Crap, it seems the patched iphb module does not solve the reboot-on-traffick issue fully (and in fact it seems stopping iphbd does not either).
[ 366.061767] : PVRSRVCacheFlushDRIBW: Start address 0x0000b000 and length 0x00000000 not wrapped [ 366.126251] : OSCpuVToPageList: get_user_pages failed (-14), trying something else [ 366.126281] : OSCpuVToPageList: Memory region does not represent memory mapped I/O (VMA flags: 0x8001875)