Description of problem:
logged in, happened immediately

Version-Release number of selected component:
plasma-workspace-5.5.5-5.fc23

Additional info:
reporter:       libreport-2.6.4
backtrace_rating: 4
cmdline:        /usr/bin/plasmashell -s --crashes 1
crash_function: pushbuf_krel
executable:     /usr/bin/plasmashell
global_pid:     1557
kernel:         4.4.6-301.fc23.x86_64
runlevel:       N 5
type:           CCpp
uid:            1000

Truncated backtrace:
Thread no. 1 (10 frames)
 #7 pushbuf_krel at pushbuf.c:238
 #8 nouveau_pushbuf_reloc at pushbuf.c:746
 #9 PUSH_RELOC at nv30/nv30_winsys.h:26
 #10 nv30_transfer_copy_data at nv30/nv30_transfer.c:740
 #11 nouveau_transfer_write at nouveau_buffer.c:211
 #12 nouveau_buffer_transfer_unmap at nouveau_buffer.c:544
 #13 pipe_transfer_unmap at util/u_inlines.h:491
 #14 u_default_transfer_inline_write at util/u_transfer.c:66
 #15 st_bufferobj_data at state_tracker/st_cb_bufferobjects.c:202
 #16 _mesa_buffer_data at main/bufferobj.c:1595