[Lldb-commits] [lldb] r307644 - NativeProcessLinux: Fix handling of raise(SIGTRAP)

[Pavel Labath via lldb-commits]

Author: labath
Date: Tue Jul 11 03:38:40 2017
New Revision: 307644

URL: http://llvm.org/viewvc/llvm-project?rev=307644&view=rev
Log:
NativeProcessLinux: Fix handling of raise(SIGTRAP)

In NativeProcessLinux::MonitorSIGTRAP we were asserting that the si_code
value is one of the codes we know about. However, that list was very
incomplete -- for example, we were not handling SI_TKILL/SI_USER,
generated by raise(SIGTRAP). A cursory examination show there are at
least a dozen codes like these that an app can generate, and more can be
added at any point.

So, instead of trying to play catchup, I change the default behavior to
treat an unknown si_code like an ordinary signal. The only reason we
needed to inspect si_code in the first place is because
watchpoint/breakpoints are notified as SIGTRAP, but we already know
about those, and us starting to use a new debug event is far less likely
than somebody introducing a new non-debug event.

I add a test case to TestRaise to verify we are handling raise(SIGTRAP)
in an application properly.

Modified:
    lldb/trunk/packages/Python/lldbsuite/test/functionalities/signal/raise/TestRaise.py
    lldb/trunk/packages/Python/lldbsuite/test/functionalities/signal/raise/main.c
    lldb/trunk/source/Plugins/Process/Linux/NativeProcessLinux.cpp

Modified: lldb/trunk/packages/Python/lldbsuite/test/functionalities/signal/raise/TestRaise.py
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/packages/Python/lldbsuite/test/functionalities/signal/raise/TestRaise.py?rev=307644&r1=307643&r2=307644&view=diff
==============================================================================
--- lldb/trunk/packages/Python/lldbsuite/test/functionalities/signal/raise/TestRaise.py (original)
+++ lldb/trunk/packages/Python/lldbsuite/test/functionalities/signal/raise/TestRaise.py Tue Jul 11 03:38:40 2017
@@ -16,6 +16,7 @@ from lldbsuite.test import lldbutil
 class RaiseTestCase(TestBase):
 
     mydir = TestBase.compute_mydir(__file__)
+    NO_DEBUG_INFO_TESTCASE = True
 
     def test_sigstop(self):
         self.build()
@@ -29,6 +30,10 @@ class RaiseTestCase(TestBase):
         self.build()
         self.signal_test('SIGRTMIN', True)
 
+    def test_sigtrap(self):
+        self.build()
+        self.signal_test('SIGTRAP', True)
+
     def launch(self, target, signal):
         # launch the process, do not stop at entry point.
         process = target.LaunchSimple(

Modified: lldb/trunk/packages/Python/lldbsuite/test/functionalities/signal/raise/main.c
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/packages/Python/lldbsuite/test/functionalities/signal/raise/main.c?rev=307644&r1=307643&r2=307644&view=diff
==============================================================================
--- lldb/trunk/packages/Python/lldbsuite/test/functionalities/signal/raise/main.c (original)
+++ lldb/trunk/packages/Python/lldbsuite/test/functionalities/signal/raise/main.c Tue Jul 11 03:38:40 2017
@@ -10,6 +10,11 @@ void handler(int signo)
 
 int main (int argc, char *argv[])
 {
+    if (signal(SIGTRAP, handler) == SIG_ERR)
+    {
+        perror("signal(SIGTRAP)");
+        return 1;
+    }
 #ifndef __APPLE__
     // Real time signals not supported on apple platforms.
     if (signal(SIGRTMIN, handler) == SIG_ERR)
@@ -27,6 +32,8 @@ int main (int argc, char *argv[])
 
     if (strcmp(argv[1], "SIGSTOP") == 0)
         raise(SIGSTOP);
+    else if (strcmp(argv[1], "SIGTRAP") == 0)
+        raise(SIGTRAP);
 #ifndef __APPLE__
     else if (strcmp(argv[1], "SIGRTMIN") == 0)
         raise(SIGRTMIN);

Modified: lldb/trunk/source/Plugins/Process/Linux/NativeProcessLinux.cpp
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Plugins/Process/Linux/NativeProcessLinux.cpp?rev=307644&r1=307643&r2=307644&view=diff
==============================================================================
--- lldb/trunk/source/Plugins/Process/Linux/NativeProcessLinux.cpp (original)
+++ lldb/trunk/source/Plugins/Process/Linux/NativeProcessLinux.cpp Tue Jul 11 03:38:40 2017
@@ -796,11 +796,9 @@ void NativeProcessLinux::MonitorSIGTRAP(
     break;
 
   default:
-    LLDB_LOG(
-        log,
-        "received unknown SIGTRAP stop event ({0}, pid {1} tid {2}, resuming",
-        info.si_code, GetID(), thread.GetID());
-    llvm_unreachable("Unexpected SIGTRAP code!");
+    LLDB_LOG(log, "received unknown SIGTRAP stop event ({0}, pid {1} tid {2}",
+             info.si_code, GetID(), thread.GetID());
+    MonitorSignal(info, thread, false);
     break;
   }
 }