On Wed, Mar 17, 2021 at 11:12:41AM -0700, Andy Lutomirski wrote:
> @@ -163,6 +163,19 @@ int copy_thread(unsigned long clone_flags, unsigned long
> sp, unsigned long arg,
> /* Kernel thread ? */
> if (unlikely(p->flags & PF_KTHREAD)) {
> memset(childregs, 0, sizeof(struct pt_regs));
> +
> + /*
> + * Even though there is no real user state here, these
> + * are were user regs belong, and kernel_execve() will
s/were/where/
> + * overwrite them with user regs. Put an obviously
> + * invalid value that nonetheless causes user_mode(regs)
> + * to return true in CS.
> + *
> + * This also prevents the unwinder from thinking that there
> + * is invalid kernel state at the top of the stack.
> + */
> + childregs->cs = 3;
> +
> kthread_frame_init(frame, sp, arg);
> return 0;
> }
Acked-by: Josh Poimboeuf <jpoim...@redhat.com>
--
Josh
