====================================================== WARNING: possible circular locking dependency detected 6.13.0-rc1-syzkaller-00268-g7ea2745766d7 #0 Not tainted ------------------------------------------------------ syz.1.501/7730 is trying to acquire lock: ffff88807fd96218 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#2){+...}-{3:3}, at: spin_lock include/linux/spinlock.h:351 [inline] ffff88807fd96218 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#2){+...}-{3:3}, at: __dev_xmit_skb net/core/dev.c:3861 [inline] ffff88807fd96218 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#2){+...}-{3:3}, at: __dev_queue_xmit+0x23f9/0x3f50 net/core/dev.c:4400 but task is already holding lock: ffff888028745918 (&qdisc_xmit_lock_key#3){+.-.}-{3:3}, at: spin_lock include/linux/spinlock.h:351 [inline] ffff888028745918 (&qdisc_xmit_lock_key#3){+.-.}-{3:3}, at: __netif_tx_lock include/linux/netdevice.h:4486 [inline] ffff888028745918 (&qdisc_xmit_lock_key#3){+.-.}-{3:3}, at: sch_direct_xmit+0x1a7/0x5d0 net/sched/sch_generic.c:341 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&qdisc_xmit_lock_key#3){+.-.}-{3:3}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849 __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:4486 [inline] sch_direct_xmit+0x1a7/0x5d0 net/sched/sch_generic.c:341 __dev_xmit_skb net/core/dev.c:3827 [inline] __dev_queue_xmit+0x1a8f/0x3f50 net/core/dev.c:4400 neigh_output include/net/neighbour.h:539 [inline] ip6_finish_output2+0x12c7/0x17b0 net/ipv6/ip6_output.c:141 ip6_finish_output+0x41e/0x840 net/ipv6/ip6_output.c:226 NF_HOOK+0x9e/0x430 include/linux/netfilter.h:314 mld_sendpack+0x843/0xdb0 net/ipv6/mcast.c:1819 mld_send_cr net/ipv6/mcast.c:2120 [inline] mld_ifc_work+0x7d9/0xd90 net/ipv6/mcast.c:2651 process_one_work kernel/workqueue.c:3229 [inline] process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3310 worker_thread+0x870/0xd30 kernel/workqueue.c:3391 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 -> #0 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#2){+...}-{3:3}: check_prev_add kernel/locking/lockdep.c:3161 [inline] check_prevs_add kernel/locking/lockdep.c:3280 [inline] validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3904 __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5226 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849 __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] __dev_xmit_skb net/core/dev.c:3861 [inline] __dev_queue_xmit+0x23f9/0x3f50 net/core/dev.c:4400 neigh_output include/net/neighbour.h:539 [inline] ip6_finish_output2+0x12c7/0x17b0 net/ipv6/ip6_output.c:141 ip6_finish_output+0x41e/0x840 net/ipv6/ip6_output.c:226 NF_HOOK include/linux/netfilter.h:314 [inline] ndisc_send_skb+0xb30/0x1450 net/ipv6/ndisc.c:511 ndisc_solicit+0x493/0x6a0 neigh_probe net/core/neighbour.c:1026 [inline] __neigh_event_send+0xef5/0x15d0 net/core/neighbour.c:1193 neigh_event_send_probe include/net/neighbour.h:463 [inline] neigh_event_send include/net/neighbour.h:469 [inline] neigh_resolve_output+0x1b5/0x740 net/core/neighbour.c:1498 neigh_output include/net/neighbour.h:539 [inline] ip6_finish_output2+0x12c7/0x17b0 net/ipv6/ip6_output.c:141 ip6_finish_output+0x41e/0x840 net/ipv6/ip6_output.c:226 ip6_send_skb+0x1b1/0x3b0 net/ipv6/ip6_output.c:1979 icmp6_send+0x16d4/0x2220 net/ipv6/icmp.c:630 __icmpv6_send include/linux/icmpv6.h:28 [inline] icmpv6_send include/linux/icmpv6.h:49 [inline] ip6_link_failure+0x3c/0x4f0 net/ipv6/route.c:2799 ip_tunnel_xmit+0x191d/0x26a0 net/ipv4/ip_tunnel.c:864 __gre_xmit+0x1cf/0x260 net/ipv4/ip_gre.c:484 erspan_xmit+0xabe/0x1310 net/ipv4/ip_gre.c:743 __netdev_start_xmit include/linux/netdevice.h:5043 [inline] netdev_start_xmit include/linux/netdevice.h:5052 [inline] xmit_one net/core/dev.c:3590 [inline] dev_hard_start_xmit+0x27a/0x7d0 net/core/dev.c:3606 sch_direct_xmit+0x29c/0x5d0 net/sched/sch_generic.c:343 qdisc_restart net/sched/sch_generic.c:408 [inline] __qdisc_run+0xc0e/0x2180 net/sched/sch_generic.c:416 __dev_xmit_skb net/core/dev.c:3896 [inline] __dev_queue_xmit+0x10dd/0x3f50 net/core/dev.c:4400 neigh_output include/net/neighbour.h:539 [inline] ip6_finish_output2+0x12c7/0x17b0 net/ipv6/ip6_output.c:141 ip6_finish_output+0x41e/0x840 net/ipv6/ip6_output.c:226 NF_HOOK include/linux/netfilter.h:314 [inline] rawv6_send_hdrinc+0xd42/0x1940 net/ipv6/raw.c:661 rawv6_sendmsg+0x195d/0x23d0 net/ipv6/raw.c:914 sock_sendmsg_nosec net/socket.c:711 [inline] __sock_sendmsg+0x1a6/0x270 net/socket.c:726 __sys_sendto+0x363/0x4c0 net/socket.c:2197 __do_sys_sendto net/socket.c:2204 [inline] __se_sys_sendto net/socket.c:2200 [inline] __x64_sys_sendto+0xde/0x100 net/socket.c:2200 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&qdisc_xmit_lock_key#3); lock(dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#2); lock(&qdisc_xmit_lock_key#3); lock(dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#2); *** DEADLOCK *** 11 locks held by syz.1.501/7730: #0: ffffffff8e937aa0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #0: ffffffff8e937aa0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #0: ffffffff8e937aa0 (rcu_read_lock){....}-{1:3}, at: rawv6_send_hdrinc+0xba8/0x1940 net/ipv6/raw.c:659 #1: ffffffff8e937aa0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #1: ffffffff8e937aa0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #1: ffffffff8e937aa0 (rcu_read_lock){....}-{1:3}, at: ip6_finish_output2+0x63a/0x17b0 net/ipv6/ip6_output.c:126 #2: ffffffff8e937b00 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #2: ffffffff8e937b00 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:901 [inline] #2: ffffffff8e937b00 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x2f4/0x3f50 net/core/dev.c:4359 #3: ffff888028745918 (&qdisc_xmit_lock_key#3){+.-.}-{3:3}, at: spin_lock include/linux/spinlock.h:351 [inline] #3: ffff888028745918 (&qdisc_xmit_lock_key#3){+.-.}-{3:3}, at: __netif_tx_lock include/linux/netdevice.h:4486 [inline] #3: ffff888028745918 (&qdisc_xmit_lock_key#3){+.-.}-{3:3}, at: sch_direct_xmit+0x1a7/0x5d0 net/sched/sch_generic.c:341 #4: ffff88814d0001d8 (k-slock-AF_INET6){+.-.}-{3:3}, at: spin_trylock include/linux/spinlock.h:361 [inline] #4: ffff88814d0001d8 (k-slock-AF_INET6){+.-.}-{3:3}, at: icmpv6_xmit_lock net/ipv6/icmp.c:108 [inline] #4: ffff88814d0001d8 (k-slock-AF_INET6){+.-.}-{3:3}, at: icmp6_send+0xc89/0x2220 net/ipv6/icmp.c:551 #5: ffffffff8e937aa0 (rcu_read_lock){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #5: ffffffff8e937aa0 (rcu_read_lock){....}-{1:3}, at: icmp6_send+0xbb8/0x2220 net/ipv6/icmp.c:542 #6: ffffffff8e937aa0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #6: ffffffff8e937aa0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #6: ffffffff8e937aa0 (rcu_read_lock){....}-{1:3}, at: ip6_send_skb+0xfd/0x3b0 net/ipv6/ip6_output.c:1978 #7: ffffffff8e937aa0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #7: ffffffff8e937aa0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #7: ffffffff8e937aa0 (rcu_read_lock){....}-{1:3}, at: ip6_finish_output2+0x63a/0x17b0 net/ipv6/ip6_output.c:126 #8: ffffffff8e937aa0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #8: ffffffff8e937aa0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #8: ffffffff8e937aa0 (rcu_read_lock){....}-{1:3}, at: ip6_nd_hdr net/ipv6/ndisc.c:454 [inline] #8: ffffffff8e937aa0 (rcu_read_lock){....}-{1:3}, at: ndisc_send_skb+0x563/0x1450 net/ipv6/ndisc.c:505 #9: ffffffff8e937aa0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #9: ffffffff8e937aa0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #9: ffffffff8e937aa0 (rcu_read_lock){....}-{1:3}, at: ip6_finish_output2+0x63a/0x17b0 net/ipv6/ip6_output.c:126 #10: ffffffff8e937b00 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #10: ffffffff8e937b00 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:901 [inline] #10: ffffffff8e937b00 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x2f4/0x3f50 net/core/dev.c:4359 stack backtrace: CPU: 0 UID: 0 PID: 7730 Comm: syz.1.501 Not tainted 6.13.0-rc1-syzkaller-00268-g7ea2745766d7 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 print_circular_bug+0x13a/0x1b0 kernel/locking/lockdep.c:2074 check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2206 check_prev_add kernel/locking/lockdep.c:3161 [inline] check_prevs_add kernel/locking/lockdep.c:3280 [inline] validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3904 __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5226 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849 __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] __dev_xmit_skb net/core/dev.c:3861 [inline] __dev_queue_xmit+0x23f9/0x3f50 net/core/dev.c:4400 neigh_output include/net/neighbour.h:539 [inline] ip6_finish_output2+0x12c7/0x17b0 net/ipv6/ip6_output.c:141 ip6_finish_output+0x41e/0x840 net/ipv6/ip6_output.c:226 NF_HOOK include/linux/netfilter.h:314 [inline] ndisc_send_skb+0xb30/0x1450 net/ipv6/ndisc.c:511 ndisc_solicit+0x493/0x6a0 neigh_probe net/core/neighbour.c:1026 [inline] __neigh_event_send+0xef5/0x15d0 net/core/neighbour.c:1193 neigh_event_send_probe include/net/neighbour.h:463 [inline] neigh_event_send include/net/neighbour.h:469 [inline] neigh_resolve_output+0x1b5/0x740 net/core/neighbour.c:1498 neigh_output include/net/neighbour.h:539 [inline] ip6_finish_output2+0x12c7/0x17b0 net/ipv6/ip6_output.c:141 ip6_finish_output+0x41e/0x840 net/ipv6/ip6_output.c:226 ip6_send_skb+0x1b1/0x3b0 net/ipv6/ip6_output.c:1979 icmp6_send+0x16d4/0x2220 net/ipv6/icmp.c:630 __icmpv6_send include/linux/icmpv6.h:28 [inline] icmpv6_send include/linux/icmpv6.h:49 [inline] ip6_link_failure+0x3c/0x4f0 net/ipv6/route.c:2799 ip_tunnel_xmit+0x191d/0x26a0 net/ipv4/ip_tunnel.c:864 __gre_xmit+0x1cf/0x260 net/ipv4/ip_gre.c:484 erspan_xmit+0xabe/0x1310 net/ipv4/ip_gre.c:743 __netdev_start_xmit include/linux/netdevice.h:5043 [inline] netdev_start_xmit include/linux/netdevice.h:5052 [inline] xmit_one net/core/dev.c:3590 [inline] dev_hard_start_xmit+0x27a/0x7d0 net/core/dev.c:3606 sch_direct_xmit+0x29c/0x5d0 net/sched/sch_generic.c:343 qdisc_restart net/sched/sch_generic.c:408 [inline] __qdisc_run+0xc0e/0x2180 net/sched/sch_generic.c:416 __dev_xmit_skb net/core/dev.c:3896 [inline] __dev_queue_xmit+0x10dd/0x3f50 net/core/dev.c:4400 neigh_output include/net/neighbour.h:539 [inline] ip6_finish_output2+0x12c7/0x17b0 net/ipv6/ip6_output.c:141 ip6_finish_output+0x41e/0x840 net/ipv6/ip6_output.c:226 NF_HOOK include/linux/netfilter.h:314 [inline] rawv6_send_hdrinc+0xd42/0x1940 net/ipv6/raw.c:661 rawv6_sendmsg+0x195d/0x23d0 net/ipv6/raw.c:914 sock_sendmsg_nosec net/socket.c:711 [inline] __sock_sendmsg+0x1a6/0x270 net/socket.c:726 __sys_sendto+0x363/0x4c0 net/socket.c:2197 __do_sys_sendto net/socket.c:2204 [inline] __se_sys_sendto net/socket.c:2200 [inline] __x64_sys_sendto+0xde/0x100 net/socket.c:2200 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7ff1c4b7fed9 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ff1c596d058 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007ff1c4d45fa0 RCX: 00007ff1c4b7fed9 RDX: 0000000000000028 RSI: 0000000020000500 RDI: 0000000000000004 RBP: 00007ff1c4bf3cc8 R08: 0000000020000440 R09: 0000000000000020 R10: 000000002004c820 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007ff1c4d45fa0 R15: 00007ffd42fe5388 syz_tun (unregistering): left promiscuous mode