CVE-2023-52842: In the Linux kernel, the following vulnerability has been resolved:  virtio/vsock: Fix uninit-value in virtio_transport_recv_pkt()  KMSAN reported the following uninit-value access issue:  ===================================================== BUG: KMSAN: uninit-value in virtio_transport_recv_pkt+0x1dfb/0x26a0 net/vmw_vsock/virtio_transport_common.c:1421  virtio_transport_recv_pkt+0x1dfb/0x26a0 net/vmw_vsock/virtio_transport_common.c:1421  vsock_loopback_work+0x3bb/0x5a0 net/vmw_vsock/vsock_loopback.c:120  process_one_work kernel/workqueue.c:2630 [inline]  process_scheduled_works+0xff6/0x1e60 kernel/workqueue.c:2703  worker_thread+0xeca/0x14d0 kernel/workqueue.c:2784  kthread+0x3cc/0x520 kernel/kthread.c:388  ret_from_fork+0x66/0x80 arch/x86/kernel/process.c:147  ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304  Uninit was stored to memory at:  virtio_transport_space_update net/vmw_vsock/virtio_transport_common.c:1274 [inline]  virtio_transport_recv_pkt+0x1ee8/0x26a0 net/vmw_vsock/virtio_transport_common.c:1415  vsock_loopback_work+0x3bb/0x5a0 net/vmw_vsock/vsock_loopback.c:120  process_one_work kernel/workqueue.c:2630 [inline]  process_scheduled_works+0xff6/0x1e60 kernel/workqueue.c:2703  worker_thread+0xeca/0x14d0 kernel/workqueue.c:2784  kthread+0x3cc/0x520 kernel/kthread.c:388  ret_from_fork+0x66/0x80 arch/x86/kernel/process.c:147  ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304  Uninit was created at:  slab_post_alloc_hook+0x105/0xad0 mm/slab.h:767  slab_alloc_node mm/slub.c:3478 [inline]  kmem_cache_alloc_node+0x5a2/0xaf0 mm/slub.c:3523  kmalloc_reserve+0x13c/0x4a0 net/core/skbuff.c:559  __alloc_skb+0x2fd/0x770 net/core/skbuff.c:650  alloc_skb include/linux/skbuff.h:1286 [inline]  virtio_vsock_alloc_skb include/linux/virtio_vsock.h:66 [inline]  virtio_transport_alloc_skb+0x90/0x11e0 net/vmw_vsock/virtio_transport_common.c:58  virtio_transport_reset_no_sock net/vmw_vsock/virtio_transport_common.c:957 [inline]  virtio_transport_recv_pkt+0x1279/0x26a0 net/vmw_vsock/virtio_transport_common.c:1387  vsock_loopback_work+0x3bb/0x5a0 net/vmw_vsock/vsock_loopback.c:120  process_one_work kernel/workqueue.c:2630 [inline]  process_scheduled_works+0xff6/0x1e60 kernel/workqueue.c:2703  worker_thread+0xeca/0x14d0 kernel/workqueue.c:2784  kthread+0x3cc/0x520 kernel/kthread.c:388  ret_from_fork+0x66/0x80 arch/x86/kernel/process.c:147  ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304  CPU: 1 PID: 10664 Comm: kworker/1:5 Not tainted 6.6.0-rc3-00146-g9f3ebbef746f #3 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-1.fc38 04/01/2014 Workqueue: vsock-loopback vsock_loopback_work =====================================================  The following simple reproducer can cause the issue described above:  int main(void) {   int sock;   struct sockaddr_vm addr = {     .svm_family = AF_VSOCK,     .svm_cid = VMADDR_CID_ANY,     .svm_port = 1234,   };    sock = socket(AF_VSOCK, SOCK_STREAM, 0);   connect(sock, (struct sockaddr *)&addr, sizeof(addr));   return 0; }  This issue occurs because the `buf_alloc` and `fwd_cnt` fields of the `struct virtio_vsock_hdr` are not initialized when a new skb is allocated in `virtio_transport_init_hdr()`. This patch resolves the issue by initializing these fields during allocation.