From: Sebastian Andrzej Siewior Date: Thu, 17 Feb 2022 10:24:00 +0000 (+0100) Subject: fork: Duplicate task_struct before stack allocation X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=546c42b2c5c161619736dd730d3df709181999d0;p=linux.git 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: Sebastian Andrzej Siewior Signed-off-by: Thomas Gleixner Acked-by: Andy Lutomirski Link: https://lore.kernel.org/r/20220217102406.3697941-3-bigeasy@linutronix.de --- diff --git a/kernel/fork.c b/kernel/fork.c index f5cc10164334a..30c01ce2ae57d 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -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;