[PATCH 4 of 5] * tapset/jstack.stp.in: Wrap heap accessors in try-catch block
Mark Wielaard
mjw at redhat.com
Wed Mar 14 03:07:03 PDT 2012
# HG changeset patch
# User Mark Wielaard <mark at klomp.org>
# Date 1331677296 -3600
# Node ID 1ab9b476f30279bd0367d539f29b5591ae0e0e7e
# Parent 131b26ec835a11d3f310fe42dd7caa5bb79463ea
* tapset/jstack.stp.in: Wrap heap accessors in try-catch block.
When we cannot read some part of the hotspot code heap catch that error
and report the frame (address) without trying to decode it.
diff --git a/ChangeLog b/ChangeLog
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2012-03-13 Mark Wielaard <mjw at redhat.com>
+
+ * tapset/jstack.stp.in: Wrap heap accessors in try-catch block to be
+ able to report unusual frames.
+
2012-03-13 Mark Wielaard <mjw at redhat.com>
* tapset/jstack.stp.in: Use @var construct if available to pick
diff --git a/tapset/jstack.stp.in b/tapset/jstack.stp.in
--- a/tapset/jstack.stp.in
+++ b/tapset/jstack.stp.in
@@ -309,129 +309,143 @@
}
block = CodeCache_low + (segment << CodeHeap_log2_segment_size);
- // Do some sanity checking.
- used = @cast(block, "HeapBlock",
- "@ABS_SERVER_LIBJVM_SO@")->_header->_used;
- if (used != 1)
+ // Some of this is "fuzzy" so catch any read error in case we
+ // "guessed" wrong.
+ try
{
- // Something very odd has happened.
- frame = sprintf("0x%x <?unused-code-block?>", pc);
- blob_name = "unused";
- trust_fp = 0;
- frame_size = 0;
- }
- else
- {
- // We don't like spaces in frames (makes it hard to return
- // a space separated frame list). So make sure they are
- // replaced by underscores when used in frames.
- blob = block + HeapBlock_Header_size;
- blob_name_ptr = @cast(blob, "CodeBlob",
- "@ABS_SERVER_LIBJVM_SO@")->_name;
- blob_name = ((blob_name_ptr == 0) ? "<unknown-code-blob>"
- : user_string(blob_name_ptr));
- }
- // For compiled code the methodOop is part of the code blob.
- // For the interpreter (and other code blobs) it is on the
- // stack relative to the frame pointer.
- if (blob_name == "nmethod")
- methodOopPtr = @cast(blob, "nmethod",
- "@ABS_SERVER_LIBJVM_SO@")->_method
- else
- methodOopPtr = user_long(fp + (-3 * ptr_size)) & ptr_mask
-
- // Start optimistic. A methodOop is only valid if it was
- // heap allocated. And if the "type class" oop equals the
- // Universe::methodKlassObj.
- if (heap_start > methodOopPtr || methodOopPtr >= heap_end)
- isMethodOop = 0
- else
- {
- methodOopKlass = @cast(methodOopPtr, "methodOopDesc",
- "@ABS_SERVER_LIBJVM_SO@")->_metadata->_klass;
- isMethodOop = (methodOopKlass == Universe_methodKlassObj[pid()]);
- }
-
- if (isMethodOop)
- {
- // The java class is the holder of the constants (strings)
- // that describe the method and signature. This constant pool
- // contains symbolic information that describe the properties
- // of the class. The indexes for methods and signaturates in
- // the constant pool are symbolOopDescs that contain utf8
- // strings (plus lenghts). (We could also sanity check that
- // the tag value is correct [CONSTANT_String = 8]).
- // Note that the class name uses '/' instead of '.' as
- // package name separator and that the method signature is
- // encoded as a method descriptor string. Both of which we
- // don't demangle here.
- constantPoolOopDesc = @cast(methodOopPtr, "methodOopDesc",
- "@ABS_SERVER_LIBJVM_SO@")->_constants;
- constantPoolOop_base = constantPoolOopDesc + constantPoolOopDesc_size;
-
- klassPtr = @cast(constantPoolOopDesc, "constantPoolOopDesc",
- "@ABS_SERVER_LIBJVM_SO@")->_pool_holder;
- klassSymbol = @cast(klassPtr + oopDesc_size, "Klass",
- "@ABS_SERVER_LIBJVM_SO@")->_name;
- klassName = &@cast(klassSymbol, "symbolOopDesc",
- "@ABS_SERVER_LIBJVM_SO@")->_body[0];
- klassLength = @cast(klassSymbol, "symbolOopDesc",
- "@ABS_SERVER_LIBJVM_SO@")->_length;
-
- methodIndex = @cast(methodOopPtr, "methodOopDesc",
- "@ABS_SERVER_LIBJVM_SO@")->_constMethod->_name_index;
- methodOopDesc = user_long(constantPoolOop_base + (methodIndex * ptr_size));
- methodName = &@cast(methodOopDesc, "symbolOopDesc",
- "@ABS_SERVER_LIBJVM_SO@")->_body[0];
- methodLength = @cast(methodOopDesc, "symbolOopDesc",
- "@ABS_SERVER_LIBJVM_SO@")->_length;
-
- if (log_sig)
+ // Do some sanity checking.
+ used = @cast(block, "HeapBlock",
+ "@ABS_SERVER_LIBJVM_SO@")->_header->_used;
+ if (used != 1)
{
- sigIndex = @cast(methodOopPtr, "methodOopDesc",
- "@ABS_SERVER_LIBJVM_SO@")->_constMethod->_signature_index;
- sigOopDesc = user_long(constantPoolOop_base
- + (sigIndex * ptr_size));
- sigName = &@cast(sigOopDesc, "symbolOopDesc",
- "@ABS_SERVER_LIBJVM_SO@")->_body[0];
- sigLength = @cast(sigOopDesc, "symbolOopDesc",
- "@ABS_SERVER_LIBJVM_SO@")->_length;
- sig = user_string_n(sigName, sigLength);
+ // Something very odd has happened.
+ frame = sprintf("<unused_code_block at 0x%x>", pc);
+ blob_name = "unused";
+ trust_fp = 0;
+ frame_size = 0;
}
else
- sig = "";
+ {
+ // We don't like spaces in frames (makes it hard to return
+ // a space separated frame list). So make sure they are
+ // replaced by underscores when used in frames.
+ blob = block + HeapBlock_Header_size;
+ blob_name_ptr = @cast(blob, "CodeBlob",
+ "@ABS_SERVER_LIBJVM_SO@")->_name;
+ blob_name = ((blob_name_ptr == 0) ? "<unknown-code-blob>"
+ : user_string(blob_name_ptr));
+ }
- code_name = (log_native
- ? sprintf("<%s at 0x%x>",
- str_replace(blob_name, " ", "_"), pc)
- : "");
+ // For compiled code the methodOop is part of the code blob.
+ // For the interpreter (and other code blobs) it is on the
+ // stack relative to the frame pointer.
+ if (blob_name == "nmethod")
+ methodOopPtr = @cast(blob, "nmethod",
+ "@ABS_SERVER_LIBJVM_SO@")->_method
+ else
+ methodOopPtr = user_long(fp + (-3 * ptr_size)) & ptr_mask
- frame = sprintf("%s.%s%s%s",
- user_string_n(klassName, klassLength),
- user_string_n(methodName, methodLength),
- sig, code_name);
+ // Start optimistic. A methodOop is only valid if it was
+ // heap allocated. And if the "type class" oop equals the
+ // Universe::methodKlassObj.
+ if (heap_start > methodOopPtr || methodOopPtr >= heap_end)
+ isMethodOop = 0
+ else
+ {
+ methodOopKlass = @cast(methodOopPtr, "methodOopDesc",
+ "@ABS_SERVER_LIBJVM_SO@")->_metadata->_klass;
+ isMethodOop = (methodOopKlass == Universe_methodKlassObj[pid()]);
+ }
+
+ if (isMethodOop)
+ {
+ // The java class is the holder of the constants (strings)
+ // that describe the method and signature. This constant pool
+ // contains symbolic information that describe the properties
+ // of the class. The indexes for methods and signaturates in
+ // the constant pool are symbolOopDescs that contain utf8
+ // strings (plus lenghts). (We could also sanity check that
+ // the tag value is correct [CONSTANT_String = 8]).
+ // Note that the class name uses '/' instead of '.' as
+ // package name separator and that the method signature is
+ // encoded as a method descriptor string. Both of which we
+ // don't demangle here.
+ constantPoolOopDesc = @cast(methodOopPtr, "methodOopDesc",
+ "@ABS_SERVER_LIBJVM_SO@")->_constants;
+ constantPoolOop_base = constantPoolOopDesc + constantPoolOopDesc_size;
+
+ klassPtr = @cast(constantPoolOopDesc, "constantPoolOopDesc",
+ "@ABS_SERVER_LIBJVM_SO@")->_pool_holder;
+ klassSymbol = @cast(klassPtr + oopDesc_size, "Klass",
+ "@ABS_SERVER_LIBJVM_SO@")->_name;
+ klassName = &@cast(klassSymbol, "symbolOopDesc",
+ "@ABS_SERVER_LIBJVM_SO@")->_body[0];
+ klassLength = @cast(klassSymbol, "symbolOopDesc",
+ "@ABS_SERVER_LIBJVM_SO@")->_length;
+
+ methodIndex = @cast(methodOopPtr, "methodOopDesc",
+ "@ABS_SERVER_LIBJVM_SO@")->_constMethod->_name_index;
+ methodOopDesc = user_long(constantPoolOop_base + (methodIndex * ptr_size));
+ methodName = &@cast(methodOopDesc, "symbolOopDesc",
+ "@ABS_SERVER_LIBJVM_SO@")->_body[0];
+ methodLength = @cast(methodOopDesc, "symbolOopDesc",
+ "@ABS_SERVER_LIBJVM_SO@")->_length;
+
+ if (log_sig)
+ {
+ sigIndex = @cast(methodOopPtr, "methodOopDesc",
+ "@ABS_SERVER_LIBJVM_SO@")->_constMethod->_signature_index;
+ sigOopDesc = user_long(constantPoolOop_base
+ + (sigIndex * ptr_size));
+ sigName = &@cast(sigOopDesc, "symbolOopDesc",
+ "@ABS_SERVER_LIBJVM_SO@")->_body[0];
+ sigLength = @cast(sigOopDesc, "symbolOopDesc",
+ "@ABS_SERVER_LIBJVM_SO@")->_length;
+ sig = user_string_n(sigName, sigLength);
+ }
+ else
+ sig = "";
+
+ code_name = (log_native
+ ? sprintf("<%s at 0x%x>",
+ str_replace(blob_name, " ", "_"), pc)
+ : "");
+
+ frame = sprintf("%s.%s%s%s",
+ user_string_n(klassName, klassLength),
+ user_string_n(methodName, methodLength),
+ sig, code_name);
+ }
+ else
+ {
+ // This is probably just an internal function, not a java
+ // method, just print the blob_name and continue.
+ // fp is probably still trusted.
+ if (log_native)
+ frame = sprintf("<%s at 0x%x>",
+ str_replace(blob_name, " ", "_"), pc);
+ }
+
+ // We cannot trust the frame pointer of compiled methods.
+ // The server (c2) jit compiler uses the fp register.
+ // We do know the method frame size on the stack. But
+ // this seems to be useful only as a hint of the minimum
+ // stack being used.
+ if (blob_name == "nmethod")
+ {
+ trust_fp = 0;
+ frame_size = @cast(blob, "CodeBlob",
+ "@ABS_SERVER_LIBJVM_SO@")->_frame_size;
+ }
+
}
- else
+ catch
{
- // This is probably just an internal function, not a java
- // method, just print the blob_name and continue.
- // fp is probably still trusted.
- if (log_native)
- frame = sprintf("<%s at 0x%x>",
- str_replace(blob_name, " ", "_"), pc);
- }
-
- // We cannot trust the frame pointer of compiled methods.
- // The server (c2) jit compiler uses the fp register.
- // We do know the method frame size on the stack. But
- // this seems to be useful only as a hint of the minimum
- // stack being used.
- if (blob_name == "nmethod")
- {
+ // Some assumption above totally failed and we got an address
+ // read error. Give up and mark frame pointer as suspect.
+ frame = sprintf("<unknown_frame at 0x%x>", pc);
trust_fp = 0;
- frame_size = @cast(blob, "CodeBlob",
- "@ABS_SERVER_LIBJVM_SO@")->_frame_size;
}
}
else
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