Description of problem:
I have started mediawriter from the command line, selected the KDE spin. When I clicked the Create Live USB button, it crashed. The following output was printed on the command line:
nouveau: kernel rejected pushbuf: Invalid argument                                                                                                                                                                                           
nouveau: ch22: krec 0 pushes 1 bufs 3 relocs 0                                                                                                                                                                                               
nouveau: ch22: buf 00000000 00000003 00000004 00000004 00000000                                                                                                                                                                              
nouveau: ch22: buf 00000001 00000006 00000004 00000000 00000004
nouveau: ch22: buf 00000002 00000021 00000004 00000004 00000000
mediawriter: pushbuf.c:727: nouveau_pushbuf_data: Assertion `kref' failed.
mediawriter: pushbuf.c:727: nouveau_pushbuf_data: Assertion `kref' failed.

As a sidenote, it looks like the nouveau driver on Fedora 25 is really flakey in a Plasma environment. I'm seeing all sorts of poor behaviour, which all appears to lead back to nouveau...

Version-Release number of selected component:
mediawriter-4.0.7-0.fc25

Additional info:
reporter:       libreport-2.8.0
backtrace_rating: 4
cmdline:        mediawriter
crash_function: nouveau_pushbuf_data
executable:     /usr/bin/mediawriter
global_pid:     8366
kernel:         4.8.11-300.fc25.x86_64
pkg_fingerprint: 4089 D8F2 FDB1 9C98
pkg_vendor:     Fedora Project
runlevel:       N 5
type:           CCpp
uid:            1000

Truncated backtrace:
Thread no. 1 (10 frames)
 #4 nouveau_pushbuf_data at pushbuf.c:727
 #6 nouveau_pushbuf_space at pushbuf.c:689
 #7 PUSH_SPACE at ./nouveau_winsys.h:31
 #8 BEGIN_1IC0 at nvc0/nvc0_winsys.h:134
 #9 nve4_update_surface_bindings at nvc0/nvc0_tex.c:1161
 #10 nvc0_validate_surfaces at nvc0/nvc0_tex.c:1189
 #11 nvc0_state_validate at nvc0/nvc0_state_validate.c:832
 #12 nvc0_state_validate_3d at nvc0/nvc0_state_validate.c:850
 #13 nvc0_draw_vbo at nvc0/nvc0_vbo.c:977
 #14 st_draw_vbo at state_tracker/st_draw.c:276

Potential duplicate: bug 1399041