Hello Dave, Currently for "bt -a" also swapper tasks on offline CPUs are printed (at least on s390). Wouldn't it be better to only print a backtrace, when the task is running on an online CPU? My suggestion would be to implement that with the following patch by only setting the panic threads for online CPUs. I also attached a second alternative patch that fills the active set array only with tasks on online CPUs. What do you think? Michael --- task.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) --- a/task.c +++ b/task.c @@ -5658,8 +5658,12 @@ populate_panic_threads(void) struct task_context *tc; if (get_active_set()) { - for (i = 0; i < NR_CPUS; i++) - tt->panic_threads[i] = tt->active_set[i]; + for (i = 0; i < NR_CPUS; i++) { + if (kt->cpu_flags[i] & ONLINE) + tt->panic_threads[i] = tt->active_set[i]; + else + tt->panic_threads[i] = 0; + } return; }