commit e9488b3feca82a8e1a5b6700eba386c49f35f499
author Yabin Cui <yabinc@google.com> Mon May 22 18:25:58 2017 +0000
committer android-build-merger <android-build-merger@google.com> Mon May 22 18:25:58 2017 +0000
tree a93c966e8c1c131d5867e5f58c289d31e80391af
parent 74e68c809757893240b2605cd4d65beb8b1436a8
parent fbc7062e9bf4d373e3f1fec32d19d460766b9ab3

Merge "simpleperf: better support kernel symbols when running as root."
am: fbc7062e9b

Change-Id: I6950f4a91a52632e5f3abe124fee88854ce5ddf5

simpleperf/cmd_record.cpp

diff --git a/simpleperf/cmd_record.cpp b/simpleperf/cmd_record.cpp
index 1eff009..acba6ab 100644
--- a/simpleperf/cmd_record.cpp
+++ b/simpleperf/cmd_record.cpp
@@ -934,7 +934,9 @@
     const std::vector<std::string>& args) {
   // Read data section of perf.data to collect hit file information.
   thread_tree_.ClearThreadAndMap();
-  Dso::ReadKernelSymbolsFromProc();
+  if (CheckKernelSymbolAddresses()) {
+    Dso::ReadKernelSymbolsFromProc();
+  }
   auto callback = [&](const Record* r) {
     thread_tree_.Update(*r);
     if (r->type() == PERF_RECORD_SAMPLE) {

simpleperf/cmd_record_test.cpp

diff --git a/simpleperf/cmd_record_test.cpp b/simpleperf/cmd_record_test.cpp
index 0d0c44a..571a3ca 100644
--- a/simpleperf/cmd_record_test.cpp
+++ b/simpleperf/cmd_record_test.cpp
@@ -331,7 +331,6 @@
     GTEST_LOG_(INFO) << "Test requires root privilege";
     return;
   }
-  system("echo 0 >/proc/sys/kernel/kptr_restrict");
   TemporaryFile tmpfile;
   ASSERT_TRUE(RunRecordCmd({"-a", "-o", tmpfile.path, "sleep", "1"}));
   std::unique_ptr<RecordFileReader> reader = RecordFileReader::CreateInstance(tmpfile.path);

simpleperf/environment.cpp

diff --git a/simpleperf/environment.cpp b/simpleperf/environment.cpp
index 0ad2d6b..d0cb835 100644
--- a/simpleperf/environment.cpp
+++ b/simpleperf/environment.cpp
@@ -451,12 +451,18 @@
     LOG(ERROR) << "failed to parse " << kptr_restrict_file << ": " << s;
     return false;
   }
+  // Accessible to everyone?
   if (value == 0) {
     return true;
   }
+  // Accessible to root?
   if (value == 1 && IsRoot()) {
     return true;
   }
+  // Can we make it accessible to us?
+  if (IsRoot() && android::base::WriteStringToFile("1", kptr_restrict_file)) {
+    return true;
+  }
   LOG(WARNING) << "Access to kernel symbol addresses is restricted. If "
       << "possible, please do `echo 0 >/proc/sys/kernel/kptr_restrict` "
       << "to fix this.";