Date: Sun, 2 Mar 2008 21:47:02 +0100 From: Juergen Lock <nox@jelal.kn-bremen.de> To: qemu-devel@nongnu.org, freebsd-emulation@FreeBSD.org Subject: qemu 2008-03-02 snapshot FreeBSD 7.0/amd64 guest regression (tcg?) Message-ID: <20080302204702.GA62895@saturn.kn-bremen.de>
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Hi! I've prepared a FreeBSD qemu-devel port update, as already mentioned on the freebsd-emulation list, and found the FreeBSD 7.0/amd64 isos now pagefault repeatedly, saying: panic: page fault cpuid = 0 kernel trap 12 with interrupts disabled Fatal trap 12: page fault while in kernel mode cpuid = 0; apic id = 00 fault virtual address = 0x20 fault code = supervisor read data, page not present instruction pointer = 0x8:0xffffffff8046c704 trap number = 12 frame pointer = 0x10:0x0 ... 0xffffffff8046c704 in the 7.0-RELEASE kernel used on the isos is in _thread_lock_flags: (kgdb) disassemble _thread_lock_flags Dump of assembler code for function _thread_lock_flags: 0xffffffff8046c6e0 <_thread_lock_flags+0>: push %r14 0xffffffff8046c6e2 <_thread_lock_flags+2>: mov %rdi,%r14 0xffffffff8046c6e5 <_thread_lock_flags+5>: push %r13 0xffffffff8046c6e7 <_thread_lock_flags+7>: push %r12 0xffffffff8046c6e9 <_thread_lock_flags+9>: push %rbp 0xffffffff8046c6ea <_thread_lock_flags+10>: push %rbx 0xffffffff8046c6eb <_thread_lock_flags+11>: mov %gs:0x0,%r13 0xffffffff8046c6f4 <_thread_lock_flags+20>: xor %r12d,%r12d 0xffffffff8046c6f7 <_thread_lock_flags+23>: callq 0xffffffff8071df80 <spinlock_enter> 0xffffffff8046c6fc <_thread_lock_flags+28>: mov (%r14),%rbp 0xffffffff8046c6ff <_thread_lock_flags+31>: mov $0x4,%eax 0xffffffff8046c704 <_thread_lock_flags+36>: lock cmpxchg %r13,0x20(%rbp) 0xffffffff8046c70a <_thread_lock_flags+42>: sete %al 0xffffffff8046c70d <_thread_lock_flags+45>: test %al,%al 0xffffffff8046c70f <_thread_lock_flags+47>: jne 0xffffffff8046c799 <_thread_lock_flags+185> 0xffffffff8046c715 <_thread_lock_flags+53>: mov 0x20(%rbp),%rdx 0xffffffff8046c719 <_thread_lock_flags+57>: cmp %r13,%rdx 0xffffffff8046c71c <_thread_lock_flags+60>: je 0xffffffff8046c7cd <_thread_lock_flags+237> 0xffffffff8046c722 <_thread_lock_flags+66>: callq 0xffffffff8071c4e0 <spinlock_exit> ---Type <return> to continue, or q <return> to quit--- 0xffffffff8046c727 <_thread_lock_flags+71>: jmp 0xffffffff8046c73c <_thread_lock_flags+92> 0xffffffff8046c729 <_thread_lock_flags+73>: data16 ... so this looks like either %rbp is indeed zero or that cmpxchg insn isnt getting correctly translated. If you want to reproduce just boot the 35 MB 7.0-RELEASE-amd64-bootonly.iso in qemu-system-x86_64 (without kqemu); you can find mirrors via http://mirrorlist.freebsd.org/ (search for isos, amd64 architecture, I used 7.0 as you can see.) Oh, if you want to look at the live kernel you can boot the 7.0-RELEASE-amd64-livefs.iso in 0.9.1 with the previously mentioned patch (see http://www.nabble.com/forum/ViewPost.jtp?post=14921171 ), select fixit->cdrom in the menu that comes up after choosing the keyboard layout, and run `kgdb /dist/boot/kernel/kernel /dev/mem'. Thanx, Juergen
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