modules/genunix/leaky_subr.c

	leaky_subr.c revision 7c478bd95313f5f23a4c958a745db2134aa03244
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

#include <mdb/mdb_param.h>
#include <mdb/mdb_modapi.h>

#include <sys/fs/ufs_inode.h>
#include <sys/kmem_impl.h>
#include <sys/vmem_impl.h>
#include <sys/modctl.h>
#include <sys/kobj.h>
#include <sys/kobj_impl.h>
#include <vm/seg_vn.h>
#include <vm/as.h>
#include <vm/seg_map.h>
#include <mdb/mdb_ctf.h>

#include "kmem.h"
#include "leaky_impl.h"

/*
 * This file defines the genunix target for leaky.c.  There are three types
 * of buffers in the kernel's heap:  TYPE_VMEM, for kmem_oversize allocations,
 * TYPE_KMEM, for kmem_cache_alloc() allocations bufctl_audit_ts, and
 * TYPE_CACHE, for kmem_cache_alloc() allocation without bufctl_audit_ts.
 *
 * See "leaky_impl.h" for the target interface definition.
 */

#define TYPE_VMEM   0       /* lkb_data is the vmem_seg's size */
#define TYPE_CACHE  1       /* lkb_cid is the bufctl's cache */
#define TYPE_KMEM   2       /* lkb_cid is the bufctl's cache */

#define LKM_CTL_BUFCTL  0   /* normal allocation, PTR is bufctl */
#define LKM_CTL_VMSEG   1   /* oversize allocation, PTR is vmem_seg_t */
#define LKM_CTL_CACHE   2   /* normal alloc, non-debug, PTR is cache */
#define LKM_CTL_MASK    3L

#define LKM_CTL(ptr, type)  (LKM_CTLPTR(ptr) | (type))
#define LKM_CTLPTR(ctl)     ((uintptr_t)(ctl) & ~(LKM_CTL_MASK))
#define LKM_CTLTYPE(ctl)    ((uintptr_t)(ctl) &  (LKM_CTL_MASK))

static int kmem_lite_count = 0; /* cache of the kernel's version */

/*ARGSUSED*/
static int
leaky_mtab(uintptr_t addr, const kmem_bufctl_audit_t *bcp, leak_mtab_t **lmp)
{
    leak_mtab_t *lm = (*lmp)++;

    lm->lkm_base = (uintptr_t)bcp->bc_addr;
    lm->lkm_bufctl = LKM_CTL(addr, LKM_CTL_BUFCTL);

    return (WALK_NEXT);
}

/*ARGSUSED*/
static int
leaky_mtab_addr(uintptr_t addr, void *ignored, leak_mtab_t **lmp)
{
    leak_mtab_t *lm = (*lmp)++;

    lm->lkm_base = addr;

    return (WALK_NEXT);
}

static int
leaky_seg(uintptr_t addr, const vmem_seg_t *seg, leak_mtab_t **lmp)
{
    leak_mtab_t *lm = (*lmp)++;

    lm->lkm_base = seg->vs_start;
    lm->lkm_limit = seg->vs_end;
    lm->lkm_bufctl = LKM_CTL(addr, LKM_CTL_VMSEG);

    return (WALK_NEXT);
}

static int
leaky_vmem_interested(const vmem_t *vmem)
{
    if (strcmp(vmem->vm_name, "kmem_oversize") != 0 &&
        strcmp(vmem->vm_name, "static_alloc") != 0)
        return (0);
    return (1);
}

static int
leaky_vmem(uintptr_t addr, const vmem_t *vmem, leak_mtab_t **lmp)
{
    if (!leaky_vmem_interested(vmem))
        return (WALK_NEXT);

    if (mdb_pwalk("vmem_alloc", (mdb_walk_cb_t)leaky_seg, lmp, addr) == -1)
        mdb_warn("can't walk vmem_alloc for kmem_oversize (%p)", addr);

    return (WALK_NEXT);
}

/*ARGSUSED*/
static int
leaky_estimate_vmem(uintptr_t addr, const vmem_t *vmem, size_t *est)
{
    if (!leaky_vmem_interested(vmem))
        return (WALK_NEXT);

    *est += (int)(vmem->vm_kstat.vk_alloc.value.ui64 -
        vmem->vm_kstat.vk_free.value.ui64);

    return (WALK_NEXT);
}

static int
leaky_interested(const kmem_cache_t *c)
{
    vmem_t vmem;

    /*
     * ignore HAT-related caches that happen to derive from kmem_default
     */
    if (strcmp(c->cache_name, "sfmmu1_cache") == 0 ||
        strcmp(c->cache_name, "sf_hment_cache") == 0 ||
        strcmp(c->cache_name, "pa_hment_cache") == 0)
        return (0);

    if (mdb_vread(&vmem, sizeof (vmem), (uintptr_t)c->cache_arena) == -1) {
        mdb_warn("cannot read arena %p for cache '%s'",
            (uintptr_t)c->cache_arena, c->cache_name);
        return (0);
    }

    /*
     * If this cache isn't allocating from the kmem_default,
     * kmem_firewall, or static vmem arenas, we're not interested.
     */
    if (strcmp(vmem.vm_name, "kmem_default") != 0 &&
        strcmp(vmem.vm_name, "kmem_firewall") != 0 &&
        strcmp(vmem.vm_name, "static") != 0)
        return (0);

    return (1);
}

static int
leaky_estimate(uintptr_t addr, const kmem_cache_t *c, size_t *est)
{
    if (!leaky_interested(c))
        return (WALK_NEXT);

    *est += kmem_estimate_allocated(addr, c);

    return (WALK_NEXT);
}

/*ARGSUSED*/
static int
leaky_cache(uintptr_t addr, const kmem_cache_t *c, leak_mtab_t **lmp)
{
    leak_mtab_t *lm = *lmp;
    mdb_walk_cb_t cb;
    const char *walk;
    int audit = (c->cache_flags & KMF_AUDIT);

    if (!leaky_interested(c))
        return (WALK_NEXT);

    if (audit) {
        walk = "bufctl";
        cb = (mdb_walk_cb_t)leaky_mtab;
    } else {
        walk = "kmem";
        cb = (mdb_walk_cb_t)leaky_mtab_addr;
    }
    if (mdb_pwalk(walk, cb, lmp, addr) == -1) {
        mdb_warn("can't walk kmem for cache %p (%s)", addr,
            c->cache_name);
        return (WALK_DONE);
    }

    for (; lm < *lmp; lm++) {
        lm->lkm_limit = lm->lkm_base + c->cache_bufsize;
        if (!audit)
            lm->lkm_bufctl = LKM_CTL(addr, LKM_CTL_CACHE);
    }

    return (WALK_NEXT);
}

/*ARGSUSED*/
static int
leaky_scan_buffer(uintptr_t addr, const void *ignored, const kmem_cache_t *c)
{
    leaky_grep(addr, c->cache_bufsize);

    /*
     * free, constructed KMF_LITE buffers keep their first uint64_t in
     * their buftag's redzone.
     */
    if (c->cache_flags & KMF_LITE) {
        /* LINTED alignment */
        kmem_buftag_t *btp = KMEM_BUFTAG(c, addr);
        leaky_grep((uintptr_t)&btp->bt_redzone,
            sizeof (btp->bt_redzone));
    }

    return (WALK_NEXT);
}

/*ARGSUSED*/
static int
leaky_scan_cache(uintptr_t addr, const kmem_cache_t *c, void *ignored)
{
    if (!leaky_interested(c))
        return (WALK_NEXT);

    /*
     * Scan all of the free, constructed buffers, since they may have
     * pointers to allocated objects.
     */
    if (mdb_pwalk("freemem_constructed",
        (mdb_walk_cb_t)leaky_scan_buffer, (void *)c, addr) == -1) {
        mdb_warn("can't walk freemem_constructed for cache %p (%s)",
            addr, c->cache_name);
        return (WALK_DONE);
    }

    return (WALK_NEXT);
}

/*ARGSUSED*/
static int
leaky_modctl(uintptr_t addr, const struct modctl *m, int *ignored)
{
    struct module mod;
    char name[MODMAXNAMELEN];

    if (m->mod_mp == NULL)
        return (WALK_NEXT);

    if (mdb_vread(&mod, sizeof (mod), (uintptr_t)m->mod_mp) == -1) {
        mdb_warn("couldn't read modctl %p's module", addr);
        return (WALK_NEXT);
    }

    if (mdb_readstr(name, sizeof (name), (uintptr_t)m->mod_modname) == -1)
        (void) mdb_snprintf(name, sizeof (name), "0x%p", addr);

    leaky_grep((uintptr_t)m->mod_mp, sizeof (struct module));
    leaky_grep((uintptr_t)mod.data, mod.data_size);
    leaky_grep((uintptr_t)mod.bss, mod.bss_size);

    return (WALK_NEXT);
}

static int
leaky_thread(uintptr_t addr, const kthread_t *t, unsigned long *pagesize)
{
    uintptr_t size, base = (uintptr_t)t->t_stkbase;
    uintptr_t stk = (uintptr_t)t->t_stk;

    /*
     * If this thread isn't in memory, we can't look at its stack.  This
     * may result in false positives, so we print a warning.
     */
    if (!(t->t_schedflag & TS_LOAD)) {
        mdb_printf("findleaks: thread %p's stack swapped out; "
            "false positives possible\n", addr);
        return (WALK_NEXT);
    }

    if (t->t_state != TS_FREE)
        leaky_grep(base, stk - base);

    /*
     * There is always gunk hanging out between t_stk and the page
     * boundary.  If this thread structure wasn't kmem allocated,
     * this will include the thread structure itself.  If the thread
     * _is_ kmem allocated, we'll be able to get to it via allthreads.
     */
    size = *pagesize - (stk & (*pagesize - 1));

    leaky_grep(stk, size);

    return (WALK_NEXT);
}

/*ARGSUSED*/
static int
leaky_kstat(uintptr_t addr, vmem_seg_t *seg, void *ignored)
{
    leaky_grep(seg->vs_start, seg->vs_end - seg->vs_start);

    return (WALK_NEXT);
}

static void
leaky_kludge(void)
{
    GElf_Sym sym;
    mdb_ctf_id_t id, rid;

    int max_mem_nodes;
    uintptr_t *counters;
    size_t ncounters;
    ssize_t hwpm_size;
    int idx;

    /*
     * Because of DR, the page counters (which live in the kmem64 segment)
     * can point into kmem_alloc()ed memory.  The "page_counters" array
     * is multi-dimensional, and each entry points to an array of
     * "hw_page_map_t"s which is "max_mem_nodes" in length.
     *
     * To keep this from having too much grotty knowledge of internals,
     * we use CTF data to get the size of the structure.  For simplicity,
     * we treat the page_counters array as a flat array of pointers, and
     * use its size to determine how much to scan.  Unused entries will
     * be NULL.
     */
    if (mdb_lookup_by_name("page_counters", &sym) == -1) {
        mdb_warn("unable to lookup page_counters");
        return;
    }

    if (mdb_readvar(&max_mem_nodes, "max_mem_nodes") == -1) {
        mdb_warn("unable to read max_mem_nodes");
        return;
    }

    if (mdb_ctf_lookup_by_name("unix`hw_page_map_t", &id) == -1 ||
        mdb_ctf_type_resolve(id, &rid) == -1 ||
        (hwpm_size = mdb_ctf_type_size(rid)) < 0) {
        mdb_warn("unable to lookup unix`hw_page_map_t");
        return;
    }

    counters = mdb_alloc(sym.st_size, UM_SLEEP | UM_GC);

    if (mdb_vread(counters, sym.st_size, (uintptr_t)sym.st_value) == -1) {
        mdb_warn("unable to read page_counters");
        return;
    }

    ncounters = sym.st_size / sizeof (counters);

    for (idx = 0; idx < ncounters; idx++) {
        uintptr_t addr = counters[idx];
        if (addr != 0)
            leaky_grep(addr, hwpm_size * max_mem_nodes);
    }
}

int
leaky_subr_estimate(size_t *estp)
{
    uintptr_t panicstr;
    int state;

    if ((state = mdb_get_state()) == MDB_STATE_RUNNING) {
        mdb_warn("findleaks: can only be run on a system "
            "dump or under kmdb; see dumpadm(1M)\n");
        return (DCMD_ERR);
    }

    if (mdb_readvar(&panicstr, "panicstr") == -1) {
        mdb_warn("can't read variable 'panicstr'");
        return (DCMD_ERR);
    }

    if (state != MDB_STATE_STOPPED && panicstr == NULL) {
        mdb_warn("findleaks: cannot be run on a live dump.\n");
        return (DCMD_ERR);
    }

    if (mdb_walk("kmem_cache", (mdb_walk_cb_t)leaky_estimate, estp) == -1) {
        mdb_warn("couldn't walk 'kmem_cache'");
        return (DCMD_ERR);
    }

    if (*estp == 0) {
        mdb_warn("findleaks: no buffers found\n");
        return (DCMD_ERR);
    }

    if (mdb_walk("vmem", (mdb_walk_cb_t)leaky_estimate_vmem, estp) == -1) {
        mdb_warn("couldn't walk 'vmem'");
        return (DCMD_ERR);
    }

    return (DCMD_OK);
}

int
leaky_subr_fill(leak_mtab_t **lmpp)
{
    if (mdb_walk("vmem", (mdb_walk_cb_t)leaky_vmem, lmpp) == -1) {
        mdb_warn("couldn't walk 'vmem'");
        return (DCMD_ERR);
    }

    if (mdb_walk("kmem_cache", (mdb_walk_cb_t)leaky_cache, lmpp) == -1) {
        mdb_warn("couldn't walk 'kmem_cache'");
        return (DCMD_ERR);
    }

    if (mdb_readvar(&kmem_lite_count, "kmem_lite_count") == -1) {
        mdb_warn("couldn't read 'kmem_lite_count'");
        kmem_lite_count = 0;
    } else if (kmem_lite_count > 16) {
        mdb_warn("kmem_lite_count nonsensical, ignored\n");
        kmem_lite_count = 0;
    }

    return (DCMD_OK);
}

int
leaky_subr_run(void)
{
    unsigned long ps;
    uintptr_t kstat_arena;

    if (mdb_readvar(&ps, "_pagesize") == -1) {
        mdb_warn("couldn't read '_pagesize'");
        return (DCMD_ERR);
    }

    leaky_kludge();

    if (mdb_walk("kmem_cache", (mdb_walk_cb_t)leaky_scan_cache,
        NULL) == -1) {
        mdb_warn("couldn't walk 'kmem_cache'");
        return (DCMD_ERR);
    }

    if (mdb_walk("modctl", (mdb_walk_cb_t)leaky_modctl, NULL) == -1) {
        mdb_warn("couldn't walk 'modctl'");
        return (DCMD_ERR);
    }

    if (mdb_walk("thread", (mdb_walk_cb_t)leaky_thread, &ps) == -1) {
        mdb_warn("couldn't walk 'thread'");
        return (DCMD_ERR);
    }

    if (mdb_walk("deathrow", (mdb_walk_cb_t)leaky_thread, &ps) == -1) {
        mdb_warn("couldn't walk 'deathrow'");
        return (DCMD_ERR);
    }

    if (mdb_readvar(&kstat_arena, "kstat_arena") == -1) {
        mdb_warn("couldn't read 'kstat_arena'");
        return (DCMD_ERR);
    }

    if (mdb_pwalk("vmem_alloc", (mdb_walk_cb_t)leaky_kstat,
        NULL, kstat_arena) == -1) {
        mdb_warn("couldn't walk kstat vmem arena");
        return (DCMD_ERR);
    }

    return (DCMD_OK);
}

void
leaky_subr_add_leak(leak_mtab_t *lmp)
{
    uintptr_t addr = LKM_CTLPTR(lmp->lkm_bufctl);
    size_t depth;

    switch (LKM_CTLTYPE(lmp->lkm_bufctl)) {
    case LKM_CTL_VMSEG: {
        vmem_seg_t vs;

        if (mdb_vread(&vs, sizeof (vs), addr) == -1) {
            mdb_warn("couldn't read leaked vmem_seg at addr %p",
                addr);
            return;
        }
        depth = MIN(vs.vs_depth, VMEM_STACK_DEPTH);

        leaky_add_leak(TYPE_VMEM, addr, vs.vs_start, vs.vs_timestamp,
            vs.vs_stack, depth, 0, (vs.vs_end - vs.vs_start));
        break;
    }
    case LKM_CTL_BUFCTL: {
        kmem_bufctl_audit_t bc;

        if (mdb_vread(&bc, sizeof (bc), addr) == -1) {
            mdb_warn("couldn't read leaked bufctl at addr %p",
                addr);
            return;
        }

        depth = MIN(bc.bc_depth, KMEM_STACK_DEPTH);

        /*
         * The top of the stack will be kmem_cache_alloc+offset.
         * Since the offset in kmem_cache_alloc() isn't interesting
         * we skip that frame for the purposes of uniquifying stacks.
         *
         * We also use the cache pointer as the leaks's cid, to
         * prevent the coalescing of leaks from different caches.
         */
        if (depth > 0)
            depth--;
        leaky_add_leak(TYPE_KMEM, addr, (uintptr_t)bc.bc_addr,
            bc.bc_timestamp, bc.bc_stack + 1, depth,
            (uintptr_t)bc.bc_cache, 0);
        break;
    }
    case LKM_CTL_CACHE: {
        kmem_cache_t cache;
        kmem_buftag_lite_t bt;
        pc_t caller;
        int depth = 0;

        /*
         * For KMF_LITE caches, we can get the allocation PC
         * out of the buftag structure.
         */
        if (mdb_vread(&cache, sizeof (cache), addr) != -1 &&
            (cache.cache_flags & KMF_LITE) &&
            kmem_lite_count > 0 &&
            mdb_vread(&bt, sizeof (bt),
            /* LINTED alignment */
            (uintptr_t)KMEM_BUFTAG(&cache, lmp->lkm_base)) != -1) {
            caller = bt.bt_history[0];
            depth = 1;
        }
        leaky_add_leak(TYPE_CACHE, lmp->lkm_base, lmp->lkm_base, 0,
            &caller, depth, addr, addr);
        break;
    }
    default:
        mdb_warn("internal error: invalid leak_bufctl_t\n");
        break;
    }
}

static void
leaky_subr_caller(const pc_t *stack, uint_t depth, char *buf, uintptr_t *pcp)
{
    int i;
    GElf_Sym sym;
    uintptr_t pc = 0;

    buf[0] = 0;

    for (i = 0; i < depth; i++) {
        pc = stack[i];

        if (mdb_lookup_by_addr(pc,
            MDB_SYM_FUZZY, buf, MDB_SYM_NAMLEN, &sym) == -1)
            continue;
        if (strncmp(buf, "kmem_", 5) == 0)
            continue;
        if (strncmp(buf, "vmem_", 5) == 0)
            continue;
        *pcp = pc;

        return;
    }

    /*
     * We're only here if the entire call chain begins with "kmem_";
     * this shouldn't happen, but we'll just use the last caller.
     */
    *pcp = pc;
}

int
leaky_subr_bufctl_cmp(const leak_bufctl_t *lhs, const leak_bufctl_t *rhs)
{
    char lbuf[MDB_SYM_NAMLEN], rbuf[MDB_SYM_NAMLEN];
    uintptr_t lcaller, rcaller;
    int rval;

    leaky_subr_caller(lhs->lkb_stack, lhs->lkb_depth, lbuf, &lcaller);
    leaky_subr_caller(rhs->lkb_stack, lhs->lkb_depth, rbuf, &rcaller);

    if (rval = strcmp(lbuf, rbuf))
        return (rval);

    if (lcaller < rcaller)
        return (-1);

    if (lcaller > rcaller)
        return (1);

    if (lhs->lkb_data < rhs->lkb_data)
        return (-1);

    if (lhs->lkb_data > rhs->lkb_data)
        return (1);

    return (0);
}

/*
 * Global state variables used by the leaky_subr_dump_* routines.  Note that
 * they are carefully cleared before use.
 */
static int lk_vmem_seen;
static int lk_cache_seen;
static int lk_kmem_seen;
static size_t lk_ttl;
static size_t lk_bytes;

void
leaky_subr_dump_start(int type)
{
    switch (type) {
    case TYPE_VMEM:
        lk_vmem_seen = 0;
        break;
    case TYPE_CACHE:
        lk_cache_seen = 0;
        break;
    case TYPE_KMEM:
        lk_kmem_seen = 0;
        break;
    default:
        break;
    }

    lk_ttl = 0;
    lk_bytes = 0;
}

void
leaky_subr_dump(const leak_bufctl_t *lkb, int verbose)
{
    const leak_bufctl_t *cur;
    kmem_cache_t cache;
    size_t min, max, size;
    char sz[30];
    char c[MDB_SYM_NAMLEN];
    uintptr_t caller;

    if (verbose) {
        lk_ttl = 0;
        lk_bytes = 0;
    }

    switch (lkb->lkb_type) {
    case TYPE_VMEM:
        if (!verbose && !lk_vmem_seen) {
            lk_vmem_seen = 1;
            mdb_printf("%-16s %7s %?s %s\n",
                "BYTES", "LEAKED", "VMEM_SEG", "CALLER");
        }

        min = max = lkb->lkb_data;

        for (cur = lkb; cur != NULL; cur = cur->lkb_next) {
            size = cur->lkb_data;

            if (size < min)
                min = size;
            if (size > max)
                max = size;

            lk_ttl++;
            lk_bytes += size;
        }

        if (min == max)
            (void) mdb_snprintf(sz, sizeof (sz), "%ld", min);
        else
            (void) mdb_snprintf(sz, sizeof (sz), "%ld-%ld",
                min, max);

        if (!verbose) {
            leaky_subr_caller(lkb->lkb_stack, lkb->lkb_depth,
                c, &caller);

            if (caller != 0) {
                (void) mdb_snprintf(c, sizeof (c),
                    "%a", caller);
            } else {
                (void) mdb_snprintf(c, sizeof (c),
                    "%s", "?");
            }
            mdb_printf("%-16s %7d %?p %s\n", sz, lkb->lkb_dups + 1,
                lkb->lkb_addr, c);
        } else {
            mdb_arg_t v;

            if (lk_ttl == 1)
                mdb_printf("kmem_oversize leak: 1 vmem_seg, "
                    "%ld bytes\n", lk_bytes);
            else
                mdb_printf("kmem_oversize leak: %d vmem_segs, "
                    "%s bytes each, %ld bytes total\n",
                    lk_ttl, sz, lk_bytes);

            v.a_type = MDB_TYPE_STRING;
            v.a_un.a_str = "-v";

            if (mdb_call_dcmd("vmem_seg", lkb->lkb_addr,
                DCMD_ADDRSPEC, 1, &v) == -1) {
                mdb_warn("'%p::vmem_seg -v' failed",
                    lkb->lkb_addr);
            }
        }
        return;

    case TYPE_CACHE:
        if (!verbose && !lk_cache_seen) {
            lk_cache_seen = 1;
            if (lk_vmem_seen)
                mdb_printf("\n");
            mdb_printf("%-?s %7s %?s %s\n",
                "CACHE", "LEAKED", "BUFFER", "CALLER");
        }

        if (mdb_vread(&cache, sizeof (cache), lkb->lkb_data) == -1) {
            /*
             * This _really_ shouldn't happen; we shouldn't
             * have been able to get this far if this
             * cache wasn't readable.
             */
            mdb_warn("can't read cache %p for leaked "
                "buffer %p", lkb->lkb_data, lkb->lkb_addr);
            return;
        }

        lk_ttl += lkb->lkb_dups + 1;
        lk_bytes += (lkb->lkb_dups + 1) * cache.cache_bufsize;

        caller = (lkb->lkb_depth == 0) ? 0 : lkb->lkb_stack[0];
        if (caller != 0) {
            (void) mdb_snprintf(c, sizeof (c), "%a", caller);
        } else {
            (void) mdb_snprintf(c, sizeof (c),
                "%s", (verbose) ? "" : "?");
        }

        if (!verbose) {
            mdb_printf("%0?p %7d %0?p %s\n", lkb->lkb_cid,
                lkb->lkb_dups + 1, lkb->lkb_addr, c);
        } else {
            if (lk_ttl == 1)
                mdb_printf("%s leak: 1 buffer, %ld bytes,\n",
                    cache.cache_name, lk_bytes);
            else
                mdb_printf("%s leak: %d buffers, "
                    "%ld bytes each, %ld bytes total,\n",
                    cache.cache_name, lk_ttl,
                    cache.cache_bufsize, lk_bytes);

            mdb_printf("    sample addr %p%s%s\n",
                lkb->lkb_addr, (caller == 0) ? "" : ", caller ", c);
        }
        return;

    case TYPE_KMEM:
        if (!verbose && !lk_kmem_seen) {
            lk_kmem_seen = 1;
            if (lk_vmem_seen || lk_cache_seen)
                mdb_printf("\n");
            mdb_printf("%-?s %7s %?s %s\n",
                "CACHE", "LEAKED", "BUFCTL", "CALLER");
        }

        if (mdb_vread(&cache, sizeof (cache), lkb->lkb_cid) == -1) {
            /*
             * This _really_ shouldn't happen; we shouldn't
             * have been able to get this far if this
             * cache wasn't readable.
             */
            mdb_warn("can't read cache %p for leaked "
                "bufctl %p", lkb->lkb_cid, lkb->lkb_addr);
            return;
        }

        lk_ttl += lkb->lkb_dups + 1;
        lk_bytes += (lkb->lkb_dups + 1) * cache.cache_bufsize;

        if (!verbose) {
            leaky_subr_caller(lkb->lkb_stack, lkb->lkb_depth,
                c, &caller);

            if (caller != 0) {
                (void) mdb_snprintf(c, sizeof (c),
                    "%a", caller);
            } else {
                (void) mdb_snprintf(c, sizeof (c),
                    "%s", "?");
            }
            mdb_printf("%0?p %7d %0?p %s\n", lkb->lkb_cid,
                lkb->lkb_dups + 1, lkb->lkb_addr, c);
        } else {
            mdb_arg_t v;

            if (lk_ttl == 1)
                mdb_printf("%s leak: 1 buffer, %ld bytes\n",
                    cache.cache_name, lk_bytes);
            else
                mdb_printf("%s leak: %d buffers, "
                    "%ld bytes each, %ld bytes total\n",
                    cache.cache_name, lk_ttl,
                    cache.cache_bufsize, lk_bytes);

            v.a_type = MDB_TYPE_STRING;
            v.a_un.a_str = "-v";

            if (mdb_call_dcmd("bufctl", lkb->lkb_addr,
                DCMD_ADDRSPEC, 1, &v) == -1) {
                mdb_warn("'%p::bufctl -v' failed",
                    lkb->lkb_addr);
            }
        }
        return;

    default:
        return;
    }
}

void
leaky_subr_dump_end(int type)
{
    int i;
    int width;
    const char *leaks;

    switch (type) {
    case TYPE_VMEM:
        if (!lk_vmem_seen)
            return;

        width = 16;
        leaks = "kmem_oversize leak";
        break;

    case TYPE_CACHE:
        if (!lk_cache_seen)
            return;

        width = sizeof (uintptr_t) * 2;
        leaks = "buffer";
        break;

    case TYPE_KMEM:
        if (!lk_kmem_seen)
            return;

        width = sizeof (uintptr_t) * 2;
        leaks = "buffer";
        break;

    default:
        return;
    }

    for (i = 0; i < 72; i++)
        mdb_printf("-");
    mdb_printf("\n%*s %7ld %s%s, %ld byte%s\n",
        width, "Total", lk_ttl, leaks, (lk_ttl == 1) ? "" : "s",
        lk_bytes, (lk_bytes == 1) ? "" : "s");
}

int
leaky_subr_invoke_callback(const leak_bufctl_t *lkb, mdb_walk_cb_t cb,
    void *cbdata)
{
    kmem_bufctl_audit_t bc;
    vmem_seg_t vs;

    switch (lkb->lkb_type) {
    case TYPE_VMEM:
        if (mdb_vread(&vs, sizeof (vs), lkb->lkb_addr) == -1) {
            mdb_warn("unable to read vmem_seg at %p",
                lkb->lkb_addr);
            return (WALK_NEXT);
        }
        return (cb(lkb->lkb_addr, &vs, cbdata));

    case TYPE_CACHE:
        return (cb(lkb->lkb_addr, NULL, cbdata));

    case TYPE_KMEM:
        if (mdb_vread(&bc, sizeof (bc), lkb->lkb_addr) == -1) {
            mdb_warn("unable to read bufctl at %p",
                lkb->lkb_addr);
            return (WALK_NEXT);
        }
        return (cb(lkb->lkb_addr, &bc, cbdata));
    default:
        return (WALK_NEXT);
    }
}