------------[ cut here ]------------ refcount_t: addition on 0; use-after-free. WARNING: CPU: 1 PID: 8488 at lib/refcount.c:25 refcount_warn_saturate+0x134/0x1f8 lib/refcount.c:25 Modules linked in: CPU: 1 PID: 8488 Comm: syz-executor Not tainted 6.1.141-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : refcount_warn_saturate+0x134/0x1f8 lib/refcount.c:25 lr : refcount_warn_saturate+0x134/0x1f8 lib/refcount.c:25 sp : ffff8000080178c0 x29: ffff8000080178c0 x28: ffff0000f18bc400 x27: ffff0000c9fd8208 x26: ffff0000f7dc3c70 x25: dfff800000000000 x24: 1fffe000193fb041 x23: ffff0000f42dac00 x22: ffff0000f7c20154 x21: ffff0000dbbaf880 x20: ffff0000f7c20154 x19: ffff800017a32000 x18: 00000000500194e2 x17: 0000000000000000 x16: ffff8000082d1c00 x15: 0000000000000000 x14: 00000000ffffffff x13: 0000000000000001 x12: 0000000000ff0100 x11: ff0080000819149c x10: 0000000000000000 x9 : 96e36b602793be00 x8 : 96e36b602793be00 x7 : 0000000000000001 x6 : 0000000000000001 x5 : ffff800008017358 x4 : ffff800015154700 x3 : ffff80000852da40 x2 : 0000000000000001 x1 : 0000000000000101 x0 : 0000000000000000 Call trace: refcount_warn_saturate+0x134/0x1f8 lib/refcount.c:25 __refcount_add include/linux/refcount.h:-1 [inline] __refcount_inc include/linux/refcount.h:250 [inline] refcount_inc include/linux/refcount.h:267 [inline] get_net include/net/net_namespace.h:257 [inline] tipc_aead_encrypt net/tipc/crypto.c:821 [inline] tipc_crypto_xmit+0x1518/0x2014 net/tipc/crypto.c:1761 tipc_bearer_xmit_skb+0x1f0/0x384 net/tipc/bearer.c:574 tipc_disc_timeout+0x4c8/0x608 net/tipc/discover.c:338 call_timer_fn+0x1b8/0x964 kernel/time/timer.c:1504 expire_timers kernel/time/timer.c:1549 [inline] __run_timers+0x460/0x6bc kernel/time/timer.c:1820 run_timer_softirq+0x7c/0x114 kernel/time/timer.c:1833 handle_softirqs+0x318/0xc6c kernel/softirq.c:596 __do_softirq+0x14/0x20 kernel/softirq.c:630 ____do_softirq+0x14/0x20 arch/arm64/kernel/irq.c:80 call_on_irq_stack+0x24/0x4c arch/arm64/kernel/entry.S:893 do_softirq_own_stack+0x20/0x2c arch/arm64/kernel/irq.c:85 invoke_softirq kernel/softirq.c:477 [inline] __irq_exit_rcu+0x23c/0x43c kernel/softirq.c:679 irq_exit_rcu+0x14/0x84 kernel/softirq.c:691 __el1_irq arch/arm64/kernel/entry-common.c:472 [inline] el1_interrupt+0x38/0x54 arch/arm64/kernel/entry-common.c:486 el1h_64_irq_handler+0x18/0x24 arch/arm64/kernel/entry-common.c:491 el1h_64_irq+0x64/0x68 arch/arm64/kernel/entry.S:581 arch_local_irq_restore arch/arm64/include/asm/irqflags.h:122 [inline] __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:151 [inline] _raw_spin_unlock_irqrestore+0x58/0xac kernel/locking/spinlock.c:194 __debug_check_no_obj_freed lib/debugobjects.c:988 [inline] debug_check_no_obj_freed+0x450/0x46c lib/debugobjects.c:1009 slab_free_hook mm/slub.c:1699 [inline] slab_free_freelist_hook+0x104/0x1ec mm/slub.c:1750 slab_free mm/slub.c:3661 [inline] kmem_cache_free+0x11c/0x324 mm/slub.c:3683 kfree_skbmem+0x10c/0x19c net/core/skbuff.c:-1 __kfree_skb net/core/skbuff.c:871 [inline] consume_skb+0xa8/0x104 net/core/skbuff.c:1035 netlink_broadcast+0xebc/0x1018 net/netlink/af_netlink.c:1508 nlmsg_multicast include/net/netlink.h:1071 [inline] nlmsg_notify+0xf4/0x1d8 net/netlink/af_netlink.c:2536 rtnl_notify+0xa0/0xd8 net/core/rtnetlink.c:796 inet_netconf_notify_devconf+0x1f0/0x25c net/ipv4/devinet.c:2141 __devinet_sysctl_register+0x280/0x2f0 net/ipv4/devinet.c:2619 devinet_sysctl_register+0x14c/0x1c0 net/ipv4/devinet.c:2653 inetdev_init+0x268/0x4a8 net/ipv4/devinet.c:280 inetdev_event+0xf0c/0x12ec net/ipv4/devinet.c:1548 notifier_call_chain kernel/notifier.c:87 [inline] raw_notifier_call_chain+0xd4/0x164 kernel/notifier.c:455 call_netdevice_notifiers_info net/core/dev.c:2001 [inline] call_netdevice_notifiers_extack net/core/dev.c:2039 [inline] call_netdevice_notifiers+0x10c/0x18c net/core/dev.c:2053 register_netdevice+0x1188/0x15cc net/core/dev.c:10225 ip6gre_newlink_common+0x31c/0x4a0 net/ipv6/ip6_gre.c:2024 ip6gre_newlink+0x19c/0x448 net/ipv6/ip6_gre.c:2055 rtnl_newlink_create net/core/rtnetlink.c:3422 [inline] __rtnl_newlink net/core/rtnetlink.c:3642 [inline] rtnl_newlink+0x102c/0x1a1c net/core/rtnetlink.c:3655 rtnetlink_rcv_msg+0x734/0xce4 net/core/rtnetlink.c:6153 netlink_rcv_skb+0x208/0x3c4 net/netlink/af_netlink.c:2493 rtnetlink_rcv+0x28/0x38 net/core/rtnetlink.c:6171 netlink_unicast_kernel net/netlink/af_netlink.c:1311 [inline] netlink_unicast+0x600/0x818 net/netlink/af_netlink.c:1337 netlink_sendmsg+0x6e8/0x9b0 net/netlink/af_netlink.c:1859 sock_sendmsg_nosec net/socket.c:718 [inline] __sock_sendmsg net/socket.c:730 [inline] __sys_sendto+0x304/0x3fc net/socket.c:2153 __do_sys_sendto net/socket.c:2165 [inline] __se_sys_sendto net/socket.c:2161 [inline] __arm64_sys_sendto+0xd8/0xf8 net/socket.c:2161 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2bc arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:204 el0_svc+0x58/0x138 arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585 irq event stamp: 15593 hardirqs last enabled at (15592): [] __up_console_sem+0xb4/0x100 kernel/printk/printk.c:261 hardirqs last disabled at (15593): [] el1_dbg+0x24/0x80 arch/arm64/kernel/entry-common.c:405 softirqs last enabled at (15316): [] neigh_parms_alloc+0x328/0x45c net/core/neighbour.c:1726 softirqs last disabled at (15341): [] __do_softirq+0x14/0x20 kernel/softirq.c:630 ---[ end trace 0000000000000000 ]--- ------------[ cut here ]------------ refcount_t: underflow; use-after-free. WARNING: CPU: 1 PID: 8488 at lib/refcount.c:28 refcount_warn_saturate+0x154/0x1f8 lib/refcount.c:28 Modules linked in: CPU: 1 PID: 8488 Comm: syz-executor Tainted: G W 6.1.141-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : refcount_warn_saturate+0x154/0x1f8 lib/refcount.c:28 lr : refcount_warn_saturate+0x154/0x1f8 lib/refcount.c:28 sp : ffff8000080178c0 x29: ffff8000080178c0 x28: ffff0000f18bc400 x27: 0000000000000000 x26: ffff0000f7dc3c70 x25: dfff800000000000 x24: 1fffe0001efb8798 x23: 1fffe00019fb7379 x22: ffff0000c9fd8200 x21: 00000000c0000000 x20: ffff0000f7c20154 x19: ffff800017a32000 x18: 00000000500194e2 x17: 0000000000000000 x16: ffff8000082d1c00 x15: 0000000000000000 x14: 00000000ffffffff x13: 0000000000000001 x12: 0000000000ff0100 x11: ff0080000819149c x10: 0000000000000000 x9 : 96e36b602793be00 x8 : 96e36b602793be00 x7 : 0000000000000001 x6 : 0000000000000001 x5 : ffff800008017358 x4 : ffff800015154700 x3 : ffff8000083115f4 x2 : 0000000000000001 x1 : 0000000000000101 x0 : 0000000000000000 Call trace: refcount_warn_saturate+0x154/0x1f8 lib/refcount.c:28 __refcount_sub_and_test include/linux/refcount.h:283 [inline] __refcount_dec_and_test include/linux/refcount.h:315 [inline] refcount_dec_and_test include/linux/refcount.h:333 [inline] put_net include/net/net_namespace.h:276 [inline] tipc_aead_encrypt net/tipc/crypto.c:829 [inline] tipc_crypto_xmit+0x1664/0x2014 net/tipc/crypto.c:1761 tipc_bearer_xmit_skb+0x1f0/0x384 net/tipc/bearer.c:574 tipc_disc_timeout+0x4c8/0x608 net/tipc/discover.c:338 call_timer_fn+0x1b8/0x964 kernel/time/timer.c:1504 expire_timers kernel/time/timer.c:1549 [inline] __run_timers+0x460/0x6bc kernel/time/timer.c:1820 run_timer_softirq+0x7c/0x114 kernel/time/timer.c:1833 handle_softirqs+0x318/0xc6c kernel/softirq.c:596 __do_softirq+0x14/0x20 kernel/softirq.c:630 ____do_softirq+0x14/0x20 arch/arm64/kernel/irq.c:80 call_on_irq_stack+0x24/0x4c arch/arm64/kernel/entry.S:893 do_softirq_own_stack+0x20/0x2c arch/arm64/kernel/irq.c:85 invoke_softirq kernel/softirq.c:477 [inline] __irq_exit_rcu+0x23c/0x43c kernel/softirq.c:679 irq_exit_rcu+0x14/0x84 kernel/softirq.c:691 __el1_irq arch/arm64/kernel/entry-common.c:472 [inline] el1_interrupt+0x38/0x54 arch/arm64/kernel/entry-common.c:486 el1h_64_irq_handler+0x18/0x24 arch/arm64/kernel/entry-common.c:491 el1h_64_irq+0x64/0x68 arch/arm64/kernel/entry.S:581 arch_local_irq_restore arch/arm64/include/asm/irqflags.h:122 [inline] __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:151 [inline] _raw_spin_unlock_irqrestore+0x58/0xac kernel/locking/spinlock.c:194 __debug_check_no_obj_freed lib/debugobjects.c:988 [inline] debug_check_no_obj_freed+0x450/0x46c lib/debugobjects.c:1009 slab_free_hook mm/slub.c:1699 [inline] slab_free_freelist_hook+0x104/0x1ec mm/slub.c:1750 slab_free mm/slub.c:3661 [inline] kmem_cache_free+0x11c/0x324 mm/slub.c:3683 kfree_skbmem+0x10c/0x19c net/core/skbuff.c:-1 __kfree_skb net/core/skbuff.c:871 [inline] consume_skb+0xa8/0x104 net/core/skbuff.c:1035 netlink_broadcast+0xebc/0x1018 net/netlink/af_netlink.c:1508 nlmsg_multicast include/net/netlink.h:1071 [inline] nlmsg_notify+0xf4/0x1d8 net/netlink/af_netlink.c:2536 rtnl_notify+0xa0/0xd8 net/core/rtnetlink.c:796 inet_netconf_notify_devconf+0x1f0/0x25c net/ipv4/devinet.c:2141 __devinet_sysctl_register+0x280/0x2f0 net/ipv4/devinet.c:2619 devinet_sysctl_register+0x14c/0x1c0 net/ipv4/devinet.c:2653 inetdev_init+0x268/0x4a8 net/ipv4/devinet.c:280 inetdev_event+0xf0c/0x12ec net/ipv4/devinet.c:1548 notifier_call_chain kernel/notifier.c:87 [inline] raw_notifier_call_chain+0xd4/0x164 kernel/notifier.c:455 call_netdevice_notifiers_info net/core/dev.c:2001 [inline] call_netdevice_notifiers_extack net/core/dev.c:2039 [inline] call_netdevice_notifiers+0x10c/0x18c net/core/dev.c:2053 register_netdevice+0x1188/0x15cc net/core/dev.c:10225 ip6gre_newlink_common+0x31c/0x4a0 net/ipv6/ip6_gre.c:2024 ip6gre_newlink+0x19c/0x448 net/ipv6/ip6_gre.c:2055 rtnl_newlink_create net/core/rtnetlink.c:3422 [inline] __rtnl_newlink net/core/rtnetlink.c:3642 [inline] rtnl_newlink+0x102c/0x1a1c net/core/rtnetlink.c:3655 rtnetlink_rcv_msg+0x734/0xce4 net/core/rtnetlink.c:6153 netlink_rcv_skb+0x208/0x3c4 net/netlink/af_netlink.c:2493 rtnetlink_rcv+0x28/0x38 net/core/rtnetlink.c:6171 netlink_unicast_kernel net/netlink/af_netlink.c:1311 [inline] netlink_unicast+0x600/0x818 net/netlink/af_netlink.c:1337 netlink_sendmsg+0x6e8/0x9b0 net/netlink/af_netlink.c:1859 sock_sendmsg_nosec net/socket.c:718 [inline] __sock_sendmsg net/socket.c:730 [inline] __sys_sendto+0x304/0x3fc net/socket.c:2153 __do_sys_sendto net/socket.c:2165 [inline] __se_sys_sendto net/socket.c:2161 [inline] __arm64_sys_sendto+0xd8/0xf8 net/socket.c:2161 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2bc arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:204 el0_svc+0x58/0x138 arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585 irq event stamp: 15625 hardirqs last enabled at (15624): [] __up_console_sem+0xb4/0x100 kernel/printk/printk.c:261 hardirqs last disabled at (15625): [] el1_dbg+0x24/0x80 arch/arm64/kernel/entry-common.c:405 softirqs last enabled at (15316): [] neigh_parms_alloc+0x328/0x45c net/core/neighbour.c:1726 softirqs last disabled at (15341): [] __do_softirq+0x14/0x20 kernel/softirq.c:630 ---[ end trace 0000000000000000 ]---