Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 396 insertions, 0 deletions

diff --git a/toolkit/components/backgroundhangmonitor/ThreadStackHelper.cpp b/toolkit/components/backgroundhangmonitor/ThreadStackHelper.cpp
new file mode 100644
index 0000000000..f7b3d0183a
--- /dev/null
+++ b/toolkit/components/backgroundhangmonitor/ThreadStackHelper.cpp
@@ -0,0 +1,396 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "ThreadStackHelper.h"
+#include "MainThreadUtils.h"
+#include "nsJSPrincipals.h"
+#include "nsScriptSecurityManager.h"
+#include "jsapi.h"
+#include "jsfriendapi.h"
+#ifdef MOZ_THREADSTACKHELPER_PROFILING_STACK
+#  include "js/ProfilingStack.h"
+#endif
+
+#include <utility>
+
+#include "mozilla/Assertions.h"
+#include "mozilla/Attributes.h"
+#include "mozilla/BasePrincipal.h"
+#include "mozilla/HangTypes.h"
+#include "mozilla/IntegerPrintfMacros.h"
+#include "mozilla/MemoryChecking.h"
+#include "mozilla/Scoped.h"
+#include "mozilla/Sprintf.h"
+#include "mozilla/UniquePtr.h"
+#include "nsThread.h"
+
+#ifdef __GNUC__
+#  pragma GCC diagnostic push
+#  pragma GCC diagnostic ignored "-Wshadow"
+#endif
+
+#if defined(MOZ_VALGRIND)
+#  include <valgrind/valgrind.h>
+#endif
+
+#include <string.h>
+#include <vector>
+#include <cstdlib>
+
+#ifdef XP_LINUX
+#  include <ucontext.h>
+#  include <unistd.h>
+#  include <sys/syscall.h>
+#endif
+
+#ifdef __GNUC__
+#  pragma GCC diagnostic pop  // -Wshadow
+#endif
+
+#if defined(XP_LINUX) || defined(XP_MACOSX)
+#  include <pthread.h>
+#endif
+
+#ifdef ANDROID
+#  ifndef SYS_gettid
+#    define SYS_gettid __NR_gettid
+#  endif
+#  if defined(__arm__) && !defined(__NR_rt_tgsigqueueinfo)
+// Some NDKs don't define this constant even though the kernel supports it.
+#    define __NR_rt_tgsigqueueinfo (__NR_SYSCALL_BASE + 363)
+#  endif
+#  ifndef SYS_rt_tgsigqueueinfo
+#    define SYS_rt_tgsigqueueinfo __NR_rt_tgsigqueueinfo
+#  endif
+#endif
+
+namespace mozilla {
+
+// A character which we append to any string which gets truncated as a a
+// result of trying to write it into a statically allocated buffer. This just
+// makes it a little easier to know that the buffer was truncated during
+// analysis.
+const char kTruncationIndicator = '$';
+
+ThreadStackHelper::ThreadStackHelper()
+    : mStackToFill(nullptr),
+      mMaxStackSize(16),
+      mMaxBufferSize(512),
+      mDesiredStackSize(0),
+      mDesiredBufferSize(0) {
+  mThreadId = profiler_current_thread_id();
+}
+
+bool ThreadStackHelper::PrepareStackBuffer(HangStack& aStack) {
+  // If we need to grow because we used more than we could store last time,
+  // increase our maximum sizes for this time.
+  if (mDesiredBufferSize > mMaxBufferSize) {
+    mMaxBufferSize = mDesiredBufferSize;
+  }
+  if (mDesiredStackSize > mMaxStackSize) {
+    mMaxStackSize = mDesiredStackSize;
+  }
+  mDesiredBufferSize = 0;
+  mDesiredStackSize = 0;
+
+  // Clear all of the stack entries.
+  aStack.stack().ClearAndRetainStorage();
+  aStack.strbuffer().ClearAndRetainStorage();
+  aStack.modules().Clear();
+
+#ifdef MOZ_THREADSTACKHELPER_PROFILING_STACK
+  // Ensure we have enough space in our stack and string buffers for the data we
+  // want to collect.
+  if (!aStack.stack().SetCapacity(mMaxStackSize, fallible) ||
+      !aStack.strbuffer().SetCapacity(mMaxBufferSize, fallible)) {
+    return false;
+  }
+  return true;
+#else
+  return false;
+#endif
+}
+
+namespace {
+template <typename T>
+class ScopedSetPtr {
+ private:
+  T*& mPtr;
+
+ public:
+  ScopedSetPtr(T*& p, T* val) : mPtr(p) { mPtr = val; }
+  ~ScopedSetPtr() { mPtr = nullptr; }
+};
+}  // namespace
+
+void ThreadStackHelper::GetStack(HangStack& aStack, nsACString& aRunnableName,
+                                 bool aStackWalk) {
+  aRunnableName.AssignLiteral("???");
+
+  if (!PrepareStackBuffer(aStack)) {
+    return;
+  }
+
+  Array<char, nsThread::kRunnableNameBufSize> runnableName;
+  runnableName[0] = '\0';
+
+  ScopedSetPtr<HangStack> _stackGuard(mStackToFill, &aStack);
+  ScopedSetPtr<Array<char, nsThread::kRunnableNameBufSize>> _runnableGuard(
+      mRunnableNameBuffer, &runnableName);
+
+  // XXX: We don't need to pass in ProfilerFeature::StackWalk to trigger
+  // stackwalking, as that is instead controlled by the last argument.
+  profiler_suspend_and_sample_thread(mThreadId, 0, *this, aStackWalk);
+
+  // Copy the name buffer allocation into the output string. We explicitly set
+  // the last byte to null in case we read in some corrupted data without a null
+  // terminator.
+  runnableName[nsThread::kRunnableNameBufSize - 1] = '\0';
+  aRunnableName.AssignASCII(runnableName.cbegin());
+}
+
+void ThreadStackHelper::SetIsMainThread() {
+  MOZ_RELEASE_ASSERT(mRunnableNameBuffer);
+
+  // NOTE: We cannot allocate any memory in this callback, as the target
+  // thread is suspended, so we first copy it into a stack-allocated buffer,
+  // and then once the target thread is resumed, we can copy it into a real
+  // nsCString.
+  //
+  // Currently we only store the names of runnables which are running on the
+  // main thread, so we only want to read sMainThreadRunnableName and copy its
+  // value in the case that we are currently suspending the main thread.
+  *mRunnableNameBuffer = nsThread::sMainThreadRunnableName;
+}
+
+void ThreadStackHelper::TryAppendFrame(HangEntry aFrame) {
+  MOZ_RELEASE_ASSERT(mStackToFill);
+
+  // We deduplicate identical Content, Jit, Wasm, ChromeScript and Suppressed
+  // frames.
+  switch (aFrame.type()) {
+    case HangEntry::THangEntryContent:
+    case HangEntry::THangEntryJit:
+    case HangEntry::THangEntryWasm:
+    case HangEntry::THangEntryChromeScript:
+    case HangEntry::THangEntrySuppressed:
+      if (!mStackToFill->stack().IsEmpty() &&
+          mStackToFill->stack().LastElement().type() == aFrame.type()) {
+        return;
+      }
+      break;
+    default:
+      break;
+  }
+
+  // Record that we _want_ to use another frame entry. If this exceeds
+  // mMaxStackSize, we'll allocate more room on the next hang.
+  mDesiredStackSize += 1;
+
+  // Perform the append if we have enough space to do so.
+  if (mStackToFill->stack().Capacity() > mStackToFill->stack().Length()) {
+    mStackToFill->stack().AppendElement(std::move(aFrame));
+  }
+}
+
+void ThreadStackHelper::CollectNativeLeafAddr(void* aAddr) {
+  MOZ_RELEASE_ASSERT(mStackToFill);
+  TryAppendFrame(HangEntryProgCounter(reinterpret_cast<uintptr_t>(aAddr)));
+}
+
+void ThreadStackHelper::CollectJitReturnAddr(void* aAddr) {
+  MOZ_RELEASE_ASSERT(mStackToFill);
+  TryAppendFrame(HangEntryJit());
+}
+
+void ThreadStackHelper::CollectWasmFrame(const char* aLabel) {
+  MOZ_RELEASE_ASSERT(mStackToFill);
+  // We don't want to collect WASM frames, as they are probably for content, so
+  // we just add a "(content wasm)" frame.
+  TryAppendFrame(HangEntryWasm());
+}
+
+namespace {
+
+bool IsChromeJSScript(JSScript* aScript) {
+  // May be called from another thread or inside a signal handler.
+  // We assume querying the script is safe but we must not manipulate it.
+
+  JSPrincipals* const principals = JS_GetScriptPrincipals(aScript);
+  return nsJSPrincipals::get(principals)->IsSystemPrincipal();
+}
+
+// Get the full path after the URI scheme, if the URI matches the scheme.
+// For example, GetFullPathForScheme("a://b/c/d/e", "a://") returns "b/c/d/e".
+template <size_t LEN>
+const char* GetFullPathForScheme(const char* filename,
+                                 const char (&scheme)[LEN]) {
+  // Account for the null terminator included in LEN.
+  if (!strncmp(filename, scheme, LEN - 1)) {
+    return filename + LEN - 1;
+  }
+  return nullptr;
+}
+
+// Get the full path after a URI component, if the URI contains the component.
+// For example, GetPathAfterComponent("a://b/c/d/e", "/c/") returns "d/e".
+template <size_t LEN>
+const char* GetPathAfterComponent(const char* filename,
+                                  const char (&component)[LEN]) {
+  const char* found = nullptr;
+  const char* next = strstr(filename, component);
+  while (next) {
+    // Move 'found' to end of the component, after the separator '/'.
+    // 'LEN - 1' accounts for the null terminator included in LEN,
+    found = next + LEN - 1;
+    // Resume searching before the separator '/'.
+    next = strstr(found - 1, component);
+  }
+  return found;
+}
+
+}  // namespace
+
+bool ThreadStackHelper::MaybeAppendDynamicStackFrame(Span<const char> aBuf) {
+  mDesiredBufferSize += aBuf.Length() + 1;
+
+  if (mStackToFill->stack().Capacity() > mStackToFill->stack().Length() &&
+      (mStackToFill->strbuffer().Capacity() -
+       mStackToFill->strbuffer().Length()) > aBuf.Length() + 1) {
+    // NOTE: We only increment this if we're going to successfully append.
+    mDesiredStackSize += 1;
+    uint32_t start = mStackToFill->strbuffer().Length();
+    mStackToFill->strbuffer().AppendElements(aBuf.Elements(), aBuf.Length());
+    mStackToFill->strbuffer().AppendElement('\0');
+    mStackToFill->stack().AppendElement(HangEntryBufOffset(start));
+    return true;
+  }
+  return false;
+}
+
+void ThreadStackHelper::CollectProfilingStackFrame(
+    const js::ProfilingStackFrame& aFrame) {
+  // For non-js frames, first try to get the dynamic string and fit it in,
+  // otherwise just get the label.
+  if (!aFrame.isJsFrame()) {
+    const char* frameLabel = aFrame.label();
+    if (aFrame.isNonsensitive() && aFrame.dynamicString()) {
+      const char* dynamicString = aFrame.dynamicString();
+      char buffer[128];
+      size_t len = SprintfLiteral(buffer, "%s %s", frameLabel, dynamicString);
+      if (len > sizeof(buffer)) {
+        buffer[sizeof(buffer) - 1] = kTruncationIndicator;
+        len = sizeof(buffer);
+      }
+      if (MaybeAppendDynamicStackFrame(Span(buffer, len))) {
+        return;
+      }
+    }
+
+    // frameLabel is a statically allocated string, so we want to store a
+    // reference to it without performing any allocations. This is important, as
+    // we aren't allowed to allocate within this function.
+    //
+    // The variant for this kind of label in our HangStack object is a
+    // `nsCString`, which normally contains heap allocated string data. However,
+    // `nsCString` has an optimization for literal strings which causes the
+    // backing data to not be copied when being copied between nsCString
+    // objects.
+    //
+    // We take advantage of that optimization by creating a nsCString object
+    // which has the LITERAL flag set. Without this optimization, this code
+    // would be incorrect.
+    nsCString label;
+    label.AssignLiteral(frameLabel, strlen(frameLabel));
+
+    // Let's make sure we don't deadlock here, by asserting that `label`'s
+    // backing data matches.
+    MOZ_RELEASE_ASSERT(label.BeginReading() == frameLabel,
+                       "String copy performed during "
+                       "ThreadStackHelper::CollectProfilingStackFrame");
+    TryAppendFrame(label);
+    return;
+  }
+
+  if (!aFrame.script()) {
+    TryAppendFrame(HangEntrySuppressed());
+    return;
+  }
+
+  if (!IsChromeJSScript(aFrame.script())) {
+    TryAppendFrame(HangEntryContent());
+    return;
+  }
+
+  // Rather than using the profiler's dynamic string, we compute our own string.
+  // This is because we want to do some size-saving strategies, and throw out
+  // information which won't help us as much.
+  const char* filename = JS_GetScriptFilename(aFrame.script());
+
+  char buffer[256];  // Should be enough to fit our longest js function and file
+                     // names.
+  size_t len = 0;
+  if (JSFunction* func = aFrame.function()) {
+    if (JSString* str = JS_GetFunctionDisplayId(func)) {
+      JSLinearString* linear = JS_ASSERT_STRING_IS_LINEAR(str);
+      len = JS::GetLinearStringLength(linear);
+      JS::LossyCopyLinearStringChars(buffer, linear,
+                                     std::min(len, sizeof(buffer)));
+      // NOTE: >= so that we account for the trailing space that we'd want to
+      // otherwise append.
+      if (len >= sizeof(buffer)) {
+        len = sizeof(buffer);
+        buffer[sizeof(buffer) - 1] = kTruncationIndicator;
+      } else {
+        buffer[len++] = ' ';
+      }
+    }
+  }
+
+  unsigned lineno = JS_PCToLineNumber(aFrame.script(), aFrame.pc());
+
+  // Some script names are in the form "foo -> bar -> baz".
+  // Here we find the origin of these redirected scripts.
+  const char* basename = GetPathAfterComponent(filename, " -> ");
+  if (basename) {
+    filename = basename;
+  }
+
+  // Strip chrome:// or resource:// off of the filename if present.
+  basename = GetFullPathForScheme(filename, "chrome://");
+  if (!basename) {
+    basename = GetFullPathForScheme(filename, "resource://");
+  }
+  if (!basename) {
+    // If we're in an add-on script, under the {profile}/extensions
+    // directory, extract the path after the /extensions/ part.
+    basename = GetPathAfterComponent(filename, "/extensions/");
+  }
+  if (!basename) {
+    // Only keep the file base name for paths outside the above formats.
+    basename = strrchr(filename, '/');
+    basename = basename ? basename + 1 : filename;
+    // Look for Windows path separator as well.
+    filename = strrchr(basename, '\\');
+    if (filename) {
+      basename = filename + 1;
+    }
+  }
+
+  len +=
+      SprintfBuf(buffer + len, sizeof(buffer) - len, "%s:%u", basename, lineno);
+  if (len > sizeof(buffer)) {
+    buffer[sizeof(buffer) - 1] = kTruncationIndicator;
+    len = sizeof(buffer);
+  }
+  if (MaybeAppendDynamicStackFrame(Span(buffer, len))) {
+    return;
+  }
+
+  TryAppendFrame(HangEntryChromeScript());
+}
+
+}  // namespace mozilla