *
   31  */
   32 
   33 #include <sys/cdefs.h>
   34 __FBSDID("$FreeBSD: releng/9.0/sys/vm/uma_dbg.c 187681 2009-01-25 09:11:24Z jeff $");
   35 
   36 #include <sys/param.h>
   37 #include <sys/systm.h>
   38 #include <sys/kernel.h>
   39 #include <sys/types.h>
   40 #include <sys/queue.h>
   41 #include <sys/lock.h>
   42 #include <sys/mutex.h>
   43 #include <sys/malloc.h>
   44 
   45 #include <vm/vm.h>
   46 #include <vm/vm_object.h>
   47 #include <vm/vm_page.h>
   48 #include <vm/uma.h>
   49 #include <vm/uma_int.h>
   50 #include <vm/uma_dbg.h>
   51 
   52 static const u_int32_t uma_junk = 0xdeadc0de;
   53 
   54 /*
   55  * Checks an item to make sure it hasn't been overwritten since it was freed,
   56  * prior to subsequent reallocation.
   57  *
   58  * Complies with standard ctor arg/return
   59  *
   60  */
   61 int
   62 trash_ctor(void *mem, int size, void *arg, int flags)
   63 {
   64         int cnt;
   65         u_int32_t *p;
   66 
   67         cnt = size / sizeof(uma_junk);
   68 
   69         for (p = mem; cnt > 0; cnt--, p++)
   70                 if (*p != uma_junk) {
   71                         printf("Memory modified after free %p(%d) val=%x @ %p\n",
   72                             mem, size, *p, p);
   73                         return (0);
   74                 }
   75         return (0);
   76 }
   77 
   78 /*
   79  * Fills an item with predictable garbage
   80  *
   81  * Complies with standard dtor arg/return
   82  *
   83  */
   84 void
   85 trash_dtor(void *mem, int size, void *arg)
   86 {
   87         int cnt;
   88         u_int32_t *p;
   89 
   90         cnt = size / sizeof(uma_junk);
   91 
   92         for (p = mem; cnt > 0; cnt--, p++)
   93                 *p = uma_junk;
   94 }
   95 
   96 /*
   97  * Fills an item with predictable garbage
   98  *
   99  * Complies with standard init arg/return
  100  *
  101  */
  102 int
  103 trash_init(void *mem, int size, int flags)
  104 {
  105         trash_dtor(mem, size, NULL);
  106         return (0);
  107 }
  108 
  109 /*
  110  * Checks an item to make sure it hasn't been overwritten since it was freed.
  111  *
  112  * Complies with standard fini arg/return
  113  *
  114  */
  115 void
  116 trash_fini(void *mem, int size)
  117 {
  118         (void)trash_ctor(mem, size, NULL, 0);
  119 }
  120 
  121 int
  122 mtrash_ctor(void *mem, int size, void *arg, int flags)
  123 {
  124         struct malloc_type **ksp;
  125         u_int32_t *p = mem;
  126         int cnt;
  127 
  128         size -= sizeof(struct malloc_type *);
  129         ksp = (struct malloc_type **)mem;
  130         ksp += size / sizeof(struct malloc_type *);
  131         cnt = size / sizeof(uma_junk);
  132 
  133         for (p = mem; cnt > 0; cnt--, p++)
  134                 if (*p != uma_junk) {
  135                         printf("Memory modified after free %p(%d) val=%x @ %p\n",
  136                             mem, size, *p, p);
  137                         panic("Most recently used by %s\n", (*ksp == NULL)?
  138                             "none" : (*ksp)->ks_shortdesc);
  139                 }
  140         return (0);
  141 }
  142 
  143 /*
  144  * Fills an item with predictable garbage
  145  *
  146  * Complies with standard dtor arg/return
  147  *
  148  */
  149 void
  150 mtrash_dtor(void *mem, int size, void *arg)
  151 {
  152         int cnt;
  153         u_int32_t *p;
  154 
  155         size -= sizeof(struct malloc_type *);
  156         cnt = size / sizeof(uma_junk);
  157 
  158         for (p = mem; cnt > 0; cnt--, p++)
  159                 *p = uma_junk;
  160 }
  161 
  162 /*
  163  * Fills an item with predictable garbage
  164  *
  165  * Complies with standard init arg/return
  166  *
  167  */
  168 int
  169 mtrash_init(void *mem, int size, int flags)
  170 {
  171         struct malloc_type **ksp;
  172 
  173         mtrash_dtor(mem, size, NULL);
  174 
  175         ksp = (struct malloc_type **)mem;
  176         ksp += (size / sizeof(struct malloc_type *)) - 1;
  177         *ksp = NULL;
  178         return (0);
  179 }
  180 
  181 /*
  182  * Checks an item to make sure it hasn't been overwritten since it was freed,
  183  * prior to freeing it back to available memory.
  184  *
  185  * Complies with standard fini arg/return
  186  *
  187  */
  188 void
  189 mtrash_fini(void *mem, int size)
  190 {
  191         (void)mtrash_ctor(mem, size, NULL, 0);
  192 }
  193 
  194 static uma_slab_t
  195 uma_dbg_getslab(uma_zone_t zone, void *item)
  196 {
  197         uma_slab_t slab;
  198         uma_keg_t keg;
  199         u_int8_t *mem;
  200 
  201         mem = (u_int8_t *)((unsigned long)item & (~UMA_SLAB_MASK));
  202         if (zone->uz_flags & UMA_ZONE_VTOSLAB) {
  203                 slab = vtoslab((vm_offset_t)mem);
  204         } else {
  205                 keg = LIST_FIRST(&zone->uz_kegs)->kl_keg;
  206                 if (keg->uk_flags & UMA_ZONE_HASH)
  207                         slab = hash_sfind(&keg->uk_hash, mem);
  208                 else
  209                         slab = (uma_slab_t)(mem + keg->uk_pgoff);
  210         }
  211 
  212         return (slab);
  213 }
  214 
  215 /*
  216  * Set up the slab's freei data such that uma_dbg_free can function.
  217  *
  218  */
  219 
  220 void
  221 uma_dbg_alloc(uma_zone_t zone, uma_slab_t slab, void *item)
  222 {
  223         uma_keg_t keg;
  224         uma_slabrefcnt_t slabref;
  225         int freei;
  226 
  227         if (slab == NULL) {
  228                 slab = uma_dbg_getslab(zone, item);
  229                 if (slab == NULL) 
  230                         panic("uma: item %p did not belong to zone %s\n",
  231                             item, zone->uz_name);
  232         }
  233         keg = slab->us_keg;
  234 
  235         freei = ((unsigned long)item - (unsigned long)slab->us_data)
  236             / keg->uk_rsize;
  237 
  238         if (keg->uk_flags & UMA_ZONE_REFCNT) {
  239                 slabref = (uma_slabrefcnt_t)slab;
  240                 slabref->us_freelist[freei].us_item = 255;
  241         } else {
  242                 slab->us_freelist[freei].us_item = 255;
  243         }
  244 
  245         return;
  246 }
  247 
  248 /*
  249  * Verifies freed addresses.  Checks for alignment, valid slab membership
  250  * and duplicate frees.
  251  *
  252  */
  253 
  254 void
  255 uma_dbg_free(uma_zone_t zone, uma_slab_t slab, void *item)
  256 {
  257         uma_keg_t keg;
  258         uma_slabrefcnt_t slabref;
  259         int freei;
  260 
  261         if (slab == NULL) {
  262                 slab = uma_dbg_getslab(zone, item);
  263                 if (slab == NULL) 
  264                         panic("uma: Freed item %p did not belong to zone %s\n",
  265                             item, zone->uz_name);
  266         }
  267         keg = slab->us_keg;
  268 
  269         freei = ((unsigned long)item - (unsigned long)slab->us_data)
  270             / keg->uk_rsize;
  271 
  272         if (freei >= keg->uk_ipers)
  273                 panic("zone: %s(%p) slab %p freelist %d out of range 0-%d\n",
  274                     zone->uz_name, zone, slab, freei, keg->uk_ipers-1);
  275 
  276         if (((freei * keg->uk_rsize) + slab->us_data) != item) {
  277                 printf("zone: %s(%p) slab %p freed address %p unaligned.\n",
  278                     zone->uz_name, zone, slab, item);
  279                 panic("should be %p\n",
  280                     (freei * keg->uk_rsize) + slab->us_data);
  281         }
  282 
  283         if (keg->uk_flags & UMA_ZONE_REFCNT) {
  284                 slabref = (uma_slabrefcnt_t)slab;
  285                 if (slabref->us_freelist[freei].us_item != 255) {
  286                         printf("Slab at %p, freei %d = %d.\n",
  287                             slab, freei, slabref->us_freelist[freei].us_item);
  288                         panic("Duplicate free of item %p from zone %p(%s)\n",
  289                             item, zone, zone->uz_name);
  290                 }
  291 
  292                 /*
  293                  * When this is actually linked into the slab this will change.
  294                  * Until then the count of valid slabs will make sure we don't
  295                  * accidentally follow this and assume it's a valid index.
  296                  */
  297                 slabref->us_freelist[freei].us_item = 0;
  298         } else {
  299                 if (slab->us_freelist[freei].us_item != 255) {
  300                         printf("Slab at %p, freei %d = %d.\n",
  301                             slab, freei, slab->us_freelist[freei].us_item);
  302                         panic("Duplicate free of item %p from zone %p(%s)\n",
  303                             item, zone, zone->uz_name);
  304                 }
  305 
  306                 /*
  307                  * When this is actually linked into the slab this will change.
  308                  * Until then the count of valid slabs will make sure we don't
  309                  * accidentally follow this and assume it's a valid index.
  310                  */
  311                 slab->us_freelist[freei].us_item = 0;
  312         }
  313 }

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