Now null pointer returned by find_vma() correctly handled

diff --git a/driver/us_proc_inst.c b/driver/us_proc_inst.c
index 22d5200..8d269aa 100644 (file)
--- a/driver/us_proc_inst.c
+++ b/driver/us_proc_inst.c
@@ -1682,10 +1682,10 @@ void find_plt_address(unsigned long addr)
 
        // Search for library structure to check whether this function plt or not
        if (strcmp(us_proc_info.path, "*")){
-               // If app lib instrumentation
+       // If app lib instrumentation
                task_inst_info = &us_proc_info;
        } else {
-               // If lib only instrumentation
+       // If lib only instrumentation
                task_inst_info = get_task_inst_node(current);
        }
        if ((task_inst_info != NULL) && (task_inst_info->is_plt != 0)) {
@@ -1712,25 +1712,28 @@ void find_plt_address(unsigned long addr)
                                        }
                                        if (!read_proc_vm_atomic(current, (unsigned long)(real_got), &real_addr, sizeof(unsigned long))) {
                                                printk("Failed to read got %p at memory address %p!\n", p_lib->p_plt[i].got_addr, real_got);
-                                               break;
+                                               return;
                                        }
                                        if (real_addr != p_lib->p_plt[i].real_func_addr) {
                                                p_lib->p_plt[i].real_func_addr =  real_addr;
                                                vma = find_vma(current->mm, real_addr);
-                                               if ((vma->vm_start <= real_addr) && (vma->vm_end > real_addr)) {
+                                               if ((vma != NULL) && (vma->vm_start <= real_addr) && (vma->vm_end > real_addr)) {
                                                        if (vma->vm_file != NULL) {
                                                                szLibPath = &(vma->vm_file->f_dentry->d_iname);
                                                        }
+                                               } else {
+                                                       printk("Failed to get vma, includes %x address\n", real_addr);
+                                                       return;
                                                }
                                                if (szLibPath) {
                                                        pack_event_info(PLT_ADDR_PROBE_ID, RECORD_RET, "ppsp", addr, real_addr, szLibPath, real_addr - vma->vm_start);
-                                                       break;
+                                                       return;
                                                } else {
                                                        pack_event_info(PLT_ADDR_PROBE_ID, RECORD_RET, "ppp", addr, real_addr, real_addr - vma->vm_start);
-                                                       break;
+                                                       return;
                                                }
                                        } else {
-                                               break;
+                                               return;
                                        }
                                }
                        }