Date: Wed, 13 Aug 2008 17:28:05 +0200 From: "Alexander Leidinger" <Alexander@Leidinger.net> To: "Kostik Belousov" <kostikbel@gmail.com> Cc: Nate Eldredge <neldredge@math.ucsd.edu>, freebsd-hackers@freebsd.org Subject: Re: Debugging reboot with Linux emulation Message-ID: <20080813172805.26324k9zft01f62o@webmail.leidinger.net> In-Reply-To: <20080813141059.GH1803@deviant.kiev.zoral.com.ua> References: <Pine.GSO.4.64.0808122344020.11980@zeno.ucsd.edu> <20080813132822.18394zk66kfg0xcs@webmail.leidinger.net> <20080813115413.GF1803@deviant.kiev.zoral.com.ua> <20080813160353.55171pui9o2wvm4g@webmail.leidinger.net> <20080813141059.GH1803@deviant.kiev.zoral.com.ua>
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Quoting "Kostik Belousov" <kostikbel@gmail.com> (from Wed, 13 Aug 2008 =20 17:10:59 +0300): > On Wed, Aug 13, 2008 at 04:03:53PM +0200, Alexander Leidinger wrote: >> Quoting "Kostik Belousov" <kostikbel@gmail.com> (from Wed, 13 Aug 2008 >> 14:54:13 +0300): >> >> >On Wed, Aug 13, 2008 at 01:28:22PM +0200, Alexander Leidinger wrote: >> >>Quoting "Nate Eldredge" <neldredge@math.ucsd.edu> (from Tue, 12 Aug >> >>2008 23:52:35 -0700 (PDT)): >> >> >> >>>Hi folks, >> >>> >> >>>I recently tried to run a Linux binary of Maple (commercial math >> >>>software) on my FreeBSD 7.0-RELEASE/amd64 box, and the machine >> >>>rebooted. I tried it again while watching the console, and no panic >> >>>message appeared to be produced. Does anyone have any ideas on how >> >>>to debug problems of this nature? I realize I may not be able to >> >>>get Maple to work, but in any case the system should not die like >> >>>this, so I can at least try to fix that bug. >> >>> >> >>>Incidentally, is it possible to run kdb with a USB keyboard? >> >>>Hitting Ctrl-Alt-Esc gives me the kdb prompt, but I can't type, so I >> >>>can do nothing except hit the power button. I do have >> >>>hint.atkbd.0.flags=3D"0x1" in /boot/device.hints. Unfortunately I >> >>>don't have a PS/2 keyboard on hand, though I can try and get a hold >> >>>of one if all else fails. >> >> >> >>A guess out of my cristallball: >> >>That's one of the cases which happen if you run a linux program >> >>without branding it as a linux program first. People tend to think it >> >>is not needed, but in some rare circumstances it just causes what you >> >>see, a reboot. So go and identify all binaries (IMPORTANT: but not the >> >>libraries!), e.g. with the file(1), and use "brandelf -t Linux" on >> >>those programs. >> > >> >That would be an enormous local hole, assuming an native FreeBSD binary >> >may cause system crash. I actually doubt that non-branded elf binary >> >ever start, due to unsatisfied dynamic dependencies. >> >> You see this behavior only for static binaries. In the non-branded >> case the image activator takes the FreeBSD image and unfortunately >> there's a common syscall in linux which matches the syscall number in >> FreeBSD which causes the reboot (IIRC reboot syscall, do we have >> something like this?). It's not a system crash (kernel panic), it's a >> real reboot. AFAIR this also only works if you run the program as >> root. So... > > Then, the issue of mixing our reboot(2)/linux fcntl(2) is irrelevant. > The original reporter said that system "just rebooted", and I believe > that filesystems where not synced and not unmounted properly. Our > reboot(2) does not have flag combination that could cause such > behaviour, I think. > > Also, I doubt that the program being run is statically linked or > run by root. Confirmation ? I will not be surprised if it is statically linked and run by root. =20 I've seen enough such cases with commercial software and users using =20 it, that my cristalball caused me to send my first reply to the problem. > Overall, this looks like a nasty bug, hopefully in the linuxolator. The linuxulator is not involved, as there's no branding it is not =20 invoked. The same will happen if the linxulator is not in the kernel. Bye, Alexander. --=20 If value corrupts then absolute value corrupts absolutely. http://www.Leidinger.net Alexander @ Leidinger.net: PGP ID =3D B0063FE7 http://www.FreeBSD.org netchild @ FreeBSD.org : PGP ID =3D 72077137
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