Re: [PATCH v3 mptcp-net 3/3] Squash-to: "mptcp: leverage the backlog for RX packet processing"

[kernel test robot <lkp@intel.com>]

Hi Paolo,

kernel test robot noticed the following build errors:

[auto build test ERROR on mptcp/export]
[cannot apply to mptcp/export-net linus/master v6.18-rc5 next-20251113]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Paolo-Abeni/mptcp-fix-grafting-corner-case/20251113-081224
base:   https://github.com/multipath-tcp/mptcp_net-next.git export
patch link:    https://lore.kernel.org/r/ee40999f77d0186abba2a6b21958c1a8c4881c57.1762992570.git.pabeni%40redhat.com
patch subject: [PATCH v3 mptcp-net 3/3] Squash-to: "mptcp: leverage the backlog for RX packet processing"
config: sparc64-defconfig (https://download.01.org/0day-ci/archive/20251113/202511131922.61JkdJO9-lkp@intel.com/config)
compiler: clang version 20.1.8 (https://github.com/llvm/llvm-project 87f0227cb60147a26a1eeb4fb06e3b505e9c7261)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251113/202511131922.61JkdJO9-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202511131922.61JkdJO9-lkp@intel.com/

All errors (new ones prefixed by >>):

>> net/mptcp/protocol.c:693:12: error: no member named 'sk_memcg' in 'struct sock'
     693 |         if (!ssk->sk_memcg)
         |              ~~~  ^
   1 error generated.


vim +693 net/mptcp/protocol.c

   654	
   655	static void __mptcp_add_backlog(struct sock *sk,
   656					struct mptcp_subflow_context *subflow,
   657					struct sk_buff *skb)
   658	{
   659		struct mptcp_sock *msk = mptcp_sk(sk);
   660		struct sk_buff *tail = NULL;
   661		struct sock *ssk = skb->sk;
   662		bool fragstolen;
   663		int delta;
   664	
   665		if (unlikely(sk->sk_state == TCP_CLOSE)) {
   666			kfree_skb_reason(skb, SKB_DROP_REASON_SOCKET_CLOSE);
   667			return;
   668		}
   669	
   670		/* Try to coalesce with the last skb in our backlog */
   671		if (!list_empty(&msk->backlog_list))
   672			tail = list_last_entry(&msk->backlog_list, struct sk_buff, list);
   673	
   674		if (tail && MPTCP_SKB_CB(skb)->map_seq == MPTCP_SKB_CB(tail)->end_seq &&
   675		    ssk == tail->sk &&
   676		    __mptcp_try_coalesce(sk, tail, skb, &fragstolen, &delta)) {
   677			skb->truesize -= delta;
   678			kfree_skb_partial(skb, fragstolen);
   679			__mptcp_subflow_lend_fwdmem(subflow, delta);
   680			goto account;
   681		}
   682	
   683		list_add_tail(&skb->list, &msk->backlog_list);
   684		mptcp_subflow_lend_fwdmem(subflow, skb);
   685		delta = skb->truesize;
   686	
   687	account:
   688		WRITE_ONCE(msk->backlog_len, msk->backlog_len + delta);
   689	
   690		/* Possibly not accept()ed yet, keep track of memory not CG
   691		 * accounted, mptcp_grapt_subflows will handle it.
   692		 */
 > 693		if (!ssk->sk_memcg)
   694			msk->backlog_unaccounted += delta;
   695	}
   696	

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