Thanks Dmitry for review. I will file CR and let you know once done.
Cheleswer -----Original Message----- From: Dmitry Samersoff Sent: Friday, March 18, 2016 2:35 PM To: Cheleswer Sahu; hotspot-runtime-...@openjdk.java.net; serviceability-dev@openjdk.java.net Subject: Re: RFR[9u-dev]: 8151442: jstack doesn't close quotation marks properly with threads' name greater than 1996 characters Cheleswer, Fix (as immediate solution) looks good for me. But IMHO, silent truncation of the output inside output stream is not a correct behavior. So please file a follow-up CR to have it addressed. -Dmitry On 2016-03-18 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 > > > > > > > -- Dmitry Samersoff Oracle Java development team, Saint Petersburg, Russia * I would love to change the world, but they won't give me the sources.
