d158fa4ade
Some best-effort consumers may find trylock behavior for stack(9) symbol resolution acceptable. Expose that behavior to such consumers. This API is ugly. If in the future the modules and linker file list locking is cleaned up such that the linker_files list can be iterated safely without acquiring a sleepable lock, this API should be removed. However, most of the time nothing will be holding the linker files lock exclusive and the acquisition can proceed. Reviewed by: markj Sponsored by: Dell EMC Isilon Differential Revision: https://reviews.freebsd.org/D17620
294 lines
6.8 KiB
C
294 lines
6.8 KiB
C
/*-
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* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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*
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* Copyright (c) 2005 Antoine Brodin
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include "opt_ddb.h"
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/kernel.h>
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#ifdef KTR
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#include <sys/ktr.h>
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#endif
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#include <sys/linker.h>
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#include <sys/malloc.h>
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#include <sys/sbuf.h>
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#include <sys/stack.h>
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#include <sys/systm.h>
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#include <sys/sysctl.h>
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FEATURE(stack, "Support for capturing kernel stack");
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static MALLOC_DEFINE(M_STACK, "stack", "Stack Traces");
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static int stack_symbol(vm_offset_t pc, char *namebuf, u_int buflen,
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long *offset, int flags);
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static int stack_symbol_ddb(vm_offset_t pc, const char **name, long *offset);
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struct stack *
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stack_create(int flags)
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{
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struct stack *st;
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st = malloc(sizeof(*st), M_STACK, flags | M_ZERO);
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return (st);
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}
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void
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stack_destroy(struct stack *st)
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{
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free(st, M_STACK);
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}
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int
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stack_put(struct stack *st, vm_offset_t pc)
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{
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if (st->depth < STACK_MAX) {
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st->pcs[st->depth++] = pc;
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return (0);
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} else
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return (-1);
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}
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void
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stack_copy(const struct stack *src, struct stack *dst)
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{
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*dst = *src;
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}
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void
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stack_zero(struct stack *st)
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{
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bzero(st, sizeof *st);
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}
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void
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stack_print(const struct stack *st)
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{
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char namebuf[64];
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long offset;
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int i;
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KASSERT(st->depth <= STACK_MAX, ("bogus stack"));
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for (i = 0; i < st->depth; i++) {
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(void)stack_symbol(st->pcs[i], namebuf, sizeof(namebuf),
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&offset, M_WAITOK);
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printf("#%d %p at %s+%#lx\n", i, (void *)st->pcs[i],
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namebuf, offset);
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}
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}
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void
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stack_print_short(const struct stack *st)
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{
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char namebuf[64];
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long offset;
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int i;
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KASSERT(st->depth <= STACK_MAX, ("bogus stack"));
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for (i = 0; i < st->depth; i++) {
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if (i > 0)
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printf(" ");
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if (stack_symbol(st->pcs[i], namebuf, sizeof(namebuf),
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&offset, M_WAITOK) == 0)
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printf("%s+%#lx", namebuf, offset);
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else
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printf("%p", (void *)st->pcs[i]);
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}
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printf("\n");
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}
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void
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stack_print_ddb(const struct stack *st)
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{
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const char *name;
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long offset;
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int i;
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KASSERT(st->depth <= STACK_MAX, ("bogus stack"));
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for (i = 0; i < st->depth; i++) {
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stack_symbol_ddb(st->pcs[i], &name, &offset);
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printf("#%d %p at %s+%#lx\n", i, (void *)st->pcs[i],
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name, offset);
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}
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}
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#if defined(DDB) || defined(WITNESS)
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void
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stack_print_short_ddb(const struct stack *st)
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{
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const char *name;
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long offset;
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int i;
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KASSERT(st->depth <= STACK_MAX, ("bogus stack"));
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for (i = 0; i < st->depth; i++) {
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if (i > 0)
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printf(" ");
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if (stack_symbol_ddb(st->pcs[i], &name, &offset) == 0)
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printf("%s+%#lx", name, offset);
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else
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printf("%p", (void *)st->pcs[i]);
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}
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printf("\n");
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}
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#endif
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/*
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* Format stack into sbuf from live kernel.
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*
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* flags - M_WAITOK or M_NOWAIT (EWOULDBLOCK).
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*/
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int
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stack_sbuf_print_flags(struct sbuf *sb, const struct stack *st, int flags)
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{
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char namebuf[64];
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long offset;
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int i, error;
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KASSERT(st->depth <= STACK_MAX, ("bogus stack"));
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for (i = 0; i < st->depth; i++) {
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error = stack_symbol(st->pcs[i], namebuf, sizeof(namebuf),
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&offset, flags);
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if (error == EWOULDBLOCK)
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return (error);
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sbuf_printf(sb, "#%d %p at %s+%#lx\n", i, (void *)st->pcs[i],
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namebuf, offset);
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}
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return (0);
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}
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void
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stack_sbuf_print(struct sbuf *sb, const struct stack *st)
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{
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(void)stack_sbuf_print_flags(sb, st, M_WAITOK);
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}
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#if defined(DDB) || defined(WITNESS)
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void
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stack_sbuf_print_ddb(struct sbuf *sb, const struct stack *st)
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{
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const char *name;
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long offset;
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int i;
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KASSERT(st->depth <= STACK_MAX, ("bogus stack"));
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for (i = 0; i < st->depth; i++) {
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(void)stack_symbol_ddb(st->pcs[i], &name, &offset);
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sbuf_printf(sb, "#%d %p at %s+%#lx\n", i, (void *)st->pcs[i],
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name, offset);
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}
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}
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#endif
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#ifdef KTR
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void
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stack_ktr(u_int mask, const char *file, int line, const struct stack *st,
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u_int depth, int cheap)
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{
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#ifdef DDB
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const char *name;
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long offset;
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int i;
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#endif
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KASSERT(st->depth <= STACK_MAX, ("bogus stack"));
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if (cheap) {
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ktr_tracepoint(mask, file, line, "#0 %p %p %p %p %p %p",
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st->pcs[0], st->pcs[1], st->pcs[2], st->pcs[3],
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st->pcs[4], st->pcs[5]);
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if (st->depth <= 6)
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return;
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ktr_tracepoint(mask, file, line, "#1 %p %p %p %p %p %p",
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st->pcs[6], st->pcs[7], st->pcs[8], st->pcs[9],
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st->pcs[10], st->pcs[11]);
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if (st->depth <= 12)
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return;
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ktr_tracepoint(mask, file, line, "#2 %p %p %p %p %p %p",
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st->pcs[12], st->pcs[13], st->pcs[14], st->pcs[15],
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st->pcs[16], st->pcs[17]);
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#ifdef DDB
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} else {
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if (depth == 0 || st->depth < depth)
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depth = st->depth;
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for (i = 0; i < depth; i++) {
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(void)stack_symbol_ddb(st->pcs[i], &name, &offset);
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ktr_tracepoint(mask, file, line, "#%d %p at %s+%#lx",
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i, st->pcs[i], (u_long)name, offset, 0, 0);
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}
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#endif
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}
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}
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#endif
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/*
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* Two variants of stack symbol lookup -- one that uses the DDB interfaces
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* and bypasses linker locking, and the other that doesn't.
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*/
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static int
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stack_symbol(vm_offset_t pc, char *namebuf, u_int buflen, long *offset,
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int flags)
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{
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int error;
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error = linker_search_symbol_name_flags((caddr_t)pc, namebuf, buflen,
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offset, flags);
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if (error == 0 || error == EWOULDBLOCK)
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return (error);
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*offset = 0;
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strlcpy(namebuf, "??", buflen);
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return (ENOENT);
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}
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static int
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stack_symbol_ddb(vm_offset_t pc, const char **name, long *offset)
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{
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linker_symval_t symval;
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c_linker_sym_t sym;
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if (linker_ddb_search_symbol((caddr_t)pc, &sym, offset) != 0)
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goto out;
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if (linker_ddb_symbol_values(sym, &symval) != 0)
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goto out;
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if (symval.name != NULL) {
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*name = symval.name;
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return (0);
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}
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out:
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*offset = 0;
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*name = "??";
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return (ENOENT);
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}
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