Re: [PATCH 3/3] kernel/hung_task convert hung_task_panic boot parameter to sysctl

Vlastimil Babka
2020-04-01T08:47:12Z

On 4/1/20 1:12 AM, Tetsuo Handa wrote:
> On 2020/03/30 20:55, Vlastimil Babka wrote:
>> @@ -63,16 +63,6 @@ static struct task_struct *watchdog_task;
>> unsigned int __read_mostly sysctl_hung_task_panic =
>> CONFIG_BOOTPARAM_HUNG_TASK_PANIC_VALUE;
>>
>> -static int __init hung_task_panic_setup(char *str)
>> -{
>> - int rc = kstrtouint(str, 0, &sysctl_hung_task_panic);
>> -
>> - if (rc)
>> - return rc;
>> - return 1;
>> -}
>> -__setup("hung_task_panic=", hung_task_panic_setup);
>
> Can we defer removal of this handler for "one release cycle" (and instead emit a line
> saying that "this parameter will be replaced by ..." during that cycle) ? I welcome

The old parameter is not removed, it's just handled differently, see patch 2.
Both old name and new sysctl.name will work.

> PATCH 1/3, but kernel testing projects (e.g. syzbot) needs to update their settings
> between PATCH 1/3 was merged into linux.git and PATCH 3/3 is merged into linux.git .
>
> https://lkml.kernel.org/r/CACT4Y+YE-j5ncjTGN6UhngfCNRgVo-QDZ3VCBGACdbs9-v+axQ@mail.gmail.com says
> "Announcing unmerged changes is too early (as this patch showed). And once it's in linux-next it's already too late.."
>
>> -
>> static int
>> hung_task_panic(struct notifier_block *this, unsigned long event, void *ptr)
>> {
>>
>