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Description of problem: chardev does not have a default backend ,when start qemu-kvm with -chardev w/o backend ,seg fault will happened. Version-Release number of selected component (if applicable): # uname -r 2.6.32-215.el6.x86_64 [root@test ~]# rpm -q qemu-kvm qemu-kvm-0.12.1.2-2.206.el6.x86_64 How reproducible: 100% Steps to Reproduce: 1.start guest with -chardev id=charchannnel0 -device virtserialport,bus=virtio-serial0.0,nr=1,chardev=charchannel0,id=channel0,name=test Actual results: segfault happened . Program received signal SIGSEGV, Segmentation fault. __strcmp_sse42 () at ../sysdeps/x86_64/multiarch/strcmp.S:515 515 movdqa (%rdi), %xmm2 (gdb) bt #0 __strcmp_sse42 () at ../sysdeps/x86_64/multiarch/strcmp.S:515 #1 0x00000000004beb38 in qemu_chr_open_opts (opts=0xf01470, init=0) at qemu-char.c:2640 #2 0x00000000004096ab in chardev_init_func (opts=<value optimized out>, opaque=<value optimized out>) at /usr/src/debug/qemu-kvm-0.12.1.2/vl.c:4756 #3 0x000000000047bc9a in qemu_opts_foreach (list=<value optimized out>, func=0x4096a0 <chardev_init_func>, opaque=0x0, abort_on_failure=<value optimized out>) at qemu-option.c:957 #4 0x000000000040d068 in main (argc=<value optimized out>, argv=<value optimized out>, envp=<value optimized out>) at /usr/src/debug/qemu-kvm-0.12.1.2/vl.c:6033 Expected results: chardev should have a default backend if user did not specify one .whatever should no segmentation fault Additional info:
Fixed upstream in 1bbd185fa826a2da7c6089b968f9f7d08438c2c8
Reproduced this issue on qemu-kvm-0.12.1.2-2.209.el6 and verified pass on qemu-kvm-0.12.1.2-2.221.el6.x86_64. Steps: Boot a guest with chardev but without backend, for example: -device virtio-serial-pci,id=virtio-serial0,max_ports=16,bus=pci.0,addr=0x7 -chardev id=channel0,host=127.0.0.1,port=12345,server,nowait -device virtserialport,bus=virtio-serial0.0,nr=1,chardev=channel0,id=channel0,name=com.redhat.rhevm.vdsm On qemu-kvm-0.12.1.2-2.209.el6, got a segment fault: Program received signal SIGSEGV, Segmentation fault. (gdb) bt #0 0x0000003243733a1a in __strcmp_ssse3 () from /lib64/libc.so.6 #1 0x00000000004bec88 in qemu_chr_open_opts (opts=0xf00d20, init=0) at qemu-char.c:2640 #2 0x00000000004096fb in chardev_init_func (opts=<value optimized out>, opaque=<value optimized out>) at /usr/src/debug/qemu-kvm-0.12.1.2/vl.c:4761 #3 0x000000000047bd0a in qemu_opts_foreach (list=<value optimized out>, func=0x4096f0 <chardev_init_func>, opaque=0x0, abort_on_failure=<value optimized out>) at qemu-option.c:957 #4 0x000000000040d068 in main (argc=<value optimized out>, argv=<value optimized out>, envp=<value optimized out>) at /usr/src/debug/qemu-kvm-0.12.1.2/vl.c:6038 On qemu-kvm-0.12.1.2-2.221.el6.x86_64, qemu gives prompt if there's no backend for a chardev: chardev: "channel0" missing backend So, this issue is fixed.
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Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. http://rhn.redhat.com/errata/RHBA-2012-0746.html