Debugging Your Program Using Valgrind Gdbserver And Gdb; Quick Start: Debugging In 3 Steps - Valgrind Software Quick Start Manual

Using and understanding the Valgrind core: Advanced Topics
VALGRIND_STACK_REGISTER(start, end):
Registers a new stack. Informs Valgrind that the memory range between start and end is a unique stack. Returns a
stack identifier that can be used with other VALGRIND_STACK_ * calls.
Valgrind will use this information to determine if a change to the stack pointer is an item pushed onto the stack or a
change over to a new stack. Use this if you're using a user-level thread package and are noticing spurious errors from
Valgrind about uninitialized memory reads.
Warning: Unfortunately, this client request is unreliable and best avoided.
VALGRIND_STACK_DEREGISTER(id):
Deregisters a previously registered stack. Informs Valgrind that previously registered memory range with stack id id
is no longer a stack.
Warning: Unfortunately, this client request is unreliable and best avoided.
VALGRIND_STACK_CHANGE(id, start, end):
Changes a previously registered stack. Informs Valgrind that the previously registered stack with stack id id has
changed its start and end values. Use this if your user-level thread package implements stack growth.
Warning: Unfortunately, this client request is unreliable and best avoided.
3.2. Debugging your program using Valgrind
gdbserver and GDB
A program running under Valgrind is not executed directly by the CPU. Instead it runs on a synthetic CPU provided
by Valgrind. This is why a debugger cannot debug your program when it runs on Valgrind.
This section describes how GDB can interact with the Valgrind gdbserver to provide a fully debuggable program under
Valgrind. Used in this way, GDB also provides an interactive usage of Valgrind core or tool functionalities, including
incremental leak search under Memcheck and on-demand Massif snapshot production.

3.2.1. Quick Start: debugging in 3 steps

The simplest way to get started is to run Valgrind with the flag --vgdb-error=0. Then follow the on-screen
directions, which give you the precise commands needed to start GDB and connect it to your program.
Otherwise, here's a slightly more verbose overview.
If you want to debug a program with GDB when using the Memcheck tool, start Valgrind like this:
valgrind --vgdb=yes --vgdb-error=0 prog
In another shell, start GDB:
gdb prog
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