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Bug 1659185 - Use child process crash annotations when generating hang reports; r=dmajor,froydnj

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When generating a hang report we need to force a hung child process to return
its annotation via the pipe that connects it to the main process. Since the
child is not responding to regular IPC messages we force it to using
platform-specific code:

* On Windows we launch a new thread using CreateRemoteThread() that will
  invoke the code used to send the crash annotations. The Windows-specific
  code also has another slight modification: it stored the pipe used to send
  the annotations in Breakpad's minidump callback context. This patch moves it
  into the `gChildCrashAnnotationReportFd` global which is what all the other
  platforms use.
* On Linux/macOS we use a signal handler for the SIGTERM signal. It would be
  simpler to use SIGUSR1 or another signal that doesn't have special meanings,
  but those are all already in use in Gecko (either by jprof or the gcov
  machinery). We don't install SIGTERM handlers for anything else but
  obvioulsy its semantics get in the way since it's used to politely kill a
  process, and Chromium IPC also uses it for that purpose. So to tell apart
  our use of SIGTERM from a "regular" terminating SIGTERM we send a magic
  value along using sigqueue(). Our signal handler will look for it and only
  send annotations when it is set. If the magic number isn't there it will
  re-install the default SIGTERM handler and raise the signal once more which
  will lead to the process being terminated as it should be.

The patch refactors some of the code so that the PIDs and process/file handles
use platform-independent types to cut down on the amount of duplication we
have there.

Differential Revision: https://phabricator.services.mozilla.com/D87759
This commit is contained in:
Gabriele Svelto 2020-09-07 16:02:26 +00:00
parent f50042da80
commit d3e714d29a
2 changed files with 91 additions and 59 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

145
toolkit/crashreporter/nsExceptionHandler.cpp
View File

@ -30,6 +30,7 @@
#include "jsfriendapi.h"
#include "ThreadAnnotation.h"
#include "private/pprio.h"
#include "base/process_util.h"
#include "common/basictypes.h"
#if defined(XP_WIN)
@ -256,19 +257,27 @@ static char* childCrashNotifyPipe;
#elif defined(XP_LINUX)
static int serverSocketFd = -1;
static int clientSocketFd = -1;
static int gMagicChildCrashReportFd =
// On Linux these file descriptors are created in the parent process and
// remapped in the child ones. See PosixProcessLauncher::DoSetup() for more
// details.
static FileHandle gMagicChildCrashReportFd =
# if defined(MOZ_WIDGET_ANDROID)
// On android the fd is set at the time of child creation.
-1
kInvalidFileHandle
# else
4
# endif // defined(MOZ_WIDGET_ANDROID)
;
#endif
#if defined(MOZ_WIDGET_ANDROID)
static int gChildCrashAnnotationReportFd = -1;
static FileHandle gChildCrashAnnotationReportFd =
#if (defined(XP_LINUX) || defined(XP_MACOSX)) && !defined(MOZ_WIDGET_ANDROID)
7
#else
kInvalidFileHandle
#endif
;
// |dumpMapLock| must protect all access to |pidToMinidump|.
static Mutex* dumpMapLock;
@ -504,25 +513,8 @@ bool copy_file(const char* from, const char* to) {
*/
class PlatformWriter {
public:
#ifdef XP_WIN
typedef HANDLE NativeFileDesc;
typedef wchar_t NativeChar;
#elif defined(XP_UNIX)
typedef int NativeFileDesc;
typedef char NativeChar;
#else
# error "Need implementation of PlatformWriter for this platform"
#endif
const NativeFileDesc kInvalidFileDesc =
#ifdef XP_WIN
INVALID_HANDLE_VALUE;
#elif defined(XP_UNIX)
-1;
#endif
PlatformWriter() : mBuffer{}, mPos(0), mFD(kInvalidFileDesc) {}
explicit PlatformWriter(const NativeChar* aPath) : PlatformWriter() {
PlatformWriter() : mBuffer{}, mPos(0), mFD(kInvalidFileHandle) {}
explicit PlatformWriter(const XP_CHAR* aPath) : PlatformWriter() {
Open(aPath);
}
@ -537,7 +529,7 @@ class PlatformWriter {
}
}
void Open(const NativeChar* aPath) {
void Open(const XP_CHAR* aPath) {
#ifdef XP_WIN
mFD = CreateFile(aPath, GENERIC_WRITE, 0, nullptr, CREATE_ALWAYS,
FILE_ATTRIBUTE_NORMAL, nullptr);
@ -546,8 +538,8 @@ class PlatformWriter {
#endif
}
void OpenHandle(NativeFileDesc aFD) { mFD = aFD; }
bool Valid() { return mFD != kInvalidFileDesc; }
void OpenHandle(FileHandle aFD) { mFD = aFD; }
bool Valid() { return mFD != kInvalidFileHandle; }
void WriteBuffer(const char* aBuffer, size_t aLen) {
if (!Valid()) {
@ -566,7 +558,7 @@ class PlatformWriter {
WriteBuffer(aStr, N - 1);
}
NativeFileDesc FileDesc() { return mFD; }
FileHandle FileDesc() { return mFD; }
private:
PlatformWriter(const PlatformWriter&) = delete;
@ -603,7 +595,7 @@ class PlatformWriter {
char mBuffer[kBufferSize];
size_t mPos;
NativeFileDesc mFD;
FileHandle mFD;
};
class JSONAnnotationWriter : public AnnotationWriter {
@ -1652,18 +1644,14 @@ static bool BuildTempPath(PathStringT& aResult) {
return true;
}
FileHandle GetAnnotationTimeCrashFd() { return gChildCrashAnnotationReportFd; }
static void PrepareChildExceptionTimeAnnotations(
void* context, const phc::AddrInfo* addrInfo) {
const phc::AddrInfo* addrInfo) {
MOZ_ASSERT(!XRE_IsParentProcess());
FileHandle f;
#ifdef XP_WIN
f = static_cast<HANDLE>(context);
#else
f = GetAnnotationTimeCrashFd();
#endif
PlatformWriter apiData;
apiData.OpenHandle(f);
apiData.OpenHandle(GetAnnotationTimeCrashFd());
BinaryAnnotationWriter writer(apiData);
char oomAllocationSizeBuffer[32] = "";
@ -1775,7 +1763,7 @@ static bool ChildMinidumpCallback(const wchar_t* dump_path,
const mozilla::phc::AddrInfo* addr_info,
bool succeeded) {
if (succeeded) {
PrepareChildExceptionTimeAnnotations(context, addr_info);
PrepareChildExceptionTimeAnnotations(addr_info);
}
return true;
@ -1841,7 +1829,7 @@ static bool ChildFilter(void* context, const phc::AddrInfo* addrInfo) {
}
mozilla::IOInterposer::Disable();
PrepareChildExceptionTimeAnnotations(context, addrInfo);
PrepareChildExceptionTimeAnnotations(addrInfo);
return true;
}
@ -1873,11 +1861,58 @@ static nsresult LocateExecutable(nsIFile* aXREDirectory,
#endif // !defined(MOZ_WIDGET_ANDROID)
#if defined(XP_WIN)
DWORD WINAPI FlushContentProcessAnnotationsThreadFunc(LPVOID aContext) {
PrepareChildExceptionTimeAnnotations(nullptr);
return 0;
}
#else
static const int kAnnotationSignal = SIGUSR2;
static void AnnotationSignalHandler(int aSignal, siginfo_t* aInfo,
void* aContext) {
PrepareChildExceptionTimeAnnotations(nullptr);
}
#endif // defined(XP_WIN)
static void InitChildAnnotationsFlusher() {
#if !defined(XP_WIN)
struct sigaction oldSigAction = {};
struct sigaction sigAction = {};
sigAction.sa_sigaction = AnnotationSignalHandler;
sigAction.sa_flags = SA_RESTART | SA_SIGINFO;
sigemptyset(&sigAction.sa_mask);
mozilla::DebugOnly<int> rv =
sigaction(kAnnotationSignal, &sigAction, &oldSigAction);
MOZ_ASSERT(rv == 0, "Failed to install the crash reporter's SIGUSR2 handler");
MOZ_ASSERT(oldSigAction.sa_sigaction == nullptr,
"A SIGUSR2 handler was already present");
#endif // !defined(XP_WIN)
}
static bool FlushContentProcessAnnotations(ProcessHandle aTargetPid) {
#if defined(XP_WIN)
nsAutoHandle hThread(CreateRemoteThread(
aTargetPid, nullptr, 0, FlushContentProcessAnnotationsThreadFunc, nullptr,
0, nullptr));
return !!hThread;
#else // POSIX platforms
return kill(aTargetPid, kAnnotationSignal) == 0;
#endif
}
static void InitializeAnnotationFacilities() {
crashReporterAPILock = new Mutex("crashReporterAPILock");
notesFieldLock = new Mutex("notesFieldLock");
notesField = new nsCString();
InitThreadAnnotation();
if (!XRE_IsParentProcess()) {
InitChildAnnotationsFlusher();
}
}
static void TeardownAnnotationFacilities() {
@ -3164,7 +3199,7 @@ bool WriteExtraFile(const nsAString& id, const AnnotationTable& annotations) {
}
static void ReadExceptionTimeAnnotations(AnnotationTable& aAnnotations,
uint32_t aPid) {
ProcessId aPid) {
// Read exception-time annotations
StaticMutexAutoLock pidMapLock(processMapLock);
if (aPid && processToCrashFd.count(aPid)) {
@ -3228,7 +3263,7 @@ static void OnChildProcessDumpRequested(void* aContext,
CreateFileFromPath(aFilePath, getter_AddRefs(minidump));
uint32_t pid = aClientInfo.pid();
ProcessId pid = aClientInfo.pid();
if (ShouldReport()) {
nsCOMPtr<nsIFile> memoryReport;
@ -3263,7 +3298,7 @@ static void OnChildProcessDumpRequested(void* aContext,
static void OnChildProcessDumpWritten(void* aContext,
const ClientInfo& aClientInfo) {
uint32_t pid = aClientInfo.pid();
ProcessId pid = aClientInfo.pid();
ChildProcessData* pd = pidToMinidump->GetEntry(pid);
MOZ_ASSERT(pd);
if (!pd->minidumpOnly) {
@ -3446,16 +3481,6 @@ void UnregisterInjectorCallback(DWORD processID) {
#endif // MOZ_CRASHREPORTER_INJECTOR
#if !defined(XP_WIN)
int GetAnnotationTimeCrashFd() {
# if defined(MOZ_WIDGET_ANDROID)
return gChildCrashAnnotationReportFd;
# else
return 7;
# endif // defined(MOZ_WIDGET_ANDROID)
}
#endif
void RegisterChildCrashAnnotationFileDescriptor(ProcessId aProcess,
PRFileDesc* aFd) {
StaticMutexAutoLock pidMapLock(processMapLock);
@ -3498,9 +3523,10 @@ bool SetRemoteExceptionHandler(const char* aCrashPipe,
InitializeAnnotationFacilities();
#if defined(XP_WIN)
gChildCrashAnnotationReportFd = (FileHandle)aCrashTimeAnnotationFile;
gExceptionHandler = new google_breakpad::ExceptionHandler(
L"", ChildFPEFilter, ChildMinidumpCallback,
reinterpret_cast<void*>(aCrashTimeAnnotationFile),
nullptr, // no callback context
google_breakpad::ExceptionHandler::HANDLER_ALL, GetMinidumpType(),
NS_ConvertASCIItoUTF16(aCrashPipe).get(), nullptr);
gExceptionHandler->set_handle_debug_exceptions(true);
@ -3600,7 +3626,7 @@ bool FinalizeOrphanedMinidump(uint32_t aChildPid, GeckoProcessType aType,
}
//-----------------------------------------------------------------------------
// CreatePairedMinidumps() and helpers
// CreateMinidumpsAndPair() and helpers
//
/*
@ -3735,7 +3761,7 @@ bool TakeMinidump(nsIFile** aResult, bool aMoveToPending) {
return true;
}
bool CreateMinidumpsAndPair(ProcessHandle aTargetPid,
bool CreateMinidumpsAndPair(ProcessHandle aTargetHandle,
ThreadId aTargetBlamedThread,
const nsACString& aIncomingPairName,
nsIFile* aIncomingDumpToPair,
@ -3748,7 +3774,7 @@ bool CreateMinidumpsAndPair(ProcessHandle aTargetPid,
AutoIOInterposerDisable disableIOInterposition;
#ifdef XP_MACOSX
mach_port_t targetThread = GetChildThread(aTargetPid, aTargetBlamedThread);
mach_port_t targetThread = GetChildThread(aTargetHandle, aTargetBlamedThread);
#else
ThreadId targetThread = aTargetBlamedThread;
#endif
@ -3763,7 +3789,7 @@ bool CreateMinidumpsAndPair(ProcessHandle aTargetPid,
// dump the target
nsCOMPtr<nsIFile> targetMinidump;
if (!google_breakpad::ExceptionHandler::WriteMinidumpForChild(
aTargetPid, targetThread, dump_path, PairedDumpCallback,
aTargetHandle, targetThread, dump_path, PairedDumpCallback,
static_cast<void*>(&targetMinidump)
#ifdef XP_WIN
,
@ -3804,8 +3830,11 @@ bool CreateMinidumpsAndPair(ProcessHandle aTargetPid,
DllBlocklist_Shutdown();
#endif
MergeContentCrashAnnotations(aTargetAnnotations);
AddCommonAnnotations(aTargetAnnotations);
PopulateContentProcessAnnotations(aTargetAnnotations);
if (FlushContentProcessAnnotations(aTargetHandle)) {
ProcessId targetPid = base::GetProcId(aTargetHandle);
ReadExceptionTimeAnnotations(aTargetAnnotations, targetPid);
}
targetMinidump.forget(aMainDumpOut);

5
toolkit/crashreporter/nsExceptionHandler.h
View File

@ -210,20 +210,23 @@ typedef HANDLE ProcessHandle;
typedef DWORD ProcessId;
typedef DWORD ThreadId;
typedef HANDLE FileHandle;
const FileHandle kInvalidFileHandle = INVALID_HANDLE_VALUE;
#elif defined(XP_MACOSX)
typedef task_t ProcessHandle;
typedef pid_t ProcessId;
typedef mach_port_t ThreadId;
typedef int FileHandle;
const FileHandle kInvalidFileHandle = -1;
#else
typedef int ProcessHandle;
typedef pid_t ProcessId;
typedef int ThreadId;
typedef int FileHandle;
const FileHandle kInvalidFileHandle = -1;
#endif
#if !defined(XP_WIN)
int GetAnnotationTimeCrashFd();
FileHandle GetAnnotationTimeCrashFd();
#endif
void RegisterChildCrashAnnotationFileDescriptor(ProcessId aProcess,
PRFileDesc* aFd);