[Bug] Fix munmap() using wrong parameter (#2519)

* fix munmap() using wrong parameter

* rename variables
Co-authored-by: Minjie Wang <wmjlyjemaine@gmail.com>

include/dgl/runtime/shared_mem.h

@@ -25,14 +25,14 @@ class SharedMemory {
    * If shared memory is created in the object, it'll be owned by the object
    * and will be responsible for deleting it when the object is destroyed.
    */
-  bool own;
+  bool own_;
 
   /* \brief the file descripter of the shared memory. */
-  int fd;
+  int fd_;
   /* \brief the address of the shared memory. */
-  void *ptr;
+  void *ptr_;
   /* \brief the size of the shared memory. */
-  size_t size;
+  size_t size_;
 
   /*
    * \brief the name of the object.
@@ -60,16 +60,16 @@ class SharedMemory {
   /*
    * \brief create shared memory.
    * It creates the file and shared memory.
-   * \param size the size of the shared memory.
+   * \param sz the size of the shared memory.
    * \return the address of the shared memory
    */
-  void *CreateNew(size_t size);
+  void *CreateNew(size_t sz);
   /*
    * \brief allocate shared memory that has been created.
-   * \param size the size of the shared memory.
+   * \param sz the size of the shared memory.
    * \return the address of the shared memory
    */
-  void *Open(size_t size);
+  void *Open(size_t sz);
 
   /*
    * \brief check if the shared memory exist.

src/runtime/shared_mem.cc

@@ -41,10 +41,10 @@ class SharedMemoryResource: public Resource {
 SharedMemory::SharedMemory(const std::string &name) {
 #ifndef _WIN32
   this->name = name;
-  this->own = false;
-  this->fd = -1;
-  this->ptr = nullptr;
-  this->size = 0;
+  this->own_ = false;
+  this->fd_ = -1;
+  this->ptr_ = nullptr;
+  this->size_ = 0;
 #else
   LOG(FATAL) << "Shared memory is not supported on Windows.";
 #endif  // _WIN32
@@ -52,11 +52,11 @@ SharedMemory::SharedMemory(const std::string &name) {
 
 SharedMemory::~SharedMemory() {
 #ifndef _WIN32
-  munmap(ptr, size);
-  close(fd);
-  if (own) {
+  CHECK(munmap(ptr_, size_) != -1) << strerror(errno);
+  close(fd_);
+  if (own_) {
     LOG(INFO) << "remove " << name << " for shared memory";
-    shm_unlink(name.c_str());
+    CHECK(shm_unlink(name.c_str()) != -1) << strerror(errno);
     // The resource has been deleted. We don't need to keep track of it any more.
     DeleteResource(name);
   }
@@ -65,38 +65,40 @@ SharedMemory::~SharedMemory() {
 #endif  // _WIN32
 }
 
-void *SharedMemory::CreateNew(size_t size) {
+void *SharedMemory::CreateNew(size_t sz) {
 #ifndef _WIN32
-  this->own = true;
+  this->own_ = true;
 
   // We need to create a shared-memory file.
   // TODO(zhengda) we need to report error if the shared-memory file exists.
   int flag = O_RDWR|O_CREAT;
-  fd = shm_open(name.c_str(), flag, S_IRUSR | S_IWUSR);
-  CHECK_NE(fd, -1) << "fail to open " << name << ": " << strerror(errno);
+  fd_ = shm_open(name.c_str(), flag, S_IRUSR | S_IWUSR);
+  CHECK_NE(fd_, -1) << "fail to open " << name << ": " << strerror(errno);
   // Shared memory cannot be deleted if the process exits abnormally.
   AddResource(name, std::shared_ptr<Resource>(new SharedMemoryResource(name)));
-  auto res = ftruncate(fd, size);
+  auto res = ftruncate(fd_, sz);
   CHECK_NE(res, -1)
       << "Failed to truncate the file. " << strerror(errno);
-  ptr = mmap(NULL, size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
-  CHECK_NE(ptr, MAP_FAILED)
+  ptr_ = mmap(NULL, sz, PROT_READ|PROT_WRITE, MAP_SHARED, fd_, 0);
+  CHECK_NE(ptr_, MAP_FAILED)
       << "Failed to map shared memory. mmap failed with error " << strerror(errno);
-  return ptr;
+  this->size_ = sz;
+  return ptr_;
 #else
   LOG(FATAL) << "Shared memory is not supported on Windows.";
 #endif  // _WIN32
 }
 
-void *SharedMemory::Open(size_t size) {
+void *SharedMemory::Open(size_t sz) {
 #ifndef _WIN32
   int flag = O_RDWR;
-  fd = shm_open(name.c_str(), flag, S_IRUSR | S_IWUSR);
-  CHECK_NE(fd, -1) << "fail to open " << name << ": " << strerror(errno);
-  ptr = mmap(NULL, size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
-  CHECK_NE(ptr, MAP_FAILED)
+  fd_ = shm_open(name.c_str(), flag, S_IRUSR | S_IWUSR);
+  CHECK_NE(fd_, -1) << "fail to open " << name << ": " << strerror(errno);
+  ptr_ = mmap(NULL, sz, PROT_READ|PROT_WRITE, MAP_SHARED, fd_, 0);
+  CHECK_NE(ptr_, MAP_FAILED)
       << "Failed to map shared memory. mmap failed with error " << strerror(errno);
-  return ptr;
+  this->size_ = sz;
+  return ptr_;
 #else
   LOG(FATAL) << "Shared memory is not supported on Windows.";
 #endif  // _WIN32
@@ -104,9 +106,9 @@ void *SharedMemory::Open(size_t size) {
 
 bool SharedMemory::Exist(const std::string &name) {
 #ifndef _WIN32
-  int fd = shm_open(name.c_str(), O_RDONLY, S_IRUSR | S_IWUSR);
-  if (fd >= 0) {
-    close(fd);
+  int fd_ = shm_open(name.c_str(), O_RDONLY, S_IRUSR | S_IWUSR);
+  if (fd_ >= 0) {
+    close(fd_);
     return true;
   } else {
     return false;