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lsstack64

Process execution stack tracer for x86_64 architecture. Per-thread tracing is possible. A fork of the pstack utility for Solaris which works only on x86 arch. Originally it's not even compilable on x86_64. The current project is an attempt to make it work on x86_64 Linux.

Sample output with Leafpad editor that runs 2 threads.

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License

While the original utility is GPLv2, the current project is licensed under GPLv3.

Compilation

Tested on Ubuntu 14.04.3 x86_64

$ sudo apt-get install binutils-dev libiberty-dev libunwind8-dev
$ git clone https://github.com/jarun/lsstack64
$ cd lsstack64
$ make
$ sudo make install

Usage

LWP stands for Light Weight Process. In simpler terms it is the thread ID. It is shown in the fourth column in the output of

$ ps -aeLf

For the main thread of a process LWD == PID, for child threads they are different.

$ unwind LWP

You might need to use sudo if you are not the owner of the process. unwind is the test program on x86_64. The functionality will be merged to lsstack64.

News

16 Jul 2015: Implemented thread tracing support.

03 Jun 2015: Merging unwind.c fnctionality to lsstack64 started. New logging mechanism incorporated into lsstack64.

25 Apr 2015: unwind.c is the new stub progam that uses libunwind to run through all the stack frames. The goal is to make unwind provide the information that pstack did.

23 Apr 2015: log.h and log.c demonstrate a tiny, easy to use and extensible logging frameowork with severity level and useful information for easy debugging.

15 Apr 2015: After some research, it turns out that x86_64 does NOT save the previous frame's frame pointer in RBP register (other than those compiled without -fomit-frame-pointer in GCC). The default optimization level in GCC is O2, which includes -fomit-frame-pointer. So the next strategy would be to use [libunwind] (http://www.nongnu.org/libunwind/).

Important links

General

http://www.nongnu.org/libunwind/index.html http://www.nongnu.org/libunwind/man/libunwind(3).html#section_3 http://www.nongnu.org/libunwind/man/libunwind-ptrace%283%29.html http://savannah.nongnu.org/git/?group=libunwind http://sourceforge.net/projects/lsstack/ http://lxr.free-electrons.com/source/arch/powerpc/boot/elf.h#L12 http://linux.die.net/man/2/ptrace http://linux.die.net/include/sys/user.h http://lxr.free-electrons.com/source/arch/x86/include/asm/ptrace.h?v=3.3 http://manpages.ubuntu.com/manpages/trusty/en/man3/libunwind-ptrace.3.html http://stackoverflow.com/questions/3194479/relation-between-program-instruction-pointerrip-and-base-frame-pointerrbp-on http://stackoverflow.com/questions/8625352/x86-64-calling-conventions-and-stack-frames http://blog.bigpixel.ro/2010/09/stack-unwinding-stack-trace-with-gcc/ http://stackoverflow.com/questions/7516273/using-libunwind-on-hp-ux-and-getting-stacktrace http://lists.nongnu.org/archive/html/libunwind-devel/2011-11/msg00002.html

Threads

http://stackoverflow.com/questions/6402160/getting-a-backtrace-of-other-thread http://comments.gmane.org/gmane.comp.lib.unwind.devel/696 http://stackoverflow.com/questions/11468333/linux-threads-suspend-resume http://stackoverflow.com/questions/18577956/how-to-use-ptrace-to-get-a-consistent-view-of-multiple-threads

Contributions

Ellié Computing contributes to this project by giving free licences of ECMerge, comparison/merge tool.