Commit 546c42b2 authored by Sebastian Andrzej Siewior's avatar Sebastian Andrzej Siewior Committed by Thomas Gleixner
Browse files

fork: Duplicate task_struct before stack allocation 



alloc_thread_stack_node() already populates the task_struct::stack
member except on IA64. The stack pointer is saved and populated again
because IA64 needs it and arch_dup_task_struct() overwrites it.

Allocate thread's stack after task_struct has been duplicated as a
preparation for further changes.

Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Acked-by: default avatarAndy Lutomirski <luto@kernel.org>
Link: https://lore.kernel.org/r/20220217102406.3697941-3-bigeasy@linutronix.de
parent be9a2277

kernel/fork.c

+4 −5
Original line number Diff line number Diff line
@@ -888,6 +888,10 @@ static struct task_struct *dup_task_struct(struct task_struct *orig, int node) 
	if (!tsk)

		return NULL;



	err = arch_dup_task_struct(tsk, orig);

	if (err)

		goto free_tsk;



	stack = alloc_thread_stack_node(tsk, node);

	if (!stack)

		goto free_tsk;
@@ -897,8 +901,6 @@ static struct task_struct *dup_task_struct(struct task_struct *orig, int node) 


	stack_vm_area = task_stack_vm_area(tsk);



	err = arch_dup_task_struct(tsk, orig);



	/*

	 * arch_dup_task_struct() clobbers the stack-related fields.  Make

	 * sure they're properly initialized before using any stack-related
@@ -912,9 +914,6 @@ static struct task_struct *dup_task_struct(struct task_struct *orig, int node) 
	refcount_set(&tsk->stack_refcount, 1);

#endif



	if (err)

		goto free_stack;



	err = scs_prepare(tsk, node);

	if (err)

		goto free_stack;