CVE-2025-38734: In the Linux kernel, the following vulnerability has been resolved:  net/smc: fix UAF on smcsk after smc_listen_out()  BPF CI testing report a UAF issue:    [   16.446633] BUG: kernel NULL pointer dereference, address: 000000000000003  0   [   16.447134] #PF: supervisor read access in kernel mod  e   [   16.447516] #PF: error_code(0x0000) - not-present pag  e   [   16.447878] PGD 0 P4D   0   [   16.448063] Oops: Oops: 0000 [#1] PREEMPT SMP NOPT  I   [   16.448409] CPU: 0 UID: 0 PID: 9 Comm: kworker/0:1 Tainted: G           OE      6.13.0-rc3-g89e8a75fda73-dirty #4  2   [   16.449124] Tainted: [O]=OOT_MODULE, [E]=UNSIGNED_MODUL  E   [   16.449502] Hardware name: QEMU Ubuntu 24.04 PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/201  4   [   16.450201] Workqueue: smc_hs_wq smc_listen_wor  k   [   16.450531] RIP: 0010:smc_listen_work+0xc02/0x159  0   [   16.452158] RSP: 0018:ffffb5ab40053d98 EFLAGS: 0001024  6   [   16.452526] RAX: 0000000000000001 RBX: 0000000000000002 RCX: 000000000000030  0   [   16.452994] RDX: 0000000000000280 RSI: 00003513840053f0 RDI: 000000000000000  0   [   16.453492] RBP: ffffa097808e3800 R08: ffffa09782dba1e0 R09: 000000000000000  5   [   16.453987] R10: 0000000000000000 R11: 0000000000000000 R12: ffffa0978274640  0   [   16.454497] R13: 0000000000000000 R14: 0000000000000000 R15: ffffa09782d4092  0   [   16.454996] FS:  0000000000000000(0000) GS:ffffa097bbc00000(0000) knlGS:000000000000000  0   [   16.455557] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003  3   [   16.455961] CR2: 0000000000000030 CR3: 0000000102788004 CR4: 0000000000770ef  0   [   16.456459] PKRU: 5555555  4   [   16.456654] Call Trace  :   [   16.456832]  <TASK  >   [   16.456989]  ? __die+0x23/0x7  0   [   16.457215]  ? page_fault_oops+0x180/0x4c  0   [   16.457508]  ? __lock_acquire+0x3e6/0x249  0   [   16.457801]  ? exc_page_fault+0x68/0x20  0   [   16.458080]  ? asm_exc_page_fault+0x26/0x3  0   [   16.458389]  ? smc_listen_work+0xc02/0x159  0   [   16.458689]  ? smc_listen_work+0xc02/0x159  0   [   16.458987]  ? lock_is_held_type+0x8f/0x10  0   [   16.459284]  process_one_work+0x1ea/0x6d  0   [   16.459570]  worker_thread+0x1c3/0x38  0   [   16.459839]  ? __pfx_worker_thread+0x10/0x1  0   [   16.460144]  kthread+0xe0/0x11  0   [   16.460372]  ? __pfx_kthread+0x10/0x1  0   [   16.460640]  ret_from_fork+0x31/0x5  0   [   16.460896]  ? __pfx_kthread+0x10/0x1  0   [   16.461166]  ret_from_fork_asm+0x1a/0x3  0   [   16.461453]  </TASK  >   [   16.461616] Modules linked in: bpf_testmod(OE) [last unloaded: bpf_testmod(OE)  ]   [   16.462134] CR2: 000000000000003  0   [   16.462380] ---[ end trace 0000000000000000 ]---   [   16.462710] RIP: 0010:smc_listen_work+0xc02/0x1590  The direct cause of this issue is that after smc_listen_out_connected(), newclcsock->sk may be NULL since it will releases the smcsk. Therefore, if the application closes the socket immediately after accept, newclcsock->sk can be NULL. A possible execution order could be as follows:  smc_listen_work                                 | userspace ----------------------------------------------------------------- lock_sock(sk)                                   | smc_listen_out_connected()                      | | \- smc_listen_out                             | |    | \- release_sock                          |      | |- sk->sk_data_ready()                   |                                                 | fd = accept();                                                 | close(fd);                                                 |  \- socket->sk = NULL; /* newclcsock->sk is NULL now */ SMC_STAT_SERV_SUCC_INC(sock_net(newclcsock->sk))  Since smc_listen_out_connected() will not fail, simply swapping the order of the code can easily fix this issue.