> Date: Wed, 5 Apr 2017 15:46:38 +0800 (+08)
> From: Paul Goyette <p...@whooppee.com>
>
> @@ -3385,6 +3428,13 @@ if_mcast_op(ifnet_t *ifp, const unsigned
> {
> int rc;
> struct ifreq ifr;
> + bool need_unlock = false;
> +
> + /* XXX if_ioctl_lock may or may not be held here */
> + if (ifp->if_ioctl_lock != NULL && !mutex_owned(ifp->if_ioctl_lock)) {
> + mutex_enter(ifp->if_ioctl_lock);
> + need_unlock = true;
> + }
>
> It is my understanding that using mutex_owned() to effect locking
> decisions is forbidden.
>
> I understand the intent of doing it this way, but perhaps we should
> revisit the callers and enforce that they always take the lock?
Quite right. Please revert this change and post a note to tech-net@
about how to resolve the issue properly if you need help, including a
statement of what code paths do or don't hold the ioctl lock and why
it's hard to address them.
>From what I recall (haven't looked recently, though) the ifioctl
locking may be broken, and may be better written with localcount(9).
