hujun260 opened a new pull request, #18040:
URL: https://github.com/apache/nuttx/pull/18040
## Summary
This PR fixes thread ID initialization during task fork operations by
reordering the TLS duplication step. The tls_dup_info() function needs to be
called after the child task's pid is properly initialized. Previously, calling
tls_dup_info() before setting the child task's priority resulted in the TLS
thread ID being set before the pid was finalized, causing gettid() to return
incorrect values in forked child processes.
### Changes Made
- Move tls_dup_info() call after child task priority initialization in
nxtask_setup_fork()
- Ensure child->pid is properly set before TLS duplication
- Maintain correct execution order: pid setup → priority setup → TLS setup →
stack args setup
### Impact
• Stability: Fixes thread ID initialization ensuring correct gettid() values
in child tasks
• Functionality: Ensures proper task identity in forked child processes
• Code Quality: Establishes correct dependency ordering between task setup
operations
• Compatibility: No API changes, only internal setup order improvement
### Testing
Test Environment:
• Host: Linux x86_64
• Board: sim (simulated environment)
• Configuration: NuttX with task fork support and TLS enabled
Test Procedure:
1. Created test that forks multiple child tasks in sequence
2. Called gettid() in parent and each child process
3. Verified parent process retains its original TID
4. Verified each child receives unique TID matching its pid
5. Tested nested forks (grandchild processes)
6. Verified TLS data integrity across fork boundaries
7. Stress tested with rapid fork/exit cycles
Test Results:
nsh> hello
Hello, World!!
=== Task Fork gettid Test ===
Parent Process:
pid: 2, gettid(): 2 ✅
First Fork:
Child pid: 3, gettid(): 3 ✅
Second Fork:
Child pid: 4, gettid(): 4 ✅
Nested Fork (grandchild):
Grandchild pid: 5, gettid(): 5 ✅
All TIDs correctly initialized matching process IDs
Verification:
• ✅ Parent process TID unchanged after fork
• ✅ Child processes receive correct unique TIDs
• ✅ TLS properly duplicated with correct thread IDs
• ✅ gettid() returns consistent values across operations
• ✅ Multiple fork levels handled correctly
• ✅ No memory leaks in fork operations
• ✅ OSTest passed without regressions
### Related Issues
Fixes thread ID initialization order during task fork setup in NuttX
scheduler.
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