On 20/05/22 00:11, Schspa Shi wrote:
> Some processes may not be stopped, such as workqueue workers.
>
> Add this dump_stack to easily figure out which process caused the problems.
>
> Before this change:
>
> <4>[ 517.545889] ------------[ cut here ]------------
> <4>[ 517.545901] Dying CPU not properly vacated!
> <4>[ 517.546366] ---[ end trace 0000000000000002 ]---
> <4>[ 518.546831] CPU6 enqueued tasks (2 total):
> <4>[ 518.546855] pid: 49, name: migration/6
> <4>[ 518.547010] pid: 6231, name: kworker/6:0
>
> Signed-off-by: Schspa Shi <[email protected]>
> ---
> kernel/sched/core.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> index 53596842f0d8..de6b5320e4d7 100644
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -9416,7 +9416,14 @@ static void dump_rq_tasks(struct rq *rq, const char *loglvl)
> continue;
>
> printk("%s\tpid: %d, name: %s\n", loglvl, p->pid, p->comm);
> + if (p != current)
> + sched_show_task(p);
> }
> + /*
> + * We need the stack of each cpu to analyze who is blocking the
> + * current cpu scheduling
> + */
> + trigger_all_cpu_backtrace();
> }
>
Given you get a WARN() when this happens, can't you get the same thing with
panic_on_warn=1
panic_print=PANIC_PRINT_ALL_CPU_BT
?
> int sched_cpu_dying(unsigned int cpu)
> --
> 2.24.3 (Apple Git-128)
Valentin Schneider <[email protected]> writes:
> On 20/05/22 00:11, Schspa Shi wrote:
>> Some processes may not be stopped, such as workqueue workers.
>>
>> Add this dump_stack to easily figure out which process caused the problems.
>>
>> Before this change:
>>
>> <4>[ 517.545889] ------------[ cut here ]------------
>> <4>[ 517.545901] Dying CPU not properly vacated!
>> <4>[ 517.546366] ---[ end trace 0000000000000002 ]---
>> <4>[ 518.546831] CPU6 enqueued tasks (2 total):
>> <4>[ 518.546855] pid: 49, name: migration/6
>> <4>[ 518.547010] pid: 6231, name: kworker/6:0
>>
>> Signed-off-by: Schspa Shi <[email protected]>
>> ---
>> kernel/sched/core.c | 7 +++++++
>> 1 file changed, 7 insertions(+)
>>
>> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
>> index 53596842f0d8..de6b5320e4d7 100644
>> --- a/kernel/sched/core.c
>> +++ b/kernel/sched/core.c
>> @@ -9416,7 +9416,14 @@ static void dump_rq_tasks(struct rq *rq, const char *loglvl)
>> continue;
>>
>> printk("%s\tpid: %d, name: %s\n", loglvl, p->pid, p->comm);
>> + if (p != current)
>> + sched_show_task(p);
>> }
>> + /*
>> + * We need the stack of each cpu to analyze who is blocking the
>> + * current cpu scheduling
>> + */
>> + trigger_all_cpu_backtrace();
>> }
>>
>
> Given you get a WARN() when this happens, can't you get the same thing with
>
> panic_on_warn=1
> panic_print=PANIC_PRINT_ALL_CPU_BT
>
> ?
Yes, I can get the information with these two parameters set.
But this is generally a difficult problem to reproduce, so wanted
to print it here so that useful information can be obtained without
turning on these switches.
>
>> int sched_cpu_dying(unsigned int cpu)
>> --
>> 2.24.3 (Apple Git-128)
--
BRs
Schspa