On 04/20, Roland McGrath wrote:
Afaics ptrace_attach() needs this lock only to pin -mm, no other other
reasons. ptrace_traceme() doesn't need it at all.
I'm pretty sure that -mm check is only meant to exclude kernel threads.
It should check PF_KTHREAD now,
Yes.
But
On 04/16, Roland McGrath wrote:
But even that is a lot of hair for the incremental patches in the first
several stages, I think. So just never deallocate it, and:
static inline int task_ptrace(struct task_struct *task)
{
return unlikely(task-ptrace_child) ?
So. We are going to make a separate, dynamically allocated structure
for tracees. Say, we add struct ptrace_child *ptrace_child into
task_struct.
Right.
attach/attachme do kmalloc() and use task_lock() to avoid races.
(with the current locking write_lock(tasklist) alone is enough).
Sure.
