diff options
| author | Karl Mehltretter <kmehltretter@gmail.com> | 2026-07-23 06:10:55 +0200 |
|---|---|---|
| committer | Geert Uytterhoeven <geert@linux-m68k.org> | 2026-08-10 11:47:59 +0200 |
| commit | 09f71dbeb287e367beea56d9ac8a3d356ef5e02a (patch) | |
| tree | 6fb0eb966f85ef4615331d0c76bac98bf9024be3 | |
| parent | 993e1b93dbf64177551271496d92512a1d2c8643 (diff) | |
m68k: Fix backtraces for non-running tasks
When no stack pointer is supplied, show_stack() starts at thread.esp0.
This is the saved userspace register frame, not where a task was switched
out. For kernel threads it points to the zeroed frame created by
copy_thread(), so sched_show_task() prints no useful backtrace.
Use thread.ksp for non-current tasks. It is saved by switch_to() and is
already used by __get_wchan(). For current, start at the current stack
frame, as is already done when no task is supplied.
Tested on qemu-system-m68k -M virt using SysRq-t. All task dumps contained
resolved frames.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Assisted-by: Claude:claude-opus-4-8
Signed-off-by: Karl Mehltretter <kmehltretter@gmail.com>
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Link: https://patch.msgid.link/20260723041055.47289-1-kmehltretter@gmail.com
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
| -rw-r--r-- | arch/m68k/kernel/traps.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/m68k/kernel/traps.c b/arch/m68k/kernel/traps.c index d2f25e8895e5..60759ba3cbd4 100644 --- a/arch/m68k/kernel/traps.c +++ b/arch/m68k/kernel/traps.c @@ -936,8 +936,8 @@ void show_stack(struct task_struct *task, unsigned long *stack, int i; if (!stack) { - if (task) - stack = (unsigned long *)task->thread.esp0; + if (task && task != current) + stack = (unsigned long *)task->thread.ksp; else stack = (unsigned long *)&stack; } |