Save errno in signal handlers #9457
Merged
Conversation
This file contains 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
alexey-milovidov
added
pr-bugfix
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
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Outdated suggestions cannot be applied.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.
Changelog category (leave one):
Changelog entry (a user-readable short description of the changes that goes to CHANGELOG.md):
Avoid extremely rare cases when the user can get wrong error message (
Successinstead of detailed error description).Detailed description / Documentation draft:
This was clearly a bug. But it's very unlikely to reproduce. It requires query profiler enabled with some high frequency (by default it is enabled with the frequency of one second) and we should have some error when we check errno (example: cannot read from file) and the profiling signal should come exactly in the instruction when we already get the error but before we have checked for errno. I have not seen this bug in practice yet. The fix comes only from theoretical observations and no test will be attached.