============================================ WARNING: possible recursive locking detected 5.19.0-syzkaller-11908-g7ebfc85e2cd7 #0 Not tainted -------------------------------------------- syz-executor.1/11259 is trying to acquire lock: ffff888146a1b0d8 (_xmit_ETHER#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:349 [inline] ffff888146a1b0d8 (_xmit_ETHER#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4256 [inline] ffff888146a1b0d8 (_xmit_ETHER#2){+.-.}-{2:2}, at: sch_direct_xmit+0x318/0xbe0 net/sched/sch_generic.c:340 but task is already holding lock: ffff888144a6f8d8 (_xmit_ETHER#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:349 [inline] ffff888144a6f8d8 (_xmit_ETHER#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4256 [inline] ffff888144a6f8d8 (_xmit_ETHER#2){+.-.}-{2:2}, at: sch_direct_xmit+0x318/0xbe0 net/sched/sch_generic.c:340 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(_xmit_ETHER#2); lock(_xmit_ETHER#2); *** DEADLOCK *** May be due to missing lock nesting notation 8 locks held by syz-executor.1/11259: #0: ffff88801d6050f0 (sk_lock-AF_INET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1687 [inline] #0: ffff88801d6050f0 (sk_lock-AF_INET){+.+.}-{0:0}, at: udp_sendmsg+0x72d/0x2740 net/ipv4/udp.c:1082 #1: ffffffff8bf891e0 (rcu_read_lock_bh){....}-{1:2}, at: lwtunnel_xmit_redirect include/net/lwtunnel.h:95 [inline] #1: ffffffff8bf891e0 (rcu_read_lock_bh){....}-{1:2}, at: ip_finish_output2+0x292/0x2170 net/ipv4/ip_output.c:214 #2: ffffffff8bf891e0 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x22f/0x3ad0 net/core/dev.c:4173 #3: ffff88807c51d258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: spin_trylock include/linux/spinlock.h:359 [inline] #3: ffff88807c51d258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:187 [inline] #3: ffff88807c51d258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:184 [inline] #3: ffff88807c51d258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3804 [inline] #3: ffff88807c51d258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_queue_xmit+0x133c/0x3ad0 net/core/dev.c:4222 #4: ffff888144a6f8d8 (_xmit_ETHER#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:349 [inline] #4: ffff888144a6f8d8 (_xmit_ETHER#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4256 [inline] #4: ffff888144a6f8d8 (_xmit_ETHER#2){+.-.}-{2:2}, at: sch_direct_xmit+0x318/0xbe0 net/sched/sch_generic.c:340 #5: ffffffff8bf891e0 (rcu_read_lock_bh){....}-{1:2}, at: lwtunnel_xmit_redirect include/net/lwtunnel.h:95 [inline] #5: ffffffff8bf891e0 (rcu_read_lock_bh){....}-{1:2}, at: ip_finish_output2+0x292/0x2170 net/ipv4/ip_output.c:214 #6: ffffffff8bf891e0 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x22f/0x3ad0 net/core/dev.c:4173 #7: ffff88801dd94258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: spin_trylock include/linux/spinlock.h:359 [inline] #7: ffff88801dd94258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:187 [inline] #7: ffff88801dd94258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:184 [inline] #7: ffff88801dd94258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3804 [inline] #7: ffff88801dd94258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_queue_xmit+0x133c/0x3ad0 net/core/dev.c:4222 stack backtrace: CPU: 0 PID: 11259 Comm: syz-executor.1 Not tainted 5.19.0-syzkaller-11908-g7ebfc85e2cd7 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_deadlock_bug kernel/locking/lockdep.c:2988 [inline] check_deadlock kernel/locking/lockdep.c:3031 [inline] validate_chain kernel/locking/lockdep.c:3816 [inline] __lock_acquire.cold+0x116/0x3a7 kernel/locking/lockdep.c:5053 lock_acquire kernel/locking/lockdep.c:5666 [inline] lock_acquire+0x1ab/0x570 kernel/locking/lockdep.c:5631 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:349 [inline] __netif_tx_lock include/linux/netdevice.h:4256 [inline] sch_direct_xmit+0x318/0xbe0 net/sched/sch_generic.c:340 __dev_xmit_skb net/core/dev.c:3817 [inline] __dev_queue_xmit+0x1568/0x3ad0 net/core/dev.c:4222 dev_queue_xmit include/linux/netdevice.h:2994 [inline] neigh_resolve_output net/core/neighbour.c:1528 [inline] neigh_resolve_output+0x517/0x840 net/core/neighbour.c:1508 neigh_output include/net/neighbour.h:550 [inline] ip_finish_output2+0x782/0x2170 net/ipv4/ip_output.c:228 __ip_finish_output net/ipv4/ip_output.c:306 [inline] __ip_finish_output+0x396/0x650 net/ipv4/ip_output.c:288 ip_finish_output+0x2d/0x280 net/ipv4/ip_output.c:316 NF_HOOK_COND include/linux/netfilter.h:296 [inline] ip_output+0x19f/0x310 net/ipv4/ip_output.c:430 dst_output include/net/dst.h:451 [inline] ip_local_out+0xaf/0x1a0 net/ipv4/ip_output.c:126 iptunnel_xmit+0x67a/0x9e0 net/ipv4/ip_tunnel_core.c:82 ip_tunnel_xmit+0x1437/0x3170 net/ipv4/ip_tunnel.c:812 erspan_xmit+0x81d/0x2820 net/ipv4/ip_gre.c:715 __netdev_start_xmit include/linux/netdevice.h:4805 [inline] netdev_start_xmit include/linux/netdevice.h:4819 [inline] xmit_one net/core/dev.c:3590 [inline] dev_hard_start_xmit+0x183/0x880 net/core/dev.c:3606 sch_direct_xmit+0x19f/0xbe0 net/sched/sch_generic.c:342 __dev_xmit_skb net/core/dev.c:3817 [inline] __dev_queue_xmit+0x1568/0x3ad0 net/core/dev.c:4222 dev_queue_xmit include/linux/netdevice.h:2994 [inline] neigh_resolve_output net/core/neighbour.c:1528 [inline] neigh_resolve_output+0x517/0x840 net/core/neighbour.c:1508 neigh_output include/net/neighbour.h:550 [inline] ip_finish_output2+0x782/0x2170 net/ipv4/ip_output.c:228 ip_do_fragment+0x12ed/0x1700 net/ipv4/ip_output.c:857 ip_fragment.constprop.0+0x16b/0x240 net/ipv4/ip_output.c:581 __ip_finish_output net/ipv4/ip_output.c:304 [inline] __ip_finish_output+0x2de/0x650 net/ipv4/ip_output.c:288 ip_finish_output+0x2d/0x280 net/ipv4/ip_output.c:316 NF_HOOK_COND include/linux/netfilter.h:296 [inline] ip_output+0x19f/0x310 net/ipv4/ip_output.c:430 dst_output include/net/dst.h:451 [inline] ip_local_out net/ipv4/ip_output.c:126 [inline] ip_send_skb+0xd4/0x260 net/ipv4/ip_output.c:1589 udp_send_skb+0x725/0x1430 net/ipv4/udp.c:969 udp_push_pending_frames net/ipv4/udp.c:997 [inline] udp_sendmsg+0x12ec/0x2740 net/ipv4/udp.c:1288 inet_sendmsg+0x99/0xe0 net/ipv4/af_inet.c:819 sock_sendmsg_nosec net/socket.c:714 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:734 __sys_sendto+0x236/0x340 net/socket.c:2117 __do_sys_sendto net/socket.c:2129 [inline] __se_sys_sendto net/socket.c:2125 [inline] __x64_sys_sendto+0xdd/0x1b0 net/socket.c:2125 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f155b089279 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f155c252168 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007f155b19bf80 RCX: 00007f155b089279 RDX: 0000000000000091 RSI: 0000000020001040 RDI: 0000000000000004 RBP: 00007f155b0e3189 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffdb1ddcfcf R14: 00007f155c252300 R15: 0000000000022000