============================================ WARNING: possible recursive locking detected 6.6.0-syzkaller-10135-g016b9332a334 #0 Not tainted -------------------------------------------- syz-executor.0/5427 is trying to acquire lock: ffff88807c9150d8 (_xmit_ETHER#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] ffff88807c9150d8 (_xmit_ETHER#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4381 [inline] ffff88807c9150d8 (_xmit_ETHER#2){+.-.}-{2:2}, at: __dev_queue_xmit+0x1a7f/0x3d10 net/core/dev.c:4340 but task is already holding lock: ffff88806f37d0d8 (_xmit_ETHER#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] ffff88806f37d0d8 (_xmit_ETHER#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4381 [inline] ffff88806f37d0d8 (_xmit_ETHER#2){+.-.}-{2:2}, at: sch_direct_xmit+0x333/0xc20 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 6 locks held by syz-executor.0/5427: #0: ffffffff8cfad3a0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:301 [inline] #0: ffffffff8cfad3a0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:747 [inline] #0: ffffffff8cfad3a0 (rcu_read_lock){....}-{1:2}, at: ip_finish_output2+0x36a/0x2550 net/ipv4/ip_output.c:228 #1: ffffffff8cfad340 (rcu_read_lock_bh){....}-{1:2}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #1: ffffffff8cfad340 (rcu_read_lock_bh){....}-{1:2}, at: rcu_read_lock_bh include/linux/rcupdate.h:799 [inline] #1: ffffffff8cfad340 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x244/0x3d10 net/core/dev.c:4269 #2: ffff88807b309258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: spin_trylock include/linux/spinlock.h:361 [inline] #2: ffff88807b309258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:194 [inline] #2: ffff88807b309258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:191 [inline] #2: ffff88807b309258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3757 [inline] #2: ffff88807b309258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_queue_xmit+0x104f/0x3d10 net/core/dev.c:4310 #3: ffff88806f37d0d8 (_xmit_ETHER#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] #3: ffff88806f37d0d8 (_xmit_ETHER#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4381 [inline] #3: ffff88806f37d0d8 (_xmit_ETHER#2){+.-.}-{2:2}, at: sch_direct_xmit+0x333/0xc20 net/sched/sch_generic.c:340 #4: ffffffff8cfad3a0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:301 [inline] #4: ffffffff8cfad3a0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:747 [inline] #4: ffffffff8cfad3a0 (rcu_read_lock){....}-{1:2}, at: ip_finish_output2+0x36a/0x2550 net/ipv4/ip_output.c:228 #5: ffffffff8cfad340 (rcu_read_lock_bh){....}-{1:2}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #5: ffffffff8cfad340 (rcu_read_lock_bh){....}-{1:2}, at: rcu_read_lock_bh include/linux/rcupdate.h:799 [inline] #5: ffffffff8cfad340 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x244/0x3d10 net/core/dev.c:4269 stack backtrace: CPU: 1 PID: 5427 Comm: syz-executor.0 Not tainted 6.6.0-syzkaller-10135-g016b9332a334 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/09/2023 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106 check_deadlock kernel/locking/lockdep.c:3062 [inline] validate_chain kernel/locking/lockdep.c:3855 [inline] __lock_acquire+0x2971/0x5de0 kernel/locking/lockdep.c:5136 lock_acquire kernel/locking/lockdep.c:5753 [inline] lock_acquire+0x1ae/0x510 kernel/locking/lockdep.c:5718 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:351 [inline] __netif_tx_lock include/linux/netdevice.h:4381 [inline] __dev_queue_xmit+0x1a7f/0x3d10 net/core/dev.c:4340 dev_queue_xmit include/linux/netdevice.h:3112 [inline] neigh_resolve_output net/core/neighbour.c:1556 [inline] neigh_resolve_output+0x58c/0x900 net/core/neighbour.c:1536 neigh_output include/net/neighbour.h:542 [inline] ip_finish_output2+0x833/0x2550 net/ipv4/ip_output.c:235 __ip_finish_output net/ipv4/ip_output.c:313 [inline] __ip_finish_output+0x38b/0x640 net/ipv4/ip_output.c:295 ip_finish_output+0x31/0x310 net/ipv4/ip_output.c:323 NF_HOOK_COND include/linux/netfilter.h:303 [inline] ip_output+0x13b/0x290 net/ipv4/ip_output.c:433 dst_output include/net/dst.h:451 [inline] ip_local_out+0xaf/0x190 net/ipv4/ip_output.c:129 iptunnel_xmit+0x618/0x9b0 net/ipv4/ip_tunnel_core.c:82 ip_tunnel_xmit+0x1dbc/0x33b0 net/ipv4/ip_tunnel.c:831 erspan_xmit+0x52b/0x1f90 net/ipv4/ip_gre.c:717 __netdev_start_xmit include/linux/netdevice.h:4918 [inline] netdev_start_xmit include/linux/netdevice.h:4932 [inline] xmit_one net/core/dev.c:3543 [inline] dev_hard_start_xmit+0x13d/0x6c0 net/core/dev.c:3559 sch_direct_xmit+0x1ac/0xc20 net/sched/sch_generic.c:342 __dev_xmit_skb net/core/dev.c:3770 [inline] __dev_queue_xmit+0x1273/0x3d10 net/core/dev.c:4310 dev_queue_xmit include/linux/netdevice.h:3112 [inline] neigh_resolve_output net/core/neighbour.c:1556 [inline] neigh_resolve_output+0x58c/0x900 net/core/neighbour.c:1536 neigh_output include/net/neighbour.h:542 [inline] ip_finish_output2+0x833/0x2550 net/ipv4/ip_output.c:235 __ip_finish_output net/ipv4/ip_output.c:313 [inline] __ip_finish_output+0x38b/0x640 net/ipv4/ip_output.c:295 ip_finish_output+0x31/0x310 net/ipv4/ip_output.c:323 NF_HOOK_COND include/linux/netfilter.h:303 [inline] ip_output+0x13b/0x290 net/ipv4/ip_output.c:433 dst_output include/net/dst.h:451 [inline] ip_local_out net/ipv4/ip_output.c:129 [inline] ip_send_skb+0xd3/0x250 net/ipv4/ip_output.c:1489 udp_send_skb+0x745/0x1530 net/ipv4/udp.c:963 udp_sendmsg+0x1a17/0x2b20 net/ipv4/udp.c:1250 udpv6_sendmsg+0xf65/0x3020 net/ipv6/udp.c:1390 inet6_sendmsg+0x9d/0xe0 net/ipv6/af_inet6.c:657 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg+0xd5/0x180 net/socket.c:745 ____sys_sendmsg+0x2ac/0x940 net/socket.c:2588 ___sys_sendmsg+0x135/0x1d0 net/socket.c:2642 __sys_sendmmsg+0x1a1/0x450 net/socket.c:2728 __do_sys_sendmmsg net/socket.c:2757 [inline] __se_sys_sendmmsg net/socket.c:2754 [inline] __x64_sys_sendmmsg+0x9c/0x100 net/socket.c:2754 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x3f/0x110 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x63/0x6b RIP: 0033:0x7f301f2791e9 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 b4 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f301e9fe0d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000133 RAX: ffffffffffffffda RBX: 00007f301f38bf60 RCX: 00007f301f2791e9 RDX: 0000000000000001 RSI: 0000000020004d80 RDI: 0000000000000004 RBP: 00007f301f2d3e76 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000004000000 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000000b R14: 00007f301f38bf60 R15: 00007fff06bca878 syz-executor.0 (5427) used greatest stack depth: 22048 bytes left