Gnome-session-c segfault is reported in dmesg

Issue

• The Gnome-session-c segfault reported in dmesg:

  $cat var/log/messages |grep -i segfault
  Apr 25 16:22:13 localhost kernel: gnome-session-c[3765]: segfault at 20 ip 00007f4f99a01624 sp 00007ffd8d380ea8 error 6 in 
  swrast_dri.so[7f4f999e4000+e09000]
  Apr 25 16:22:23 localhost kernel: gnome-session-c[4527]: segfault at 20 ip 00007f1e35613624 sp 00007ffdbb697de8 error 6 in 
  swrast_dri.so[7f1e355f6000+e09000]
  Apr 25 16:41:26 localhost kernel: gnome-session-c[3860]: segfault at 20 ip 00007fe947db8624 sp 00007fff7ef2c1d8 error 6 in 
  swrast_dri.so[7fe947d9b000+e09000]
  Apr 25 16:44:32 localhost kernel: gnome-session-c[3373]: segfault at 20 ip 00007fd12cb78624 sp 00007ffc1e971b18 error 6 in 
  swrast_dri.so[7fd12cb5b000+e09000]
  Apr 25 16:48:42 localhost kernel: gnome-session-c[4305]: segfault at 20 ip 00007f2298d38624 sp 00007ffc5c92b9b8 error 6 in 
  swrast_dri.so[7f2298d1b000+e09000]
  Apr 25 16:51:53 localhost kernel: gnome-session-c[3385]: segfault at 20 ip 00007fa310bed624 sp 00007ffcaecbeb98 error 6 in 
  swrast_dri.so[7fa310bd0000+e09000]
  Apr 25 16:52:54 localhost kernel: gnome-session-c[6828]: segfault at 20 ip 00007fc3b5ffd624 sp 00007ffcfb4c7c98 error 6 in 
  swrast_dri.so[7fa310bd0000+e09000]
  

• Segfault due to missing NULL check.