fix: crash while exec ctgShowDbCache.

[xiao-77]

Description

Issue(s)

• Close/close/Fix/fix/Resolve/resolve: Issue Link

Checklist

Please check the items in the checklist if applicable.

• Is the user manual updated?
• Are the test cases passed and automated?
• Is there no significant decrease in test coverage?

[gemini-code-assist]

Summary of Changes

Hello @xiao-77, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request resolves a crash that occurred during the execution of the ctgdShowDBCache function. The fix addresses an issue with the synchronization mechanism by adjusting the placement of lock and unlock operations. This ensures that the vgCache is consistently protected, preventing potential race conditions or invalid memory access that could lead to a crash.

Highlights

• Locking Mechanism Fix: The CTG_LOCK and CTG_UNLOCK operations for dbCache->vgCache.vgLock have been relocated. The lock is now acquired unconditionally before checking dbCache->vgCache.vgInfo, and the unlock is performed unconditionally after the entire block, ensuring proper resource protection and release.

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Changelog

• source/libs/catalog/src/ctgDbg.c
  • Moved the CTG_LOCK(CTG_READ, &dbCache->vgCache.vgLock) call from inside the if (dbCache->vgCache.vgInfo) block to immediately before it, ensuring the lock is always acquired.
  • Moved the CTG_UNLOCK(CTG_READ, &dbCache->vgCache.vgLock) call from inside the if (dbCache->vgCache.vgInfo) block to immediately after it, ensuring the lock is always released regardless of the vgInfo status.

Activity

• The pull request was created by xiao-77 to address a crash in ctgdShowDbCache.
• The author has provided a standard PR template, indicating the intent to fix a crash.
• No specific review comments or discussions have been recorded yet.

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[gemini-code-assist]

Code Review

This pull request fixes a crash in ctgdShowDbCache by introducing a lock to prevent a race condition when accessing dbCache->vgCache.vgInfo. However, the fix is partial, as several unprotected accesses to vgInfo and cfgInfo earlier in the function still pose a risk of race conditions and crashes when debug logging is enabled. Furthermore, potential thread-safety issues were identified in other debug iteration functions where hash tables are traversed without sufficient global locking against concurrent modifications from the background update thread.

[Copilot]

Pull request overview

Fixes a crash in the catalog debug path when running ctgShowDbCache/ctgdShowDBCache, by adjusting how vgroup cache locking is performed during DB cache dumping.

Changes:

• Move CTG_LOCK(CTG_READ, &dbCache->vgCache.vgLock) to cover the vgInfo presence check before iterating vgroups.
• Ensure CTG_UNLOCK(CTG_READ, &dbCache->vgCache.vgLock) is executed after the vgroup debug dump block.

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