sched/task: fix null pointer dereference in fork address environment …

[hujun260]

Summary

Fix null pointer dereference in fork operation when setting up address environments. The addrenv_join() function accesses the child task's group pointer (child->group), which is initialized by group_initialize(). By moving addrenv_join() to occur after group_initialize(), the code ensures child->group is properly set before it is accessed, eliminating the null pointer dereference.

Changes

• sched/task/task_fork.c:
  • Move address environment join block in nxtask_setup_fork() from before group_initialize() to after it
  • Relocate addrenv_join() call and its error handling to execute after group_initialize()
  • Maintain all other fork operation sequencing and error handling

Benefits & Technical Details

• Null pointer safety: child->group is now guaranteed to be initialized before addrenv_join() accesses it
• Correct sequencing: Task group initialization must precede address environment operations
• Error handling: All error paths correctly handled with existing cleanup logic
• Fork correctness: Child task inherits parent's address environment with proper initialization

Testing

• Verified fork operations complete without null pointer dereference
• Confirmed child task group is properly initialized before address environment join
• Tested fork with CONFIG_ARCH_ADDRENV enabled and disabled
• Validated child task inherits correct address environment from parent
• Confirmed no regression in fork functionality or child task creation

Impact

• Correctness: Fixes crash in fork when CONFIG_ARCH_ADDRENV is enabled
• Compatibility: Fully backward compatible, no API changes
• Configuration: Particularly important for builds with CONFIG_ARCH_ADDRENV
• Scope: Affects fork-based task creation with address environment support