Re: [PATCH net 2/3] net: hsr: clone before updating path and LAN IDs in tagged frames

Clone first, privatize with skb_cow(), reacquire the header or trailer
pointer, then write the id: this removes the shared-buffer mutation for
both hsr_create_tagged_frame() and prp_create_tagged_frame(). The error
paths (clone failure, cow failure, NULL trailer) all free the clone and
return NULL, and adding kfree_skb() on the NULL-trailer path also closes
a leak. Using skb_cow() rather than skb_cow_head() is right since the PRP
RCT sits at the linear tail.

Reviewed-by: Ali Ahmet Memis <[email protected]>