On 02/20/2019 08:19 AM, Vasily Averin wrote:
> Thank you for explanation,
> though this happen in real life and triggers BUG_ON only if receiving side is
> located on the same host.
> Is it probably makes sense to add WARN_ON into skb_can_coalesce to detect
> such cases?
Yes, but please do it only in the sendpage() path, or only in
CONFIG_DEBUG_PAGEALLOC / CONFIG_DEBUG_VM cases.
tcp_sendmsg() uses a per task page (look at sk_page_frag()), and it seems
strange to recheck what we already know (it is a page not backed/used by SLAB)
