Do not read /proc/self/exe before forking if Chrome is ran under Valgrind....

chrome/common/child_process_host.cc

 // Copyright (c) 2010 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/common/child_process_host.h"
 
 #include "base/command_line.h"
 #include "base/metrics/histogram.h"
 #include "base/path_service.h"
+#include "base/third_party/dynamic_annotations/dynamic_annotations.h"
 #include "chrome/common/child_process_info.h"
 #include "chrome/common/chrome_constants.h"
 #include "chrome/common/chrome_paths_internal.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/plugin_messages.h"
 #include "ipc/ipc_logging.h"
 
 #if defined(OS_LINUX)
 #include "base/linux_util.h"
 #endif  // OS_LINUX
@@ skipping 29 matching lines @@
 #if defined(OS_MACOSX)
   // On the Mac, the child executable lives at a predefined location within
   // the app bundle's versioned directory.
   return chrome::GetVersionedDirectory().
       Append(chrome::kHelperProcessExecutablePath);
 #endif
 
 #if defined(OS_LINUX)
   // Use /proc/self/exe rather than our known binary path so updates
   // can't swap out the binary from underneath us.
-  if (allow_self)
+  // When running under Valgrind, forking /proc/self/exe ends up forking the
+  // Valgrind executable, which then crashes. However, it's almost safe to
+  // assume that the updates won't happen while testing with Valgrind tools.
+  if (allow_self && !RunningOnValgrind())
     return FilePath("/proc/self/exe");
 #endif
 
   // On most platforms, the child executable is the same as the current
   // executable.
   PathService::Get(base::FILE_EXE, &child_path);

[evanm, 2011/01/14 17:19:20]

Do we know if this returns /proc/self/exe too?  My vague memory is that it reads
the /proc/self/exe symlink and returns that path...

   return child_path;
 }
 
 #if defined(OS_WIN)
 // static
 void ChildProcessHost::PreCacheFont(LOGFONT font) {
   // If a child process is running in a sandbox, GetTextMetrics()
   // can sometimes fail. If a font has not been loaded
   // previously, GetTextMetrics() will try to load the font
   // from the font file. However, the sandboxed process does
@@ skipping 133 matching lines @@
   for (size_t i = 0; i < host_->filters_.size(); ++i)
     host_->filters_[i]->OnChannelError();
 
   // This will delete host_, which will also destroy this!
   host_->OnChildDied();
 }
 
 void ChildProcessHost::ForceShutdown() {
   Send(new PluginProcessMsg_Shutdown());
 }