Hello Cheleswer,

It is possible to create a regression test for that?

Dmitry

On 18.03.2016 10:54, Cheleswer Sahu wrote:

Hi,

Please review the code changes for https://bugs.openjdk.java.net/browse/JDK-8151442.

Webrev Link: http://cr.openjdk.java.net/~csahu/8151442/

Bug Brief:

In jstack thread dumps , thread name greater than 1996 characters doesn’t close quotation marks properly.

Problem Identified:

Jstack is using below code to print thread name

src/share/vm/runtime/thread.cpp

void JavaThread::print_on(outputStream *st) const {

  st->print("\"%s\" ", get_thread_name());

Here “st->print()”  internally uses max buffer length as O_BUFLEN (2000).

void outputStream::do_vsnprintf_and_write_with_automatic_buffer(const char* format, va_list ap, bool add_cr) {
  char buffer[O_BUFLEN];

do_vsnprintf_and_write_with_automatic_buffer() finally calls “vsnprintf()” which truncates the anything greater than the max size(2000). In this case thread’s name(> 1996) along with quotation marks (2)

plus one terminating character exceeds the max buffer size (2000), therefore the closing quotation marks gets truncated.

Solution:

Split the  “st->print("\"%s\" ", get_thread_name())” in two statements

1.st->print("\"%s", get_thread_name());

2.st->print("\" “);

This will ensure presence of closing quotation mark always.

Regards,

Cheleswer


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