Commit 7c24a4e87e21 for kernel

commit 7c24a4e87e219072e5e106f6791146cbf3b056b3
Author: Ilia Gavrilov <Ilia.Gavrilov@infotecs.ru>
Date:   Thu Oct 8 14:41:17 2026 +0000

    vsock: Fix memory leak in vmci_transport_recv_dgram_cb()

    During the closure of a datagram socket, the vmci_transport_recv_dgram_cb()
    function may be called, which will add the packets
    to the socket's backlog; then, after the receive queue is cleared,
    the __release_sock() function will move the packet back from the socket's
    backlog to the receive queue, which will lead to a memory leak.

    sock_close
      __sock_release
        __vsock_release
          // take ownership by user-space
          lock_sock_nested
          sock_set_flag(sk, SOCK_DEAD)
          vmci_transport_release
                                          vmci_dispatch_dgs
                                            vmci_datagram_invoke_guest_handler
                                              vmci_transport_recv_dgram_cb
                                                sk_receive_skb
                                                  if (!sock_owned_by_user(sk))
                                                      [...]
                                             (!)  else if sk_add_backlog()
                                                      [...]
      (!) skb_queue_purge(&sk->sk_receive_queue)

          release_sock
            __release_sock
              // move all packets from the backlog
              // to the receive queue
       (!)    sk_backlog_rcv
                vsock_queue_rcv_skb
                [...]
                  __sock_queue_rcv_skb
                    if (!sock_flag(sk, SOCK_DEAD))
                      // Since the socket is "dead", the function will not
                      // be called
                      sk->sk_data_ready(sk)
            sock_release_ownership(sk);
            sock_put

    Add a receive queue cleanup in the socket destructor to fix this.

    syzkaller report:

    unreferenced object 0xffff8880117bfb80 (size 240):
      comm "irq/56-vmw_vmci", pid 205, jiffies 4295064448 (age 73.992s)
      hex dump (first 32 bytes):
        78 dc 26 1e 80 88 ff ff 78 dc 26 1e 80 88 ff ff  x.&.....x.&.....
        00 00 00 00 00 00 00 00 c0 da 26 1e 80 88 ff ff  ..........&.....
      backtrace:
        [<ffffffff82be8d97>] __alloc_skb+0x287/0x330 net/core/skbuff.c:505
        [<ffffffffa114bcbd>] vmci_transport_recv_dgram_cb+0xbd/0x210 [vmw_vsock_vmci_transport]
        [<ffffffffa05072c6>] vmci_datagram_invoke_guest_handler+0x366/0x450 [vmw_vmci]
        [<ffffffffa050ad75>] vmci_dispatch_dgs+0x235/0x490 [vmw_vmci]
        [<ffffffffa050b025>] vmci_interrupt+0x55/0x290 [vmw_vmci]
        [<ffffffff8137ad2b>] irq_thread_fn+0x8b/0x1a0 kernel/irq/manage.c:1205
        [<ffffffff8137c7ae>] irq_thread+0x28e/0x530 kernel/irq/manage.c:1314
        [<ffffffff81253dd6>] kthread+0x2e6/0x3a0 kernel/kthread.c:376
        [<ffffffff81004392>] ret_from_fork+0x22/0x30 arch/x86/entry/entry_64.S:295

    Found by InfoTeCS on behalf of Linux Verification Center
    (linuxtesting.org) with Syzkaller.

    Fixes: d021c344051a ("VSOCK: Introduce VM Sockets")
    Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
    Signed-off-by: Ilia Gavrilov <Ilia.Gavrilov@infotecs.ru>
    Link: https://patch.msgid.link/20261008144046.90853-1-Ilia.Gavrilov@infotecs.ru
    Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index 9b71479a2b29..533c733618df 100644
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c
@@ -1048,6 +1048,8 @@ static void vsock_sk_destruct(struct sock *sk)
 {
 	struct vsock_sock *vsk = vsock_sk(sk);

+	/* Socket buffers may remain in the queue in VMCI datagram mode */
+	__skb_queue_purge(&sk->sk_receive_queue);
 	/* Flush MSG_ZEROCOPY leftovers. */
 	__skb_queue_purge(&sk->sk_error_queue);