Fix null pointer dereference in traffic_crashlog #12756
Merged
+5
−0
Conversation
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
ServerBacktrace() can return 0 (success) but leave the trace pointer null when the target process has already exited. This caused a SEGV when fprintf() was called with the null trace pointer. Add a null check before using the trace pointer.
Contributor
There was a problem hiding this comment.
Pull request overview
This PR fixes a null pointer dereference bug in traffic_crashlog that occurs when attempting to retrieve a backtrace from a process that has already exited. The fix adds a null check after the ServerBacktrace() call to prevent dereferencing a null pointer before writing to the crash log file.
Key changes:
- Added null pointer check for the
tracevariable afterServerBacktrace()returns successfully - Added informative error message when backtrace retrieval fails due to null trace
💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.
masaori335
approved these changes
Dec 14, 2025
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Outdated suggestions cannot be applied.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.
Summary
crashlog_write_backtrace()whenServerBacktrace()returns 0 but leavestracepointer nullfprintf()with the trace pointerRoot Cause
Introduced in PR #10811 which moved backtrace logging from traffic_manager to traffic_crashlog but didn't account for
tracebeing null.Test plan
cmake --preset dev-asan)