Messages in this thread Patch in this message | | | From | Florian Rommel <> | Subject | [PATCH 4/4] scripts/gdb: Fix detection of current CPU in KGDB | Date | Thu, 25 Apr 2024 17:35:01 +0200 |
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Directly read the current CPU number from the kgdb_active variable.
Before, the active CPU was obtained through the current task, which required searching the task list for the pid of GDB's selected thread. Obtaining the pid was buggy: GDB may use selected_thread().ptid[1] (LWPID) instead of .ptid[2] (TID) to store the threads pid; see https://sourceware.org/gdb/current/onlinedocs/gdb.html/Threads-In-Python.html As a result, the detection could return the wrong CPU number, leading to incorrect results for $lx_per_cpu and $lx_current.
As a side effect, the patch significantly speeds up $lx_per_cpu and $lx_current in KGDB by avoiding the task-list iteration.
Signed-off-by: Florian Rommel <mail@florommel.de> --- scripts/gdb/linux/cpus.py | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-)
diff --git a/scripts/gdb/linux/cpus.py b/scripts/gdb/linux/cpus.py index 2b51a3abd363..2f11c4f9c345 100644 --- a/scripts/gdb/linux/cpus.py +++ b/scripts/gdb/linux/cpus.py @@ -26,11 +26,7 @@ def get_current_cpu(): if utils.get_gdbserver_type() == utils.GDBSERVER_QEMU: return gdb.selected_thread().num - 1 elif utils.get_gdbserver_type() == utils.GDBSERVER_KGDB: - tid = gdb.selected_thread().ptid[2] - if tid > (0x100000000 - MAX_CPUS - 2): - return 0x100000000 - tid - 2 - else: - return tasks.get_thread_info(tasks.get_task_by_pid(tid))['cpu'] + return gdb.parse_and_eval("kgdb_active.counter") else: raise gdb.GdbError("Sorry, obtaining the current CPU is not yet " "supported with this gdb server.") -- 2.44.0
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