there have been a few kernel: NMI watchdog: BUG: soft lockup - CPU#1 stuck for bugs .... seconds in various kernels
and the rcu-stall can sometimes get called when that happens
for example , and not necessarily the problem you are seeing.
https://bugzilla.redhat.com/show_bug.cgi?id=1185519what would probably help is if you can interrupt the kernel boot and change the boot args so we can see some more info.
you do this by doing e for edit while in the boot menu, picking the line to edit and then appending it with some options.
debug would be the first i would try,
but heres an example from the archwiki site,
https://wiki.archlinux.org/index.php/Boot_debuggingdebug ignore_loglevel log_buf_len=10M print_fatal_signals=1 LOGLEVEL=8 earlyprintk=vga,keep sched_debug
not sure how much of that would work, but it may give a bit more incite into the problem.
ps the sound issue i get that on my asus laptop also.
check your pulse audio output devices... the answer is there speakers verses headphone
regards peter