Add support for sanitizers and fix issues they have found

Former-commit-id: 58971a430dd3e4e8c39c7b5288211bc2ba7699ed

src/Makefile

@@ -45,6 +45,17 @@ endif
 endif
 
 USEASM?=true
+
+ifneq ($(SANITIZE),)
+	CC=clang
+	CXX=clang++
+	CFLAGS+= -fsanitize=$(SANITIZE) -DSANITIZE
+	CXXFLAGS+= -fsanitize=$(SANITIZE) -DSANITIZE
+	LDFLAGS+= -fsanitize=$(SANITIZE)
+	MALLOC=libc
+	USEASM=false
+endif
+
 # Do we use our assembly spinlock? X64 only
 ifeq ($(uname_S),Linux)
 ifeq ($(uname_M),x86_64)

src/fastlock.cpp

@@ -57,6 +57,7 @@
 #define UNUSED(x) ((void)x)
 #endif
 
+
 /****************************************************
  *
  *      Implementation of a fair spinlock.  To promote fairness we
@@ -64,12 +65,74 @@
  * 
  ****************************************************/
 
+
+#if !defined(__has_feature)
+    #define __has_feature(x) 0
+#endif
+
+#if __has_feature(thread_sanitizer)
+
+    /* Report that a lock has been created at address "lock". */
+    #define ANNOTATE_RWLOCK_CREATE(lock) \
+        AnnotateRWLockCreate(__FILE__, __LINE__, lock)
+
+    /* Report that the lock at address "lock" is about to be destroyed. */
+    #define ANNOTATE_RWLOCK_DESTROY(lock) \
+        AnnotateRWLockDestroy(__FILE__, __LINE__, lock)
+
+    /* Report that the lock at address "lock" has been acquired.
+       is_w=1 for writer lock, is_w=0 for reader lock. */
+    #define ANNOTATE_RWLOCK_ACQUIRED(lock, is_w) \
+        AnnotateRWLockAcquired(__FILE__, __LINE__, lock, is_w)
+
+    /* Report that the lock at address "lock" is about to be released. */
+    #define ANNOTATE_RWLOCK_RELEASED(lock, is_w) \
+      AnnotateRWLockReleased(__FILE__, __LINE__, lock, is_w)
+
+    #if defined(DYNAMIC_ANNOTATIONS_WANT_ATTRIBUTE_WEAK)
+        #if defined(__GNUC__)
+            #define DYNAMIC_ANNOTATIONS_ATTRIBUTE_WEAK __attribute__((weak))
+        #else
+            /* TODO(glider): for Windows support we may want to change this macro in order
+               to prepend __declspec(selectany) to the annotations' declarations. */
+            #error weak annotations are not supported for your compiler
+        #endif
+    #else
+        #define DYNAMIC_ANNOTATIONS_ATTRIBUTE_WEAK
+    #endif
+
+    extern "C" {
+    void AnnotateRWLockCreate(
+        const char *file, int line,
+        const volatile void *lock) DYNAMIC_ANNOTATIONS_ATTRIBUTE_WEAK;
+    void AnnotateRWLockDestroy(
+        const char *file, int line,
+        const volatile void *lock) DYNAMIC_ANNOTATIONS_ATTRIBUTE_WEAK;
+    void AnnotateRWLockAcquired(
+        const char *file, int line,
+        const volatile void *lock, long is_w) DYNAMIC_ANNOTATIONS_ATTRIBUTE_WEAK;
+    void AnnotateRWLockReleased(
+        const char *file, int line,
+        const volatile void *lock, long is_w) DYNAMIC_ANNOTATIONS_ATTRIBUTE_WEAK;
+    }
+
+#else
+
+    #define ANNOTATE_RWLOCK_CREATE(lock)
+    #define ANNOTATE_RWLOCK_DESTROY(lock)
+    #define ANNOTATE_RWLOCK_ACQUIRED(lock, is_w)
+    #define ANNOTATE_RWLOCK_RELEASED(lock, is_w)
+
+#endif
+
 static_assert(sizeof(pid_t) <= sizeof(fastlock::m_pidOwner), "fastlock::m_pidOwner not large enough");
 uint64_t g_longwaits = 0;
 
 uint64_t fastlock_getlongwaitcount()
 {
-    return g_longwaits;
+    uint64_t rval;
+    __atomic_load(&g_longwaits, &rval, __ATOMIC_RELAXED);
+    return rval;
 }
 
 #ifndef ASM_SPINLOCK
@@ -107,12 +170,15 @@ extern "C" void fastlock_init(struct fastlock *lock)
     lock->m_depth = 0;
     lock->m_pidOwner = -1;
     lock->futex = 0;
+    ANNOTATE_RWLOCK_CREATE(lock);
 }
 
 #ifndef ASM_SPINLOCK
 extern "C" void fastlock_lock(struct fastlock *lock)
 {
-    if ((int)__atomic_load_4(&lock->m_pidOwner, __ATOMIC_ACQUIRE) == gettid())
+    int pidOwner;
+    __atomic_load(&lock->m_pidOwner, &pidOwner, __ATOMIC_ACQUIRE);
+    if (pidOwner == gettid())
     {
         ++lock->m_depth;
         return;
@@ -124,8 +190,12 @@ extern "C" void fastlock_lock(struct fastlock *lock)
 #endif
     int cloops = 0;
     ticket ticketT;
-    while (((ticketT.u = __atomic_load_4(&lock->m_ticket.m_active, __ATOMIC_ACQUIRE)) & 0xffff) != myticket)
+    for (;;)
     {
+        __atomic_load(&lock->m_ticket.u, &ticketT.u, __ATOMIC_ACQUIRE);
+        if ((ticketT.u & 0xffff) == myticket)
+            break;
+
 #if defined(__i386__) || defined(__amd64__)
         __asm__ ("pause");
 #endif
@@ -136,28 +206,34 @@ extern "C" void fastlock_lock(struct fastlock *lock)
             futex(&lock->m_ticket.u, FUTEX_WAIT_BITSET_PRIVATE, ticketT.u, nullptr, mask);
             __atomic_fetch_and(&lock->futex, ~mask, __ATOMIC_RELEASE);
 #endif
-            ++g_longwaits;
+            __atomic_fetch_add(&g_longwaits, 1, __ATOMIC_RELAXED);
         }
     }
 
     lock->m_depth = 1;
-    __atomic_store_4(&lock->m_pidOwner, gettid(), __ATOMIC_RELEASE);
+    int tid = gettid();
+    __atomic_store(&lock->m_pidOwner, &tid, __ATOMIC_RELEASE);
+    ANNOTATE_RWLOCK_ACQUIRED(lock, true);
     std::atomic_thread_fence(std::memory_order_acquire);
 }
 
 extern "C" int fastlock_trylock(struct fastlock *lock, int fWeak)
 {
-    if ((int)__atomic_load_4(&lock->m_pidOwner, __ATOMIC_ACQUIRE) == gettid())
+    int tid;
+    __atomic_load(&lock->m_pidOwner, &tid, __ATOMIC_ACQUIRE);
+    if (tid == gettid())
     {
         ++lock->m_depth;
         return true;
     }
 
     // cheap test
-    if (lock->m_ticket.m_active != lock->m_ticket.m_avail)
+    struct ticket ticketT;
+    __atomic_load(&lock->m_ticket.u, &ticketT.u, __ATOMIC_ACQUIRE);
+    if (ticketT.m_active != ticketT.m_avail)
         return false;
 
-    uint16_t active = __atomic_load_2(&lock->m_ticket.m_active, __ATOMIC_RELAXED);
+    uint16_t active = ticketT.m_active;
     uint16_t next = active + 1;
 
     struct ticket ticket_expect { { { active, active } } };
@@ -165,7 +241,9 @@ extern "C" int fastlock_trylock(struct fastlock *lock, int fWeak)
     if (__atomic_compare_exchange(&lock->m_ticket, &ticket_expect, &ticket_setiflocked, fWeak /*weak*/, __ATOMIC_ACQUIRE, __ATOMIC_RELAXED))
     {
         lock->m_depth = 1;
-        __atomic_store_4(&lock->m_pidOwner, gettid(), __ATOMIC_RELEASE);
+        tid = gettid();
+        __atomic_store(&lock->m_pidOwner, &tid,  __ATOMIC_RELEASE);
+        ANNOTATE_RWLOCK_ACQUIRED(lock, true);
         return true;
     }
     return false;
@@ -176,13 +254,20 @@ extern "C" int fastlock_trylock(struct fastlock *lock, int fWeak)
 void unlock_futex(struct fastlock *lock, uint16_t ifutex)
 {
     unsigned mask = (1U << (ifutex % 32));
-    unsigned futexT = __atomic_load_4(&lock->futex, __ATOMIC_RELAXED) & mask;
+    unsigned futexT;
+    __atomic_load(&lock->futex, &futexT, __ATOMIC_RELAXED);
+    futexT &= mask;
     
     if (futexT == 0)
         return;
     
-    while (__atomic_load_4(&lock->futex, __ATOMIC_ACQUIRE) & mask)
+    for (;;)
     {
+        __atomic_load(&lock->futex, &futexT, __ATOMIC_ACQUIRE);
+        futexT &= mask;
+        if (!futexT)
+            break;
+
         if (futex(&lock->m_ticket.u, FUTEX_WAKE_BITSET_PRIVATE, INT_MAX, nullptr, mask) == 1)
             break;
     }
@@ -194,9 +279,13 @@ extern "C" void fastlock_unlock(struct fastlock *lock)
     --lock->m_depth;
     if (lock->m_depth == 0)
     {
-        assert((int)__atomic_load_4(&lock->m_pidOwner, __ATOMIC_RELAXED) >= 0);  // unlock after free
+        int pidT;
-        lock->m_pidOwner = -1;
+        __atomic_load(&lock->m_pidOwner, &pidT, __ATOMIC_RELAXED);
+        assert(pidT >= 0);  // unlock after free
+        int t = -1;
+        __atomic_store(&lock->m_pidOwner, &t, __ATOMIC_RELEASE);
         std::atomic_thread_fence(std::memory_order_release);
+        ANNOTATE_RWLOCK_RELEASED(lock, true);
         uint16_t activeNew = __atomic_add_fetch(&lock->m_ticket.m_active, 1, __ATOMIC_RELEASE);  // on x86 the atomic is not required here, but ASM handles that case
 #ifdef __linux__
         unlock_futex(lock, activeNew);
@@ -213,12 +302,15 @@ extern "C" void fastlock_free(struct fastlock *lock)
     assert((lock->m_ticket.m_active == lock->m_ticket.m_avail)                                        // Asser the lock is unlocked
         || (lock->m_pidOwner == gettid() && (lock->m_ticket.m_active == lock->m_ticket.m_avail-1)));  // OR we own the lock and nobody else is waiting
     lock->m_pidOwner = -2;  // sentinal value indicating free
+    ANNOTATE_RWLOCK_DESTROY(lock);
 }
 
 
 bool fastlock::fOwnLock()
 {
-    return gettid() == m_pidOwner;
+    int tid;
+    __atomic_load(&m_pidOwner, &tid, __ATOMIC_RELAXED);
+    return gettid() == tid;
 }
 
 int fastlock_unlock_recursive(struct fastlock *lock)

src/networking.cpp

@@ -1631,7 +1631,7 @@ int handleClientsWithPendingWrites(int iel) {
         if (writeToClient(c->fd,c,0) == C_ERR) {
             if (c->flags & CLIENT_CLOSE_ASAP)
             {
-                c->lock.lock();
+                lock.release(); // still locked
                 AeLocker ae;
                 ae.arm(c);
                 freeClient(c);  // writeToClient will only async close, but there's no need to wait

src/new.cpp

@@ -2,6 +2,14 @@
 #include "server.h"
 #include "new.h"
 
+#ifdef SANITIZE
+void *operator new(size_t size, enum MALLOC_CLASS mclass)
+{
+    (void)mclass;
+    return ::operator new(size);
+}
+
+#else
 [[deprecated]]
 void *operator new(size_t size)
 {
@@ -21,4 +29,6 @@ void operator delete(void * p) noexcept
 void operator delete(void *p, std::size_t) noexcept
 {
     zfree(p);
-}
+}
+
+#endif

src/new.h

@@ -1,10 +1,12 @@
 #pragma once
 #include <cstddef>  // std::size_t
 
+void *operator new(size_t size, enum MALLOC_CLASS mclass);
+
+#ifndef SANITIZE
 [[deprecated]]
 void *operator new(size_t size);
 
-void *operator new(size_t size, enum MALLOC_CLASS mclass);
-
 void operator delete(void * p) noexcept;
 void operator delete(void *p, std::size_t) noexcept;
+#endif

src/object.cpp

@@ -356,7 +356,7 @@ void incrRefCount(robj_roptr o) {
 }
 
 void decrRefCount(robj_roptr o) {
-    if (o->refcount == 1) {
+    if (o->refcount.load(std::memory_order_acquire) == 1) {
         switch(o->type) {
         case OBJ_STRING: freeStringObject(o); break;
         case OBJ_LIST: freeListObject(o); break;

src/server.cpp

@@ -1023,7 +1023,7 @@ extern "C" void nolocks_localtime(struct tm *tmp, time_t t, time_t tz, int dst);
  * serverLog() is to prefer. */
 void serverLogRaw(int level, const char *msg) {
     const int syslogLevelMap[] = { LOG_DEBUG, LOG_INFO, LOG_NOTICE, LOG_WARNING };
-    const char *c = ".-*#";
+    const char *c = ".-*#                                                             ";
     FILE *fp;
     char buf[64];
     int rawmode = (level & LL_RAW);
@@ -1749,7 +1749,8 @@ void databasesCron(void) {
  * a lot faster than calling time(NULL) */
 void updateCachedTime(void) {
     g_pserver->unixtime = time(NULL);
-    g_pserver->mstime = mstime();
+    long long ms = mstime();
+    __atomic_store(&g_pserver->mstime, &ms, __ATOMIC_RELAXED);
 
     /* To get information about daylight saving time, we need to call
      * localtime_r and cache the result. However calling localtime_r in this
@@ -4941,13 +4942,20 @@ int redisIsSupervised(int mode) {
 
 uint64_t getMvccTstamp()
 {
-    return g_pserver->mvcc_tstamp;
+    uint64_t rval;
+    __atomic_load(&g_pserver->mvcc_tstamp, &rval, __ATOMIC_ACQUIRE);
+    return rval;
 }
 
 void incrementMvccTstamp()
 {
-    uint64_t msPrev = g_pserver->mvcc_tstamp >> 20;
+    uint64_t msPrev;
-    if (msPrev >= (uint64_t)g_pserver->mstime)  // we can be greater if the count overflows
+    __atomic_load(&g_pserver->mvcc_tstamp, &msPrev, __ATOMIC_ACQUIRE);
+    msPrev >>= 20;  // convert to milliseconds
+
+    long long mst;
+    __atomic_load(&g_pserver->mstime, &mst, __ATOMIC_RELAXED);
+    if (msPrev >= (uint64_t)mst)  // we can be greater if the count overflows
     {
         atomicIncr(g_pserver->mvcc_tstamp, 1);
     }