--- /dev/null
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+/*
+ * Ceph - scalable distributed file system
+ *
+ * Copyright (C) 2008-2011 New Dream Network
+ *
+ * This is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License version 2.1, as published by the Free Software
+ * Foundation. See file COPYING.
+ *
+ */
+#include "lockdep.h"
+#include "common/dout.h"
+#include "common/valgrind.h"
+
+#if defined(__FreeBSD__) && defined(__LP64__) // On FreeBSD pthread_t is a pointer.
+namespace std {
+ template<>
+ struct hash<pthread_t>
+ {
+ size_t
+ operator()(pthread_t __x) const
+ { return (uintptr_t)__x; }
+ };
+} // namespace std
+#endif
+
+/******* Constants **********/
+#define lockdep_dout(v) lsubdout(g_lockdep_ceph_ctx, lockdep, v)
+#define MAX_LOCKS 4096 // increase me as needed
+#define BACKTRACE_SKIP 2
+
+/******* Globals **********/
+int g_lockdep = 0;
+struct lockdep_stopper_t {
+ // disable lockdep when this module destructs.
+ ~lockdep_stopper_t() {
+ g_lockdep = 0;
+ }
+};
+static pthread_mutex_t lockdep_mutex = PTHREAD_MUTEX_INITIALIZER;
+static CephContext *g_lockdep_ceph_ctx = NULL;
+static lockdep_stopper_t lockdep_stopper;
+static ceph::unordered_map<std::string, int> lock_ids;
+static map<int, std::string> lock_names;
+static map<int, int> lock_refs;
+static char free_ids[MAX_LOCKS/8]; // bit set = free
+static ceph::unordered_map<pthread_t, map<int,BackTrace*> > held;
+static char follows[MAX_LOCKS][MAX_LOCKS/8]; // follows[a][b] means b taken after a
+static BackTrace *follows_bt[MAX_LOCKS][MAX_LOCKS];
+unsigned current_maxid;
+int last_freed_id;
+
+static bool lockdep_force_backtrace()
+{
+ return (g_lockdep_ceph_ctx != NULL &&
+ g_lockdep_ceph_ctx->_conf->lockdep_force_backtrace);
+}
+
+/******* Functions **********/
+void lockdep_register_ceph_context(CephContext *cct)
+{
+ static_assert((MAX_LOCKS > 0) && (MAX_LOCKS % 8 == 0),
+ "lockdep's MAX_LOCKS needs to be divisible by 8 to operate correctly.");
+ pthread_mutex_lock(&lockdep_mutex);
+ if (g_lockdep_ceph_ctx == NULL) {
+ ANNOTATE_BENIGN_RACE_SIZED(&g_lockdep_ceph_ctx, sizeof(g_lockdep_ceph_ctx),
+ "lockdep cct");
+ ANNOTATE_BENIGN_RACE_SIZED(&g_lockdep, sizeof(g_lockdep),
+ "lockdep enabled");
+ g_lockdep = true;
+ g_lockdep_ceph_ctx = cct;
+ lockdep_dout(1) << "lockdep start" << dendl;
+ current_maxid = 0;
+ last_freed_id = -1;
+
+ memset((void*) &free_ids[0], 255, sizeof(free_ids));
+ }
+ pthread_mutex_unlock(&lockdep_mutex);
+}
+
+void lockdep_unregister_ceph_context(CephContext *cct)
+{
+ pthread_mutex_lock(&lockdep_mutex);
+ if (cct == g_lockdep_ceph_ctx) {
+ lockdep_dout(1) << "lockdep stop" << dendl;
+ // this cct is going away; shut it down!
+ g_lockdep = false;
+ g_lockdep_ceph_ctx = NULL;
+
+ // blow away all of our state, too, in case it starts up again.
+ for (unsigned i = 0; i < current_maxid; ++i) {
+ for (unsigned j = 0; j < current_maxid; ++j) {
+ delete follows_bt[i][j];
+ }
+ }
+
+ held.clear();
+ lock_names.clear();
+ lock_ids.clear();
+ lock_refs.clear();
+ memset((void*)&free_ids[0], 0, sizeof(free_ids));
+ memset((void*)&follows[0][0], 0, current_maxid * MAX_LOCKS/8);
+ memset((void*)&follows_bt[0][0], 0, sizeof(BackTrace*) * current_maxid * MAX_LOCKS);
+ current_maxid = 0;
+ last_freed_id = -1;
+ }
+ pthread_mutex_unlock(&lockdep_mutex);
+}
+
+int lockdep_dump_locks()
+{
+ pthread_mutex_lock(&lockdep_mutex);
+
+ for (ceph::unordered_map<pthread_t, map<int,BackTrace*> >::iterator p = held.begin();
+ p != held.end();
+ ++p) {
+ lockdep_dout(0) << "--- thread " << p->first << " ---" << dendl;
+ for (map<int,BackTrace*>::iterator q = p->second.begin();
+ q != p->second.end();
+ ++q) {
+ lockdep_dout(0) << " * " << lock_names[q->first] << "\n";
+ if (q->second)
+ *_dout << *(q->second);
+ *_dout << dendl;
+ }
+ }
+
+ pthread_mutex_unlock(&lockdep_mutex);
+ return 0;
+}
+
+int lockdep_get_free_id(void)
+{
+ // if there's id known to be freed lately, reuse it
+ if ((last_freed_id >= 0) &&
+ (free_ids[last_freed_id/8] & (1 << (last_freed_id % 8)))) {
+ int tmp = last_freed_id;
+ last_freed_id = -1;
+ free_ids[tmp/8] &= 255 - (1 << (tmp % 8));
+ lockdep_dout(1) << "lockdep reusing last freed id " << tmp << dendl;
+ return tmp;
+ }
+
+ // walk through entire array and locate nonzero char, then find
+ // actual bit.
+ for (int i = 0; i < MAX_LOCKS / 8; ++i) {
+ if (free_ids[i] != 0) {
+ for (int j = 0; j < 8; ++j) {
+ if (free_ids[i] & (1 << j)) {
+ free_ids[i] &= 255 - (1 << j);
+ lockdep_dout(1) << "lockdep using id " << i * 8 + j << dendl;
+ return i * 8 + j;
+ }
+ }
+ }
+ }
+
+ // not found
+ lockdep_dout(0) << "failing miserably..." << dendl;
+ return -1;
+}
+
+int lockdep_register(const char *name)
+{
+ int id;
+
+ pthread_mutex_lock(&lockdep_mutex);
+ ceph::unordered_map<std::string, int>::iterator p = lock_ids.find(name);
+ if (p == lock_ids.end()) {
+ id = lockdep_get_free_id();
+ if (id < 0) {
+ lockdep_dout(0) << "ERROR OUT OF IDS .. have 0"
+ << " max " << MAX_LOCKS << dendl;
+ for (auto& p : lock_names) {
+ lockdep_dout(0) << " lock " << p.first << " " << p.second << dendl;
+ }
+ assert(false);
+ }
+ if (current_maxid <= (unsigned)id) {
+ current_maxid = (unsigned)id + 1;
+ }
+ lock_ids[name] = id;
+ lock_names[id] = name;
+ lockdep_dout(10) << "registered '" << name << "' as " << id << dendl;
+ } else {
+ id = p->second;
+ lockdep_dout(20) << "had '" << name << "' as " << id << dendl;
+ }
+
+ ++lock_refs[id];
+ pthread_mutex_unlock(&lockdep_mutex);
+
+ return id;
+}
+
+void lockdep_unregister(int id)
+{
+ if (id < 0) {
+ return;
+ }
+
+ pthread_mutex_lock(&lockdep_mutex);
+
+ map<int, std::string>::iterator p = lock_names.find(id);
+ assert(p != lock_names.end());
+
+ int &refs = lock_refs[id];
+ if (--refs == 0) {
+ // reset dependency ordering
+ memset((void*)&follows[id][0], 0, MAX_LOCKS/8);
+ for (unsigned i=0; i<current_maxid; ++i) {
+ delete follows_bt[id][i];
+ follows_bt[id][i] = NULL;
+
+ delete follows_bt[i][id];
+ follows_bt[i][id] = NULL;
+ follows[i][id / 8] &= 255 - (1 << (id % 8));
+ }
+
+ lockdep_dout(10) << "unregistered '" << p->second << "' from " << id
+ << dendl;
+ lock_ids.erase(p->second);
+ lock_names.erase(id);
+ lock_refs.erase(id);
+ free_ids[id/8] |= (1 << (id % 8));
+ last_freed_id = id;
+ } else {
+ lockdep_dout(20) << "have " << refs << " of '" << p->second << "' "
+ << "from " << id << dendl;
+ }
+ pthread_mutex_unlock(&lockdep_mutex);
+}
+
+
+// does b follow a?
+static bool does_follow(int a, int b)
+{
+ if (follows[a][b/8] & (1 << (b % 8))) {
+ lockdep_dout(0) << "\n";
+ *_dout << "------------------------------------" << "\n";
+ *_dout << "existing dependency " << lock_names[a] << " (" << a << ") -> "
+ << lock_names[b] << " (" << b << ") at:\n";
+ if (follows_bt[a][b]) {
+ follows_bt[a][b]->print(*_dout);
+ }
+ *_dout << dendl;
+ return true;
+ }
+
+ for (unsigned i=0; i<current_maxid; i++) {
+ if ((follows[a][i/8] & (1 << (i % 8))) &&
+ does_follow(i, b)) {
+ lockdep_dout(0) << "existing intermediate dependency " << lock_names[a]
+ << " (" << a << ") -> " << lock_names[i] << " (" << i << ") at:\n";
+ if (follows_bt[a][i]) {
+ follows_bt[a][i]->print(*_dout);
+ }
+ *_dout << dendl;
+ return true;
+ }
+ }
+
+ return false;
+}
+
+int lockdep_will_lock(const char *name, int id, bool force_backtrace)
+{
+ pthread_t p = pthread_self();
+ if (id < 0) id = lockdep_register(name);
+
+ pthread_mutex_lock(&lockdep_mutex);
+ lockdep_dout(20) << "_will_lock " << name << " (" << id << ")" << dendl;
+
+ // check dependency graph
+ map<int, BackTrace *> &m = held[p];
+ for (map<int, BackTrace *>::iterator p = m.begin();
+ p != m.end();
+ ++p) {
+ if (p->first == id) {
+ lockdep_dout(0) << "\n";
+ *_dout << "recursive lock of " << name << " (" << id << ")\n";
+ BackTrace *bt = new BackTrace(BACKTRACE_SKIP);
+ bt->print(*_dout);
+ if (p->second) {
+ *_dout << "\npreviously locked at\n";
+ p->second->print(*_dout);
+ }
+ delete bt;
+ *_dout << dendl;
+ ceph_abort();
+ }
+ else if (!(follows[p->first][id/8] & (1 << (id % 8)))) {
+ // new dependency
+
+ // did we just create a cycle?
+ if (does_follow(id, p->first)) {
+ BackTrace *bt = new BackTrace(BACKTRACE_SKIP);
+ lockdep_dout(0) << "new dependency " << lock_names[p->first]
+ << " (" << p->first << ") -> " << name << " (" << id << ")"
+ << " creates a cycle at\n";
+ bt->print(*_dout);
+ *_dout << dendl;
+
+ lockdep_dout(0) << "btw, i am holding these locks:" << dendl;
+ for (map<int, BackTrace *>::iterator q = m.begin();
+ q != m.end();
+ ++q) {
+ lockdep_dout(0) << " " << lock_names[q->first] << " (" << q->first << ")" << dendl;
+ if (q->second) {
+ lockdep_dout(0) << " ";
+ q->second->print(*_dout);
+ *_dout << dendl;
+ }
+ }
+
+ lockdep_dout(0) << "\n" << dendl;
+
+ // don't add this dependency, or we'll get aMutex. cycle in the graph, and
+ // does_follow() won't terminate.
+
+ ceph_abort(); // actually, we should just die here.
+ } else {
+ BackTrace *bt = NULL;
+ if (force_backtrace || lockdep_force_backtrace()) {
+ bt = new BackTrace(BACKTRACE_SKIP);
+ }
+ follows[p->first][id/8] |= 1 << (id % 8);
+ follows_bt[p->first][id] = bt;
+ lockdep_dout(10) << lock_names[p->first] << " -> " << name << " at" << dendl;
+ //bt->print(*_dout);
+ }
+ }
+ }
+
+ pthread_mutex_unlock(&lockdep_mutex);
+ return id;
+}
+
+int lockdep_locked(const char *name, int id, bool force_backtrace)
+{
+ pthread_t p = pthread_self();
+
+ if (id < 0) id = lockdep_register(name);
+
+ pthread_mutex_lock(&lockdep_mutex);
+ lockdep_dout(20) << "_locked " << name << dendl;
+ if (force_backtrace || lockdep_force_backtrace())
+ held[p][id] = new BackTrace(BACKTRACE_SKIP);
+ else
+ held[p][id] = 0;
+ pthread_mutex_unlock(&lockdep_mutex);
+ return id;
+}
+
+int lockdep_will_unlock(const char *name, int id)
+{
+ pthread_t p = pthread_self();
+
+ if (id < 0) {
+ //id = lockdep_register(name);
+ assert(id == -1);
+ return id;
+ }
+
+ pthread_mutex_lock(&lockdep_mutex);
+ lockdep_dout(20) << "_will_unlock " << name << dendl;
+
+ // don't assert.. lockdep may be enabled at any point in time
+ //assert(held.count(p));
+ //assert(held[p].count(id));
+
+ delete held[p][id];
+ held[p].erase(id);
+ pthread_mutex_unlock(&lockdep_mutex);
+ return id;
+}
+
+
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