Merge pull request iovisor#2030 from vijunag/master

Fix symbol resolution across mount namespaces (iovisor#2029)

src/cc/bcc_syms.cc

@@ -122,13 +122,13 @@ int ProcSyms::_add_load_sections(uint64_t v_addr, uint64_t mem_sz,
 }
 
 void ProcSyms::load_exe() {
+ ProcMountNSGuard g(mount_ns_instance_.get());
  std::string exe = ebpf::get_pid_exe(pid_);
  Module module(exe.c_str(), mount_ns_instance_.get(), &symbol_option_);
 
  if (module.type_ != ModuleType::EXEC)
  return;
 
- ProcMountNSGuard g(mount_ns_instance_.get());
 
  bcc_elf_foreach_load_section(exe.c_str(), &_add_load_sections, &module);
 
@@ -163,6 +163,7 @@ int ProcSyms::_add_module(const char *modname, uint64_t start, uint64_t end,
  // It only gives the mmap offset. We need the real offset for symbol
  // lookup.
  if (module.type_ == ModuleType::SO) {
+ ProcMountNSGuard g(ps->mount_ns_instance_.get());
  if (bcc_elf_get_text_scn_info(modname, &module.elf_so_addr_,
  &module.elf_so_offset_) < 0) {
  fprintf(stderr, "WARNING: Couldn't find .text section in %s\n", modname);