fix(profiling): never enable fast copy memory if interpreter is embedded [backport 4.12] - #19927
Open
KowalskiThomas wants to merge 1 commit into
Open
fix(profiling): never enable fast copy memory if interpreter is embedded [backport 4.12]#19927KowalskiThomas wants to merge 1 commit into
KowalskiThomas wants to merge 1 commit into
Conversation
Codeowners resolved as |
Circular import analysis
|
![chatgpt-codex-connector[bot]](https://avatars.githubusercontent.com/in/1144995?s=60&v=4){kind=small}
There was a problem hiding this comment.
💡 Codex Review
Here are some automated review suggestions for this pull request.
Reviewed commit: f70c1b6626
ℹ️ About Codex in GitHub
Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you
- Open a pull request for review
- Mark a draft as ready
- Comment "@codex review".
If Codex has suggestions, it will comment; otherwise it will react with 👍.
Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".
gyuheon0h
approved these changes
Aug 28, 2026
Contributor
|
KowalskiThomas
enabled auto-merge (squash)
August 28, 2026 15:22
Fast memory copy (safe_memcpy) relies on installing SIGSEGV/SIGBUS signal handlers to recover from faults. When Python is embedded in another process (e.g. the Datadog Agent), those handlers can displace signal handlers owned by the host process and cause crashes. This change detects whether the interpreter is embedded (by checking whether the process executable looks like a Python binary) and, if so, skips installing the signal handlers and disables fast copy on both the native (vm.cc) and Python config (profiling.py) sides.
KowalskiThomas
force-pushed
the
kowalski/backport-19920-to-4.12
branch
from
August 29, 2026 07:36
f70c1b6 to
1b3741d
Compare
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Backport of PR #19920 to branch
4.12.Description
This PR changes the logic for the enablement of fast copy memory (signal handler-based) to never install signal handlers / try to use fast copy memory when the Python interpreter is running embedded in another application.
The reason we originally want to do that is we received crash reports originating from the Datadog Agent where running Python instrumentation in the Agent caused the Agent to crash. It makes sense generally speaking to be as quiet as possible, and as non-dangerous as possible, when running within another process. Hence this change.
Notes on conflict resolution
The
4.12branch'sddtrace/internal/settings/profiling.pyhas diverged structurally frommain(it lacks the native heap / exception-profiling availability checks and themax_frames/gc_enabledconfig options present onmain). The equivalent change was applied by hand:_is_python_embedded()helper and its imports (os,sys).config.stack.fast_copyoverride in the same style as the other availability-override blocks in this file (after thestack_is_availablecheck, before tag enrichment), since4.12has no laterreport_configuration(config)call to place it before.vm.ccand the new test file/CMakeLists.txt entries were unchanged frommainand applied as-is.Note: source PR #19920 was not yet merged at the time this backport was prepared (approved and mergeable); this backport is created from its current head commit.