Comment 9 for bug 1303926

At the point when the ioctl fails, this is the backtrace:

(gdb) where
#0 kvm_physical_sync_dirty_bitmap (section=0x7fffffffd820) at /home/serge/src/qemu/kvm-all.c:446
#1 0x000055555580e30c in kvm_log_sync (listener=<optimized out>, section=<optimized out>) at /home/serge/src/qemu/kvm-all.c:803
#2 0x000055555581390e in memory_region_sync_dirty_bitmap (mr=mr@entry=0x555556257ca8) at /home/serge/src/qemu/memory.c:1210
#3 0x00005555557d943f in vga_sync_dirty_bitmap (s=0x555556257c98) at /home/serge/src/qemu/hw/display/vga.c:1618
#4 vga_draw_graphic (full_update=0, s=0x555556257c98) at /home/serge/src/qemu/hw/display/vga.c:1653
#5 vga_update_display (opaque=0x555556257c98) at /home/serge/src/qemu/hw/display/vga.c:1913
#6 0x0000555555780d92 in dpy_refresh (s=0x555556203690) at ui/console.c:1416
#7 gui_update (opaque=0x555556203690) at ui/console.c:194
#8 0x0000555555764bd9 in timerlist_run_timers (timer_list=0x5555561d2460) at qemu-timer.c:488
#9 0x0000555555764e44 in qemu_clock_run_timers (type=<optimized out>) at qemu-timer.c:499
#10 qemu_clock_run_all_timers () at qemu-timer.c:605
#11 0x0000555555729dbc in main_loop_wait (nonblocking=<optimized out>) at main-loop.c:490
#12 0x00005555555e6196 in main_loop () at vl.c:2051
#13 main (argc=<optimized out>, argv=<optimized out>, envp=<optimized out>) at vl.c:4506