According to various sourcess Linux at x86 tries to get rid of segmentation by setting all 4 segments (user code, user data, kernel code, kernel data) to base 0x00000000 and limit 0xfffff, and handles memory access at paging level. 

With this setup, why is it still possible to get SIGSEGV (segfault)? 

Or is SIGSEGV used in broader "access violation" meaning here and actual cause is pagefault?