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NetBSD/sys/kern/subr_lockdebug.c

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/* $NetBSD: subr_lockdebug.c,v 1.72 2019/05/28 07:39:16 ryo Exp $ */
/*-
* Copyright (c) 2006, 2007, 2008 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Andrew Doran.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
/*
* Basic lock debugging code shared among lock primitives.
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: subr_lockdebug.c,v 1.72 2019/05/28 07:39:16 ryo Exp $");
#ifdef _KERNEL_OPT
#include "opt_ddb.h"
#endif
#include <sys/param.h>
#include <sys/proc.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/kmem.h>
#include <sys/lockdebug.h>
#include <sys/sleepq.h>
#include <sys/cpu.h>
#include <sys/atomic.h>
#include <sys/lock.h>
#include <sys/rbtree.h>
#include <sys/ksyms.h>
#include <machine/lock.h>
unsigned int ld_panic;
#ifdef LOCKDEBUG
#ifdef __ia64__
#define LD_BATCH_SHIFT 16
#else
#define LD_BATCH_SHIFT 9
#endif
#define LD_BATCH (1 << LD_BATCH_SHIFT)
#define LD_BATCH_MASK (LD_BATCH - 1)
#define LD_MAX_LOCKS 1048576
#define LD_SLOP 16
#define LD_LOCKED 0x01
#define LD_SLEEPER 0x02
#define LD_WRITE_LOCK 0x80000000
typedef struct lockdebug {
struct rb_node ld_rb_node;
__cpu_simple_lock_t ld_spinlock;
_TAILQ_ENTRY(struct lockdebug, volatile) ld_chain;
_TAILQ_ENTRY(struct lockdebug, volatile) ld_achain;
volatile void *ld_lock;
lockops_t *ld_lockops;
struct lwp *ld_lwp;
uintptr_t ld_locked;
uintptr_t ld_unlocked;
uintptr_t ld_initaddr;
uint16_t ld_shares;
uint16_t ld_cpu;
uint8_t ld_flags;
uint8_t ld_shwant; /* advisory */
uint8_t ld_exwant; /* advisory */
uint8_t ld_unused;
} volatile lockdebug_t;
typedef _TAILQ_HEAD(lockdebuglist, struct lockdebug, volatile) lockdebuglist_t;
__cpu_simple_lock_t ld_mod_lk;
lockdebuglist_t ld_free = TAILQ_HEAD_INITIALIZER(ld_free);
lockdebuglist_t ld_all = TAILQ_HEAD_INITIALIZER(ld_all);
int ld_nfree;
int ld_freeptr;
int ld_recurse;
bool ld_nomore;
lockdebug_t ld_prime[LD_BATCH];
static void lockdebug_abort1(const char *, size_t, lockdebug_t *, int,
const char *, bool);
static int lockdebug_more(int);
static void lockdebug_init(void);
static void lockdebug_dump(lockdebug_t *, void (*)(const char *, ...)
__printflike(1, 2));
static signed int
ld_rbto_compare_nodes(void *ctx, const void *n1, const void *n2)
{
const lockdebug_t *ld1 = n1;
const lockdebug_t *ld2 = n2;
const uintptr_t a = (uintptr_t)ld1->ld_lock;
const uintptr_t b = (uintptr_t)ld2->ld_lock;
if (a < b)
return -1;
if (a > b)
return 1;
return 0;
}
static signed int
ld_rbto_compare_key(void *ctx, const void *n, const void *key)
{
const lockdebug_t *ld = n;
const uintptr_t a = (uintptr_t)ld->ld_lock;
const uintptr_t b = (uintptr_t)key;
if (a < b)
return -1;
if (a > b)
return 1;
return 0;
}
static rb_tree_t ld_rb_tree;
static const rb_tree_ops_t ld_rb_tree_ops = {
.rbto_compare_nodes = ld_rbto_compare_nodes,
.rbto_compare_key = ld_rbto_compare_key,
.rbto_node_offset = offsetof(lockdebug_t, ld_rb_node),
.rbto_context = NULL
};
static inline lockdebug_t *
lockdebug_lookup1(const volatile void *lock)
{
lockdebug_t *ld;
struct cpu_info *ci;
ci = curcpu();
__cpu_simple_lock(&ci->ci_data.cpu_ld_lock);
ld = rb_tree_find_node(&ld_rb_tree, (void *)(intptr_t)lock);
__cpu_simple_unlock(&ci->ci_data.cpu_ld_lock);
if (ld == NULL) {
return NULL;
}
__cpu_simple_lock(&ld->ld_spinlock);
return ld;
}
static void
lockdebug_lock_cpus(void)
{
CPU_INFO_ITERATOR cii;
struct cpu_info *ci;
for (CPU_INFO_FOREACH(cii, ci)) {
__cpu_simple_lock(&ci->ci_data.cpu_ld_lock);
}
}
static void
lockdebug_unlock_cpus(void)
{
CPU_INFO_ITERATOR cii;
struct cpu_info *ci;
for (CPU_INFO_FOREACH(cii, ci)) {
__cpu_simple_unlock(&ci->ci_data.cpu_ld_lock);
}
}
/*
* lockdebug_lookup:
*
* Find a lockdebug structure by a pointer to a lock and return it locked.
*/
static inline lockdebug_t *
lockdebug_lookup(const char *func, size_t line, const volatile void *lock,
uintptr_t where)
{
lockdebug_t *ld;
ld = lockdebug_lookup1(lock);
if (__predict_false(ld == NULL)) {
panic("%s,%zu: uninitialized lock (lock=%p, from=%08"
PRIxPTR ")", func, line, lock, where);
}
return ld;
}
/*
* lockdebug_init:
*
* Initialize the lockdebug system. Allocate an initial pool of
* lockdebug structures before the VM system is up and running.
*/
static void
lockdebug_init(void)
{
lockdebug_t *ld;
int i;
TAILQ_INIT(&curcpu()->ci_data.cpu_ld_locks);
TAILQ_INIT(&curlwp->l_ld_locks);
__cpu_simple_lock_init(&curcpu()->ci_data.cpu_ld_lock);
__cpu_simple_lock_init(&ld_mod_lk);
rb_tree_init(&ld_rb_tree, &ld_rb_tree_ops);
ld = ld_prime;
for (i = 1, ld++; i < LD_BATCH; i++, ld++) {
__cpu_simple_lock_init(&ld->ld_spinlock);
TAILQ_INSERT_TAIL(&ld_free, ld, ld_chain);
TAILQ_INSERT_TAIL(&ld_all, ld, ld_achain);
}
ld_freeptr = 1;
ld_nfree = LD_BATCH - 1;
}
/*
* lockdebug_alloc:
*
* A lock is being initialized, so allocate an associated debug
* structure.
*/
bool
lockdebug_alloc(const char *func, size_t line, volatile void *lock,
lockops_t *lo, uintptr_t initaddr)
{
struct cpu_info *ci;
lockdebug_t *ld;
int s;
if (__predict_false(lo == NULL || panicstr != NULL || ld_panic))
return false;
if (__predict_false(ld_freeptr == 0))
lockdebug_init();
s = splhigh();
__cpu_simple_lock(&ld_mod_lk);
if (__predict_false((ld = lockdebug_lookup1(lock)) != NULL)) {
__cpu_simple_unlock(&ld_mod_lk);
lockdebug_abort1(func, line, ld, s, "already initialized",
true);
return false;
}
/*
* Pinch a new debug structure. We may recurse because we call
* kmem_alloc(), which may need to initialize new locks somewhere
* down the path. If not recursing, we try to maintain at least
* LD_SLOP structures free, which should hopefully be enough to
* satisfy kmem_alloc(). If we can't provide a structure, not to
* worry: we'll just mark the lock as not having an ID.
*/
ci = curcpu();
ci->ci_lkdebug_recurse++;
if (TAILQ_EMPTY(&ld_free)) {
if (ci->ci_lkdebug_recurse > 1 || ld_nomore) {
ci->ci_lkdebug_recurse--;
__cpu_simple_unlock(&ld_mod_lk);
splx(s);
return false;
}
s = lockdebug_more(s);
} else if (ci->ci_lkdebug_recurse == 1 && ld_nfree < LD_SLOP) {
s = lockdebug_more(s);
}
if (__predict_false((ld = TAILQ_FIRST(&ld_free)) == NULL)) {
__cpu_simple_unlock(&ld_mod_lk);
splx(s);
return false;
}
TAILQ_REMOVE(&ld_free, ld, ld_chain);
ld_nfree--;
ci->ci_lkdebug_recurse--;
if (__predict_false(ld->ld_lock != NULL)) {
panic("%s,%zu: corrupt table ld %p", func, line, ld);
}
/* Initialise the structure. */
ld->ld_lock = lock;
ld->ld_lockops = lo;
ld->ld_locked = 0;
ld->ld_unlocked = 0;
ld->ld_lwp = NULL;
ld->ld_initaddr = initaddr;
ld->ld_flags = (lo->lo_type == LOCKOPS_SLEEP ? LD_SLEEPER : 0);
lockdebug_lock_cpus();
(void)rb_tree_insert_node(&ld_rb_tree, __UNVOLATILE(ld));
lockdebug_unlock_cpus();
__cpu_simple_unlock(&ld_mod_lk);
splx(s);
return true;
}
/*
* lockdebug_free:
*
* A lock is being destroyed, so release debugging resources.
*/
void
lockdebug_free(const char *func, size_t line, volatile void *lock)
{
lockdebug_t *ld;
int s;
if (__predict_false(panicstr != NULL || ld_panic))
return;
s = splhigh();
__cpu_simple_lock(&ld_mod_lk);
ld = lockdebug_lookup(func, line, lock,
(uintptr_t) __builtin_return_address(0));
if (__predict_false(ld == NULL)) {
__cpu_simple_unlock(&ld_mod_lk);
panic("%s,%zu: destroying uninitialized object %p"
"(ld_lock=%p)", func, line, lock, ld->ld_lock);
return;
}
if (__predict_false((ld->ld_flags & LD_LOCKED) != 0 ||
ld->ld_shares != 0)) {
__cpu_simple_unlock(&ld_mod_lk);
lockdebug_abort1(func, line, ld, s, "is locked or in use",
true);
return;
}
lockdebug_lock_cpus();
rb_tree_remove_node(&ld_rb_tree, __UNVOLATILE(ld));
lockdebug_unlock_cpus();
ld->ld_lock = NULL;
TAILQ_INSERT_TAIL(&ld_free, ld, ld_chain);
ld_nfree++;
__cpu_simple_unlock(&ld->ld_spinlock);
__cpu_simple_unlock(&ld_mod_lk);
splx(s);
}
/*
* lockdebug_more:
*
* Allocate a batch of debug structures and add to the free list.
* Must be called with ld_mod_lk held.
*/
static int
lockdebug_more(int s)
{
lockdebug_t *ld;
void *block;
int i, base, m;
/*
* Can't call kmem_alloc() if in interrupt context. XXX We could
* deadlock, because we don't know which locks the caller holds.
*/
if (cpu_intr_p() || cpu_softintr_p()) {
return s;
}
while (ld_nfree < LD_SLOP) {
__cpu_simple_unlock(&ld_mod_lk);
splx(s);
block = kmem_zalloc(LD_BATCH * sizeof(lockdebug_t), KM_SLEEP);
s = splhigh();
__cpu_simple_lock(&ld_mod_lk);
if (ld_nfree > LD_SLOP) {
/* Somebody beat us to it. */
__cpu_simple_unlock(&ld_mod_lk);
splx(s);
kmem_free(block, LD_BATCH * sizeof(lockdebug_t));
s = splhigh();
__cpu_simple_lock(&ld_mod_lk);
continue;
}
base = ld_freeptr;
ld_nfree += LD_BATCH;
ld = block;
base <<= LD_BATCH_SHIFT;
m = uimin(LD_MAX_LOCKS, base + LD_BATCH);
if (m == LD_MAX_LOCKS)
ld_nomore = true;
for (i = base; i < m; i++, ld++) {
__cpu_simple_lock_init(&ld->ld_spinlock);
TAILQ_INSERT_TAIL(&ld_free, ld, ld_chain);
TAILQ_INSERT_TAIL(&ld_all, ld, ld_achain);
}
membar_producer();
}
return s;
}
/*
* lockdebug_wantlock:
*
* Process the preamble to a lock acquire. The "shared"
* parameter controls which ld_{ex,sh}want counter is
* updated; a negative value of shared updates neither.
*/
void
lockdebug_wantlock(const char *func, size_t line,
const volatile void *lock, uintptr_t where, int shared)
{
struct lwp *l = curlwp;
lockdebug_t *ld;
bool recurse;
int s;
(void)shared;
recurse = false;
if (__predict_false(panicstr != NULL || ld_panic))
return;
s = splhigh();
if ((ld = lockdebug_lookup(func, line, lock, where)) == NULL) {
splx(s);
return;
}
if ((ld->ld_flags & LD_LOCKED) != 0 || ld->ld_shares != 0) {
if ((ld->ld_flags & LD_SLEEPER) != 0) {
if (ld->ld_lwp == l)
recurse = true;
} else if (ld->ld_cpu == (uint16_t)cpu_index(curcpu()))
recurse = true;
}
if (cpu_intr_p()) {
if (__predict_false((ld->ld_flags & LD_SLEEPER) != 0)) {
lockdebug_abort1(func, line, ld, s,
"acquiring sleep lock from interrupt context",
true);
return;
}
}
if (shared > 0)
ld->ld_shwant++;
else if (shared == 0)
ld->ld_exwant++;
if (__predict_false(recurse)) {
lockdebug_abort1(func, line, ld, s, "locking against myself",
true);
return;
}
__cpu_simple_unlock(&ld->ld_spinlock);
splx(s);
}
/*
* lockdebug_locked:
*
* Process a lock acquire operation.
*/
void
lockdebug_locked(const char *func, size_t line,
volatile void *lock, void *cvlock, uintptr_t where, int shared)
{
struct lwp *l = curlwp;
lockdebug_t *ld;
int s;
if (__predict_false(panicstr != NULL || ld_panic))
return;
s = splhigh();
if ((ld = lockdebug_lookup(func, line, lock, where)) == NULL) {
splx(s);
return;
}
if (cvlock) {
KASSERT(ld->ld_lockops->lo_type == LOCKOPS_CV);
if (lock == (void *)&lbolt) {
/* nothing */
} else if (ld->ld_shares++ == 0) {
ld->ld_locked = (uintptr_t)cvlock;
} else if (__predict_false(cvlock != (void *)ld->ld_locked)) {
lockdebug_abort1(func, line, ld, s,
"multiple locks used with condition variable",
true);
return;
}
} else if (shared) {
l->l_shlocks++;
ld->ld_locked = where;
ld->ld_shares++;
ld->ld_shwant--;
} else {
if (__predict_false((ld->ld_flags & LD_LOCKED) != 0)) {
lockdebug_abort1(func, line, ld, s, "already locked",
true);
return;
}
ld->ld_flags |= LD_LOCKED;
ld->ld_locked = where;
ld->ld_exwant--;
if ((ld->ld_flags & LD_SLEEPER) != 0) {
TAILQ_INSERT_TAIL(&l->l_ld_locks, ld, ld_chain);
} else {
TAILQ_INSERT_TAIL(&curcpu()->ci_data.cpu_ld_locks,
ld, ld_chain);
}
}
ld->ld_cpu = (uint16_t)cpu_index(curcpu());
ld->ld_lwp = l;
__cpu_simple_unlock(&ld->ld_spinlock);
splx(s);
}
/*
* lockdebug_unlocked:
*
* Process a lock release operation.
*/
void
lockdebug_unlocked(const char *func, size_t line,
volatile void *lock, uintptr_t where, int shared)
{
struct lwp *l = curlwp;
lockdebug_t *ld;
int s;
if (__predict_false(panicstr != NULL || ld_panic))
return;
s = splhigh();
if ((ld = lockdebug_lookup(func, line, lock, where)) == NULL) {
splx(s);
return;
}
if (ld->ld_lockops->lo_type == LOCKOPS_CV) {
if (lock == (void *)&lbolt) {
/* nothing */
} else {
ld->ld_shares--;
}
} else if (shared) {
if (__predict_false(l->l_shlocks == 0)) {
lockdebug_abort1(func, line, ld, s,
"no shared locks held by LWP", true);
return;
}
if (__predict_false(ld->ld_shares == 0)) {
lockdebug_abort1(func, line, ld, s,
"no shared holds on this lock", true);
return;
}
l->l_shlocks--;
ld->ld_shares--;
if (ld->ld_lwp == l) {
ld->ld_unlocked = where;
ld->ld_lwp = NULL;
}
if (ld->ld_cpu == (uint16_t)cpu_index(curcpu()))
ld->ld_cpu = (uint16_t)-1;
} else {
if (__predict_false((ld->ld_flags & LD_LOCKED) == 0)) {
lockdebug_abort1(func, line, ld, s, "not locked", true);
return;
}
if ((ld->ld_flags & LD_SLEEPER) != 0) {
if (__predict_false(ld->ld_lwp != curlwp)) {
lockdebug_abort1(func, line, ld, s,
"not held by current LWP", true);
return;
}
TAILQ_REMOVE(&l->l_ld_locks, ld, ld_chain);
} else {
uint16_t idx = (uint16_t)cpu_index(curcpu());
if (__predict_false(ld->ld_cpu != idx)) {
lockdebug_abort1(func, line, ld, s,
"not held by current CPU", true);
return;
}
TAILQ_REMOVE(&curcpu()->ci_data.cpu_ld_locks, ld,
ld_chain);
}
ld->ld_flags &= ~LD_LOCKED;
ld->ld_unlocked = where;
ld->ld_lwp = NULL;
}
__cpu_simple_unlock(&ld->ld_spinlock);
splx(s);
}
/*
* lockdebug_wakeup:
*
* Process a wakeup on a condition variable.
*/
void
lockdebug_wakeup(const char *func, size_t line, volatile void *lock,
uintptr_t where)
{
lockdebug_t *ld;
int s;
if (__predict_false(panicstr != NULL || ld_panic || lock == (void *)&lbolt))
return;
s = splhigh();
/* Find the CV... */
if ((ld = lockdebug_lookup(func, line, lock, where)) == NULL) {
splx(s);
return;
}
/*
* If it has any waiters, ensure that they are using the
* same interlock.
*/
if (__predict_false(ld->ld_shares != 0 &&
!mutex_owned((kmutex_t *)ld->ld_locked))) {
lockdebug_abort1(func, line, ld, s, "interlocking mutex not "
"held during wakeup", true);
return;
}
__cpu_simple_unlock(&ld->ld_spinlock);
splx(s);
}
/*
* lockdebug_barrier:
*
* Panic if we hold more than one specified spin lock, and optionally,
* if we hold sleep locks.
*/
void
lockdebug_barrier(const char *func, size_t line, volatile void *spinlock,
int slplocks)
{
struct lwp *l = curlwp;
lockdebug_t *ld;
int s;
if (__predict_false(panicstr != NULL || ld_panic))
return;
s = splhigh();
if ((l->l_pflag & LP_INTR) == 0) {
TAILQ_FOREACH(ld, &curcpu()->ci_data.cpu_ld_locks, ld_chain) {
if (ld->ld_lock == spinlock) {
continue;
}
__cpu_simple_lock(&ld->ld_spinlock);
lockdebug_abort1(func, line, ld, s,
"spin lock held", true);
return;
}
}
if (slplocks) {
splx(s);
return;
}
ld = TAILQ_FIRST(&l->l_ld_locks);
if (__predict_false(ld != NULL)) {
__cpu_simple_lock(&ld->ld_spinlock);
lockdebug_abort1(func, line, ld, s, "sleep lock held", true);
return;
}
splx(s);
if (l->l_shlocks != 0) {
TAILQ_FOREACH(ld, &ld_all, ld_achain) {
if (ld->ld_lockops->lo_type == LOCKOPS_CV)
continue;
if (ld->ld_lwp == l)
lockdebug_dump(ld, printf);
}
panic("%s,%zu: holding %d shared locks", func, line,
l->l_shlocks);
}
}
/*
* lockdebug_mem_check:
*
* Check for in-use locks within a memory region that is
* being freed.
*/
void
lockdebug_mem_check(const char *func, size_t line, void *base, size_t sz)
{
lockdebug_t *ld;
struct cpu_info *ci;
int s;
if (__predict_false(panicstr != NULL || ld_panic))
return;
s = splhigh();
ci = curcpu();
__cpu_simple_lock(&ci->ci_data.cpu_ld_lock);
ld = (lockdebug_t *)rb_tree_find_node_geq(&ld_rb_tree, base);
if (ld != NULL) {
const uintptr_t lock = (uintptr_t)ld->ld_lock;
if (__predict_false((uintptr_t)base > lock))
panic("%s,%zu: corrupt tree ld=%p, base=%p, sz=%zu",
func, line, ld, base, sz);
if (lock >= (uintptr_t)base + sz)
ld = NULL;
}
__cpu_simple_unlock(&ci->ci_data.cpu_ld_lock);
if (__predict_false(ld != NULL)) {
__cpu_simple_lock(&ld->ld_spinlock);
lockdebug_abort1(func, line, ld, s,
"allocation contains active lock", !cold);
return;
}
splx(s);
}
/*
* lockdebug_dump:
*
* Dump information about a lock on panic, or for DDB.
*/
static void
lockdebug_dump(lockdebug_t *ld, void (*pr)(const char *, ...)
__printflike(1, 2))
{
int sleeper = (ld->ld_flags & LD_SLEEPER);
(*pr)(
"lock address : %#018lx type : %18s\n"
"initialized : %#018lx",
(long)ld->ld_lock, (sleeper ? "sleep/adaptive" : "spin"),
(long)ld->ld_initaddr);
if (ld->ld_lockops->lo_type == LOCKOPS_CV) {
(*pr)(" interlock: %#018lx\n", (long)ld->ld_locked);
} else {
(*pr)("\n"
"shared holds : %18u exclusive: %18u\n"
"shares wanted: %18u exclusive: %18u\n"
"current cpu : %18u last held: %18u\n"
"current lwp : %#018lx last held: %#018lx\n"
"last locked%c : %#018lx unlocked%c: %#018lx\n",
(unsigned)ld->ld_shares, ((ld->ld_flags & LD_LOCKED) != 0),
(unsigned)ld->ld_shwant, (unsigned)ld->ld_exwant,
(unsigned)cpu_index(curcpu()), (unsigned)ld->ld_cpu,
(long)curlwp, (long)ld->ld_lwp,
((ld->ld_flags & LD_LOCKED) ? '*' : ' '),
(long)ld->ld_locked,
((ld->ld_flags & LD_LOCKED) ? ' ' : '*'),
(long)ld->ld_unlocked);
}
if (ld->ld_lockops->lo_dump != NULL)
(*ld->ld_lockops->lo_dump)(ld->ld_lock, pr);
if (sleeper) {
(*pr)("\n");
turnstile_print(ld->ld_lock, pr);
}
}
/*
* lockdebug_abort1:
*
* An error has been trapped - dump lock info and panic.
*/
static void
lockdebug_abort1(const char *func, size_t line, lockdebug_t *ld, int s,
const char *msg, bool dopanic)
{
/*
* Don't make the situation worse if the system is already going
* down in flames. Once a panic is triggered, lockdebug state
* becomes stale and cannot be trusted.
*/
if (atomic_inc_uint_nv(&ld_panic) != 1) {
__cpu_simple_unlock(&ld->ld_spinlock);
splx(s);
return;
}
printf_nolog("%s error: %s,%zu: %s\n\n", ld->ld_lockops->lo_name,
func, line, msg);
lockdebug_dump(ld, printf_nolog);
__cpu_simple_unlock(&ld->ld_spinlock);
splx(s);
printf_nolog("\n");
if (dopanic)
panic("LOCKDEBUG: %s error: %s,%zu: %s",
ld->ld_lockops->lo_name, func, line, msg);
}
#endif /* LOCKDEBUG */
/*
* lockdebug_lock_print:
*
* Handle the DDB 'show lock' command.
*/
#ifdef DDB
#include <machine/db_machdep.h>
#include <ddb/db_interface.h>
void
lockdebug_lock_print(void *addr,
void (*pr)(const char *, ...) __printflike(1, 2))
{
#ifdef LOCKDEBUG
lockdebug_t *ld;
TAILQ_FOREACH(ld, &ld_all, ld_achain) {
if (ld->ld_lock == NULL)
continue;
if (addr == NULL || ld->ld_lock == addr) {
lockdebug_dump(ld, pr);
if (addr != NULL)
return;
}
}
if (addr != NULL) {
(*pr)("Sorry, no record of a lock with address %p found.\n",
addr);
}
#else
(*pr)("Sorry, kernel not built with the LOCKDEBUG option.\n");
#endif /* LOCKDEBUG */
}
#ifdef LOCKDEBUG
static void
lockdebug_show_one(lockdebug_t *ld, int i,
void (*pr)(const char *, ...) __printflike(1, 2))
{
const char *sym;
ksyms_getname(NULL, &sym, (vaddr_t)ld->ld_initaddr,
KSYMS_CLOSEST|KSYMS_PROC|KSYMS_ANY);
(*pr)("Lock %d (initialized at %s)\n", i++, sym);
lockdebug_dump(ld, pr);
}
static void
lockdebug_show_trace(const void *ptr,
void (*pr)(const char *, ...) __printflike(1, 2))
{
db_stack_trace_print((db_expr_t)(intptr_t)ptr, true, 32, "a", pr);
}
static void
lockdebug_show_all_locks_lwp(void (*pr)(const char *, ...) __printflike(1, 2),
bool show_trace)
{
struct proc *p;
LIST_FOREACH(p, &allproc, p_list) {
struct lwp *l;
LIST_FOREACH(l, &p->p_lwps, l_sibling) {
lockdebug_t *ld;
int i = 0;
if (TAILQ_EMPTY(&l->l_ld_locks))
continue;
(*pr)("Locks held by an LWP (%s):\n",
l->l_name ? l->l_name : p->p_comm);
TAILQ_FOREACH(ld, &l->l_ld_locks, ld_chain) {
lockdebug_show_one(ld, i++, pr);
}
if (show_trace)
lockdebug_show_trace(l, pr);
(*pr)("\n");
}
}
}
static void
lockdebug_show_all_locks_cpu(void (*pr)(const char *, ...) __printflike(1, 2),
bool show_trace)
{
lockdebug_t *ld;
CPU_INFO_ITERATOR cii;
struct cpu_info *ci;
for (CPU_INFO_FOREACH(cii, ci)) {
int i = 0;
if (TAILQ_EMPTY(&ci->ci_data.cpu_ld_locks))
continue;
(*pr)("Locks held on CPU %u:\n", ci->ci_index);
TAILQ_FOREACH(ld, &ci->ci_data.cpu_ld_locks, ld_chain) {
lockdebug_show_one(ld, i++, pr);
if (show_trace)
#ifdef MULTIPROCESSOR
lockdebug_show_trace(ci->ci_curlwp, pr);
#else
lockdebug_show_trace(curlwp, pr);
#endif
(*pr)("\n");
}
}
}
#endif /* LOCKDEBUG */
void
lockdebug_show_all_locks(void (*pr)(const char *, ...) __printflike(1, 2),
const char *modif)
{
#ifdef LOCKDEBUG
bool show_trace = false;
if (modif[0] == 't')
show_trace = true;
(*pr)("[Locks tracked through LWPs]\n");
lockdebug_show_all_locks_lwp(pr, show_trace);
(*pr)("\n");
(*pr)("[Locks tracked through CPUs]\n");
lockdebug_show_all_locks_cpu(pr, show_trace);
(*pr)("\n");
#else
(*pr)("Sorry, kernel not built with the LOCKDEBUG option.\n");
#endif /* LOCKDEBUG */
}
void
lockdebug_show_lockstats(void (*pr)(const char *, ...) __printflike(1, 2))
{
#ifdef LOCKDEBUG
lockdebug_t *ld;
void *_ld;
uint32_t n_null = 0;
uint32_t n_spin_mutex = 0;
uint32_t n_adaptive_mutex = 0;
uint32_t n_rwlock = 0;
uint32_t n_cv = 0;
uint32_t n_others = 0;
RB_TREE_FOREACH(_ld, &ld_rb_tree) {
ld = _ld;
if (ld->ld_lock == NULL) {
n_null++;
continue;
}
if (ld->ld_lockops->lo_type == LOCKOPS_CV) {
n_cv++;
continue;
}
if (ld->ld_lockops->lo_name[0] == 'M') {
if (ld->ld_lockops->lo_type == LOCKOPS_SLEEP)
n_adaptive_mutex++;
else
n_spin_mutex++;
continue;
}
if (ld->ld_lockops->lo_name[0] == 'R') {
n_rwlock++;
continue;
}
n_others++;
}
(*pr)(
"condvar: %u\n"
"spin mutex: %u\n"
"adaptive mutex: %u\n"
"rwlock: %u\n"
"null locks: %u\n"
"others: %u\n",
n_cv, n_spin_mutex, n_adaptive_mutex, n_rwlock,
n_null, n_others);
#else
(*pr)("Sorry, kernel not built with the LOCKDEBUG option.\n");
#endif /* LOCKDEBUG */
}
#endif /* DDB */
/*
* lockdebug_dismiss:
*
* The system is rebooting, and potentially from an unsafe
* place so avoid any future aborts.
*/
void
lockdebug_dismiss(void)
{
atomic_inc_uint_nv(&ld_panic);
}
/*
* lockdebug_abort:
*
* An error has been trapped - dump lock info and call panic().
*/
void
lockdebug_abort(const char *func, size_t line, const volatile void *lock,
lockops_t *ops, const char *msg)
{
#ifdef LOCKDEBUG
lockdebug_t *ld;
int s;
s = splhigh();
if ((ld = lockdebug_lookup(func, line, lock,
(uintptr_t) __builtin_return_address(0))) != NULL) {
lockdebug_abort1(func, line, ld, s, msg, true);
return;
}
splx(s);
#endif /* LOCKDEBUG */
/*
* Don't make the situation worse if the system is already going
* down in flames. Once a panic is triggered, lockdebug state
* becomes stale and cannot be trusted.
*/
if (atomic_inc_uint_nv(&ld_panic) > 1)
return;
printf_nolog("%s error: %s,%zu: %s\n\n"
"lock address : %#018lx\n"
"current cpu : %18d\n"
"current lwp : %#018lx\n",
ops->lo_name, func, line, msg, (long)lock,
(int)cpu_index(curcpu()), (long)curlwp);
(*ops->lo_dump)(lock, printf_nolog);
printf_nolog("\n");
panic("lock error: %s: %s,%zu: %s: lock %p cpu %d lwp %p",
ops->lo_name, func, line, msg, lock, cpu_index(curcpu()), curlwp);
}
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