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0.25 Release Notes

Below are some highlights from this release. For a full list of changes, check out the release notes on github:

What's New​

There are some exiciting new, but unstable, features in this release like imports, c-interop, and compile time functions. They're marked as "unstable" because we're still polishing/testing the exact API but please feel free to experiment with them and give us your feedback.

Additionally, there are lot of internal changes to bpftrace that are not noticable on the surface. We've been working hard to clean up a lot of tech debt, especially in regards to the bpftrace compile pipeline, our type system (leaning into BTF), probe expansion, code generation, and our new standard library. In fact there have been 397 commits between version 0.24.2 and 0.25.0 - that's huge!

Records​

Similar to tuples, except you can name fields and use those field names to access members:

interval:s:1 {
  $a = (color="green", size=2);
  print($a);        // { .color = "green", .size = 2 }
  print($a.size);   // 2
  $a = (size=10, color="blue");
  print($a.color);  // blue
}

Script Formatting​

bpftrace now provides canonical script formatting via the --fmt flag, e.g.

# bpftrace --fmt my_script.bt

build_id Stack mode​

ustack(build_id)

This is so users can get the build_id + file offset for stacks instead of just the instruction pointer, which is useful if you want to do symbolication after bpftrace has exited.

Standard Library Additions​

  • syscall_name() to convert system call numbers into names
  • pcomm to get the name of the process for the passed task or the current task
  • signal_thread() to target the current thread
  • probetype to get the current probe type, e.g. "kprobe", "uprobe"
  • find to get map value if it exists
  • uaddr now supports PIE and dynamic library symbols

What's Changed​

  • Increase RLIMIT_NOFILE on startup as needed
  • Root user check replaced with check for required capabilities (CAP_BPF, CAP_PERFMON, CAP_DAC_READ_SEARCH, CAP_DAC_OVERRIDE)
  • Remove automatic type promotion for integers, making them more flexible
  • Stabilize macros and map declarations

What's Fixed​

  • Fix missing lines in ustack/kstack resolution
  • Fix error in listing multiple probes
  • Fix interval probe attachment when CPU 0 is offline
  • Improved tuple binop comparison
  • Fix handling of void ptr and function ptr BTF types

Feedback​

As always feedback is welcome and appreciated. Please let us know how we can improve your experience with bpftrace.