[IA64] binfmt_elf32.c: BUG if insert_vm_struct fails

It seems that in ia64_elf32_init, instead of calling return, if we insert
an overlapping vma, we should instead BUG(). We should never get into this
code path, because the vma's are set above PAGE_OFFSET, and thus a
Xmalicious user can not trigger this code path. This change is being
suggested mainly for clarity. Thanks to Stephen Tweedie for pointing out
that returning early in ia64_elf32_init could have unpredictable results.
Signed-off-by: Tony Luck <tony.luck@intel.com>

arch/ia64/ia32/binfmt_elf32.c

@@ -103,7 +103,7 @@ ia64_elf32_init (struct pt_regs *regs)
 			if (insert_vm_struct(current->mm, vma)) {
 				kmem_cache_free(vm_area_cachep, vma);
 				up_write(&current->mm->mmap_sem);
-				return;
+				BUG();
 			}
 		}
 		up_write(&current->mm->mmap_sem);
@@ -130,7 +130,7 @@ ia64_elf32_init (struct pt_regs *regs)
 			if (insert_vm_struct(current->mm, vma)) {
 				kmem_cache_free(vm_area_cachep, vma);
 				up_write(&current->mm->mmap_sem);
-				return;
+				BUG();
 			}
 		}
 		up_write(&current->mm->mmap_sem);
@@ -153,7 +153,7 @@ ia64_elf32_init (struct pt_regs *regs)
 			if (insert_vm_struct(current->mm, vma)) {
 				kmem_cache_free(vm_area_cachep, vma);
 				up_write(&current->mm->mmap_sem);
-				return;
+				BUG();
 			}
 		}
 		up_write(&current->mm->mmap_sem);