Lock thread gdb. Now, I keep typing n to make the thread 2 run. When you continue the stopped thread, all other threads will also continue, unless you do set scheduler-locking on. Without a doubt, we can debug multi-threaded programs with gdb. The execution of the other one is blocked in Linux scheduler. What I want to do is to make the thread 2 run while making the thread 3 keep stopping. Moreover, in general other threads stop in the middle of a statement, rather than at a clean statement boundary, when the program stops. Now, I want to keep thread 3 wherever it is, and keep stepping through thread 2 (by executing c in gdb). 2. Thread Stops (Debugging with GDB) GDB supports debugging programs with multiple threads (see Debugging Programs with Multiple Threads). Note that any of step, next, etc. See documentation for set scheduler-locking on. In this tutorial, we’ll look at how to debug threads using GDB, along with some helpful examples. Jun 29, 2023 · Why doesn't set scheduler-locking off stop trapping on breakpoints on threads other than the current thread completely, but only trap on the current thread? gdb disable breakpoint in particular thr Nov 1, 2015 · GDB is a powerful debugger. Thread-Specific Breakpoints (Debugging with GDB) There are several ways for a thread to disappear, such as a regular thread exit, but also when you detach from the process with the detach command (see Debugging an Already-running Process), or if GDB loses the remote connection (see Remote Debugging), etc. 1 Enable & Disable In non-stop mode, you can pause some threads while keep WatchPoint Debugging multithreaded code with GDB: thread names Threading bugs can be tricky to diagnose! Thankfully, GDB has some great functionality for helping to debug threads. It covers command-line debugging tools, memory analysis, log configuration, and troubleshooting workflows for Linux-based Matter applications. In particular, GDB cannot single-step all threads in lockstep. So you'll want to set breakpoints, then set scheduler-locking on, then continue or finish in thread 1 (thread 2 is still stopped), then Ctrl-C to regain control of GDB, switch to thread 2, continue (thread 1 is still stopped), etc. For network 6 days ago · A deadlock occurs when two or more threads are each waiting for the other to release a resource, resulting in all of them being stuck forever. I get three threads (thread 2 and 3 are pthreads) and the program is at thread 2 (waiting at sleep(1)). The specific relationship between thread IDs can differ from one OS and Pthreads library implementation to another, but on most systems there is a one-to-one-to-one correspondence between a Pthreads ID, an LWP ID, and a GDB thread ID. Since thread scheduling is up to your debugging target’s operating system (not controlled by GDB), other threads may execute more than one statement while the current thread completes a single step. In my experience, most of debugging of threaded apps is putting May 2, 2018 · Other threads may run while stepping over a function call ('next'). 3 days ago · Linux Debugging Tips Relevant source files Purpose and Scope This page provides debugging techniques and tools specifically for Matter SDK development on Linux platforms. Then I run the program. What is the 'normal' way folks debug threaded apps You can never debug thread correctness, you can only design it in. Instead, the SIGINT is delivered to GDB, allowing you to decide whether to resume or terminate the target process. Nov 25, 2025 · Conclusion Suspending uninteresting threads is a critical skill for debugging multi-threaded pthread applications. For general troubleshooting issues, see Common Issues and Solutions. In particular, we can switch between threads, inspect the stack, and dump the registers. In this post, I would like to start with the Dining Philosophers Problem, which was first coined by Edsger Dijkstra. gdb's thread analysis capabilities let you examine the state of every thread and identify which locks they are waiting on. However, it seems that thread 3 is executed too because of typing n on the May 13, 2009 · In all-stop mode (the only mode supported by currently released versions) GDB will stop all threads as soon as any thread stops (due to a breakpoint or a signal). We would like to show you a description here but the site won’t allow us. With GDB’s thread suspend and scheduler locking, you can isolate target threads, simplify debug output, and diagnose concurrency issues with confidence. continues current (and thus all other) thread (after setting a temporary breakpoint Then I run the program. With the scheduler-locking enabled, GDB only let the current thread run. We present a few GDB basics for debugging threaded programs in GDB. If you press Ctrl+C to interrupt the target process, the process is not terminated immediately. Note that with some targets, GDB is only able to detect a thread has exited when the user Feb 7, 2017 · So if you want to force a single-thread behavior (that is, everytime you're sure that there should't be any deadlock during the function call), set GDB's scheduler-locking. Since thread scheduling is up to your debugging target's operating system (not controlled by GDB), other threads may execute more than one statement while the current thread completes a single step. Non-stop Mode 2. Sep 14, 2020 · So thread 1 is the main function, thread 2 and thread 3 are the two threads of func. There are two modes of controlling execution of your program within the debugger. Beware: if you suspend other threads, and if one of them holds a lock, and if your interesting thread needs that lock at some point while stepping, you'll deadlock. What I have tried is set scheduler-locking on, but it does not seem to work as I expected. Then I execute thread 2 to switch to the thread 2. 6 days ago · Step-by-step guide on debug deadlocks with gdb thread analysis using Red Hat Enterprise Linux 9. In the default mode, referred to as all-stop mode, when any thread in your program stops (for example, at a breakpoint or while being stepped), all other threads in the program When set to ‘on’, GDB prints extra messages whenever threads are created or destroyed. Here is the problem statement for Dining Philosophers Problem: Several philosophers are sitting in . bam byx gkgft tzydc pitqln xfzro kbiseuo grkqj gcfa nayzat