------------[ cut here ]------------ refcount_t: addition on 0; use-after-free. WARNING: CPU: 1 PID: 24 at lib/refcount.c:25 refcount_warn_saturate+0xfa/0x1d0 lib/refcount.c:25 Modules linked in: CPU: 1 UID: 0 PID: 24 Comm: kworker/1:0 Not tainted 6.15.0-syzkaller-12058-g64980441d269 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Workqueue: usb_hub_wq hub_event RIP: 0010:refcount_warn_saturate+0xfa/0x1d0 lib/refcount.c:25 Code: 00 00 e8 09 2d ff fc 5b 41 5e e9 d1 4a a7 06 cc e8 fb 2c ff fc c6 05 63 ca c9 0a 01 90 48 c7 c7 c0 38 e2 8b e8 17 db c2 fc 90 <0f> 0b 90 90 eb d7 e8 db 2c ff fc c6 05 44 ca c9 0a 01 90 48 c7 c7 RSP: 0018:ffffc90000a08828 EFLAGS: 00010246 RAX: d24eab6b3a1cbf00 RBX: 0000000000000002 RCX: ffff88801d6f8000 RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000002 RBP: ffffc90000a089b0 R08: ffffffff8fa100f7 R09: 1ffffffff1f4201e R10: dffffc0000000000 R11: fffffbfff1f4201f R12: ffff88802fa90000 R13: dffffc0000000000 R14: ffff88802fa9016c R15: ffff88805d1e6400 FS: 0000000000000000(0000) GS:ffff888125d55000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c33d0f7 CR3: 00000000772f4000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 00000000ffff000b DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: __refcount_add include/linux/refcount.h:-1 [inline] __refcount_inc include/linux/refcount.h:366 [inline] refcount_inc include/linux/refcount.h:383 [inline] get_net include/net/net_namespace.h:268 [inline] tipc_aead_encrypt net/tipc/crypto.c:821 [inline] tipc_crypto_xmit+0x1820/0x22c0 net/tipc/crypto.c:1761 tipc_bearer_xmit_skb+0x245/0x400 net/tipc/bearer.c:572 tipc_disc_timeout+0x580/0x6d0 net/tipc/discover.c:338 call_timer_fn+0x17b/0x5f0 kernel/time/timer.c:1747 expire_timers kernel/time/timer.c:1798 [inline] __run_timers kernel/time/timer.c:2372 [inline] __run_timer_base+0x61a/0x860 kernel/time/timer.c:2384 run_timer_base kernel/time/timer.c:2393 [inline] run_timer_softirq+0xb7/0x180 kernel/time/timer.c:2403 handle_softirqs+0x286/0x870 kernel/softirq.c:579 __do_softirq kernel/softirq.c:613 [inline] invoke_softirq kernel/softirq.c:453 [inline] __irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:680 irq_exit_rcu+0x9/0x30 kernel/softirq.c:696 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1050 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:console_flush_all+0x7f7/0xc40 kernel/printk/printk.c:3227 Code: 48 21 c3 0f 85 e9 01 00 00 e8 95 20 1f 00 48 8b 5c 24 20 4d 85 f6 75 07 e8 86 20 1f 00 eb 06 e8 7f 20 1f 00 fb 48 8b 44 24 28 <42> 80 3c 20 00 74 08 48 89 df e8 2a 92 82 00 48 8b 1b 48 8b 44 24 RSP: 0018:ffffc900001e6ce0 EFLAGS: 00000287 RAX: 1ffffffff1d36acf RBX: ffffffff8e9b5678 RCX: 0000000000100000 RDX: ffffc90018990000 RSI: 0000000000009940 RDI: 0000000000009941 RBP: ffffc900001e6e30 R08: ffffffff8fa100f7 R09: 1ffffffff1f4201e R10: dffffc0000000000 R11: fffffbfff1f4201f R12: dffffc0000000000 R13: 0000000000000001 R14: 0000000000000200 R15: ffffffff8e9b5620 __console_flush_and_unlock kernel/printk/printk.c:3285 [inline] console_unlock+0xc4/0x270 kernel/printk/printk.c:3325 vprintk_emit+0x5b7/0x7a0 kernel/printk/printk.c:2450 dev_vprintk_emit+0x337/0x3f0 drivers/base/core.c:4917 dev_printk_emit+0xe0/0x130 drivers/base/core.c:4928 _dev_notice+0x10a/0x160 drivers/base/core.c:4985 usb_parse_endpoint drivers/usb/core/config.c:421 [inline] usb_parse_interface drivers/usb/core/config.c:630 [inline] usb_parse_configuration drivers/usb/core/config.c:843 [inline] usb_get_configuration+0x296e/0x52c0 drivers/usb/core/config.c:992 usb_enumerate_device drivers/usb/core/hub.c:2495 [inline] usb_new_device+0x146/0x16c0 drivers/usb/core/hub.c:2633 hub_port_connect drivers/usb/core/hub.c:5531 [inline] hub_port_connect_change drivers/usb/core/hub.c:5671 [inline] port_event drivers/usb/core/hub.c:5831 [inline] hub_event+0x2941/0x4a00 drivers/usb/core/hub.c:5913 process_one_work kernel/workqueue.c:3238 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3321 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402 kthread+0x70e/0x8a0 kernel/kthread.c:464 ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 ---------------- Code disassembly (best guess): 0: 48 21 c3 and %rax,%rbx 3: 0f 85 e9 01 00 00 jne 0x1f2 9: e8 95 20 1f 00 call 0x1f20a3 e: 48 8b 5c 24 20 mov 0x20(%rsp),%rbx 13: 4d 85 f6 test %r14,%r14 16: 75 07 jne 0x1f 18: e8 86 20 1f 00 call 0x1f20a3 1d: eb 06 jmp 0x25 1f: e8 7f 20 1f 00 call 0x1f20a3 24: fb sti 25: 48 8b 44 24 28 mov 0x28(%rsp),%rax * 2a: 42 80 3c 20 00 cmpb $0x0,(%rax,%r12,1) <-- trapping instruction 2f: 74 08 je 0x39 31: 48 89 df mov %rbx,%rdi 34: e8 2a 92 82 00 call 0x829263 39: 48 8b 1b mov (%rbx),%rbx 3c: 48 rex.W 3d: 8b .byte 0x8b 3e: 44 rex.R 3f: 24 .byte 0x24