repeatable panic on pageout with 945GM

With KDE and compositing enabled, I randomly get the following:

(kgdb) info stack
#0  doadump (textdump=<value optimized out>) at pcpu.h:221
#1  0xffffffff8064e98e in kern_reboot (howto=260) at
/usr/src/sys/kern/kern_shutdown.c:366
#2  0xffffffff8064eea1 in vpanic (fmt=<value optimized out>, ap=<value
optimized out>) at /usr/src/sys/kern/kern_shutdown.c:759
#3  0xffffffff8064ed13 in panic (fmt=0x0) at
/usr/src/sys/kern/kern_shutdown.c:690
#4  0xffffffff809d18ed in vm_fault_hold (map=<value optimized out>,
vaddr=<value optimized out>, fault_type=<value optimized out>,
    fault_flags=<value optimized out>, m_hold=<value optimized out>) at
/usr/src/sys/vm/vm_fault.c:327
#5  0xffffffff809cf548 in vm_fault (map=0xfffff80002000000, vaddr=<value
optimized out>, fault_type=1 '\001', fault_flags=<value optimized out>)
    at /usr/src/sys/vm/vm_fault.c:273
#6  0xffffffff80a1849f in trap_pfault (frame=<value optimized out>,
usermode=0) at /usr/src/sys/amd64/amd64/trap.c:741
#7  0xffffffff80a17b30 in trap (frame=0xfffffe00dbec5830) at
/usr/src/sys/amd64/amd64/trap.c:442
#8  0xffffffff809fd5a1 in calltrap () at
/usr/src/sys/amd64/amd64/exception.S:236
#9  0xffffffff80a0a3bb in pmap_remove_all (m=<value optimized out>) at
/usr/src/sys/amd64/amd64/pmap.c:3950
#10 0xffffffff809c0c57 in cdev_pager_free_page (object=<value optimized
out>, m=0xfffffe0001e410d0) at /usr/src/sys/vm/device_pager.c:214
#11 0xffffffff816aff33 in i915_gem_release_mmap (obj=<value optimized
out>) at
/usr/src/sys/modules/drm2/i915kms/../../../dev/drm2/i915/i915_gem.c:1691
#12 0xffffffff816b104b in i915_gem_object_unbind
(obj=0xfffff8008ef11400) at
/usr/src/sys/modules/drm2/i915kms/../../../dev/drm2/i915/i915_gem.c:2738
#13 0xffffffff816b47c8 in __i915_gem_shrink (dev_priv=<value optimized
out>, target=-1, purgeable_only=<value optimized out>)
    at
/usr/src/sys/modules/drm2/i915kms/../../../dev/drm2/i915/i915_gem.c:2056
#14 0xffffffff816b3f47 in i915_gem_inactive_shrink (arg=<value optimized
out>) at
/usr/src/sys/modules/drm2/i915kms/../../../dev/drm2/i915/i915_gem.c:4755
#15 0xffffffff809ec628 in vm_pageout () at /usr/src/sys/vm/vm_pageout.c:899
#16 0xffffffff80609dcc in fork_exit (callout=0xffffffff809ec260
<vm_pageout>, arg=0x0, frame=0xfffffe00dbec5c00) at
/usr/src/sys/kern/kern_fork.c:1034
#17 0xffffffff809fdade in fork_trampoline () at
/usr/src/sys/amd64/amd64/exception.S:611
#18 0x0000000000000000 in ?? ()

Any hints?

	imb