Date: Wed, 24 Apr 2013 00:03:08 +0200 From: Dimitry Andric <dim@FreeBSD.org> To: Andriy Gapon <avg@FreeBSD.org> Cc: Jeremy Chadwick <jdc@koitsu.org>, freebsd-hackers@FreeBSD.org, Joshua Isom <jrisom@gmail.com> Subject: Re: Rebooting from loader causes a "fault" in VMware Workstation Message-ID: <650A4439-B258-4FDA-BD5C-C9DEF5DC81ED@FreeBSD.org> In-Reply-To: <51770149.6020802@FreeBSD.org> References: <20130419162834.GA90217@icarus.home.lan> <006B20F1-F67B-4E9D-B0DF-D4ED843F7E8E@FreeBSD.org> <5176B238.7030306@FreeBSD.org> <201304231231.38765.jhb@freebsd.org> <51770149.6020802@FreeBSD.org>
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On Apr 23, 2013, at 23:46, Andriy Gapon <avg@FreeBSD.org> wrote: > on 23/04/2013 19:31 John Baldwin said the following: >> On Tuesday, April 23, 2013 12:09:28 pm Andriy Gapon wrote: ... >>> 0x00000000000090e8: lgdtl 0x95d0 >>> 0x00000000000090ef: ljmpw $0x18,$0x90f5 >>>=20 >>> Triple fault >>> CPU Reset (CPU 0) >>> ESI=3D0004503c EDI=3D3fe50968 EBP=3D00094a80 ESP=3D00001800 >>> EIP=3D000090ef EFL=3D00000046 [---Z-P-] CPL=3D0 II=3D0 A20=3D1 SMM=3D0= HLT=3D0 >>> ES =3D0033 0000a000 ffffffff 00cff300 DPL=3D3 DS [-WA] >>> CS =3D0008 00000000 ffffffff 00cf9a00 DPL=3D0 CS32 [-R-] >>> SS =3D0010 00000000 ffffffff 00cf9300 DPL=3D0 DS [-WA] >>> DS =3D0033 0000a000 ffffffff 00cff300 DPL=3D3 DS [-WA] >>> FS =3D0033 0000a000 ffffffff 00cff300 DPL=3D3 DS [-WA] >>> GS =3D0033 0000a000 ffffffff 00cff300 DPL=3D3 DS [-WA] >>> LDT=3D0000 00000000 0000ffff 00008200 DPL=3D0 LDT >>> TR =3D0038 00005f98 00002067 00008900 DPL=3D0 TSS32-avl >>> GDT=3D ff85c789 00000000 >>=20 >> This seems wrong (address is way too high). I wonder if the gdtdesc = was=20 >> trashed by something? Can you dump memory before the lgdtl = instruction at the=20 >> 0x95d0 address? >=20 > Looks correct: > Breakpoint 1, 0x000090e8 in ?? () > (gdb) x/i $eip > 0x90e8: lgdtl 0x95d0 > (gdb) x/3xh 0x95d0 > 0x95d0: 0x003f 0x9590 0x0000 > (gdb) x/16xh 0x9590 > 0x9590: 0x0000 0x0000 0x0000 0x0000 0xffff 0x0000 0x9a00 0x00cf > 0x95a0: 0xffff 0x0000 0x9300 0x00cf 0xffff 0x0000 0x9a00 0x0000 >=20 > Nevertheless doing stepi leads to exactly the same triple fault. Is it because lgdt loads the GDT from the ds segment, and ds is now 33, not 0 (or equal to CS, I'm not sure which is correct here)?
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