commit 773acaa18eef5140a1a23bb4fdfda15a2c37817e
author Peter Collingbourne <pcc@google.com> Wed Nov 10 16:29:23 2021 -0800
committer Peter Collingbourne <pcc@google.com> Thu Nov 11 15:05:47 2021 -0800
tree 5c51ada8ce820dfca2694e7dab2f5b1868bb4fde
parent d0a4e710e9241fbf427fbebf107648841663e0a4

Improvements to tombstone output.

- Use "likelihood" instead of "probability" since that has connotations
  of being less precise, and our probability ordering isn't very precise
  anyway.

- Hide the fault address with SEGV_MTEAERR because it is not available.

- Pad the fault address with leading zeroes to make it clearer which
  bits of the top byte (and any following bytes such as PAC signature
  bits) are set.

Bug: 206015287
Change-Id: I5e1e99b7f3e967c44781d8550bbd7158eb421b64

debuggerd/libdebuggerd/scudo.cpp

diff --git a/debuggerd/libdebuggerd/scudo.cpp b/debuggerd/libdebuggerd/scudo.cpp
index f4690ba..a89f385 100644
--- a/debuggerd/libdebuggerd/scudo.cpp
+++ b/debuggerd/libdebuggerd/scudo.cpp
@@ -135,7 +135,7 @@
   if (error_info_.reports[1].error_type != UNKNOWN) {
     _LOG(log, logtype::HEADER,
          "\nNote: multiple potential causes for this crash were detected, listing them in "
-         "decreasing order of probability.\n");
+         "decreasing order of likelihood.\n");
   }
 
   size_t report_num = 0;

debuggerd/libdebuggerd/tombstone_proto_to_text.cpp

diff --git a/debuggerd/libdebuggerd/tombstone_proto_to_text.cpp b/debuggerd/libdebuggerd/tombstone_proto_to_text.cpp
index 681b963..c248fae 100644
--- a/debuggerd/libdebuggerd/tombstone_proto_to_text.cpp
+++ b/debuggerd/libdebuggerd/tombstone_proto_to_text.cpp
@@ -292,6 +292,7 @@
 
 static void print_main_thread(CallbackType callback, const Tombstone& tombstone,
                               const Thread& thread) {
+  int word_size = pointer_width(tombstone);
   print_thread_header(callback, tombstone, thread, true);
 
   const Signal& signal_info = tombstone.signal_info();
@@ -307,7 +308,7 @@
   } else {
     std::string fault_addr_desc;
     if (signal_info.has_fault_address()) {
-      fault_addr_desc = StringPrintf("0x%" PRIx64, signal_info.fault_address());
+      fault_addr_desc = StringPrintf("0x%0*" PRIx64, 2 * word_size, signal_info.fault_address());
     } else {
       fault_addr_desc = "--------";
     }
@@ -331,7 +332,7 @@
   if (tombstone.causes_size() > 1) {
     CBS("");
     CBL("Note: multiple potential causes for this crash were detected, listing them in decreasing "
-        "order of probability.");
+        "order of likelihood.");
   }
 
   for (const Cause& cause : tombstone.causes()) {
@@ -369,7 +370,6 @@
     return;
   }
 
-  int word_size = pointer_width(tombstone);
   const auto format_pointer = [word_size](uint64_t ptr) -> std::string {
     if (word_size == 8) {
       uint64_t top = ptr >> 32;

debuggerd/libdebuggerd/utility.cpp

diff --git a/debuggerd/libdebuggerd/utility.cpp b/debuggerd/libdebuggerd/utility.cpp
index a7506b7..4370130 100644
--- a/debuggerd/libdebuggerd/utility.cpp
+++ b/debuggerd/libdebuggerd/utility.cpp
@@ -275,9 +275,10 @@
     case SIGBUS:
     case SIGFPE:
     case SIGILL:
-    case SIGSEGV:
     case SIGTRAP:
       return true;
+    case SIGSEGV:
+      return si->si_code != SEGV_MTEAERR;
     default:
       return false;
   }