How do I get the backtrace for all the threads in GDB?

Question

Is there an equivalent command in GDB to that of WinDbg's !process 0 7?

I want to extract all the threads in a dump file along with their backtraces in GDB. info threads doesn't output the stack traces. So, is there a command that does?

Araby

The corresponding command for LLDB is bt all — in case someone found this via Google (who thinks GDB == LLDB). – Devanagari

With python the following works " (gdb) python for thread in gdb.selected_inferior().threads(): thread.switch(); print(thread.num);gdb.execute('where')" – Finney

@Devanagari this is good enough to be put in a question IMO – Luminous

In fact, I created the exact question: #67820906 – Luminous

Answer 1

Generally, the backtrace is used to get the stack of the current thread, but if there is a necessity to get the stack trace of all the threads, use the following command.

thread apply all bt

Monaural

To save the output to a file: gdb <binary> <coredump> -ex "thread apply all bt" -ex "quit" > output.log – Edana

You can shorten this to t a a bt – Brunn

The command in @Edana comment hangs for me. Better try with gdb <binary> <coredump> -ex "thread apply all bt" -ex "detach" -ex "quit" > output.log, to avoid a question from gdb that blocks the command waiting for input. – Sangfroid

The more generic syntax is thread apply [threadno] [all] args, where [threadno] can also be a space-separated list of thread identifiers (e.g. 2 3 4), or a range (e.g. 2-6). – Muss

@MarianoPaniga, or use --batch. – Introspect

Answer 2

Is there a command that does?

thread apply all where

Ingunna

A synonym for backtrace. – Inconsonant

Just tried, this is not a synonym for backtrace. – Maida

From info gdb where: The names 'where' and 'info stack' (abbreviated 'info s') are additional aliases for 'backtrace'. – Introspect

Answer 3

When debugging with several threads, it is also useful to switch to a particular thread number and get the backtrace for that thread only.

From the GNU GDB threads documentation

For debugging purposes, GDB associates its own thread number--a small integer assigned in thread-creation order--with each thread in your program.

Usage:

info threads

Then identify the thread that you want to look at.

thread <thread_id>

Finally, use backtrace for just that thread:

bt

Relish

Answer 4

If your process is running:

pstack $pid

Incurrent

Your answer could be improved with additional supporting information. Please edit to add further details, such as citations or documentation, so that others can confirm that your answer is correct. You can find more information on how to write good answers in the help center. – Gidgetgie