Description of problem:
Ws experimenting with a prime number sieve written in c.   Had the program open in gedit, a terminal session to compile with gcc and run.   Was looking into segment fault related to size of array sieve.   Was not running prime number sieve at time of error.    Segfault had occured a number of times this afternoon and evening.

Additional info:
reporter:       libreport-2.5.1
WARNING: CPU: 6 PID: 1840 at drivers/gpu/drm/radeon/radeon_object.c:84 radeon_ttm_bo_destroy+0xf1/0x100 [radeon]()
Modules linked in: ccm rfcomm fuse xt_CHECKSUM ipt_MASQUERADE nf_nat_masquerade_ipv4 tun nf_conntrack_netbios_ns nf_conntrack_broadcast ip6t_rpfilter ip6t_REJECT nf_reject_ipv6 xt_conntrack ebtable_nat ebtable_broute bridge ebtable_filter ebtables ip6table_nat nf_conntrack_ipv6 nf_defrag_ipv6 nf_nat_ipv6 ip6table_mangle ip6table_security ip6table_raw ip6table_filter ip6_tables iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack iptable_mangle iptable_security iptable_raw bnep arc4 intel_rapl iosf_mbi tpm_infineon x86_pkg_temp_thermal coretemp iTCO_wdt ppdev iTCO_vendor_support hp_wmi sparse_keymap iwlmvm snd_hda_codec_realtek mac80211 snd_hda_codec_generic snd_hda_codec_hdmi kvm snd_hda_intel snd_hda_controller snd_hda_codec crct10dif_pclmul crc32_pclmul crc32c_intel
 snd_hwdep iwlwifi snd_seq uvcvideo btusb snd_seq_device videobuf2_vmalloc videobuf2_core videobuf2_memops cfg80211 bluetooth ghash_clmulni_intel snd_pcm v4l2_common serio_raw videodev snd_timer i2c_i801 media hid_logitech_hidpp mei_me snd parport_pc rtsx_pci_ms memstick rfkill lpc_ich soundcore mei parport hp_accel lis3lv02d video ie31200_edac input_polldev edac_core wmi tpm_tis shpchp hp_wireless tpm nfsd auth_rpcgss nfs_acl lockd grace sunrpc mmc_block uas usb_storage hid_logitech_dj 8021q garp stp llc mrp radeon rtsx_pci_sdmmc mmc_core i2c_algo_bit drm_kms_helper ttm drm e1000e rtsx_pci mfd_core ptp pps_core
CPU: 6 PID: 1840 Comm: Xorg Not tainted 4.0.4-303.fc22.x86_64 #1
Hardware name: Hewlett-Packard HP ZBook 17 G2/2255, BIOS M70 Ver. 01.07 02/26/2015
 0000000000000000 00000000fd57a1e7 ffff880877c03b88 ffffffff81783124
 0000000000000000 0000000000000000 ffff880877c03bc8 ffffffff8109c66a
 00000000ffffffff ffff88083ed80468 ffff88083ed80400 ffffffffffffffff
Call Trace:
 [<ffffffff81783124>] dump_stack+0x45/0x57
 [<ffffffff8109c66a>] warn_slowpath_common+0x8a/0xc0
 [<ffffffff8109c79a>] warn_slowpath_null+0x1a/0x20
 [<ffffffffa0189f81>] radeon_ttm_bo_destroy+0xf1/0x100 [radeon]
 [<ffffffffa00e51d6>] ttm_bo_release_list+0xa6/0x1a0 [ttm]
 [<ffffffffa00e5635>] ttm_bo_release+0x1a5/0x250 [ttm]
 [<ffffffffa00e570d>] ttm_bo_unref+0x2d/0x30 [ttm]
 [<ffffffffa018a4c9>] radeon_bo_unref+0x39/0x70 [radeon]
 [<ffffffffa019f9ab>] radeon_gem_object_free+0x4b/0x70 [radeon]
 [<ffffffffa007d417>] drm_gem_object_free+0x27/0x40 [drm]
 [<ffffffffa007d968>] drm_gem_object_handle_unreference_unlocked+0xd8/0x120 [drm]
 [<ffffffffa007da56>] drm_gem_handle_delete+0xa6/0x100 [drm]
 [<ffffffffa007e0f0>] drm_gem_close_ioctl+0x20/0x30 [drm]
 [<ffffffffa007ea5b>] drm_ioctl+0x1db/0x640 [drm]
 [<ffffffffa007e0d0>] ? drm_gem_handle_create+0x50/0x50 [drm]
 [<ffffffff81105659>] ? enqueue_hrtimer+0x29/0x90
 [<ffffffffa016904c>] radeon_drm_ioctl+0x4c/0x80 [radeon]
 [<ffffffff81232046>] do_vfs_ioctl+0x2c6/0x4d0
 [<ffffffff812322d1>] SyS_ioctl+0x81/0xa0
 [<ffffffff81789749>] system_call_fastpath+0x12/0x17