PSTACK(1) - General Commands Manual

pstack - print stack traces of threads in a running process or a core file

pstack [-a] [-j] [-n] [-p] [-s] [-t] [-v] [-b seconds] [-g directory] <executable | pid | core> *
pstack -d elf-file
pstack -D elf-file
pstack -V
pstack -h

Displays the stack traces of each thread in the running process with process id pid or from the core file core

Normal invocation prints the stack trace from a core file or running process. This implementation understands the stack unwinding data in eh_frame sections, and properly unwinds through stack frames of code compiled with -fomit-frame-pointer and on x86_64

Arguments are as follows.

-a

Show values of arguments passed to functions if possible (requires DWARF debug data for function's code). This also works in python mode.

-j

Use JSON format for the stack output

-n

Do not attempt to find external debug information. DWARF debug information and symbol tables may be contained in separate ELF objects, as referenced by either the .gnu_debuglink or inferred by the GNU "build ID" ELF note.

-p

Attempt to print the stack trace from any discovered python interpreters and threads. This feature is experimental, and only works with Python 2.7.

-s

Do not attempt to locate source code information (file and line number) for each frame. Finding the source locations may slow down stack tracing.

-t

Do not use the thread_db library to associate userland thread data structures with kernel level LWPs. For modern linux systems, LWPs and user mode threads are effectively the same thing. At this point the only benefit of using this library is to associated pthread IDs with the LWPs.

-v

Produce more verbose diagnostics. Can be repeated to increase verbosity further.

-b N

Poll-mode: repeatedly trace stacks every N seconds, until interrupted.

-g directory

Use directory as a potential location to find debug ELF images, as referred to by a build-id note or gnu_debuglink section. The default directory is /usr/lib/debug

<executable | core | pid>

List of core files or PIDs to trace. An executable image specified on the command line will override the executable derived from the core or processes specified after it until a different executable image is provided

There are some options to aid debugging issues with ELF and DWARF binaries. Namely

pstack -D ELF-image

Format DWARF debugging information of the provided ELF-image in JSON

pstack -d ELF-image

Format ELF information of the provided ELF-image in JSON

pstack -V

Print git commit-id used to build pstack

pstack -h

Print usage synopsis pstack

procfs(5) ptrace(2)

• Support rela for object files

• This actually works on ARM (i.e., raspi), but needs debug_frame. Apparently, ARM has its own magical sections for storing unwind information that it might be worth implementing.

• Support inlined subroutines, so we show the surrounding scopes as part of the stack trace.

works on x86_64 and i686 only.

Peter Edwards <peadar (at) isainmdom dot net>

Debian - March 29, 2018