commit da9432c88810f1ffcbb97d2c0744282e56fe0372
author Josh Gao <jmgao@google.com> Tue Jun 13 17:21:12 2017 +0000
committer Josh Gao <jmgao@google.com> Tue Jun 13 17:21:12 2017 +0000
tree 9043da9aff38bfb1445ba06fde57498ebdb3c1f2
parent c9c94a758d0f73e208634159be9302594a9a6e07

Revert "crash_dump: defer pausing threads until we're ready."

This reverts commit 8a2a2d182a2ce14638142e78ea4308670984d2e0.

Bug: http://b/62572585
Change-Id: Ia4278bca52178eb7b7b28b30d0930b292d97f353

debuggerd/Android.bp

diff --git a/debuggerd/Android.bp b/debuggerd/Android.bp
index 42c3023..5565cfd 100644
--- a/debuggerd/Android.bp
+++ b/debuggerd/Android.bp
@@ -7,7 +7,6 @@
         "-Wno-nullability-completeness",
         "-Os",
     ],
-    cpp_std: "experimental",
 
     local_include_dirs: ["include"],
 }

debuggerd/crash_dump.cpp

diff --git a/debuggerd/crash_dump.cpp b/debuggerd/crash_dump.cpp
index 3ca9c92..df7201d 100644
--- a/debuggerd/crash_dump.cpp
+++ b/debuggerd/crash_dump.cpp
@@ -95,6 +95,11 @@
     return false;
   }
 
+  // Put the task into ptrace-stop state.
+  if (ptrace(PTRACE_INTERRUPT, tid, 0, 0) != 0) {
+    PLOG(FATAL) << "failed to interrupt thread " << tid;
+  }
+
   return true;
 }
 
@@ -279,38 +284,36 @@
   // Die if we take too long.
   alarm(2);
 
-  std::string process_name = get_process_name(main_tid);
   std::string attach_error;
 
   std::map<pid_t, std::string> threads;
 
   {
-    ATRACE_NAME("ptrace_interrupt");
-
+    ATRACE_NAME("ptrace");
     // Seize the main thread.
     if (!ptrace_seize_thread(target_proc_fd, main_tid, &attach_error)) {
       LOG(FATAL) << attach_error;
     }
 
-    threads.emplace(main_tid, get_thread_name(main_tid));
-
-    // Seize its siblings.
-    std::set<pid_t> siblings;
-    if (!android::procinfo::GetProcessTids(target, &siblings)) {
-      PLOG(FATAL) << "failed to get process siblings";
-    }
-
-    // but not the already attached main thread.
-    siblings.erase(main_tid);
-    // or the handler pseudothread.
-    siblings.erase(pseudothread_tid);
-
-    for (pid_t sibling_tid : siblings) {
-      if (!ptrace_seize_thread(target_proc_fd, sibling_tid, &attach_error)) {
-        LOG(WARNING) << attach_error;
-        continue;
+    // Seize the siblings.
+    {
+      std::set<pid_t> siblings;
+      if (!android::procinfo::GetProcessTids(target, &siblings)) {
+        PLOG(FATAL) << "failed to get process siblings";
       }
-      threads.emplace(sibling_tid, get_thread_name(sibling_tid));
+
+      // but not the already attached main thread.
+      siblings.erase(main_tid);
+      // or the handler pseudothread.
+      siblings.erase(pseudothread_tid);
+
+      for (pid_t sibling_tid : siblings) {
+        if (!ptrace_seize_thread(target_proc_fd, sibling_tid, &attach_error)) {
+          LOG(WARNING) << attach_error;
+        } else {
+          threads.emplace(sibling_tid, get_thread_name(sibling_tid));
+        }
+      }
     }
   }
 
@@ -331,6 +334,9 @@
     populate_open_files_list(target, &open_files);
   }
 
+  std::string process_name = get_process_name(main_tid);
+  threads.emplace(main_tid, get_thread_name(main_tid));
+
   // Drop our capabilities now that we've attached to the threads we care about.
   drop_capabilities();
 
@@ -341,16 +347,6 @@
     tombstoned_connected = tombstoned_connect(target, &tombstoned_socket, &output_fd, dump_type_enum);
   }
 
-  // Pause the threads.
-  {
-    ATRACE_NAME("ptrace_interrupt");
-    for (const auto& [sibling_tid, _] : threads) {
-      if (ptrace(PTRACE_INTERRUPT, sibling_tid, 0, 0) != 0) {
-        PLOG(FATAL) << "failed to interrupt thread " << sibling_tid;
-      }
-    }
-  }
-
   // Write a '\1' to stdout to tell the crashing process to resume.
   // It also restores the value of PR_SET_DUMPABLE at this point.
   if (TEMP_FAILURE_RETRY(write(STDOUT_FILENO, "\1", 1)) == -1) {