System waits for input before booting even while ddb.panic=0
Extra info
The problem is that after a panic the system might wait for input while
saying it is syncing disks.
It looks like the problem is as follows:
In subr_prf.c:
panic calls db_stack_dump which calls db_stack_trace_print which has printf
as callback argument.
printf calls kprintf which calls KPRINTF_PUTCHAR which calls kputchar which
calls db_putchar.
Then in db_output.c:
db_putchar calls db_more (for long stacktraces) which calls
switch(cngetc()).
cngetc prevents rebooting straight away as the system is waiting for input.
A workaround is to recompile the kernel with the following change in
db_output.c:
replacing: switch(cngetc()) {...}
with just: db_output_line = 0;
I doubt this solution is acceptable as a bug fix though.
I cannot test it, since an apt panic seems not be enforceable.
with kind regards
Johan
