Mercurial > hg > release > icedtea7-2.2
changeset 2526:5cc05c7552ef
* 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.
| author | Mark Wielaard <mark@klomp.org> |
|---|---|
| date | Tue, 13 Mar 2012 23:21:36 +0100 |
| parents | 3622f089d9f3 |
| children | 527807ac6196 |
| files | ChangeLog tapset/jstack.stp.in |
| diffstat | 2 files changed, 132 insertions(+), 113 deletions(-) [+] |
line wrap: on
line diff
--- a/ChangeLog Tue Mar 13 17:24:50 2012 +0100 +++ b/ChangeLog Tue Mar 13 23:21:36 2012 +0100 @@ -1,3 +1,8 @@ +2012-03-13 Mark Wielaard <mjw@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@redhat.com> * tapset/jstack.stp.in: Use @var construct if available to pick
--- a/tapset/jstack.stp.in Tue Mar 13 17:24:50 2012 +0100 +++ b/tapset/jstack.stp.in Tue Mar 13 23:21:36 2012 +0100 @@ -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) - { - // Something very odd has happened. - frame = sprintf("0x%x <?unused-code-block?>", pc); - blob_name = "unused"; - trust_fp = 0; - frame_size = 0; - } - else + // Some of this is "fuzzy" so catch any read error in case we + // "guessed" wrong. + try { - // 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@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)); + } + + // 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 - code_name = (log_native - ? sprintf("<%s@0x%x>", - str_replace(blob_name, " ", "_"), pc) - : ""); + // 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; - frame = sprintf("%s.%s%s%s", - user_string_n(klassName, klassLength), - user_string_n(methodName, methodLength), - sig, code_name); + 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@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@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@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@0x%x>", pc); trust_fp = 0; - frame_size = @cast(blob, "CodeBlob", - "@ABS_SERVER_LIBJVM_SO@")->_frame_size; } } else