UProbes are set on group_leader instead of first found tid

Fixed: Kernel panic: pbzip2, libc, libpthread instrumentation #140
- During instrumentation of multi-threaded program, situation with instrumentation of finished thread may happen

diff --git a/driver/us_proc_inst.c b/driver/us_proc_inst.c
index 969945d..36306f4 100644 (file)
--- a/driver/us_proc_inst.c
+++ b/driver/us_proc_inst.c
@@ -303,6 +303,7 @@ static int find_task_by_path (const char *path, struct task_struct **p_task, str
 
        if (*p_task) {
                DPRINTF ("found pid %d for %s.", (*p_task)->pid, path);
+               *p_task = (*p_task)->group_leader;
                gl_nNotifyTgid = (*p_task)->tgid;
        } else {
                DPRINTF ("pid for %s not found!", path);
@@ -913,6 +914,8 @@ void do_page_fault_ret_pre_code (void)
        struct mm_struct *mm;
        struct vm_area_struct *vma = 0;
        inst_us_proc_t *task_inst_info = NULL;
+       /* task_struct of task current->group_leader */
+       struct task_struct *task = current->group_leader;
 
        //if user-space instrumentation is not set
        if (!us_proc_info.path)
@@ -973,17 +976,17 @@ void do_page_fault_ret_pre_code (void)
                }
                if (vma)
                {
-                       DPRINTF ("do_page_fault found target proc %s(%d)", current->comm, current->pid);
-                       task_inst_info->tgid = current->pid;
-                       gl_nNotifyTgid = current->tgid;
+                    DPRINTF ("do_page_fault found target proc %s(%d)", task->comm, task->pid);
+                    task_inst_info->tgid = task->pid;
+                    gl_nNotifyTgid = task->tgid;
                }
        }
-       if (task_inst_info->tgid == current->tgid)
+       if (task_inst_info->tgid == task->tgid)
        {
                //DPRINTF("do_page_fault from target proc %d", task_inst_info->tgid);
-               install_mapped_ips (current, &us_proc_info, 1);
+               install_mapped_ips (task, &us_proc_info, 1);
        }
-       //DPRINTF("do_page_fault from proc %d-%d exit", current->pid, task_inst_info->pid);
+       //DPRINTF("do_page_fault from proc %d-%d exit", task->pid, task_inst_info->pid);
 }
 
 EXPORT_SYMBOL_GPL(do_page_fault_ret_pre_code);