Tagged with: til

TIL: Debugging go programs with gdb

 
$ gdb --args podman info
(gdb) run
Starting program: /usr/bin/podman info
[Thread debugging using libthread_db enabled]
...
WARN[0000] Found incomplete layer "6748b9a4e6f2d75763acd0d8351dfb92d4281a0b3546cc68042fb8cb5e1b7c3c", deleting it

Thread 9 "podman" received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0x7fbacbfff6c0 (LWP 10496)]
Downloading source file /usr/src/debug/podman-5.3.1-1.fc41.x86_64/vendor/github.com/containers/storage/layers.go
github.com/containers/storage.(*layerStore).load (r=0xc00024c140, lockedForWriting=true, ~r0=<optimized out>, ~r0=<optimized out>, ~r1=..., ~r1=...) at /usr/src/debug/podman-5.3.1-1.fc41.x86_64/vendor/github.com/containers/storage/layers.go:917
917                     if layer.Flags == nil {

<Freeze frame, record scratch>

You might be wondering how I got here…

And no, I wasn’t trying to work on podman!

TIL: Inspecting Python Threads

One of my favourite things about Python is that pretty much everything about the language can be inspected at runtime and today I found out this is true even for threads.

While working on this PR I kept running into issues where the esbonio process would not terminate, despite everything to my knowledge at least, was being shutdown as expected. Having encountered issues like this before, I knew the culprit was likely to be some background thread was stuck on something and keeping the process alive. The problem was I had no idea which thread it could be or what it was doing.