Do not attempt syscall on invalid stack_id

Limnotation · Mar 26, 2018 · d364800 · d364800
1 parent 581052a
commit d364800
Showing 1 changed file with 4 additions and 0 deletions.
diff --git a/src/cc/api/BPFTable.cc b/src/cc/api/BPFTable.cc
@@ -178,6 +178,8 @@ void BPFStackTable::clear_table_non_atomic() {
 std::vector<uintptr_t> BPFStackTable::get_stack_addr(int stack_id) {
  std::vector<uintptr_t> res;
  stacktrace_t stack;
+ if (stack_id < 0)
+ return res;
  if (!lookup(&stack_id, &stack))
  return res;
  for (int i = 0; (i < BPF_MAX_STACK_DEPTH) && (stack.ip[i] != 0); i++)
@@ -189,6 +191,8 @@ std::vector<std::string> BPFStackTable::get_stack_symbol(int stack_id,
  int pid) {
  auto addresses = get_stack_addr(stack_id);
  std::vector<std::string> res;
+ if (addresses.empty())
+ return res;
  res.reserve(addresses.size());
 
  if (pid < 0)