Merge pull request #9348 from richardkchapman/better-backtrace

HPCC-16644 Improve reporting of segfaults

Reviewed-by: Gavin Halliday <ghalliday@hpccsystems.com>

system/jlib/jexcept.cpp

@@ -1013,7 +1013,6 @@ void excsighandler(int signum, siginfo_t *info, void *extra)
     __int64 ip = uc->uc_mcontext.gregs[REG_RIP];
     __int64 sp = uc->uc_mcontext.gregs[REG_RSP];
 #endif
-    
     excsignal = signum;
     s.appendf("SIG: %s(%d), accessing " I64X ", IP=" I64X, strsignal(signum),signum, (__int64)info->si_addr, ip);
     
@@ -1021,6 +1020,10 @@ void excsighandler(int signum, siginfo_t *info, void *extra)
     PROGLOG("Signal:    %d %s",signum,strsignal(signum));
     PROGLOG("Fault IP:  " I64X "", ip);
     PROGLOG("Accessing: " I64X "", (unsigned __int64) info->si_addr);
+#ifdef _EXECINFO_H
+    printStackReport(ip);
+#endif
+
     PROGLOG("Registers:" );
     PROGLOG("EAX:" I64X "  EBX:" I64X "  ECX:" I64X "  EDX:" I64X "  ESI:" I64X "  EDI:" I64X "",
 #ifdef __APPLE__
@@ -1060,6 +1063,10 @@ void excsighandler(int signum, siginfo_t *info, void *extra)
     PROGLOG("Signal:    %d %s",signum,strsignal(signum));
     PROGLOG("Fault IP:  %08X", ip);
     PROGLOG("Accessing: %08X", (unsigned) info->si_addr);
+#ifdef _EXECINFO_H
+    printStackReport(ip);
+#endif
+
     PROGLOG("Registers:" );
     PROGLOG("EAX:%08X  EBX:%08X  ECX:%08X  EDX:%08X  ESI:%08X  EDI:%08X",
         uc->uc_mcontext.gregs[REG_EAX], uc->uc_mcontext.gregs[REG_EBX], 
@@ -1190,9 +1197,6 @@ void excsighandler(int signum, siginfo_t *info, void *extra)
 
 #endif
 
-#ifdef _EXECINFO_H
-    printStackReport();
-#endif  
     StringBuffer threadlist;
     PROGLOG( "ThreadList:\n%s",getThreadList(threadlist).str());
     queryLogMsgManager()->flushQueue(10*1000);
@@ -1376,7 +1380,7 @@ void jlib_decl serializeException(IException * e, MemoryBuffer & out)
 }
 
 
-void printStackReport()
+void printStackReport(__int64 startIP)
 {
     if (!queryLogMsgManager())
         return;
@@ -1388,7 +1392,21 @@ void printStackReport()
     void *btarray[100];
     unsigned btn = backtrace (btarray, 100);
     char **strings = backtrace_symbols (btarray, btn);
-    for (unsigned i=0; i<btn; i++)
+    unsigned i;
+    unsigned firstReal = 0;
+    if (startIP)
+    {
+        VStringBuffer iptext("[%p]", (void *) startIP);
+        for (i=0; i<btn; i++)
+        {
+            if (strstr(strings[i], iptext) != nullptr)
+            {
+                firstReal = i;
+                break;
+            }
+        }
+    }
+    for (i=firstReal; i<btn; i++)
         DBGLOG("  %s", strings[i]);
     free (strings);
 #endif

system/jlib/jexcept.hpp

@@ -142,7 +142,7 @@ __declspec(noreturn) void jlib_decl throwUnexpectedException(const char * where,
 IException jlib_decl * deserializeException(MemoryBuffer & in); 
 void jlib_decl serializeException(IException * e, MemoryBuffer & out); 
 
-void  jlib_decl printStackReport();
+void  jlib_decl printStackReport(__int64 startIP = 0);
 // Macro for legacy name of above function
 #define PrintStackReport printStackReport