Hi Lianbo

1. Fixed Thread-Specific Register Retrieval

   * What was changed: In arm64_get_current_task_reg, the index was changed from a global pointer (extra_stacks_idx - 1) to a thread-specific ID (sid

     - 1).

   * Why it was fixed: Previously, the code always returned registers for the last added stack segment, regardless of which GDB thread was being

     inspected. This led to register data corruption when a task had multiple stack transitions (e.g., IRQ stack to Process stack). Now, it correctly

     maps each GDB thread to its corresponding register set.

 

  2. Eliminated Redundant Initial Backtrace for Panic Task

   * What was changed: Added (bt->task != tt->panic_task) checks in both arm64_back_trace_cmd and arm64_back_trace_cmd_v2 before adding the initial

     context as a GDB substack.

   * Why it was fixed:

       * For the Crashing (Panic) Task, GDB’s main thread (Thread 0) is already initialized with the correct registers from the ELF notes/crash notes.

       * Adding it again as a substack created a "Clone" (Thread 1) with identical registers, causing the backtrace to repeat itself (e.g., showing

         frames #0-20 and then repeating them as #21-41).

       * By skipping this initial substack for the panic task only, we prevent the duplication while still allowing other tasks to correctly register

         their contexts.

 

  Summary of Benefits:

   * No more duplicate frames: The gdb bt output for the crashing task will now start from frame #0 and continue linearly without repeating the entire

     stack.

   * Correct Register Data: Multiple stack segments (like IRQ or Exception stacks) will now show the correct register values for their respective

     frames because the indexing is no longer hardcoded to the "last" segment.

 

Could you please test using the attached patch?

Thanks

Li Pengfei