linux-kernel - Re: [PATCH] um: Stop conflating task_struct::stack with thread

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Date:	Mon, 18 Jul 2016 15:25:59 -0700
From:	Andy Lutomirski <luto@...capital.net>
To:	Andy Lutomirski <luto@...nel.org>,
	Richard Weinberger <richard@....at>,
	Jeff Dike <jdike@...toit.com>
Cc:	X86 ML <x86@...nel.org>, Borislav Petkov <bp@...en8.de>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>
Subject: Re: [PATCH] um: Stop conflating task_struct::stack with thread_info

On Mon, Jul 18, 2016 at 3:22 PM, Andy Lutomirski <luto@...nel.org> wrote:
> From: Linus Torvalds <torvalds@...ux-foundation.org>
>
> thread_info may move in the future, so use the accessors.
>
> [Andy Lutomirski wrote this changelog message and changed
>  "task_thread_info(child)->cpu" to "task_cpu(child)".]
>
> Message-Id: <CA+55aFxvZhBu9U1cqpVm4frv0p5mqu=0TxsSqE-=95ft8HvCVA@...l.gmail.com>
> Signed-off-by: Andy Lutomirski <luto@...nel.org>

Forgot to cc maintainers...

> ---
>  arch/x86/um/ptrace_32.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/arch/x86/um/ptrace_32.c b/arch/x86/um/ptrace_32.c
> index ebd4dd6ef73b..2a6f781ce9cf 100644
> --- a/arch/x86/um/ptrace_32.c
> +++ b/arch/x86/um/ptrace_32.c
> @@ -191,7 +191,7 @@ int peek_user(struct task_struct *child, long addr, long data)
>
>  static int get_fpregs(struct user_i387_struct __user *buf, struct task_struct *child)
>  {
> -       int err, n, cpu = ((struct thread_info *) child->stack)->cpu;
> +       int err, n, cpu = task_cpu(child);
>         struct user_i387_struct fpregs;
>
>         err = save_i387_registers(userspace_pid[cpu],
> @@ -208,7 +208,7 @@ static int get_fpregs(struct user_i387_struct __user *buf, struct task_struct *c
>
>  static int set_fpregs(struct user_i387_struct __user *buf, struct task_struct *child)
>  {
> -       int n, cpu = ((struct thread_info *) child->stack)->cpu;
> +       int n, cpu = task_cpu(child);
>         struct user_i387_struct fpregs;
>
>         n = copy_from_user(&fpregs, buf, sizeof(fpregs));
> @@ -221,7 +221,7 @@ static int set_fpregs(struct user_i387_struct __user *buf, struct task_struct *c
>
>  static int get_fpxregs(struct user_fxsr_struct __user *buf, struct task_struct *child)
>  {
> -       int err, n, cpu = ((struct thread_info *) child->stack)->cpu;
> +       int err, n, cpu = task_cpu(child);
>         struct user_fxsr_struct fpregs;
>
>         err = save_fpx_registers(userspace_pid[cpu], (unsigned long *) &fpregs);
> @@ -237,7 +237,7 @@ static int get_fpxregs(struct user_fxsr_struct __user *buf, struct task_struct *
>
>  static int set_fpxregs(struct user_fxsr_struct __user *buf, struct task_struct *child)
>  {
> -       int n, cpu = ((struct thread_info *) child->stack)->cpu;
> +       int n, cpu = task_cpu(child);
>         struct user_fxsr_struct fpregs;
>
>         n = copy_from_user(&fpregs, buf, sizeof(fpregs));
> --
> 2.7.4
>



-- 
Andy Lutomirski
AMA Capital Management, LLC