On Thu, Sep 21, 2017 at 8:18 AM, Baolin Wang <baolin.wang@xxxxxxxxxx> wrote:
> +static int snd_timer_user_tread(void __user *argp, struct snd_timer_user *tu,
> + unsigned int cmd)
> +{
> + int __user *p = argp;
> + int xarg, old_tread;
> +
> + if (tu->timeri) /* too late */
> + return -EBUSY;
> + if (get_user(xarg, p))
> + return -EFAULT;
> +
> + old_tread = tu->tread;
> +#if __BITS_PER_LONG == 64
> + tu->tread = xarg ? 2 : 0;
> +#ifdef IA32_EMULATION
> + tu->tread = xarg ? 3 : 0;
> +#endif
> +#else
> + if (cmd == SNDRV_TIMER_IOCTL_TREAD64)
> + tu->tread = xarg ? 2 : 0;
> + else
> + tu->tread = xarg ? 1 : 0;
> +#endif
The 64-bit case looks broken here:
- The tread flag is different for compat and native mode, so you
must pass a flag to identify whether you are called from
__snd_timer_user_ioctl or from snd_timer_user_ioctl_compat().
- On x86, you have to check whether calling user space process uses
the i386 or the x32 ABI by checking in_x32_syscall()
Arnd
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