Re: [BUG?] false positive in soft lockup detector while unlzma initramfs on slow cpu

[Andrew Morton <akpm@linux-foundation.org>]

On Tue, 29 Jan 2013 10:33:48 -0500
Don Zickus <dzickus@redhat.com> wrote:

> --- a/kernel/watchdog.c
> +++ b/kernel/watchdog.c
> @@ -79,6 +79,14 @@ static int __init softlockup_panic_setup(char *str)
>  }
>  __setup("softlockup_panic=", softlockup_panic_setup);
>  
> +static int __init watchdog_thresh_setup(char *str)
> +{
> +	watchdog_thresh = simple_strtoul(str, NULL, 0);
> +
> +	return 1;
> +}
> +__setup("watchdog_thresh=", watchdog_thresh_setup);

I wonder if there's some magical way in which we can set any sysctl
from the kernel command line.  Add sys.vm.min_free_kbytes=42 to the
command line, walk the hierarchy late in boot...

To address Mike's bug I suggest we poke a touch_softlockup_watchdog()
into the appropriate place.  Presumably the loop in
lib/decompress_unlzma.c:unlzma().  The decompress code makes me cry.