Kernel: Make PerformanceEventBuffer::add_process fallible with ErrorOr

Cnidarias · Jan 12, 2022 · 8a4654a · 8a4654a
1 parent d2ffcfb
commit 8a4654a
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Showing 4 changed files with 22 additions and 16 deletions.
diff --git a/Kernel/PerformanceEventBuffer.cpp b/Kernel/PerformanceEventBuffer.cpp
@@ -313,29 +313,34 @@ OwnPtr<PerformanceEventBuffer> PerformanceEventBuffer::try_create_with_size(size
  return adopt_own_if_nonnull(new (nothrow) PerformanceEventBuffer(buffer_or_error.release_value()));
 }
 
-void PerformanceEventBuffer::add_process(const Process& process, ProcessEventType event_type)
+ErrorOr<void> PerformanceEventBuffer::add_process(const Process& process, ProcessEventType event_type)
 {
  SpinlockLocker locker(process.address_space().get_lock());
 
  OwnPtr<KString> executable;
  if (process.executable())
- executable = MUST(process.executable()->try_serialize_absolute_path());
+ executable = TRY(process.executable()->try_serialize_absolute_path());
  else
- executable = MUST(KString::formatted("<{}>", process.name()));
+ executable = TRY(KString::formatted("<{}>", process.name()));
 
- [[maybe_unused]] auto rc = append_with_ip_and_bp(process.pid(), 0, 0, 0,
+ TRY(append_with_ip_and_bp(process.pid(), 0, 0, 0,
  event_type == ProcessEventType::Create ? PERF_EVENT_PROCESS_CREATE : PERF_EVENT_PROCESS_EXEC,
- 0, process.pid().value(), 0, executable->view());
+ 0, process.pid().value(), 0, executable->view()));
 
+ ErrorOr<void> result;
  process.for_each_thread([&](auto& thread) {
- [[maybe_unused]] auto rc = append_with_ip_and_bp(process.pid(), thread.tid().value(),
+ result = append_with_ip_and_bp(process.pid(), thread.tid().value(),
  0, 0, PERF_EVENT_THREAD_CREATE, 0, 0, 0, nullptr);
+ return result.is_error() ? IterationDecision::Break : IterationDecision::Continue;
  });
+ TRY(result);
 
  for (auto const& region : process.address_space().regions()) {
- [[maybe_unused]] auto rc = append_with_ip_and_bp(process.pid(), 0,
- 0, 0, PERF_EVENT_MMAP, 0, region->range().base().get(), region->range().size(), region->name());
+ TRY(append_with_ip_and_bp(process.pid(), 0,
+ 0, 0, PERF_EVENT_MMAP, 0, region->range().base().get(), region->range().size(), region->name()));
  }
+
+ return {};
 }
 
 ErrorOr<FlatPtr> PerformanceEventBuffer::register_string(NonnullOwnPtr<KString> string)

diff --git a/Kernel/PerformanceEventBuffer.h b/Kernel/PerformanceEventBuffer.h
@@ -121,7 +121,7 @@ class PerformanceEventBuffer {
 
  ErrorOr<void> to_json(KBufferBuilder&) const;
 
- void add_process(const Process&, ProcessEventType event_type);
+ ErrorOr<void> add_process(const Process&, ProcessEventType event_type);
 
  ErrorOr<FlatPtr> register_string(NonnullOwnPtr<KString>);
 

diff --git a/Kernel/PerformanceManager.h b/Kernel/PerformanceManager.h
@@ -18,14 +18,14 @@ class PerformanceManager {
  {
  if (g_profiling_all_threads) {
  VERIFY(g_global_perf_events);
- g_global_perf_events->add_process(process, ProcessEventType::Create);
+ (void)g_global_perf_events->add_process(process, ProcessEventType::Create);
  }
  }
 
  inline static void add_process_exec_event(Process& process)
  {
  if (auto* event_buffer = process.current_perf_events_buffer()) {
- event_buffer->add_process(process, ProcessEventType::Exec);
+ (void)event_buffer->add_process(process, ProcessEventType::Exec);
  }
  }
 

diff --git a/Kernel/Process.cpp b/Kernel/Process.cpp
@@ -788,11 +788,12 @@ void Process::tracer_trap(Thread& thread, const RegisterState& regs)
 
 bool Process::create_perf_events_buffer_if_needed()
 {
- if (!m_perf_event_buffer) {
- m_perf_event_buffer = PerformanceEventBuffer::try_create_with_size(4 * MiB);
- m_perf_event_buffer->add_process(*this, ProcessEventType::Create);
- }
- return !!m_perf_event_buffer;
+ if (m_perf_event_buffer)
+ return true;
+ m_perf_event_buffer = PerformanceEventBuffer::try_create_with_size(4 * MiB);
+ if (!m_perf_event_buffer)
+ return false;
+ return !m_perf_event_buffer->add_process(*this, ProcessEventType::Create).is_error();
 }
 
 void Process::delete_perf_events_buffer()