CVE-2026-23150: In the Linux kernel, the following vulnerability has been resolved:  nfc: llcp: Fix memleak in nfc_llcp_send_ui_frame().  syzbot reported various memory leaks related to NFC, struct nfc_llcp_sock, sk_buff, nfc_dev, etc. [0]  The leading log hinted that nfc_llcp_send_ui_frame() failed to allocate skb due to sock_error(sk) being -ENXIO.  ENXIO is set by nfc_llcp_socket_release() when struct nfc_llcp_local is destroyed by local_cleanup().  The problem is that there is no synchronisation between nfc_llcp_send_ui_frame() and local_cleanup(), and skb could be put into local->tx_queue after it was purged in local_cleanup():    CPU1                          CPU2   ----                          ----   nfc_llcp_send_ui_frame()      local_cleanup()   |- do {                       '      |- pdu = nfc_alloc_send_skb(..., &err)      |                          .      |                          |- nfc_llcp_socket_release(local, false, ENXIO);      |                          |- skb_queue_purge(&local->tx_queue);      |      |                          '                                          |      |- skb_queue_tail(&local->tx_queue, pdu);                             |     ...                                                                    |      |- pdu = nfc_alloc_send_skb(..., &err)                                |                                        ^._________________________________.'  local_cleanup() is called for struct nfc_llcp_local only after nfc_llcp_remove_local() unlinks it from llcp_devices.  If we hold local->tx_queue.lock then, we can synchronise the thread and nfc_llcp_send_ui_frame().  Let's do that and check list_empty(&local->list) before queuing skb to local->tx_queue in nfc_llcp_send_ui_frame().  [0]: [   56.074943][ T6096] llcp: nfc_llcp_send_ui_frame: Could not allocate PDU (error=-6) [   64.318868][ T5813] kmemleak: 6 new suspected memory leaks (see /sys/kernel/debug/kmemleak) BUG: memory leak unreferenced object 0xffff8881272f6800 (size 1024):   comm "syz.0.17", pid 6096, jiffies 4294942766   hex dump (first 32 bytes):     00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................     27 00 03 40 00 00 00 00 00 00 00 00 00 00 00 00  '..@............   backtrace (crc da58d84d):     kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]     slab_post_alloc_hook mm/slub.c:4979 [inline]     slab_alloc_node mm/slub.c:5284 [inline]     __do_kmalloc_node mm/slub.c:5645 [inline]     __kmalloc_noprof+0x3e3/0x6b0 mm/slub.c:5658     kmalloc_noprof include/linux/slab.h:961 [inline]     sk_prot_alloc+0x11a/0x1b0 net/core/sock.c:2239     sk_alloc+0x36/0x360 net/core/sock.c:2295     nfc_llcp_sock_alloc+0x37/0x130 net/nfc/llcp_sock.c:979     llcp_sock_create+0x71/0xd0 net/nfc/llcp_sock.c:1044     nfc_sock_create+0xc9/0xf0 net/nfc/af_nfc.c:31     __sock_create+0x1a9/0x340 net/socket.c:1605     sock_create net/socket.c:1663 [inline]     __sys_socket_create net/socket.c:1700 [inline]     __sys_socket+0xb9/0x1a0 net/socket.c:1747     __do_sys_socket net/socket.c:1761 [inline]     __se_sys_socket net/socket.c:1759 [inline]     __x64_sys_socket+0x1b/0x30 net/socket.c:1759     do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]     do_syscall_64+0xa4/0xfa0 arch/x86/entry/syscall_64.c:94     entry_SYSCALL_64_after_hwframe+0x77/0x7f  BUG: memory leak unreferenced object 0xffff88810fbd9800 (size 240):   comm "syz.0.17", pid 6096, jiffies 4294942850   hex dump (first 32 bytes):     68 f0 ff 08 81 88 ff ff 68 f0 ff 08 81 88 ff ff  h.......h.......     00 00 00 00 00 00 00 00 00 68 2f 27 81 88 ff ff  .........h/'....   backtrace (crc 6cc652b1):     kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]     slab_post_alloc_hook mm/slub.c:4979 [inline]     slab_alloc_node mm/slub.c:5284 [inline]     kmem_cache_alloc_node_noprof+0x36f/0x5e0 mm/slub.c:5336     __alloc_skb+0x203/0x240 net/core/skbuff.c:660     alloc_skb include/linux/skbuff.h:1383 [inline]     alloc_skb_with_frags+0x69/0x3f0 net/core/sk ---truncated---