Hi Rich, I spend several days on this issue but still cannot figure out the root cause. Sometimes, guestfs_lauch() gets stuck, sometimes, it is ok. I reproduced this issue using guestfish: -bash-4.2# guestfish Welcome to guestfish, the guest filesystem shell for editing virtual machine filesystems and disk images. Type: 'help' for help on commands 'man' to read the manual 'quit' to quit the shell
<fs> add /dev/xvdc <fs> run | 75% [#####################################################################################################################################################################--------------------------------------------------------] 00:15
It has been stuck for about 10 minutes. I can see if is in guestfs_launch(): -bash-4.2# gdb -p `pidof guestfish` -ex "set confirm off" -ex "bt" -ex "q" 0x00007fe6f6b5a680 in __poll_nocancel () at ../sysdeps/unix/syscall-template.S:81 81 T_PSEUDO (SYSCALL_SYMBOL, SYSCALL_NAME, SYSCALL_NARGS) #0 0x00007fe6f6b5a680 in __poll_nocancel () at ../sysdeps/unix/syscall-template.S:81 #1 0x00007fe6f795eea4 in poll (__timeout=-1, __nfds=2, __fds=0x7ffe4c0537b0) at /usr/include/bits/poll2.h:41 #2 read_data (g=0x7fe6f8e04bd0, connv=0x7fe6f8df9100, bufv=<optimized out>, len=4) at conn-socket.c:162 #3 0x00007fe6f7983f0c in recv_from_daemon (buf_rtn=0x7ffe4c053908, buf_rtn@entry=0x7ffe4c053658, size_rtn=0x7ffe4c0538e4, size_rtn@entry=0x7ffe4c053634, g=0x7fe6f8e04bd0, g@entry=0x7ffe4c053840) at proto.c:515 #4 guestfs_int_recv_from_daemon (g=g@entry=0x7fe6f8e04bd0, size_rtn=size_rtn@entry=0x7ffe4c0538e4, buf_rtn=buf_rtn@entry=0x7ffe4c053908) at proto.c:611 #5 0x00007fe6f797dae0 in launch_libvirt (g=0x7fe6f8e04bd0, datav=0x7fe6f8e04d90, libvirt_uri=<optimized out>) at launch-libvirt.c:573 #6 0x00007fe6f7973b2b in guestfs_impl_launch (g=g@entry=0x7fe6f8e04bd0) at launch.c:93 #7 0x00007fe6f790fb4d in guestfs_launch (g=0x7fe6f8e04bd0) at actions-3.c:142 #8 0x00007fe6f86e7eda in run_launch (cmd=<optimized out>, argc=<optimized out>, argv=<optimized out>) at cmds.c:13411 #9 0x00007fe6f870276c in issue_command (cmd=0x7fe6f8df5170 "run", argv=argv@entry=0x7ffe4c053f98, pipecmd=0x0, rc_exit_on_error_flag=<optimized out>) at fish.c:1181 #10 0x00007fe6f870334e in script (prompt=prompt@entry=1) at fish.c:733 #11 0x00007fe6f86c7262 in interactive () at fish.c:630 #12 main (argc=1, argv=0x7ffe4c0543f8) at fish.c:577 I tried export LIBGUESTFS_BACKEND=direct, and it is also stuck for more than 10 minutes, here is the call stack: 0x00007f2dd9ac6ee0 in __nanosleep_nocancel () at ../sysdeps/unix/syscall-template.S:81 81 T_PSEUDO (SYSCALL_SYMBOL, SYSCALL_NAME, SYSCALL_NARGS) #0 0x00007f2dd9ac6ee0 in __nanosleep_nocancel () at ../sysdeps/unix/syscall-template.S:81 #1 0x00007f2dd9ac6d94 in __sleep (seconds=0, seconds@entry=2) at ../sysdeps/unix/sysv/linux/sleep.c:137 #2 0x00007f2dda912089 in launch_direct (g=0x7f2ddc527bd0, datav=<optimized out>, arg=<optimized out>) at launch-direct.c:814 #3 0x00007f2dda90eb2b in guestfs_impl_launch (g=g@entry=0x7f2ddc527bd0) at launch.c:93 #4 0x00007f2dda8aab4d in guestfs_launch (g=0x7f2ddc527bd0) at actions-3.c:142 #5 0x00007f2ddb682eda in run_launch (cmd=<optimized out>, argc=<optimized out>, argv=<optimized out>) at cmds.c:13411 #6 0x00007f2ddb69d76c in issue_command (cmd=0x7f2ddc518170 "run", argv=argv@entry=0x7ffd9f69fe28, pipecmd=0x0, rc_exit_on_error_flag=<optimized out>) at fish.c:1181 #7 0x00007f2ddb69e34e in script (prompt=prompt@entry=1) at fish.c:733 #8 0x00007f2ddb662262 in interactive () at fish.c:630 #9 main (argc=1, argv=0x7ffd9f6a0288) at fish.c:577 Has anyone seen this? Thanks. Allen 2016-08-30 7:11 GMT+08:00 Baochuan Wu <wildpointercs@gmail.com>:
Thanks Rich. I have used libguestfs for several month. It worked perfectly before, the issue appears recently. I am trying guestfs_set_backend (g, "direct").
Thanks, Allen
2016-08-29 23:31 GMT+08:00 Richard W.M. Jones <rjones@redhat.com>:
On Mon, Aug 29, 2016 at 11:19:04PM +0800, Baochuan Wu wrote:
Thanks Rich for you quick reply. I enabled logs and the program stuck again, here is the call stack and log: Thread 1 (Thread 0x7fac58edc8c0 (LWP 1271)): #0 0x00007fac578fac20 in __poll_nocancel () from /lib64/libc.so.6 #1 0x00007fac56df3c5a in virNetClientIOEventLoop () from /lib64/libvirt.so.0 #2 0x00007fac56df441b in virNetClientSendInternal () from /lib64/libvirt.so.0 #3 0x00007fac56df5843 in virNetClientSendWithReply () from /lib64/libvirt.so.0 #4 0x00007fac56df6052 in virNetClientProgramCall () from /lib64/libvirt.so.0 #5 0x00007fac56dcbfe2 in callFull.isra.2 () from /lib64/libvirt.so.0 #6 0x00007fac56de213d in remoteDomainCreateXML () from /lib64/libvirt.so.0 #7 0x00007fac56d82151 in virDomainCreateXML () from /lib64/libvirt.so.0 #8 0x00007fac58acca50 in launch_libvirt () from /lib64/libguestfs.so.0 #9 0x00007fac58ac2b2b in guestfs_impl_launch () from /lib64/libguestfs.so.0 #10 0x00007fac58a5eba5 in guestfs_launch () from /lib64/libguestfs.so.0 #11 0x00000000004117ca in main () ... libguestfs: [62900ms] launch libvirt guest
The error is happening in libvirt's virDomainCreateXML call, called from libguestfs here:
https://github.com/libguestfs/libguestfs/blob/master/src/lau nch-libvirt.c#L600
Unfortunately libvirt isn't a simple C library. It will launch and talk to a daemon (usually ``libvirt --timeout=30'' process, if you are not running as root). Debugging into libvirtd is described here:
http://libguestfs.org/guestfs-faq.1.html#debugging-libvirt
A workaround is to set LIBGUESTFS_BACKEND=direct [or use the equivalent call ``guestfs_set_backend (g, "direct")''] which will cause libguestfs to run qemu directly instead of going through libvirt.
http://libguestfs.org/guestfs.3.html#backend
Rich.
-- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtualization blog: http://rwmj.wordpress.com virt-df lists disk usage of guests without needing to install any software inside the virtual machine. Supports Linux and Windows. http://people.redhat.com/~rjones/virt-df/