On 2012-07-26 13:58, Chris Clayton wrote: > On 07/26/12 11:01, Avi Kivity wrote: >> On 07/26/2012 12:52 PM, Chris Clayton wrote: >>> On 07/19/12 19:23, Chris Clayton wrote: >>>> On 07/19/12 13:17, Avi Kivity wrote: >>>>> On 07/19/2012 03:14 PM, Chris Clayton wrote: >>>>> >>>>>>> Change of diagnostics, unfortunately. qemu-kvm-1.0.1 can, in fact, >>>>>>> crash >>>>>>> on 3.5.0-rc6 (and rc7). I didn't get it earlier because it takes many >>>>>>> times more invocations before the crash occurs with 1.0.1 and I >>>>>>> haven't >>>>>>> used qemu-kvm much in the past few weeks. >>>>>>> >>>>>>> I'm now checking whether I can get crashes (with 1.0.1 and/or >>>>>>> 1.1.0) on >>>>>>> linux-3.4.4. I'll report back in a day or two. >>>>>> >>>>>> I've started up qemu-kvm on kernel 3.4.4 many times and not see a >>>>>> crash. >>>>>> That would indicate that the problem is in the kernel. However, I >>>>>> pulled >>>>>> the latest and greatest from Linus yesterday evening and I now can't >>>>>> get >>>>>> the crash there either, so whatever it was seems to have been fixed. If >>>>>> I checkout and build 3.5.0-rc[1..7], I can get the crash pretty >>>>>> quickly, >>>>>> so it's been fixed in the last few days. >>>>> >>>>> There were no kvm changes post-rc7. >>>>> >>>> Yes, I'm aware of that, Avi. This thread started because I was getting a >>>> crash in qemu-kvm, which I thought was only in v1.1.0. Later it turned >>>> out the the problem was also present in v1.0.1, but much harder to hit. >>>> However, it only ever happened with 3.5.0 kernels. 3.4.4, with either >>>> version of qemu-kvm, was stable. So then it seemed that the problem was >>>> in the kernel, (but not necessarily in the kvm code). >>>> >>>> Something that's changed since rc7 has either fixed the problem or made >>>> it much harder to hit. With rc7 and earlier I can recreate the crash >>>> quite easily with qemu-kvm-1.1.0 and with enough runs of 1.0.1. With >>>> rc7+, I haven't been able to get a crash at all. >>>> >>> Well, I'm getting the crash again, but this time I've managed to get a >>> backtrace: >>> >>> Program received signal SIGSEGV, Segmentation fault. >>> [Switching to Thread 0xb60ffb40 (LWP 9405)] >>> 0xb7803d77 in __strcmp_sse4_2 () from /lib/libc.so.6 >>> (gdb) bt >>> #0 0xb7803d77 in __strcmp_sse4_2 () from /lib/libc.so.6 >>> #1 0xb7e65333 in g_str_equal () from /usr/lib/libglib-2.0.so.0 >>> #2 0xb7e6458d in g_hash_table_lookup () from /usr/lib/libglib-2.0.so.0 >>> #3 0x8014e2cf in type_table_lookup (name=0x802b0c50 "apic-common") at >>> qom/object.c:94 >>> #4 type_get_by_name (name=name@entry=0x802b0c50 "apic-common") at >>> qom/object.c:149 >>> #5 0x8014e933 in object_dynamic_cast (obj=obj@entry=0x80a5d818, >>> typename=typename@entry=0x802b0c50 "apic-common") >>> at qom/object.c:416 >>> #6 0x8014e8b9 in object_dynamic_cast_assert (obj=obj@entry=0x80a5d818, >>> typename=typename@entry=0x802b0c50 "apic-common") at qom/object.c:478 >>> #7 0x80193462 in cpu_set_apic_tpr (d=0x80a5d818, val=8 '\b') >>> at /home/chris/rpm/BUILD/qemu-kvm-1.1.1/hw/apic_common.c:60 >>> #8 0x801d0560 in kvm_arch_post_run (env=env@entry=0x80a55a60, >>> run=run@entry=0xb6239000) >>> at /home/chris/rpm/BUILD/qemu-kvm-1.1.1/target-i386/kvm.c:1695 >>> #9 0x801cb05f in kvm_cpu_exec (env=env@entry=0x80a55a60) at >>> /home/chris/rpm/BUILD/qemu-kvm-1.1.1/kvm-all.c:1269 >>> #10 0x80199d1e in qemu_kvm_cpu_thread_fn (arg=0x80a55a60) at >>> /home/chris/rpm/BUILD/qemu-kvm-1.1.1/cpus.c:752 >>> #11 0xb7a1fd9e in start_thread () from /lib/libpthread.so.0 >>> #12 0xb77bbbbe in clone () from /lib/libc.so.6 >>> >>> This is with kernel 3.5.0 and qemu-kvm-1.1.1. glibc is 2.16.0 built >> >> It looks like general memory corruption. Is this repeatable? What's >> the guest uptime when it happens (i.e. is it immediate?) > > I've just done 10 runs of WinXP SP3 and 5 of them crashed. Three crashed Hmm, I'm running various XP SP3 here against qemu.git (now widely equivalent to qemu-kvm), and I saw no crashes at all. > early as XP was starting up - well before the desktop would have > appeared. The other two crashed as XP was closing down, having been > running for a few minutes (but not doing much). > > The error messages seen through dmesg are: > > qemu-kvm[12778] general protection ip:b6c43d77 sp:b5e800fc error:0 in > libc-2.16.so[b6b06000+1b4000] > qemu-kvm[12813] general protection ip:b6bf6d77 sp:b54ff0fc error:0 in > libc-2.16.so[b6ab9000+1b4000] > qemu-kvm[12986] general protection ip:b6cd3d77 sp:b55ff0fc error:0 in > libc-2.16.so[b6b96000+1b4000] > qemu-kvm[13045] general protection ip:b6c91d77 sp:b54ff0fc error:0 in > libc-2.16.so[b6b54000+1b4000] > qemu-kvm[13225] general protection ip:b6c5bd77 sp:b54ff0fc error:0 in > libc-2.16.so[b6b1e000+1b4000] Oh, you are running 32-bit userland? Also 32-bit kernel? Most of us do 64-on-64. Jan -- Siemens AG, Corporate Technology, CT RTC ITP SDP-DE Corporate Competence Center Embedded Linux -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
