Adding upstream version 124.0.1.upstream/124.0.1

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

3 files changed, 1153 insertions, 0 deletions

diff --git a/toolkit/crashreporter/breakpad-client/linux/microdump_writer/microdump_writer.cc b/toolkit/crashreporter/breakpad-client/linux/microdump_writer/microdump_writer.cc
new file mode 100644
index 0000000000..8f25b7be02
--- /dev/null
+++ b/toolkit/crashreporter/breakpad-client/linux/microdump_writer/microdump_writer.cc
@@ -0,0 +1,664 @@
+// Copyright (c) 2014, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// This translation unit generates microdumps into the console (logcat on
+// Android). See crbug.com/410294 for more info and design docs.
+
+#include "linux/microdump_writer/microdump_writer.h"
+
+#include <limits>
+
+#include <sys/utsname.h>
+
+#include "linux/dump_writer_common/thread_info.h"
+#include "linux/dump_writer_common/ucontext_reader.h"
+#include "linux/handler/exception_handler.h"
+#include "linux/handler/microdump_extra_info.h"
+#include "linux/log/log.h"
+#include "linux/minidump_writer/linux_ptrace_dumper.h"
+#include "common/linux/file_id.h"
+#include "common/linux/linux_libc_support.h"
+#include "common/memory_allocator.h"
+
+namespace {
+
+using google_breakpad::auto_wasteful_vector;
+using google_breakpad::ExceptionHandler;
+using google_breakpad::kDefaultBuildIdSize;
+using google_breakpad::LinuxDumper;
+using google_breakpad::LinuxPtraceDumper;
+using google_breakpad::MappingInfo;
+using google_breakpad::MappingList;
+using google_breakpad::MicrodumpExtraInfo;
+using google_breakpad::RawContextCPU;
+using google_breakpad::ThreadInfo;
+using google_breakpad::UContextReader;
+
+const size_t kLineBufferSize = 2048;
+
+#if !defined(__LP64__)
+// The following are only used by DumpFreeSpace, so need to be compiled
+// in conditionally in the same way.
+
+template <typename Dst, typename Src>
+Dst saturated_cast(Src src) {
+  if (src >= std::numeric_limits<Dst>::max())
+    return std::numeric_limits<Dst>::max();
+  if (src <= std::numeric_limits<Dst>::min())
+    return std::numeric_limits<Dst>::min();
+  return static_cast<Dst>(src);
+}
+
+int Log2Floor(uint64_t n) {
+  // Copied from chromium src/base/bits.h
+  if (n == 0)
+    return -1;
+  int log = 0;
+  uint64_t value = n;
+  for (int i = 5; i >= 0; --i) {
+    int shift = (1 << i);
+    uint64_t x = value >> shift;
+    if (x != 0) {
+      value = x;
+      log += shift;
+    }
+  }
+  assert(value == 1u);
+  return log;
+}
+
+bool MappingsAreAdjacent(const MappingInfo& a, const MappingInfo& b) {
+  // Because of load biasing, we can end up with a situation where two
+  // mappings actually overlap. So we will define adjacency to also include a
+  // b start address that lies within a's address range (including starting
+  // immediately after a).
+  // Because load biasing only ever moves the start address backwards, the end
+  // address should still increase.
+  return a.start_addr <= b.start_addr && a.start_addr + a.size >= b.start_addr;
+}
+
+bool MappingLessThan(const MappingInfo* a, const MappingInfo* b) {
+  // Return true if mapping a is before mapping b.
+  // For the same reason (load biasing) we compare end addresses, which - unlike
+  // start addresses - will not have been modified.
+  return a->start_addr + a->size < b->start_addr + b->size;
+}
+
+size_t NextOrderedMapping(
+    const google_breakpad::wasteful_vector<MappingInfo*>& mappings,
+    size_t curr) {
+  // Find the mapping that directly follows mappings[curr].
+  // If no such mapping exists, return |invalid| to indicate this.
+  const size_t invalid = std::numeric_limits<size_t>::max();
+  size_t best = invalid;
+  for (size_t next = 0; next < mappings.size(); ++next) {
+    if (MappingLessThan(mappings[curr], mappings[next]) &&
+        (best == invalid || MappingLessThan(mappings[next], mappings[best]))) {
+      best = next;
+    }
+  }
+  return best;
+}
+
+#endif  // !__LP64__
+
+class MicrodumpWriter {
+ public:
+  MicrodumpWriter(const ExceptionHandler::CrashContext* context,
+                  const MappingList& mappings,
+                  bool skip_dump_if_principal_mapping_not_referenced,
+                  uintptr_t address_within_principal_mapping,
+                  bool sanitize_stack,
+                  const MicrodumpExtraInfo& microdump_extra_info,
+                  LinuxDumper* dumper)
+      : ucontext_(context ? &context->context : NULL),
+#if !defined(__ARM_EABI__) && !defined(__mips__)
+        float_state_(context ? &context->float_state : NULL),
+#endif
+        dumper_(dumper),
+        mapping_list_(mappings),
+        skip_dump_if_principal_mapping_not_referenced_(
+            skip_dump_if_principal_mapping_not_referenced),
+        address_within_principal_mapping_(address_within_principal_mapping),
+        sanitize_stack_(sanitize_stack),
+        microdump_extra_info_(microdump_extra_info),
+        log_line_(NULL),
+        stack_copy_(NULL),
+        stack_len_(0),
+        stack_lower_bound_(0),
+        stack_pointer_(0) {
+    log_line_ = reinterpret_cast<char*>(Alloc(kLineBufferSize));
+    if (log_line_)
+      log_line_[0] = '\0';  // Clear out the log line buffer.
+  }
+
+  ~MicrodumpWriter() { dumper_->ThreadsResume(); }
+
+  bool Init() {
+    // In the exceptional case where the system was out of memory and there
+    // wasn't even room to allocate the line buffer, bail out. There is nothing
+    // useful we can possibly achieve without the ability to Log. At least let's
+    // try to not crash.
+    if (!dumper_->Init() || !log_line_)
+      return false;
+    return dumper_->ThreadsSuspend() && dumper_->LateInit();
+  }
+
+  void Dump() {
+    CaptureResult stack_capture_result = CaptureCrashingThreadStack(-1);
+    if (stack_capture_result == CAPTURE_UNINTERESTING) {
+      LogLine("Microdump skipped (uninteresting)");
+      return;
+    }
+
+    LogLine("-----BEGIN BREAKPAD MICRODUMP-----");
+    DumpProductInformation();
+    DumpOSInformation();
+    DumpProcessType();
+    DumpCrashReason();
+    DumpGPUInformation();
+#if !defined(__LP64__)
+    DumpFreeSpace();
+#endif
+    if (stack_capture_result == CAPTURE_OK)
+      DumpThreadStack();
+    DumpCPUState();
+    DumpMappings();
+    LogLine("-----END BREAKPAD MICRODUMP-----");
+  }
+
+ private:
+  enum CaptureResult { CAPTURE_OK, CAPTURE_FAILED, CAPTURE_UNINTERESTING };
+
+  // Writes one line to the system log.
+  void LogLine(const char* msg) {
+#if defined(__ANDROID__)
+    logger::writeToCrashLog(msg);
+#else
+    logger::write(msg, my_strlen(msg));
+    logger::write("\n", 1);
+#endif
+  }
+
+  // Stages the given string in the current line buffer.
+  void LogAppend(const char* str) {
+    my_strlcat(log_line_, str, kLineBufferSize);
+  }
+
+  // As above (required to take precedence over template specialization below).
+  void LogAppend(char* str) {
+    LogAppend(const_cast<const char*>(str));
+  }
+
+  // Stages the hex repr. of the given int type in the current line buffer.
+  template<typename T>
+  void LogAppend(T value) {
+    // Make enough room to hex encode the largest int type + NUL.
+    static const char HEX[] = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
+                               'A', 'B', 'C', 'D', 'E', 'F'};
+    char hexstr[sizeof(T) * 2 + 1];
+    for (int i = sizeof(T) * 2 - 1; i >= 0; --i, value >>= 4)
+      hexstr[i] = HEX[static_cast<uint8_t>(value) & 0x0F];
+    hexstr[sizeof(T) * 2] = '\0';
+    LogAppend(hexstr);
+  }
+
+  // Stages the buffer content hex-encoded in the current line buffer.
+  void LogAppend(const void* buf, size_t length) {
+    const uint8_t* ptr = reinterpret_cast<const uint8_t*>(buf);
+    for (size_t i = 0; i < length; ++i, ++ptr)
+      LogAppend(*ptr);
+  }
+
+  // Writes out the current line buffer on the system log.
+  void LogCommitLine() {
+    LogLine(log_line_);
+    log_line_[0] = 0;
+  }
+
+  CaptureResult CaptureCrashingThreadStack(int max_stack_len) {
+    stack_pointer_ = UContextReader::GetStackPointer(ucontext_);
+
+    if (!dumper_->GetStackInfo(reinterpret_cast<const void**>(&stack_lower_bound_),
+                               &stack_len_, stack_pointer_)) {
+      return CAPTURE_FAILED;
+    }
+
+    if (max_stack_len >= 0 &&
+        stack_len_ > static_cast<size_t>(max_stack_len)) {
+      stack_len_ = max_stack_len;
+    }
+
+    stack_copy_ = reinterpret_cast<uint8_t*>(Alloc(stack_len_));
+    dumper_->CopyFromProcess(stack_copy_, dumper_->crash_thread(),
+                             reinterpret_cast<const void*>(stack_lower_bound_),
+                             stack_len_);
+
+    if (!skip_dump_if_principal_mapping_not_referenced_) return CAPTURE_OK;
+
+    const MappingInfo* principal_mapping =
+        dumper_->FindMappingNoBias(address_within_principal_mapping_);
+    if (!principal_mapping) return CAPTURE_UNINTERESTING;
+
+    uintptr_t low_addr = principal_mapping->system_mapping_info.start_addr;
+    uintptr_t high_addr = principal_mapping->system_mapping_info.end_addr;
+    uintptr_t pc = UContextReader::GetInstructionPointer(ucontext_);
+    if (low_addr <= pc && pc <= high_addr) return CAPTURE_OK;
+
+    if (dumper_->StackHasPointerToMapping(stack_copy_, stack_len_,
+                                          stack_pointer_ - stack_lower_bound_,
+                                          *principal_mapping)) {
+      return CAPTURE_OK;
+    }
+    return CAPTURE_UNINTERESTING;
+  }
+
+  void DumpProductInformation() {
+    LogAppend("V ");
+    if (microdump_extra_info_.product_info) {
+      LogAppend(microdump_extra_info_.product_info);
+    } else {
+      LogAppend("UNKNOWN:0.0.0.0");
+    }
+    LogCommitLine();
+  }
+
+  void DumpProcessType() {
+    LogAppend("P ");
+    if (microdump_extra_info_.process_type) {
+      LogAppend(microdump_extra_info_.process_type);
+    } else {
+      LogAppend("UNKNOWN");
+    }
+    LogCommitLine();
+  }
+
+  void DumpCrashReason() {
+    LogAppend("R ");
+    LogAppend(dumper_->crash_signal());
+    LogAppend(" ");
+    LogAppend(dumper_->GetCrashSignalString());
+    LogAppend(" ");
+    LogAppend(dumper_->crash_address());
+    LogCommitLine();
+  }
+
+  void DumpOSInformation() {
+    const uint8_t n_cpus = static_cast<uint8_t>(sysconf(_SC_NPROCESSORS_CONF));
+
+#if defined(__ANDROID__)
+    const char kOSId[] = "A";
+#else
+    const char kOSId[] = "L";
+#endif
+
+// Dump the runtime architecture. On multiarch devices it might not match the
+// hw architecture (the one returned by uname()), for instance in the case of
+// a 32-bit app running on a aarch64 device.
+#if defined(__aarch64__)
+    const char kArch[] = "arm64";
+#elif defined(__ARMEL__)
+    const char kArch[] = "arm";
+#elif defined(__x86_64__)
+    const char kArch[] = "x86_64";
+#elif defined(__i386__)
+    const char kArch[] = "x86";
+#elif defined(__mips__)
+# if _MIPS_SIM == _ABIO32
+    const char kArch[] = "mips";
+# elif _MIPS_SIM == _ABI64
+    const char kArch[] = "mips64";
+# else
+#  error "This mips ABI is currently not supported (n32)"
+#endif
+#else
+#error "This code has not been ported to your platform yet"
+#endif
+
+    LogAppend("O ");
+    LogAppend(kOSId);
+    LogAppend(" ");
+    LogAppend(kArch);
+    LogAppend(" ");
+    LogAppend(n_cpus);
+    LogAppend(" ");
+
+    // Dump the HW architecture (e.g., armv7l, aarch64).
+    struct utsname uts;
+    const bool has_uts_info = (uname(&uts) == 0);
+    const char* hwArch = has_uts_info ? uts.machine : "unknown_hw_arch";
+    LogAppend(hwArch);
+    LogAppend(" ");
+
+    // If the client has attached a build fingerprint to the MinidumpDescriptor
+    // use that one. Otherwise try to get some basic info from uname().
+    if (microdump_extra_info_.build_fingerprint) {
+      LogAppend(microdump_extra_info_.build_fingerprint);
+    } else if (has_uts_info) {
+      LogAppend(uts.release);
+      LogAppend(" ");
+      LogAppend(uts.version);
+    } else {
+      LogAppend("no build fingerprint available");
+    }
+    LogCommitLine();
+  }
+
+  void DumpGPUInformation() {
+    LogAppend("G ");
+    if (microdump_extra_info_.gpu_fingerprint) {
+      LogAppend(microdump_extra_info_.gpu_fingerprint);
+    } else {
+      LogAppend("UNKNOWN");
+    }
+    LogCommitLine();
+  }
+
+  void DumpThreadStack() {
+    if (sanitize_stack_) {
+      dumper_->SanitizeStackCopy(stack_copy_, stack_len_, stack_pointer_,
+                                 stack_pointer_ - stack_lower_bound_);
+    }
+
+    LogAppend("S 0 ");
+    LogAppend(stack_pointer_);
+    LogAppend(" ");
+    LogAppend(stack_lower_bound_);
+    LogAppend(" ");
+    LogAppend(stack_len_);
+    LogCommitLine();
+
+    const size_t STACK_DUMP_CHUNK_SIZE = 384;
+    for (size_t stack_off = 0; stack_off < stack_len_;
+         stack_off += STACK_DUMP_CHUNK_SIZE) {
+      LogAppend("S ");
+      LogAppend(stack_lower_bound_ + stack_off);
+      LogAppend(" ");
+      LogAppend(stack_copy_ + stack_off,
+                std::min(STACK_DUMP_CHUNK_SIZE, stack_len_ - stack_off));
+      LogCommitLine();
+    }
+  }
+
+  void DumpCPUState() {
+    RawContextCPU cpu;
+    my_memset(&cpu, 0, sizeof(RawContextCPU));
+#if !defined(__ARM_EABI__) && !defined(__mips__)
+    UContextReader::FillCPUContext(&cpu, ucontext_, float_state_);
+#else
+    UContextReader::FillCPUContext(&cpu, ucontext_);
+#endif
+    LogAppend("C ");
+    LogAppend(&cpu, sizeof(cpu));
+    LogCommitLine();
+  }
+
+  // If there is caller-provided information about this mapping
+  // in the mapping_list_ list, return true. Otherwise, return false.
+  bool HaveMappingInfo(const MappingInfo& mapping) {
+    for (MappingList::const_iterator iter = mapping_list_.begin();
+         iter != mapping_list_.end();
+         ++iter) {
+      // Ignore any mappings that are wholly contained within
+      // mappings in the mapping_info_ list.
+      if (mapping.start_addr >= iter->first.start_addr &&
+          (mapping.start_addr + mapping.size) <=
+              (iter->first.start_addr + iter->first.size)) {
+        return true;
+      }
+    }
+    return false;
+  }
+
+  // Dump information about the provided |mapping|. If |identifier| is non-NULL,
+  // use it instead of calculating a file ID from the mapping.
+  void DumpModule(const MappingInfo& mapping,
+                  bool member,
+                  unsigned int mapping_id,
+                  const std::vector<uint8_t>* identifier) {
+
+    auto_wasteful_vector<uint8_t, kDefaultBuildIdSize> identifier_bytes(
+        dumper_->allocator());
+
+    if (identifier) {
+      // GUID was provided by caller.
+      identifier_bytes.insert(identifier_bytes.end(),
+                              identifier->begin(),
+                              identifier->end());
+    } else {
+      dumper_->ElfFileIdentifierForMapping(
+          mapping,
+          member,
+          mapping_id,
+          identifier_bytes);
+    }
+
+    // Copy as many bytes of |identifier| as will fit into a MDGUID
+    MDGUID module_identifier = {0};
+    memcpy(&module_identifier, &identifier_bytes[0],
+           std::min(sizeof(MDGUID), identifier_bytes.size()));
+
+    char file_name[NAME_MAX];
+    char file_path[NAME_MAX];
+    dumper_->GetMappingEffectiveNameAndPath(
+        mapping, file_path, sizeof(file_path), file_name, sizeof(file_name));
+
+    LogAppend("M ");
+    LogAppend(static_cast<uintptr_t>(mapping.start_addr));
+    LogAppend(" ");
+    LogAppend(mapping.offset);
+    LogAppend(" ");
+    LogAppend(mapping.size);
+    LogAppend(" ");
+    LogAppend(module_identifier.data1);
+    LogAppend(module_identifier.data2);
+    LogAppend(module_identifier.data3);
+    LogAppend(module_identifier.data4[0]);
+    LogAppend(module_identifier.data4[1]);
+    LogAppend(module_identifier.data4[2]);
+    LogAppend(module_identifier.data4[3]);
+    LogAppend(module_identifier.data4[4]);
+    LogAppend(module_identifier.data4[5]);
+    LogAppend(module_identifier.data4[6]);
+    LogAppend(module_identifier.data4[7]);
+    LogAppend("0 ");  // Age is always 0 on Linux.
+    LogAppend(file_name);
+    LogCommitLine();
+  }
+
+#if !defined(__LP64__)
+  void DumpFreeSpace() {
+    const MappingInfo* stack_mapping = nullptr;
+    ThreadInfo info;
+    if (dumper_->GetThreadInfoByIndex(dumper_->GetMainThreadIndex(), &info)) {
+      stack_mapping = dumper_->FindMappingNoBias(info.stack_pointer);
+    }
+
+    const google_breakpad::wasteful_vector<MappingInfo*>& mappings =
+        dumper_->mappings();
+    if (mappings.size() == 0) return;
+
+    // This is complicated by the fact that mappings is not in order. It should
+    // be mostly in order, however the mapping that contains the entry point for
+    // the process is always at the front of the vector.
+
+    static const int HBITS = sizeof(size_t) * 8;
+    size_t hole_histogram[HBITS];
+    my_memset(hole_histogram, 0, sizeof(hole_histogram));
+
+    // Find the lowest address mapping.
+    size_t curr = 0;
+    for (size_t i = 1; i < mappings.size(); ++i) {
+      if (mappings[i]->start_addr < mappings[curr]->start_addr) curr = i;
+    }
+
+    uintptr_t lo_addr = mappings[curr]->start_addr;
+
+    size_t hole_cnt = 0;
+    size_t hole_max = 0;
+    size_t hole_sum = 0;
+
+    while (true) {
+      // Skip to the end of an adjacent run of mappings. This is an optimization
+      // for the fact that mappings is mostly sorted.
+      while (curr != mappings.size() - 1 &&
+             MappingsAreAdjacent(*mappings[curr], *mappings[curr + 1])) {
+        ++curr;
+      }
+
+      if (mappings[curr] == stack_mapping) {
+        // Because we can't determine the top of userspace mappable
+        // memory we treat the start of the process stack as the top
+        // of the allocatable address space. Once we reach
+        // |stack_mapping| we are done scanning for free space regions.
+        break;
+      }
+
+      size_t next = NextOrderedMapping(mappings, curr);
+      if (next == std::numeric_limits<size_t>::max())
+        break;
+
+      uintptr_t hole_lo = mappings[curr]->start_addr + mappings[curr]->size;
+      uintptr_t hole_hi = mappings[next]->start_addr;
+
+      if (hole_hi > hole_lo) {
+        size_t hole_sz = hole_hi - hole_lo;
+        hole_sum += hole_sz;
+        hole_max = std::max(hole_sz, hole_max);
+        ++hole_cnt;
+        ++hole_histogram[Log2Floor(hole_sz)];
+      }
+      curr = next;
+    }
+
+    uintptr_t hi_addr = mappings[curr]->start_addr + mappings[curr]->size;
+
+    LogAppend("H ");
+    LogAppend(lo_addr);
+    LogAppend(" ");
+    LogAppend(hi_addr);
+    LogAppend(" ");
+    LogAppend(saturated_cast<uint16_t>(hole_cnt));
+    LogAppend(" ");
+    LogAppend(hole_max);
+    LogAppend(" ");
+    LogAppend(hole_sum);
+    for (unsigned int i = 0; i < HBITS; ++i) {
+      if (!hole_histogram[i]) continue;
+      LogAppend(" ");
+      LogAppend(saturated_cast<uint8_t>(i));
+      LogAppend(":");
+      LogAppend(saturated_cast<uint8_t>(hole_histogram[i]));
+    }
+    LogCommitLine();
+  }
+#endif
+
+  // Write information about the mappings in effect.
+  void DumpMappings() {
+    // First write all the mappings from the dumper
+    for (unsigned i = 0; i < dumper_->mappings().size(); ++i) {
+      const MappingInfo& mapping = *dumper_->mappings()[i];
+      if (mapping.name[0] == 0 ||  // only want modules with filenames.
+          !mapping.exec ||  // only want executable mappings.
+          mapping.size < 4096 || // too small to get a signature for.
+          HaveMappingInfo(mapping)) {
+        continue;
+      }
+
+      DumpModule(mapping, true, i, NULL);
+    }
+    // Next write all the mappings provided by the caller
+    for (MappingList::const_iterator iter = mapping_list_.begin();
+         iter != mapping_list_.end();
+         ++iter) {
+      DumpModule(iter->first, false, 0, &iter->second);
+    }
+  }
+
+  void* Alloc(unsigned bytes) { return dumper_->allocator()->Alloc(bytes); }
+
+  const ucontext_t* const ucontext_;
+#if !defined(__ARM_EABI__) && !defined(__mips__)
+  const google_breakpad::fpstate_t* const float_state_;
+#endif
+  LinuxDumper* dumper_;
+  const MappingList& mapping_list_;
+  bool skip_dump_if_principal_mapping_not_referenced_;
+  uintptr_t address_within_principal_mapping_;
+  bool sanitize_stack_;
+  const MicrodumpExtraInfo microdump_extra_info_;
+  char* log_line_;
+
+  // The local copy of crashed process stack memory, beginning at
+  // |stack_lower_bound_|.
+  uint8_t* stack_copy_;
+
+  // The length of crashed process stack copy.
+  size_t stack_len_;
+
+  // The address of the page containing the stack pointer in the
+  // crashed process. |stack_lower_bound_| <= |stack_pointer_|
+  uintptr_t stack_lower_bound_;
+
+  // The stack pointer of the crashed thread.
+  uintptr_t stack_pointer_;
+};
+}  // namespace
+
+namespace google_breakpad {
+
+bool WriteMicrodump(pid_t crashing_process,
+                    const void* blob,
+                    size_t blob_size,
+                    const MappingList& mappings,
+                    bool skip_dump_if_principal_mapping_not_referenced,
+                    uintptr_t address_within_principal_mapping,
+                    bool sanitize_stack,
+                    const MicrodumpExtraInfo& microdump_extra_info) {
+  LinuxPtraceDumper dumper(crashing_process);
+  const ExceptionHandler::CrashContext* context = NULL;
+  if (blob) {
+    if (blob_size != sizeof(ExceptionHandler::CrashContext))
+      return false;
+    context = reinterpret_cast<const ExceptionHandler::CrashContext*>(blob);
+    dumper.SetCrashInfoFromSigInfo(context->siginfo);
+    dumper.set_crash_thread(context->tid);
+  }
+  MicrodumpWriter writer(context, mappings,
+                         skip_dump_if_principal_mapping_not_referenced,
+                         address_within_principal_mapping, sanitize_stack,
+                         microdump_extra_info, &dumper);
+  if (!writer.Init())
+    return false;
+  writer.Dump();
+  return true;
+}
+
+}  // namespace google_breakpad
diff --git a/toolkit/crashreporter/breakpad-client/linux/microdump_writer/microdump_writer.h b/toolkit/crashreporter/breakpad-client/linux/microdump_writer/microdump_writer.h
new file mode 100644
index 0000000000..63b5463247
--- /dev/null
+++ b/toolkit/crashreporter/breakpad-client/linux/microdump_writer/microdump_writer.h
@@ -0,0 +1,68 @@
+// Copyright (c) 2014, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#ifndef CLIENT_LINUX_MINIDUMP_WRITER_MICRODUMP_WRITER_H_
+#define CLIENT_LINUX_MINIDUMP_WRITER_MICRODUMP_WRITER_H_
+
+#include <stdint.h>
+#include <sys/types.h>
+
+#include "linux/dump_writer_common/mapping_info.h"
+
+namespace google_breakpad {
+
+struct MicrodumpExtraInfo;
+
+// Writes a microdump (a reduced dump containing only the state of the crashing
+// thread) on the console (logcat on Android). These functions do not malloc nor
+// use libc functions which may. Thus, it can be used in contexts where the
+// state of the heap may be corrupt.
+// Args:
+//   crashing_process: the pid of the crashing process. This must be trusted.
+//   blob: a blob of data from the crashing process. See exception_handler.h
+//   blob_size: the length of |blob| in bytes.
+//   mappings: a list of additional mappings provided by the application.
+//   build_fingerprint: a (optional) C string which determines the OS
+//     build fingerprint (e.g., aosp/occam/mako:5.1.1/LMY47W/1234:eng/dev-keys).
+//   product_info: a (optional) C string which determines the product name and
+//     version (e.g., WebView:42.0.2311.136).
+//
+// Returns true iff successful.
+bool WriteMicrodump(pid_t crashing_process,
+                    const void* blob,
+                    size_t blob_size,
+                    const MappingList& mappings,
+                    bool skip_dump_if_main_module_not_referenced,
+                    uintptr_t address_within_main_module,
+                    bool sanitize_stack,
+                    const MicrodumpExtraInfo& microdump_extra_info);
+
+}  // namespace google_breakpad
+
+#endif  // CLIENT_LINUX_MINIDUMP_WRITER_MICRODUMP_WRITER_H_
diff --git a/toolkit/crashreporter/breakpad-client/linux/microdump_writer/microdump_writer_unittest.cc b/toolkit/crashreporter/breakpad-client/linux/microdump_writer/microdump_writer_unittest.cc
new file mode 100644
index 0000000000..6b7fb5f6ac
--- /dev/null
+++ b/toolkit/crashreporter/breakpad-client/linux/microdump_writer/microdump_writer_unittest.cc
@@ -0,0 +1,421 @@
+// Copyright (c) 2014 Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include <ctype.h>
+#include <sys/syscall.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <ucontext.h>
+
+#include <sstream>
+#include <string>
+
+#include "breakpad_googletest_includes.h"
+#include "linux/handler/exception_handler.h"
+#include "linux/handler/microdump_extra_info.h"
+#include "linux/microdump_writer/microdump_writer.h"
+#include "common/linux/breakpad_getcontext.h"
+#include "common/linux/eintr_wrapper.h"
+#include "common/linux/ignore_ret.h"
+#include "common/scoped_ptr.h"
+#include "common/tests/auto_tempdir.h"
+#include "common/using_std_string.h"
+
+using namespace google_breakpad;
+
+extern "C" {
+extern char __executable_start;
+extern char __etext;
+}
+
+namespace {
+
+typedef testing::Test MicrodumpWriterTest;
+
+MicrodumpExtraInfo MakeMicrodumpExtraInfo(
+    const char* build_fingerprint,
+    const char* product_info,
+    const char* gpu_fingerprint) {
+  MicrodumpExtraInfo info;
+  info.build_fingerprint = build_fingerprint;
+  info.product_info = product_info;
+  info.gpu_fingerprint = gpu_fingerprint;
+  info.process_type = "Browser";
+  return info;
+}
+
+bool ContainsMicrodump(const std::string& buf) {
+  return std::string::npos != buf.find("-----BEGIN BREAKPAD MICRODUMP-----") &&
+         std::string::npos != buf.find("-----END BREAKPAD MICRODUMP-----");
+}
+
+const char kIdentifiableString[] = "_IDENTIFIABLE_";
+const uintptr_t kCrashAddress = 0xdeaddeadu;
+
+void CrashAndGetMicrodump(const MappingList& mappings,
+                          const MicrodumpExtraInfo& microdump_extra_info,
+                          std::string* microdump,
+                          bool skip_dump_if_principal_mapping_not_referenced = false,
+                          uintptr_t address_within_principal_mapping = 0,
+                          bool sanitize_stack = false) {
+  int fds[2];
+  ASSERT_NE(-1, pipe(fds));
+
+  AutoTempDir temp_dir;
+  string stderr_file = temp_dir.path() + "/stderr.log";
+  int err_fd = open(stderr_file.c_str(), O_CREAT | O_RDWR, S_IRUSR | S_IWUSR);
+  ASSERT_NE(-1, err_fd);
+
+  char identifiable_string[sizeof(kIdentifiableString)];
+
+  // This string should not appear in the resulting microdump if it
+  // has been sanitized.
+  strcpy(identifiable_string, kIdentifiableString);
+  // Force the strcpy to not be optimized away.
+  IGNORE_RET(write(STDOUT_FILENO, identifiable_string, 0));
+
+  const pid_t child = fork();
+  if (child == 0) {
+    close(fds[1]);
+    char b;
+    IGNORE_RET(HANDLE_EINTR(read(fds[0], &b, sizeof(b))));
+    close(fds[0]);
+    syscall(__NR_exit);
+  }
+  close(fds[0]);
+
+  ExceptionHandler::CrashContext context;
+  memset(&context, 0, sizeof(context));
+  // Pretend the current context is the child context (which is
+  // approximately right) so that we have a valid stack pointer, and
+  // can fetch child stack data via ptrace.
+  getcontext(&context.context);
+  // Set a non-zero tid to avoid tripping asserts.
+  context.tid = child;
+  context.siginfo.si_signo = MD_EXCEPTION_CODE_LIN_DUMP_REQUESTED;
+  context.siginfo.si_addr = reinterpret_cast<void*>(kCrashAddress);
+
+  // Redirect temporarily stderr to the stderr.log file.
+  int save_err = dup(STDERR_FILENO);
+  ASSERT_NE(-1, save_err);
+  ASSERT_NE(-1, dup2(err_fd, STDERR_FILENO));
+
+  ASSERT_TRUE(WriteMicrodump(child, &context, sizeof(context), mappings,
+                             skip_dump_if_principal_mapping_not_referenced,
+                             address_within_principal_mapping, sanitize_stack,
+                             microdump_extra_info));
+
+  // Revert stderr back to the console.
+  dup2(save_err, STDERR_FILENO);
+  close(save_err);
+
+  // Read back the stderr file and check for the microdump marker.
+  fsync(err_fd);
+  lseek(err_fd, 0, SEEK_SET);
+
+  microdump->clear();
+  char buf[1024];
+
+  while (true) {
+    int bytes_read = IGNORE_EINTR(read(err_fd, buf, 1024));
+    if (bytes_read <= 0) break;
+    microdump->append(buf, buf + bytes_read);
+  }
+  close(err_fd);
+  close(fds[1]);
+}
+
+void ExtractMicrodumpStackContents(const string& microdump_content,
+                                   string* result) {
+  std::istringstream iss(microdump_content);
+  result->clear();
+  for (string line; std::getline(iss, line);) {
+    if (line.find("S ") == 0) {
+      std::istringstream stack_data(line);
+      std::string key;
+      std::string addr;
+      std::string data;
+      stack_data >> key >> addr >> data;
+      EXPECT_TRUE((data.size() & 1u) == 0u);
+      result->reserve(result->size() + data.size() / 2);
+      for (size_t i = 0; i < data.size(); i += 2) {
+        std::string byte = data.substr(i, 2);
+        result->push_back(static_cast<char>(strtoul(byte.c_str(), NULL, 16)));
+      }
+    }
+  }
+}
+
+void CheckMicrodumpContents(const string& microdump_content,
+                            const MicrodumpExtraInfo& expected_info) {
+  std::istringstream iss(microdump_content);
+  bool did_find_os_info = false;
+  bool did_find_product_info = false;
+  bool did_find_process_type = false;
+  bool did_find_crash_reason = false;
+  bool did_find_gpu_info = false;
+  for (string line; std::getline(iss, line);) {
+    if (line.find("O ") == 0) {
+      std::istringstream os_info_tokens(line);
+      string token;
+      os_info_tokens.ignore(2); // Ignore the "O " preamble.
+      // Check the OS descriptor char (L=Linux, A=Android).
+      os_info_tokens >> token;
+      ASSERT_TRUE(token == "L" || token == "A");
+
+      os_info_tokens >> token; // HW architecture.
+      os_info_tokens >> token; // Number of cpus.
+      for (size_t i = 0; i < token.size(); ++i)
+        ASSERT_TRUE(isxdigit(token[i]));
+      os_info_tokens >> token; // SW architecture.
+
+      // Check that the build fingerprint is in the right place.
+      os_info_tokens >> token;
+      ASSERT_FALSE(os_info_tokens.fail());
+      if (expected_info.build_fingerprint)
+        ASSERT_EQ(expected_info.build_fingerprint, token);
+      did_find_os_info = true;
+    } else if (line.find("P ") == 0) {
+      if (expected_info.process_type)
+        ASSERT_EQ(string("P ") + expected_info.process_type, line);
+      did_find_process_type = true;
+    } else if (line.find("R ") == 0) {
+      std::istringstream crash_reason_tokens(line);
+      string token;
+      unsigned crash_reason;
+      string crash_reason_str;
+      uintptr_t crash_address;
+      crash_reason_tokens.ignore(2); // Ignore the "R " preamble.
+      crash_reason_tokens >> std::hex >> crash_reason >> crash_reason_str >>
+          crash_address;
+      ASSERT_FALSE(crash_reason_tokens.fail());
+      ASSERT_EQ(MD_EXCEPTION_CODE_LIN_DUMP_REQUESTED, crash_reason);
+      ASSERT_EQ("DUMP_REQUESTED", crash_reason_str);
+      ASSERT_EQ(kCrashAddress, crash_address);
+      did_find_crash_reason = true;
+    } else if (line.find("V ") == 0) {
+      if (expected_info.product_info)
+        ASSERT_EQ(string("V ") + expected_info.product_info, line);
+      did_find_product_info = true;
+    } else if (line.find("G ") == 0) {
+      if (expected_info.gpu_fingerprint)
+        ASSERT_EQ(string("G ") + expected_info.gpu_fingerprint, line);
+      did_find_gpu_info = true;
+    }
+  }
+  ASSERT_TRUE(did_find_os_info);
+  ASSERT_TRUE(did_find_product_info);
+  ASSERT_TRUE(did_find_process_type);
+  ASSERT_TRUE(did_find_crash_reason);
+  ASSERT_TRUE(did_find_gpu_info);
+}
+
+bool MicrodumpStackContains(const string& microdump_content,
+                            const string& expected_content) {
+  string result;
+  ExtractMicrodumpStackContents(microdump_content, &result);
+  return result.find(kIdentifiableString) != string::npos;
+}
+
+void CheckMicrodumpContents(const string& microdump_content,
+                            const string& expected_fingerprint,
+                            const string& expected_product_info,
+                            const string& expected_gpu_fingerprint) {
+  CheckMicrodumpContents(
+      microdump_content,
+      MakeMicrodumpExtraInfo(expected_fingerprint.c_str(),
+                             expected_product_info.c_str(),
+                             expected_gpu_fingerprint.c_str()));
+}
+
+TEST(MicrodumpWriterTest, BasicWithMappings) {
+  // Push some extra mapping to check the MappingList logic.
+  const uint32_t memory_size = sysconf(_SC_PAGESIZE);
+  const char* kMemoryName = "libfoo.so";
+  const uint8_t kModuleGUID[sizeof(MDGUID)] = {
+     0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77,
+     0x88, 0x99, 0xAA, 0xBB, 0xCC, 0xDD, 0xEE, 0xFF
+  };
+
+  MappingInfo info;
+  info.start_addr = memory_size;
+  info.size = memory_size;
+  info.offset = 42;
+  strcpy(info.name, kMemoryName);
+
+  MappingList mappings;
+  MappingEntry mapping;
+  mapping.first = info;
+  mapping.second.assign(std::begin(kModuleGUID), std::end(kModuleGUID));
+  mappings.push_back(mapping);
+
+  std::string buf;
+  CrashAndGetMicrodump(mappings, MicrodumpExtraInfo(), &buf);
+  ASSERT_TRUE(ContainsMicrodump(buf));
+
+#ifdef __LP64__
+  ASSERT_NE(std::string::npos,
+            buf.find("M 0000000000001000 000000000000002A 0000000000001000 "
+                     "33221100554477668899AABBCCDDEEFF0 libfoo.so"));
+#else
+  ASSERT_NE(std::string::npos,
+            buf.find("M 00001000 0000002A 00001000 "
+                     "33221100554477668899AABBCCDDEEFF0 libfoo.so"));
+#endif
+
+  // In absence of a product info in the minidump, the writer should just write
+  // an unknown marker.
+  ASSERT_NE(std::string::npos, buf.find("V UNKNOWN:0.0.0.0"));
+}
+
+// Ensure that no output occurs if the interest region is set, but
+// doesn't overlap anything on the stack.
+TEST(MicrodumpWriterTest, NoOutputIfUninteresting) {
+  const char kProductInfo[] = "MockProduct:42.0.2311.99";
+  const char kBuildFingerprint[] =
+      "aosp/occam/mako:5.1.1/LMY47W/12345678:userdegbug/dev-keys";
+  const char kGPUFingerprint[] =
+      "Qualcomm;Adreno (TM) 330;OpenGL ES 3.0 V@104.0 AU@  (GIT@Id3510ff6dc)";
+  const MicrodumpExtraInfo kMicrodumpExtraInfo(
+      MakeMicrodumpExtraInfo(kBuildFingerprint, kProductInfo, kGPUFingerprint));
+
+  std::string buf;
+  MappingList no_mappings;
+
+  CrashAndGetMicrodump(no_mappings, kMicrodumpExtraInfo, &buf, true, 0);
+  ASSERT_FALSE(ContainsMicrodump(buf));
+}
+
+// Ensure that stack content does not contain an identifiable string if the
+// stack is sanitized.
+TEST(MicrodumpWriterTest, StringRemovedBySanitization) {
+  const char kProductInfo[] = "MockProduct:42.0.2311.99";
+  const char kBuildFingerprint[] =
+      "aosp/occam/mako:5.1.1/LMY47W/12345678:userdegbug/dev-keys";
+  const char kGPUFingerprint[] =
+      "Qualcomm;Adreno (TM) 330;OpenGL ES 3.0 V@104.0 AU@  (GIT@Id3510ff6dc)";
+
+  const MicrodumpExtraInfo kMicrodumpExtraInfo(
+      MakeMicrodumpExtraInfo(kBuildFingerprint, kProductInfo, kGPUFingerprint));
+
+  std::string buf;
+  MappingList no_mappings;
+
+  CrashAndGetMicrodump(no_mappings, kMicrodumpExtraInfo, &buf, false, 0u, true);
+  ASSERT_TRUE(ContainsMicrodump(buf));
+  ASSERT_FALSE(MicrodumpStackContains(buf, kIdentifiableString));
+}
+
+// Ensure that stack content does contain an identifiable string if the
+// stack is not sanitized.
+TEST(MicrodumpWriterTest, StringPresentIfNotSanitized) {
+  const char kProductInfo[] = "MockProduct:42.0.2311.99";
+  const char kBuildFingerprint[] =
+      "aosp/occam/mako:5.1.1/LMY47W/12345678:userdegbug/dev-keys";
+  const char kGPUFingerprint[] =
+      "Qualcomm;Adreno (TM) 330;OpenGL ES 3.0 V@104.0 AU@  (GIT@Id3510ff6dc)";
+
+  const MicrodumpExtraInfo kMicrodumpExtraInfo(
+      MakeMicrodumpExtraInfo(kBuildFingerprint, kProductInfo, kGPUFingerprint));
+
+  std::string buf;
+  MappingList no_mappings;
+
+  CrashAndGetMicrodump(no_mappings, kMicrodumpExtraInfo, &buf, false, 0u, false);
+  ASSERT_TRUE(ContainsMicrodump(buf));
+  ASSERT_TRUE(MicrodumpStackContains(buf, kIdentifiableString));
+}
+
+// Ensure that output occurs if the interest region is set, and
+// does overlap something on the stack.
+TEST(MicrodumpWriterTest, OutputIfInteresting) {
+  const char kProductInfo[] = "MockProduct:42.0.2311.99";
+  const char kBuildFingerprint[] =
+      "aosp/occam/mako:5.1.1/LMY47W/12345678:userdegbug/dev-keys";
+  const char kGPUFingerprint[] =
+      "Qualcomm;Adreno (TM) 330;OpenGL ES 3.0 V@104.0 AU@  (GIT@Id3510ff6dc)";
+
+  const MicrodumpExtraInfo kMicrodumpExtraInfo(
+      MakeMicrodumpExtraInfo(kBuildFingerprint, kProductInfo, kGPUFingerprint));
+
+  std::string buf;
+  MappingList no_mappings;
+
+  CrashAndGetMicrodump(no_mappings, kMicrodumpExtraInfo, &buf, true,
+                       reinterpret_cast<uintptr_t>(CrashAndGetMicrodump));
+  ASSERT_TRUE(ContainsMicrodump(buf));
+}
+
+// Ensure that the product info and build fingerprint metadata show up in the
+// final microdump if present.
+TEST(MicrodumpWriterTest, BuildFingerprintAndProductInfo) {
+  const char kProductInfo[] = "MockProduct:42.0.2311.99";
+  const char kBuildFingerprint[] =
+      "aosp/occam/mako:5.1.1/LMY47W/12345678:userdegbug/dev-keys";
+  const char kGPUFingerprint[] =
+      "Qualcomm;Adreno (TM) 330;OpenGL ES 3.0 V@104.0 AU@  (GIT@Id3510ff6dc)";
+  const MicrodumpExtraInfo kMicrodumpExtraInfo(
+      MakeMicrodumpExtraInfo(kBuildFingerprint, kProductInfo, kGPUFingerprint));
+  std::string buf;
+  MappingList no_mappings;
+
+  CrashAndGetMicrodump(no_mappings, kMicrodumpExtraInfo, &buf);
+  ASSERT_TRUE(ContainsMicrodump(buf));
+  CheckMicrodumpContents(buf, kMicrodumpExtraInfo);
+}
+
+TEST(MicrodumpWriterTest, NoProductInfo) {
+  const char kBuildFingerprint[] = "foobar";
+  const char kGPUFingerprint[] = "bazqux";
+  std::string buf;
+  MappingList no_mappings;
+
+  const MicrodumpExtraInfo kMicrodumpExtraInfoNoProductInfo(
+      MakeMicrodumpExtraInfo(kBuildFingerprint, NULL, kGPUFingerprint));
+
+  CrashAndGetMicrodump(no_mappings, kMicrodumpExtraInfoNoProductInfo, &buf);
+  ASSERT_TRUE(ContainsMicrodump(buf));
+  CheckMicrodumpContents(buf, kBuildFingerprint, "UNKNOWN:0.0.0.0",
+                         kGPUFingerprint);
+}
+
+TEST(MicrodumpWriterTest, NoGPUInfo) {
+  const char kProductInfo[] = "bazqux";
+  const char kBuildFingerprint[] = "foobar";
+  std::string buf;
+  MappingList no_mappings;
+
+  const MicrodumpExtraInfo kMicrodumpExtraInfoNoGPUInfo(
+      MakeMicrodumpExtraInfo(kBuildFingerprint, kProductInfo, NULL));
+
+  CrashAndGetMicrodump(no_mappings, kMicrodumpExtraInfoNoGPUInfo, &buf);
+  ASSERT_TRUE(ContainsMicrodump(buf));
+  CheckMicrodumpContents(buf, kBuildFingerprint, kProductInfo, "UNKNOWN");
+}
+}  // namespace