Date: Thu, 9 Aug 2018 14:02:45 +0300 From: Konstantin Belousov <kostikbel@gmail.com> To: Johannes Lundberg <johalun0@gmail.com> Cc: freebsd-current <freebsd-current@freebsd.org> Subject: Re: Early kernel boot log? Message-ID: <20180809110245.GJ1884@kib.kiev.ua> In-Reply-To: <CAECmPws1ZU%2BJoXhDy86Bpquc9yvDh5PMQAj5kJZ6VfuckpzmPw@mail.gmail.com> References: <CAECmPwuJELN%2BL05z1a36DZd5FKCC=kRNS7swCjuqdA2uGPMpRA@mail.gmail.com> <20180809082904.GI1884@kib.kiev.ua> <CAECmPws1ZU%2BJoXhDy86Bpquc9yvDh5PMQAj5kJZ6VfuckpzmPw@mail.gmail.com>
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On Thu, Aug 09, 2018 at 10:26:06AM +0100, Johannes Lundberg wrote: > On Thu, Aug 9, 2018 at 9:29 AM Konstantin Belousov <kostikbel@gmail.com> > wrote: > > > On Thu, Aug 09, 2018 at 08:54:31AM +0100, Johannes Lundberg wrote: > > > Hi > > > > > > So I believe the reason I'm not seeing and printf output in dmesg is that > > > it is too early in some functions. > > > For example > > > machdep.s > > > getmemsize() > > > add_efi_map_entries() > > > etc > > > > > > However, these functions do contain debug printf statements so if they're > > > logging to somewhere, where/how can I see this? > > > > > > I also tried booting in bhyve too see if I could get any output via > > serial > > > console but nothing there either. > > Disable efi console, only leaving comconsole around, then set > > debug.late_console=0 > > in loader. > > > > Thanks for the tip. I found the comment in machdep.c that explains this > now. > However, running in bhyve with > console="comconsole" (not needed in bhyve I guess?) > debug.late_console=0 > > Boot hangs after > Booting... > output. > Caused by late_console=0. That early hangs are typically due to an exception occuring before IDT is set up and trap machinery operational. Double-check that there is no any early framebuffer access, as a drastic measure remove all framebuffer drivers from your kernel config. I do not remember, where gdb stubs added to bhyve ? Is there a way to inspect the vm guest state in bhyve by other means ?
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