netlink: 'syz-executor.0': attribute type 27 has an invalid length. ====================================================== WARNING: possible circular locking dependency detected 6.8.0-rc3-syzkaller-00010-gf735966ee23c #0 Not tainted ------------------------------------------------------ syz-executor.0/6642 is trying to acquire lock: ffff0000da87d0d0 (&priv->j1939_socks_lock){+.-.}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:356 [inline] ffff0000da87d0d0 (&priv->j1939_socks_lock){+.-.}-{2:2}, at: j1939_sk_errqueue+0x90/0x144 net/can/j1939/socket.c:1083 but task is already holding lock: ffff0000da87d088 (&priv->active_session_list_lock){+.-.}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:356 [inline] ffff0000da87d088 (&priv->active_session_list_lock){+.-.}-{2:2}, at: j1939_session_list_lock net/can/j1939/transport.c:238 [inline] ffff0000da87d088 (&priv->active_session_list_lock){+.-.}-{2:2}, at: j1939_cancel_active_session+0x54/0x414 net/can/j1939/transport.c:2183 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&priv->active_session_list_lock){+.-.}-{2:2}: __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline] _raw_spin_lock_bh+0x48/0x60 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:356 [inline] j1939_session_list_lock net/can/j1939/transport.c:238 [inline] j1939_session_activate+0x60/0x378 net/can/j1939/transport.c:1564 j1939_sk_queue_activate_next_locked net/can/j1939/socket.c:181 [inline] j1939_sk_queue_activate_next+0x230/0x3b4 net/can/j1939/socket.c:208 j1939_session_deactivate_activate_next net/can/j1939/transport.c:1108 [inline] j1939_session_completed net/can/j1939/transport.c:1222 [inline] j1939_xtp_rx_eoma_one net/can/j1939/transport.c:1395 [inline] j1939_xtp_rx_eoma+0x2c0/0x4c0 net/can/j1939/transport.c:1410 j1939_tp_cmd_recv net/can/j1939/transport.c:2099 [inline] j1939_tp_recv+0x714/0xe14 net/can/j1939/transport.c:2144 j1939_can_recv+0x5bc/0x930 net/can/j1939/main.c:112 deliver net/can/af_can.c:572 [inline] can_rcv_filter+0x308/0x714 net/can/af_can.c:606 can_receive+0x33c/0x49c net/can/af_can.c:663 can_rcv+0x128/0x23c net/can/af_can.c:687 __netif_receive_skb_one_core net/core/dev.c:5534 [inline] __netif_receive_skb+0x18c/0x400 net/core/dev.c:5648 process_backlog+0x3c0/0x70c net/core/dev.c:5976 __napi_poll+0xb4/0x654 net/core/dev.c:6576 napi_poll net/core/dev.c:6645 [inline] net_rx_action+0x5e4/0xdc4 net/core/dev.c:6778 __do_softirq+0x2d8/0xce4 kernel/softirq.c:553 ____do_softirq+0x14/0x20 arch/arm64/kernel/irq.c:81 call_on_irq_stack+0x24/0x4c arch/arm64/kernel/entry.S:889 do_softirq_own_stack+0x20/0x2c arch/arm64/kernel/irq.c:86 invoke_softirq kernel/softirq.c:434 [inline] __irq_exit_rcu+0x1d8/0x434 kernel/softirq.c:632 irq_exit_rcu+0x14/0x84 kernel/softirq.c:644 __el1_irq arch/arm64/kernel/entry-common.c:503 [inline] el1_interrupt+0x38/0x68 arch/arm64/kernel/entry-common.c:517 el1h_64_irq_handler+0x18/0x24 arch/arm64/kernel/entry-common.c:522 el1h_64_irq+0x64/0x68 arch/arm64/kernel/entry.S:594 __daif_local_irq_restore arch/arm64/include/asm/irqflags.h:176 [inline] arch_local_irq_restore arch/arm64/include/asm/irqflags.h:196 [inline] lock_acquire+0x278/0x71c kernel/locking/lockdep.c:5757 __mutex_lock_common+0x190/0x21a0 kernel/locking/mutex.c:608 __mutex_lock kernel/locking/mutex.c:752 [inline] mutex_lock_nested+0x2c/0x38 kernel/locking/mutex.c:804 __ipv6_dev_mc_dec+0x7c/0x324 net/ipv6/mcast.c:970 addrconf_leave_solict net/ipv6/addrconf.c:2204 [inline] __ipv6_ifa_notify+0x784/0xf60 net/ipv6/addrconf.c:6221 addrconf_ifdown+0xdc4/0x17c8 net/ipv6/addrconf.c:3920 addrconf_notify+0x340/0xce8 notifier_call_chain+0x1a4/0x510 kernel/notifier.c:93 raw_notifier_call_chain+0x3c/0x50 kernel/notifier.c:461 __dev_notify_flags+0x2c4/0x550 dev_change_flags+0xd0/0x15c net/core/dev.c:8725 do_setlink+0xadc/0x3794 net/core/rtnetlink.c:2903 rtnl_group_changelink net/core/rtnetlink.c:3452 [inline] __rtnl_newlink net/core/rtnetlink.c:3711 [inline] rtnl_newlink+0xe4c/0x1bcc net/core/rtnetlink.c:3748 rtnetlink_rcv_msg+0x748/0xdbc net/core/rtnetlink.c:6615 netlink_rcv_skb+0x214/0x3c4 net/netlink/af_netlink.c:2543 rtnetlink_rcv+0x28/0x38 net/core/rtnetlink.c:6633 netlink_unicast_kernel net/netlink/af_netlink.c:1341 [inline] netlink_unicast+0x65c/0x898 net/netlink/af_netlink.c:1367 netlink_sendmsg+0x83c/0xb20 net/netlink/af_netlink.c:1908 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg net/socket.c:745 [inline] ____sys_sendmsg+0x56c/0x840 net/socket.c:2584 ___sys_sendmsg net/socket.c:2638 [inline] __sys_sendmsg+0x26c/0x33c net/socket.c:2667 __do_sys_sendmsg net/socket.c:2676 [inline] __se_sys_sendmsg net/socket.c:2674 [inline] __arm64_sys_sendmsg+0x80/0x94 net/socket.c:2674 __invoke_syscall arch/arm64/kernel/syscall.c:37 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:51 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:136 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:155 el0_svc+0x54/0x158 arch/arm64/kernel/entry-common.c:678 el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:696 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598 -> #1 (&jsk->sk_session_queue_lock){+.-.}-{2:2}: __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline] _raw_spin_lock_bh+0x48/0x60 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:356 [inline] j1939_sk_queue_drop_all+0x4c/0x200 net/can/j1939/socket.c:139 j1939_sk_netdev_event_netdown+0xe0/0x144 net/can/j1939/socket.c:1282 j1939_netdev_notify+0xf0/0x144 net/can/j1939/main.c:381 notifier_call_chain+0x1a4/0x510 kernel/notifier.c:93 raw_notifier_call_chain+0x3c/0x50 kernel/notifier.c:461 __dev_notify_flags+0x2c4/0x550 dev_change_flags+0xd0/0x15c net/core/dev.c:8725 do_setlink+0xadc/0x3794 net/core/rtnetlink.c:2903 rtnl_group_changelink net/core/rtnetlink.c:3452 [inline] __rtnl_newlink net/core/rtnetlink.c:3711 [inline] rtnl_newlink+0xe4c/0x1bcc net/core/rtnetlink.c:3748 rtnetlink_rcv_msg+0x748/0xdbc net/core/rtnetlink.c:6615 netlink_rcv_skb+0x214/0x3c4 net/netlink/af_netlink.c:2543 rtnetlink_rcv+0x28/0x38 net/core/rtnetlink.c:6633 netlink_unicast_kernel net/netlink/af_netlink.c:1341 [inline] netlink_unicast+0x65c/0x898 net/netlink/af_netlink.c:1367 netlink_sendmsg+0x83c/0xb20 net/netlink/af_netlink.c:1908 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg net/socket.c:745 [inline] ____sys_sendmsg+0x56c/0x840 net/socket.c:2584 ___sys_sendmsg net/socket.c:2638 [inline] __sys_sendmsg+0x26c/0x33c net/socket.c:2667 __do_sys_sendmsg net/socket.c:2676 [inline] __se_sys_sendmsg net/socket.c:2674 [inline] __arm64_sys_sendmsg+0x80/0x94 net/socket.c:2674 __invoke_syscall arch/arm64/kernel/syscall.c:37 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:51 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:136 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:155 el0_svc+0x54/0x158 arch/arm64/kernel/entry-common.c:678 el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:696 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598 -> #0 (&priv->j1939_socks_lock){+.-.}-{2:2}: check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain kernel/locking/lockdep.c:3869 [inline] __lock_acquire+0x3384/0x763c kernel/locking/lockdep.c:5137 lock_acquire+0x23c/0x71c kernel/locking/lockdep.c:5754 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline] _raw_spin_lock_bh+0x48/0x60 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:356 [inline] j1939_sk_errqueue+0x90/0x144 net/can/j1939/socket.c:1083 __j1939_session_release net/can/j1939/transport.c:294 [inline] kref_put include/linux/kref.h:65 [inline] j1939_session_put+0xf0/0x4b4 net/can/j1939/transport.c:299 j1939_session_deactivate_locked net/can/j1939/transport.c:1086 [inline] j1939_cancel_active_session+0x2ec/0x414 net/can/j1939/transport.c:2194 j1939_netdev_notify+0xe8/0x144 net/can/j1939/main.c:380 notifier_call_chain+0x1a4/0x510 kernel/notifier.c:93 raw_notifier_call_chain+0x3c/0x50 kernel/notifier.c:461 __dev_notify_flags+0x2c4/0x550 dev_change_flags+0xd0/0x15c net/core/dev.c:8725 do_setlink+0xadc/0x3794 net/core/rtnetlink.c:2903 rtnl_group_changelink net/core/rtnetlink.c:3452 [inline] __rtnl_newlink net/core/rtnetlink.c:3711 [inline] rtnl_newlink+0xe4c/0x1bcc net/core/rtnetlink.c:3748 rtnetlink_rcv_msg+0x748/0xdbc net/core/rtnetlink.c:6615 netlink_rcv_skb+0x214/0x3c4 net/netlink/af_netlink.c:2543 rtnetlink_rcv+0x28/0x38 net/core/rtnetlink.c:6633 netlink_unicast_kernel net/netlink/af_netlink.c:1341 [inline] netlink_unicast+0x65c/0x898 net/netlink/af_netlink.c:1367 netlink_sendmsg+0x83c/0xb20 net/netlink/af_netlink.c:1908 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg net/socket.c:745 [inline] ____sys_sendmsg+0x56c/0x840 net/socket.c:2584 ___sys_sendmsg net/socket.c:2638 [inline] __sys_sendmsg+0x26c/0x33c net/socket.c:2667 __do_sys_sendmsg net/socket.c:2676 [inline] __se_sys_sendmsg net/socket.c:2674 [inline] __arm64_sys_sendmsg+0x80/0x94 net/socket.c:2674 __invoke_syscall arch/arm64/kernel/syscall.c:37 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:51 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:136 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:155 el0_svc+0x54/0x158 arch/arm64/kernel/entry-common.c:678 el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:696 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598 other info that might help us debug this: Chain exists of: &priv->j1939_socks_lock --> &jsk->sk_session_queue_lock --> &priv->active_session_list_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&priv->active_session_list_lock); lock(&jsk->sk_session_queue_lock); lock(&priv->active_session_list_lock); lock(&priv->j1939_socks_lock); *** DEADLOCK *** 2 locks held by syz-executor.0/6642: #0: ffff80009191dde8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline] #0: ffff80009191dde8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x704/0xdbc net/core/rtnetlink.c:6612 #1: ffff0000da87d088 (&priv->active_session_list_lock){+.-.}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:356 [inline] #1: ffff0000da87d088 (&priv->active_session_list_lock){+.-.}-{2:2}, at: j1939_session_list_lock net/can/j1939/transport.c:238 [inline] #1: ffff0000da87d088 (&priv->active_session_list_lock){+.-.}-{2:2}, at: j1939_cancel_active_session+0x54/0x414 net/can/j1939/transport.c:2183 stack backtrace: CPU: 0 PID: 6642 Comm: syz-executor.0 Not tainted 6.8.0-rc3-syzkaller-00010-gf735966ee23c #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023 Call trace: dump_backtrace+0x1b8/0x1e4 arch/arm64/kernel/stacktrace.c:291 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:298 __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd0/0x124 lib/dump_stack.c:106 dump_stack+0x1c/0x28 lib/dump_stack.c:113 print_circular_bug+0x150/0x1b8 kernel/locking/lockdep.c:2060 check_noncircular+0x310/0x404 kernel/locking/lockdep.c:2187 check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain kernel/locking/lockdep.c:3869 [inline] __lock_acquire+0x3384/0x763c kernel/locking/lockdep.c:5137 lock_acquire+0x23c/0x71c kernel/locking/lockdep.c:5754 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline] _raw_spin_lock_bh+0x48/0x60 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:356 [inline] j1939_sk_errqueue+0x90/0x144 net/can/j1939/socket.c:1083 __j1939_session_release net/can/j1939/transport.c:294 [inline] kref_put include/linux/kref.h:65 [inline] j1939_session_put+0xf0/0x4b4 net/can/j1939/transport.c:299 j1939_session_deactivate_locked net/can/j1939/transport.c:1086 [inline] j1939_cancel_active_session+0x2ec/0x414 net/can/j1939/transport.c:2194 j1939_netdev_notify+0xe8/0x144 net/can/j1939/main.c:380 notifier_call_chain+0x1a4/0x510 kernel/notifier.c:93 raw_notifier_call_chain+0x3c/0x50 kernel/notifier.c:461 __dev_notify_flags+0x2c4/0x550 dev_change_flags+0xd0/0x15c net/core/dev.c:8725 do_setlink+0xadc/0x3794 net/core/rtnetlink.c:2903 rtnl_group_changelink net/core/rtnetlink.c:3452 [inline] __rtnl_newlink net/core/rtnetlink.c:3711 [inline] rtnl_newlink+0xe4c/0x1bcc net/core/rtnetlink.c:3748 rtnetlink_rcv_msg+0x748/0xdbc net/core/rtnetlink.c:6615 netlink_rcv_skb+0x214/0x3c4 net/netlink/af_netlink.c:2543 rtnetlink_rcv+0x28/0x38 net/core/rtnetlink.c:6633 netlink_unicast_kernel net/netlink/af_netlink.c:1341 [inline] netlink_unicast+0x65c/0x898 net/netlink/af_netlink.c:1367 netlink_sendmsg+0x83c/0xb20 net/netlink/af_netlink.c:1908 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg net/socket.c:745 [inline] ____sys_sendmsg+0x56c/0x840 net/socket.c:2584 ___sys_sendmsg net/socket.c:2638 [inline] __sys_sendmsg+0x26c/0x33c net/socket.c:2667 __do_sys_sendmsg net/socket.c:2676 [inline] __se_sys_sendmsg net/socket.c:2674 [inline] __arm64_sys_sendmsg+0x80/0x94 net/socket.c:2674 __invoke_syscall arch/arm64/kernel/syscall.c:37 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:51 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:136 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:155 el0_svc+0x54/0x158 arch/arm64/kernel/entry-common.c:678 el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:696 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598