oom lca -- fork bombing killer v2.2

diff -pruN 2.6.12-rc3-mm2/include/linux/init_task.h 2.6.12-rc3-mm2-cy/include/linux/init_task.h
@@ -90,6 +90,9 @@ extern struct group_info init_groups;
 	.parent		= &tsk,						\
 	.children	= LIST_HEAD_INIT(tsk.children),			\
 	.sibling	= LIST_HEAD_INIT(tsk.sibling),			\
+	.bio_parent	= &tsk,						\
+	.bio_children	= LIST_HEAD_INIT(tsk.bio_children),		\
+	.bio_sibling	= LIST_HEAD_INIT(tsk.bio_sibling),		\
 	.group_leader	= &tsk,						\
 	.group_info	= &init_groups,					\
 	.cap_effective	= CAP_INIT_EFF_SET,				\

diff -pruN 2.6.12-rc3-mm2/include/linux/sched.h 2.6.12-rc3-mm2-cy/include/linux/sched.h
@@ -661,11 +661,7 @@ struct task_struct {
 	unsigned did_exec:1;
 	pid_t pid;
 	pid_t tgid;
-	/* 
-	 * pointers to (original) parent process, youngest child, younger sibling,
-	 * older sibling, respectively.  (p->father can be replaced with 
-	 * p->parent->pid)
-	 */
+
 	struct task_struct *real_parent; /* real parent process (when being debugged) */
 	struct task_struct *parent;	/* parent process */
 	/*

@@ -674,6 +670,9 @@ struct task_struct {
 	 */
 	struct list_head children;	/* list of my children */
 	struct list_head sibling;	/* linkage in my parent's children list */
+	struct task_struct *bio_parent;	/* biological parent process */
+	struct list_head bio_children;
+	struct list_head bio_sibling;
 	struct task_struct *group_leader;	/* threadgroup leader */
 
 	/* PID/PID hash table linkage. */

diff -pruN 2.6.12-rc3-mm2/kernel/exit.c 2.6.12-rc3-mm2-cy/kernel/exit.c
@@ -55,6 +55,7 @@ static void __unhash_process(struct task
 	}
 
 	REMOVE_LINKS(p);
+	list_del_init(&p->bio_sibling);
 }
 
 void release_task(struct task_struct * p)

@@ -224,6 +225,9 @@ static inline int has_stopped_jobs(int p
  * been inherited from a user process, so we reset them to sane values here.
  *
  * NOTE that reparent_to_init() gives the caller full capabilities.
+ *
+ * We change kernel threads' current->bio_*, thus find_lca()
+ * will not catch it.  -- coywolf
  */
 static inline void reparent_to_init(void)
 {

@@ -235,6 +239,9 @@ static inline void reparent_to_init(void
 	current->parent = child_reaper;
 	current->real_parent = child_reaper;
 	SET_LINKS(current);
+	list_del_init(&current->bio_sibling);
+	current->bio_parent = child_reaper;
+	list_add_tail(&current->bio_sibling, &child_reaper->bio_children);
 
 	/* Set the exit signal to SIGCHLD so we signal init on exit */
 	current->exit_signal = SIGCHLD;

@@ -514,7 +521,7 @@ static void exit_mm(struct task_struct *
 	mmput(mm);
 }
 
-static inline void choose_new_parent(task_t *p, task_t *reaper, task_t *child_reaper)
+static inline void choose_new_parent(task_t *p, task_t *reaper)
 {
 	/*
 	 * Make sure we're not reparenting to ourselves and that

@@ -591,6 +598,7 @@ static inline void reparent_thread(task_
 static inline void forget_original_parent(struct task_struct * father,
 					  struct list_head *to_release)
 {
+	extern struct task_struct *last_chosen_parent;
 	struct task_struct *p, *reaper = father;
 	struct list_head *_p, *_n;
 

@@ -611,7 +619,7 @@ static inline void forget_original_paren
 	 * Search them and reparent children.
 	 */
 	list_for_each_safe(_p, _n, &father->children) {
-		int ptrace;
+		long ptrace;
 		p = list_entry(_p,struct task_struct,sibling);
 
 		ptrace = p->ptrace;

@@ -621,7 +629,7 @@ static inline void forget_original_paren
 
 		if (father == p->real_parent) {
 			/* reparent with a reaper, real father it's us */
-			choose_new_parent(p, reaper, child_reaper);
+			choose_new_parent(p, reaper);
 			reparent_thread(p, father, 0);
 		} else {
 			/* reparent ptraced task to its real parent */

@@ -642,9 +650,22 @@ static inline void forget_original_paren
 	}
 	list_for_each_safe(_p, _n, &father->ptrace_children) {
 		p = list_entry(_p,struct task_struct,ptrace_list);
-		choose_new_parent(p, reaper, child_reaper);
+		choose_new_parent(p, reaper);
 		reparent_thread(p, father, 1);
 	}
+
+	list_for_each_safe(_p, _n,  &father->bio_children) {
+		p = list_entry(_p, struct task_struct, bio_sibling);
+		list_del_init(&p->bio_sibling);
+		p->bio_parent = father->bio_parent;
+		list_add_tail(&p->bio_sibling, &(p->bio_parent)->bio_children);
+	}
+
+	if (unlikely(father == last_chosen_parent)) {
+		last_chosen_parent = father->bio_parent;
+		if (last_chosen_parent->pid == 1)
+			last_chosen_parent = NULL;
+	}
 }
 
 /*

diff -pruN 2.6.12-rc3-mm2/kernel/fork.c 2.6.12-rc3-mm2-cy/kernel/fork.c
@@ -911,6 +911,8 @@ static task_t *copy_process(unsigned lon
 
 	INIT_LIST_HEAD(&p->children);
 	INIT_LIST_HEAD(&p->sibling);
+	INIT_LIST_HEAD(&p->bio_children);
+	INIT_LIST_HEAD(&p->bio_sibling);
 	p->vfork_done = NULL;
 	spin_lock_init(&p->alloc_lock);
 	spin_lock_init(&p->proc_lock);

@@ -1043,6 +1045,7 @@ static task_t *copy_process(unsigned lon
 	else
 		p->real_parent = current;
 	p->parent = p->real_parent;
+	p->bio_parent = current;
 
 	if (clone_flags & CLONE_THREAD) {
 		spin_lock(&current->sighand->siglock);

@@ -1093,6 +1096,7 @@ static task_t *copy_process(unsigned lon
 	p->ioprio = current->ioprio;
 
 	SET_LINKS(p);
+	list_add_tail(&p->bio_sibling, &current->bio_children);
 	if (unlikely(p->ptrace & PT_PTRACED))
 		__ptrace_link(p, current->parent);
 

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