8240956: SEGV in DwarfParser::process_dwarf after JDK-8234624

Reviewed-by: sspitsyn, kevinw

src/jdk.hotspot.agent/linux/native/libsaproc/dwarf.cpp

@@ -75,7 +75,6 @@ bool DwarfParser::process_cie(unsigned char *start_of_entry, uint32_t id) {
 
   char *augmentation_string = reinterpret_cast<char *>(_buf);
   bool has_ehdata = (strcmp("eh", augmentation_string) == 0);
-  bool fde_encoded = (strchr(augmentation_string, 'R') != NULL);
   _buf += strlen(augmentation_string) + 1; // includes '\0'
   if (has_ehdata) {
     _buf += sizeof(void *); // Skip EH data
@@ -85,8 +84,16 @@ bool DwarfParser::process_cie(unsigned char *start_of_entry, uint32_t id) {
   _data_factor = static_cast<int>(read_leb(true));
   _return_address_reg = static_cast<enum DWARF_Register>(*_buf++);
 
-  if (fde_encoded) {
-    uintptr_t augmentation_length = read_leb(false);
+  if (strpbrk(augmentation_string, "LP") != NULL) {
+    // Language personality routine (P) and Language Specific Data Area (LSDA:L)
+    // are not supported because we need compliant Unwind Library Interface,
+    // but we want to unwind without it.
+    //
+    //   Unwind Library Interface (SysV ABI AMD64 6.2)
+    //     https://software.intel.com/sites/default/files/article/402129/mpx-linux64-abi.pdf
+    return false;
+  } else if (strchr(augmentation_string, 'R') != NULL) {
+    read_leb(false); // augmentation length
     _encoding = *_buf++;
   }
 
@@ -285,7 +292,8 @@ unsigned int DwarfParser::get_pc_range() {
 bool DwarfParser::process_dwarf(const uintptr_t pc) {
   // https://refspecs.linuxfoundation.org/LSB_3.0.0/LSB-PDA/LSB-PDA/ehframechpt.html
   _buf = _lib->eh_frame.data;
-  while (true) {
+  unsigned char *end = _lib->eh_frame.data + _lib->eh_frame.size;
+  while (_buf <= end) {
     uint64_t length = get_entry_length();
     if (length == 0L) {
       return false;
@@ -310,12 +318,12 @@ bool DwarfParser::process_dwarf(const uintptr_t pc) {
 
         // Process FDE
         parse_dwarf_instructions(pc_begin, pc, next_entry);
-        break;
+        return true;
       }
     }
 
     _buf = next_entry;
   }
 
-  return true;
+  return false;
 }

src/jdk.hotspot.agent/linux/native/libsaproc/libproc_impl.c

@@ -224,6 +224,7 @@ bool read_eh_frame(struct ps_prochandle* ph, lib_info* lib) {
       lib->eh_frame.library_base_addr = lib->base;
       lib->eh_frame.v_addr = sh->sh_addr;
       lib->eh_frame.data = read_section_data(lib->fd, &ehdr, sh);
+      lib->eh_frame.size = sh->sh_size;
       break;
     }
   }

src/jdk.hotspot.agent/linux/native/libsaproc/libproc_impl.h

@@ -39,6 +39,7 @@ typedef struct eh_frame_info {
   uintptr_t library_base_addr;
   uintptr_t v_addr;
   unsigned char* data;
+  int size;
 } eh_frame_info;
 
 // list of shared objects

src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/debugger/linux/amd64/LinuxAMD64CFrame.java

@@ -38,17 +38,20 @@ final public class LinuxAMD64CFrame extends BasicCFrame {
       DwarfParser dwarf = null;
 
       if (libptr != null) { // Native frame
+        dwarf = new DwarfParser(libptr);
         try {
-          dwarf = new DwarfParser(libptr);
           dwarf.processDwarf(rip);
-          cfa = ((dwarf.getCFARegister() == AMD64ThreadContext.RBP) &&
-                 !dwarf.isBPOffsetAvailable())
-                    ? context.getRegisterAsAddress(AMD64ThreadContext.RBP)
-                    : context.getRegisterAsAddress(dwarf.getCFARegister())
-                             .addOffsetTo(dwarf.getCFAOffset());
         } catch (DebuggerException e) {
-          // Bail out to Java frame case
+          // DWARF processing should succeed when the frame is native
+          // but it might fail if Common Information Entry (CIE) has language
+          // personality routine and/or Language Specific Data Area (LSDA).
+          return new LinuxAMD64CFrame(dbg, cfa, rip, dwarf, true);
         }
+        cfa = ((dwarf.getCFARegister() == AMD64ThreadContext.RBP) &&
+               !dwarf.isBPOffsetAvailable())
+                  ? context.getRegisterAsAddress(AMD64ThreadContext.RBP)
+                  : context.getRegisterAsAddress(dwarf.getCFARegister())
+                           .addOffsetTo(dwarf.getCFAOffset());
       }
 
       return (cfa == null) ? null
@@ -56,11 +59,16 @@ final public class LinuxAMD64CFrame extends BasicCFrame {
    }
 
    private LinuxAMD64CFrame(LinuxDebugger dbg, Address cfa, Address rip, DwarfParser dwarf) {
+      this(dbg, cfa, rip, dwarf, false);
+   }
+
+   private LinuxAMD64CFrame(LinuxDebugger dbg, Address cfa, Address rip, DwarfParser dwarf, boolean finalFrame) {
       super(dbg.getCDebugger());
       this.cfa = cfa;
       this.rip = rip;
       this.dbg = dbg;
       this.dwarf = dwarf;
+      this.finalFrame = finalFrame;
    }
 
    // override base class impl to avoid ELF parsing
@@ -123,7 +131,19 @@ final public class LinuxAMD64CFrame extends BasicCFrame {
      return isValidFrame(nextCFA, context) ? nextCFA : null;
    }
 
-   private DwarfParser getNextDwarf(Address nextPC) {
+   @Override
+   public CFrame sender(ThreadProxy thread) {
+     if (finalFrame) {
+       return null;
+     }
+
+     ThreadContext context = thread.getContext();
+
+     Address nextPC = getNextPC(dwarf != null);
+     if (nextPC == null) {
+       return null;
+     }
+
      DwarfParser nextDwarf = null;
 
      if ((dwarf != null) && dwarf.isIn(nextPC)) {
@@ -140,22 +160,16 @@ final public class LinuxAMD64CFrame extends BasicCFrame {
      }
 
      if (nextDwarf != null) {
-       nextDwarf.processDwarf(nextPC);
+       try {
+         nextDwarf.processDwarf(nextPC);
+       } catch (DebuggerException e) {
+         // DWARF processing should succeed when the frame is native
+         // but it might fail if Common Information Entry (CIE) has language
+         // personality routine and/or Language Specific Data Area (LSDA).
+         return new LinuxAMD64CFrame(dbg, null, nextPC, nextDwarf, true);
+       }
      }
 
-     return nextDwarf;
-   }
-
-   @Override
-   public CFrame sender(ThreadProxy thread) {
-     ThreadContext context = thread.getContext();
-
-     Address nextPC = getNextPC(dwarf != null);
-     if (nextPC == null) {
-       return null;
-     }
-
-     DwarfParser nextDwarf = getNextDwarf(nextPC);
      Address nextCFA = getNextCFA(nextDwarf, context);
      return isValidFrame(nextCFA, context) ? new LinuxAMD64CFrame(dbg, nextCFA, nextPC, nextDwarf)
                                            : null;
@@ -167,4 +181,5 @@ final public class LinuxAMD64CFrame extends BasicCFrame {
    private Address cfa;
    private LinuxDebugger dbg;
    private DwarfParser dwarf;
+   private boolean finalFrame;
 }

test/hotspot/jtreg/ProblemList.txt

@@ -115,7 +115,7 @@ serviceability/sa/ClhsdbPmap.java 8193639 solaris-all
 serviceability/sa/ClhsdbPrintAll.java 8193639 solaris-all
 serviceability/sa/ClhsdbPrintAs.java 8193639 solaris-all
 serviceability/sa/ClhsdbPrintStatics.java 8193639 solaris-all
-serviceability/sa/ClhsdbPstack.java 8193639,8240956 solaris-all,linux-all
+serviceability/sa/ClhsdbPstack.java 8193639 solaris-all
 serviceability/sa/ClhsdbRegionDetailsScanOopsForG1.java 8193639 solaris-all
 serviceability/sa/ClhsdbScanOops.java 8193639,8235220,8230731 solaris-all,linux-x64,macosx-x64,windows-x64
 serviceability/sa/ClhsdbSource.java 8193639 solaris-all