If the whole system has only one cpu, that cpu won't be able to be offlined, so there is no need onoff task is stil running.
Signed-off-by: Boqun Feng <[email protected]> --- I hit something like the following while I was running rcutorture in a guest with only one vCPU: [ 31.197457] rcu-torture:torture_onoff task: offlining 0 [ 31.197508] rcu-torture:torture_onoff task: offline 0 failed: errno -16 I know this is an expected behavior, but think we could just stop the onoff task if there is only one cpu. kernel/torture.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/kernel/torture.c b/kernel/torture.c index fb39a06bbef5..a85b7d61d9dd 100644 --- a/kernel/torture.c +++ b/kernel/torture.c @@ -194,6 +194,12 @@ torture_onoff(void *arg) for_each_online_cpu(cpu) maxcpu = cpu; WARN_ON(maxcpu < 0); + + if (maxcpu == 0) { + VERBOSE_TOROUT_STRING("only one cpu is found, onoff is impossible"); + goto stop; + } + if (onoff_holdoff > 0) { VERBOSE_TOROUT_STRING("torture_onoff begin holdoff"); schedule_timeout_interruptible(onoff_holdoff); @@ -209,6 +215,8 @@ torture_onoff(void *arg) &sum_online, &min_online, &max_online); schedule_timeout_interruptible(onoff_interval); } + +stop: torture_kthread_stopping("torture_onoff"); return 0; } -- 2.8.0
