============================================ WARNING: possible recursive locking detected 5.15.0-syzkaller #0 Not tainted -------------------------------------------- syz-executor.4/12702 is trying to acquire lock: ffff88807d221098 (_xmit_ETHER#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:349 [inline] ffff88807d221098 (_xmit_ETHER#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4406 [inline] ffff88807d221098 (_xmit_ETHER#2){+.-.}-{2:2}, at: sch_direct_xmit+0x30f/0xbc0 net/sched/sch_generic.c:340 but task is already holding lock: ffff888067e6d098 (_xmit_ETHER#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:349 [inline] ffff888067e6d098 (_xmit_ETHER#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4406 [inline] ffff888067e6d098 (_xmit_ETHER#2){+.-.}-{2:2}, at: sch_direct_xmit+0x30f/0xbc0 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.4/12702: #0: ffff888026ac49a0 (sk_lock-AF_INET ){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1645 [inline] ){+.+.}-{0:0}, at: udp_sendmsg+0x722/0x2740 net/ipv4/udp.c:1079 #1: ffffffff8b9839c0 (rcu_read_lock_bh){....}-{1:2}, at: lwtunnel_xmit_redirect include/net/lwtunnel.h:95 [inline] #1: ffffffff8b9839c0 (rcu_read_lock_bh){....}-{1:2}, at: ip_finish_output2+0x28c/0x2160 net/ipv4/ip_output.c:207 #2: ffffffff8b9839c0 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x1e3/0x3630 net/core/dev.c:4153 #3: ffff888027d18258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: spin_trylock include/linux/spinlock.h:359 [inline] #3: ffff888027d18258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:187 [inline] #3: ffff888027d18258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:184 [inline] #3: ffff888027d18258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3804 [inline] #3: ffff888027d18258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_queue_xmit+0x126f/0x3630 net/core/dev.c:4194 #4: ffff888067e6d098 (_xmit_ETHER#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:349 [inline] #4: ffff888067e6d098 (_xmit_ETHER#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4406 [inline] #4: ffff888067e6d098 (_xmit_ETHER#2){+.-.}-{2:2}, at: sch_direct_xmit+0x30f/0xbc0 net/sched/sch_generic.c:340 #5: ffffffff8b9839c0 (rcu_read_lock_bh){....}-{1:2}, at: lwtunnel_xmit_redirect include/net/lwtunnel.h:95 [inline] #5: ffffffff8b9839c0 (rcu_read_lock_bh){....}-{1:2}, at: ip_finish_output2+0x28c/0x2160 net/ipv4/ip_output.c:207 #6: ffffffff8b9839c0 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x1e3/0x3630 net/core/dev.c:4153 #7: ffff8880249a4258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: spin_trylock include/linux/spinlock.h:359 [inline] #7: ffff8880249a4258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:187 [inline] #7: ffff8880249a4258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:184 [inline] #7: ffff8880249a4258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3804 [inline] #7: ffff8880249a4258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_queue_xmit+0x126f/0x3630 net/core/dev.c:4194 stack backtrace: CPU: 1 PID: 12702 Comm: syz-executor.4 Not tainted 5.15.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 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:2956 [inline] check_deadlock kernel/locking/lockdep.c:2999 [inline] validate_chain kernel/locking/lockdep.c:3788 [inline] __lock_acquire.cold+0x149/0x3ab kernel/locking/lockdep.c:5027 lock_acquire kernel/locking/lockdep.c:5637 [inline] lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5602 __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:4406 [inline] sch_direct_xmit+0x30f/0xbc0 net/sched/sch_generic.c:340 __dev_xmit_skb net/core/dev.c:3817 [inline] __dev_queue_xmit+0x149c/0x3630 net/core/dev.c:4194 neigh_hh_output include/net/neighbour.h:511 [inline] neigh_output include/net/neighbour.h:525 [inline] ip_finish_output2+0x14cb/0x2160 net/ipv4/ip_output.c:221 __ip_finish_output net/ipv4/ip_output.c:299 [inline] __ip_finish_output+0x396/0x640 net/ipv4/ip_output.c:281 ip_finish_output+0x32/0x200 net/ipv4/ip_output.c:309 NF_HOOK_COND include/linux/netfilter.h:296 [inline] ip_mc_output+0x212/0x700 net/ipv4/ip_output.c:408 dst_output include/net/dst.h:450 [inline] ip_local_out+0xaf/0x1a0 net/ipv4/ip_output.c:126 iptunnel_xmit+0x628/0xa50 net/ipv4/ip_tunnel_core.c:82 ip_tunnel_xmit+0x10a6/0x2b60 net/ipv4/ip_tunnel.c:810 erspan_xmit+0x7e2/0x29c0 net/ipv4/ip_gre.c:712 __netdev_start_xmit include/linux/netdevice.h:4987 [inline] netdev_start_xmit include/linux/netdevice.h:5001 [inline] xmit_one net/core/dev.c:3590 [inline] dev_hard_start_xmit+0x1eb/0x920 net/core/dev.c:3606 sch_direct_xmit+0x19f/0xbc0 net/sched/sch_generic.c:342 __dev_xmit_skb net/core/dev.c:3817 [inline] __dev_queue_xmit+0x149c/0x3630 net/core/dev.c:4194 neigh_resolve_output net/core/neighbour.c:1523 [inline] neigh_resolve_output+0x50e/0x820 net/core/neighbour.c:1503 neigh_output include/net/neighbour.h:527 [inline] ip_finish_output2+0x77f/0x2160 net/ipv4/ip_output.c:221 ip_do_fragment+0x10f4/0x1430 net/ipv4/ip_output.c:840 ip_fragment.constprop.0+0x174/0x240 net/ipv4/ip_output.c:574 __ip_finish_output net/ipv4/ip_output.c:297 [inline] __ip_finish_output+0x2de/0x640 net/ipv4/ip_output.c:281 ip_finish_output+0x32/0x200 net/ipv4/ip_output.c:309 NF_HOOK_COND include/linux/netfilter.h:296 [inline] ip_mc_output+0x212/0x700 net/ipv4/ip_output.c:408 dst_output include/net/dst.h:450 [inline] ip_local_out net/ipv4/ip_output.c:126 [inline] ip_send_skb+0xd4/0x260 net/ipv4/ip_output.c:1554 udp_send_skb+0x6cd/0x11a0 net/ipv4/udp.c:966 udp_push_pending_frames net/ipv4/udp.c:994 [inline] udp_sendmsg+0x12dd/0x2740 net/ipv4/udp.c:1285 inet_sendmsg+0x99/0xe0 net/ipv4/af_inet.c:819 sock_sendmsg_nosec net/socket.c:704 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:724 sock_write_iter+0x289/0x3c0 net/socket.c:1057 call_write_iter include/linux/fs.h:2162 [inline] new_sync_write+0x429/0x660 fs/read_write.c:503 vfs_write+0x7cd/0xae0 fs/read_write.c:590 ksys_write+0x1ee/0x250 fs/read_write.c:643 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+0x44/0xae RIP: 0033:0x7feb64810ae9 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 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007feb61d86188 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007feb64923f60 RCX: 00007feb64810ae9 RDX: 000000000000fa38 RSI: 0000000020000200 RDI: 0000000000000006 RBP: 00007feb6486af6d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffcf4a9b42f R14: 00007feb61d86300 R15: 0000000000022000