------------[ cut here ]------------ refcount_t: underflow; use-after-free. WARNING: CPU: 0 PID: 0 at lib/refcount.c:28 refcount_warn_saturate+0x15a/0x1d0 lib/refcount.c:28 Modules linked in: CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 6.10.0-syzkaller-12610-g743ff02152bc #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024 RIP: 0010:refcount_warn_saturate+0x15a/0x1d0 lib/refcount.c:28 Code: 00 17 40 8c e8 67 97 a5 fc 90 0f 0b 90 90 eb 99 e8 1b 89 e3 fc c6 05 76 7d 31 0b 01 90 48 c7 c7 60 17 40 8c e8 47 97 a5 fc 90 <0f> 0b 90 90 e9 76 ff ff ff e8 f8 88 e3 fc c6 05 50 7d 31 0b 01 90 RSP: 0018:ffffc900000076a0 EFLAGS: 00010246 RAX: 9ce7031b7bf45900 RBX: ffff88802d9fc224 RCX: ffffffff8e494680 RDX: 0000000000000101 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000003 R08: ffffffff81559432 R09: fffffbfff1cb9f88 R10: dffffc0000000000 R11: fffffbfff1cb9f88 R12: ffff88802c02c468 R13: ffff88802d9fc224 R14: 1ffff11005805898 R15: ffff88802c02c400 FS: 0000000000000000(0000) GS:ffff8880b9200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055b3e8e4e5d8 CR3: 000000007d3fa000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: kfree_skb_reason include/linux/skbuff.h:1260 [inline] kfree_skb include/linux/skbuff.h:1269 [inline] j1939_session_destroy net/can/j1939/transport.c:282 [inline] __j1939_session_release net/can/j1939/transport.c:294 [inline] kref_put include/linux/kref.h:65 [inline] j1939_session_put+0x1e7/0x440 net/can/j1939/transport.c:299 j1939_xtp_rx_dat net/can/j1939/transport.c:1957 [inline] j1939_tp_recv+0x31e/0x1050 net/can/j1939/transport.c:2151 j1939_can_recv+0x732/0xb20 net/can/j1939/main.c:108 deliver net/can/af_can.c:572 [inline] can_rcv_filter+0x359/0x7f0 net/can/af_can.c:606 can_receive+0x31c/0x470 net/can/af_can.c:663 can_rcv+0x144/0x260 net/can/af_can.c:687 __netif_receive_skb_one_core net/core/dev.c:5660 [inline] __netif_receive_skb+0x2e0/0x650 net/core/dev.c:5774 process_backlog+0x662/0x15b0 net/core/dev.c:6107 __napi_poll+0xcb/0x490 net/core/dev.c:6771 napi_poll net/core/dev.c:6840 [inline] net_rx_action+0x89b/0x1240 net/core/dev.c:6962 handle_softirqs+0x2c4/0x970 kernel/softirq.c:554 __do_softirq kernel/softirq.c:588 [inline] invoke_softirq kernel/softirq.c:428 [inline] __irq_exit_rcu+0xf4/0x1c0 kernel/softirq.c:637 irq_exit_rcu+0x9/0x30 kernel/softirq.c:649 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1043 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:native_irq_disable arch/x86/include/asm/irqflags.h:37 [inline] RIP: 0010:arch_local_irq_disable arch/x86/include/asm/irqflags.h:92 [inline] RIP: 0010:acpi_safe_halt+0x21/0x30 drivers/acpi/processor_idle.c:112 Code: 90 90 90 90 90 90 90 90 90 65 48 8b 04 25 40 d7 03 00 48 f7 00 08 00 00 00 75 10 66 90 0f 00 2d b5 e0 94 00 f3 0f 1e fa fb f4 c3 cc cc cc cc 66 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 RSP: 0018:ffffffff8e407ca8 EFLAGS: 00000246 RAX: ffffffff8e494680 RBX: ffff88801b2f5864 RCX: 0000000000025c51 RDX: 0000000000000001 RSI: ffff88801b2f5800 RDI: ffff88801b2f5864 RBP: 000000000003a6b8 R08: ffff8880b9237c7b R09: 1ffff11017246f8f R10: dffffc0000000000 R11: ffffffff8bb537c0 R12: ffff88801bf89800 R13: 0000000000000000 R14: 0000000000000001 R15: ffffffff8eedb0e0 acpi_idle_enter+0xe4/0x140 drivers/acpi/processor_idle.c:702 cpuidle_enter_state+0x112/0x480 drivers/cpuidle/cpuidle.c:267 cpuidle_enter+0x5d/0xa0 drivers/cpuidle/cpuidle.c:388 call_cpuidle kernel/sched/idle.c:155 [inline] cpuidle_idle_call kernel/sched/idle.c:230 [inline] do_idle+0x375/0x5d0 kernel/sched/idle.c:326 cpu_startup_entry+0x42/0x60 kernel/sched/idle.c:424 rest_init+0x2dc/0x300 init/main.c:747 start_kernel+0x47a/0x500 init/main.c:1103 x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:507 x86_64_start_kernel+0x9f/0xa0 arch/x86/kernel/head64.c:488 common_startup_64+0x13e/0x147 ---------------- Code disassembly (best guess): 0: 90 nop 1: 90 nop 2: 90 nop 3: 90 nop 4: 90 nop 5: 90 nop 6: 90 nop 7: 90 nop 8: 90 nop 9: 65 48 8b 04 25 40 d7 mov %gs:0x3d740,%rax 10: 03 00 12: 48 f7 00 08 00 00 00 testq $0x8,(%rax) 19: 75 10 jne 0x2b 1b: 66 90 xchg %ax,%ax 1d: 0f 00 2d b5 e0 94 00 verw 0x94e0b5(%rip) # 0x94e0d9 24: f3 0f 1e fa endbr64 28: fb sti 29: f4 hlt * 2a: fa cli <-- trapping instruction 2b: c3 ret 2c: cc int3 2d: cc int3 2e: cc int3 2f: cc int3 30: 66 0f 1f 84 00 00 00 nopw 0x0(%rax,%rax,1) 37: 00 00 39: 90 nop 3a: 90 nop 3b: 90 nop 3c: 90 nop 3d: 90 nop 3e: 90 nop 3f: 90 nop