Commit 5efc447b authored by Zheng Zucheng's avatar Zheng Zucheng Committed by Zheng Zengkai
Browse files

fork: Allocate a new task_struct_resvd object for fork task 

hulk inclusion
category: feature
bugzilla: 187196, https://gitee.com/openeuler/kernel/issues/I612CS



-------------------------------

Allocate a new task_struct_resvd object for the recently cloned task

Signed-off-by: default avatarZheng Zucheng <zhengzucheng@huawei.com>
Reviewed-by: default avatarZhang Qiao <zhangqiao22@huawei.com>
Reviewed-by: default avatarZhang Qiao <zhangqiao22@huawei.com>
Reviewed-by: default avatarNanyong Sun <sunnanyong@huawei.com>
Reviewed-by: default avatarZhang Qiao <zhangqiao22@huawei.com>
Reviewed-by: default avatarchenhui 00515652 <judy.chenhui@huawei.com>
Signed-off-by: default avatarZheng Zengkai <zhengzengkai@huawei.com>
parent d10d0c69

include/linux/sched.h

+2 −0
Original line number Diff line number Diff line
@@ -677,6 +677,8 @@ struct wake_q_node { 
* struct task_struct_resvd - KABI extension struct

*/

struct task_struct_resvd {

	/* pointer back to the main task_struct */

	struct task_struct	*task;

};



struct task_struct {

init/init_task.c

+5 −0
Original line number Diff line number Diff line
@@ -57,6 +57,10 @@ unsigned long init_shadow_call_stack[SCS_SIZE / sizeof(long)] 
};

#endif



static struct task_struct_resvd init_task_struct_resvd = {

	.task = &init_task,

};



/*

 * Set up the first task table, touch at your own risk!. Base=0,

 * limit=0x1fffff (=2MB)
@@ -213,6 +217,7 @@ struct task_struct init_task 
#ifdef CONFIG_SECCOMP_FILTER

	.seccomp	= { .filter_count = ATOMIC_INIT(0) },

#endif

	._resvd = &init_task_struct_resvd,

};

EXPORT_SYMBOL(init_task);

kernel/fork.c

+20 −1
Original line number Diff line number Diff line
@@ -173,6 +173,7 @@ static inline struct task_struct *alloc_task_struct_node(int node) 


static inline void free_task_struct(struct task_struct *tsk)

{

	kfree(tsk->_resvd);

	kmem_cache_free(task_struct_cachep, tsk);

}

#endif
@@ -851,6 +852,18 @@ void set_task_stack_end_magic(struct task_struct *tsk) 
	*stackend = STACK_END_MAGIC;	/* for overflow detection */

}



static bool dup_resvd_task_struct(struct task_struct *dst,

				  struct task_struct *orig, int node)

{

	dst->_resvd = kmalloc_node(sizeof(struct task_struct_resvd),

					  GFP_KERNEL, node);

	if (!dst->_resvd)

		return false;



	dst->_resvd->task = dst;

	return true;

}



static struct task_struct *dup_task_struct(struct task_struct *orig, int node)

{

	struct task_struct *tsk;
@@ -863,6 +876,12 @@ static struct task_struct *dup_task_struct(struct task_struct *orig, int node) 
	tsk = alloc_task_struct_node(node);

	if (!tsk)

		return NULL;

	/*

	 * before proceeding, we need to make tsk->_resvd = NULL,

	 * otherwise the error paths below, if taken, might end up causing

	 * a double-free for task_struct_resvd extension object.

	 */

	WRITE_ONCE(tsk->_resvd, NULL);



	stack = alloc_thread_stack_node(tsk, node);

	if (!stack)
@@ -888,7 +907,7 @@ static struct task_struct *dup_task_struct(struct task_struct *orig, int node) 
	refcount_set(&tsk->stack_refcount, 1);

#endif



	if (err)

	if (err || !dup_resvd_task_struct(tsk, orig, node))

		goto free_stack;



	err = scs_prepare(tsk, node);