====================================================== WARNING: possible circular locking dependency detected 6.14.0-rc7-syzkaller-00050-gfc444ada1310 #0 Not tainted ------------------------------------------------------ syz.2.23080/22314 is trying to acquire lock: ffff888026770218 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#3){+...}-{3:3}, at: spin_lock include/linux/spinlock.h:351 [inline] ffff888026770218 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#3){+...}-{3:3}, at: __dev_xmit_skb net/core/dev.c:4076 [inline] ffff888026770218 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#3){+...}-{3:3}, at: __dev_queue_xmit+0x3343/0x43e0 net/core/dev.c:4618 but task is already holding lock: ffff888068cccd18 (&qdisc_xmit_lock_key#3){+.-.}-{3:3}, at: spin_lock include/linux/spinlock.h:351 [inline] ffff888068cccd18 (&qdisc_xmit_lock_key#3){+.-.}-{3:3}, at: __netif_tx_lock include/linux/netdevice.h:4591 [inline] ffff888068cccd18 (&qdisc_xmit_lock_key#3){+.-.}-{3:3}, at: sch_direct_xmit+0x340/0xc30 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}: __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:4591 [inline] sch_direct_xmit+0x340/0xc30 net/sched/sch_generic.c:341 __dev_xmit_skb net/core/dev.c:4042 [inline] __dev_queue_xmit+0x13d4/0x43e0 net/core/dev.c:4618 dev_queue_xmit include/linux/netdevice.h:3313 [inline] neigh_resolve_output net/core/neighbour.c:1514 [inline] neigh_resolve_output+0x53a/0x940 net/core/neighbour.c:1494 neigh_output include/net/neighbour.h:539 [inline] ip6_finish_output2+0xb20/0x20a0 net/ipv6/ip6_output.c:141 __ip6_finish_output net/ipv6/ip6_output.c:215 [inline] ip6_finish_output+0x3f9/0x1360 net/ipv6/ip6_output.c:226 NF_HOOK_COND include/linux/netfilter.h:303 [inline] ip6_output+0x1f8/0x540 net/ipv6/ip6_output.c:247 dst_output include/net/dst.h:459 [inline] NF_HOOK include/linux/netfilter.h:314 [inline] NF_HOOK include/linux/netfilter.h:308 [inline] mld_sendpack+0x9f0/0x11d0 net/ipv6/mcast.c:1868 mld_send_cr net/ipv6/mcast.c:2169 [inline] mld_ifc_work+0x740/0xca0 net/ipv6/mcast.c:2702 process_one_work+0x9c5/0x1ba0 kernel/workqueue.c:3238 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x6c8/0xf00 kernel/workqueue.c:3400 kthread+0x3af/0x750 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 -> #0 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#3){+...}-{3:3}: check_prev_add kernel/locking/lockdep.c:3163 [inline] check_prevs_add kernel/locking/lockdep.c:3282 [inline] validate_chain kernel/locking/lockdep.c:3906 [inline] __lock_acquire+0x249e/0x3c40 kernel/locking/lockdep.c:5228 lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5851 __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:4076 [inline] __dev_queue_xmit+0x3343/0x43e0 net/core/dev.c:4618 dev_queue_xmit include/linux/netdevice.h:3313 [inline] neigh_hh_output include/net/neighbour.h:523 [inline] neigh_output include/net/neighbour.h:537 [inline] ip6_finish_output2+0xed9/0x20a0 net/ipv6/ip6_output.c:141 __ip6_finish_output net/ipv6/ip6_output.c:215 [inline] ip6_finish_output+0x3f9/0x1360 net/ipv6/ip6_output.c:226 NF_HOOK_COND include/linux/netfilter.h:303 [inline] ip6_output+0x1f8/0x540 net/ipv6/ip6_output.c:247 dst_output include/net/dst.h:459 [inline] ip6_local_out+0xcd/0x4a0 net/ipv6/output_core.c:155 ip6_send_skb+0x112/0x460 net/ipv6/ip6_output.c:1980 ip6_push_pending_frames+0xe0/0x110 net/ipv6/ip6_output.c:2001 icmpv6_push_pending_frames+0x2dc/0x460 net/ipv6/icmp.c:311 icmp6_send+0x1e90/0x2bb0 net/ipv6/icmp.c:632 __icmpv6_send include/linux/icmpv6.h:28 [inline] icmpv6_send include/linux/icmpv6.h:49 [inline] ip6_link_failure+0x31/0x5a0 net/ipv6/route.c:2799 dst_link_failure include/net/dst.h:429 [inline] ip_tunnel_xmit+0x2fdb/0x37a0 net/ipv4/ip_tunnel.c:864 __gre_xmit+0x8bc/0xc00 net/ipv4/ip_gre.c:484 erspan_xmit+0x570/0x25b0 net/ipv4/ip_gre.c:743 __netdev_start_xmit include/linux/netdevice.h:5151 [inline] netdev_start_xmit include/linux/netdevice.h:5160 [inline] xmit_one net/core/dev.c:3800 [inline] dev_hard_start_xmit+0x9a/0x7b0 net/core/dev.c:3816 sch_direct_xmit+0x1ae/0xc30 net/sched/sch_generic.c:343 qdisc_restart net/sched/sch_generic.c:408 [inline] __qdisc_run+0x53f/0x1a10 net/sched/sch_generic.c:416 __dev_xmit_skb net/core/dev.c:4111 [inline] __dev_queue_xmit+0x2aa4/0x43e0 net/core/dev.c:4618 dev_queue_xmit include/linux/netdevice.h:3313 [inline] neigh_resolve_output net/core/neighbour.c:1514 [inline] neigh_resolve_output+0x53a/0x940 net/core/neighbour.c:1494 neigh_output include/net/neighbour.h:539 [inline] ip6_finish_output2+0xb20/0x20a0 net/ipv6/ip6_output.c:141 __ip6_finish_output net/ipv6/ip6_output.c:215 [inline] ip6_finish_output+0x3f9/0x1360 net/ipv6/ip6_output.c:226 NF_HOOK_COND include/linux/netfilter.h:303 [inline] ip6_output+0x1f8/0x540 net/ipv6/ip6_output.c:247 dst_output include/net/dst.h:459 [inline] NF_HOOK include/linux/netfilter.h:314 [inline] NF_HOOK include/linux/netfilter.h:308 [inline] ip6_xmit+0x12d2/0x2300 net/ipv6/ip6_output.c:366 sctp_v6_xmit+0xc9a/0x1180 net/sctp/ipv6.c:248 sctp_packet_transmit+0x1e89/0x2fd0 net/sctp/output.c:653 sctp_packet_singleton+0x19f/0x370 net/sctp/outqueue.c:783 sctp_outq_flush_ctrl net/sctp/outqueue.c:914 [inline] sctp_outq_flush+0x54d/0x3380 net/sctp/outqueue.c:1212 sctp_cmd_interpreter net/sctp/sm_sideeffect.c:1818 [inline] sctp_side_effects net/sctp/sm_sideeffect.c:1198 [inline] sctp_do_sm+0x179c/0x5c90 net/sctp/sm_sideeffect.c:1169 sctp_primitive_ASSOCIATE+0x9c/0xd0 net/sctp/primitive.c:73 sctp_sendmsg_to_asoc+0xa4d/0x1ad0 net/sctp/socket.c:1841 sctp_sendmsg+0xf0a/0x1eb0 net/sctp/socket.c:2031 inet_sendmsg+0x119/0x140 net/ipv4/af_inet.c:851 sock_sendmsg_nosec net/socket.c:718 [inline] __sock_sendmsg net/socket.c:733 [inline] ____sys_sendmsg+0x98c/0xc90 net/socket.c:2573 ___sys_sendmsg+0x135/0x1e0 net/socket.c:2627 __sys_sendmmsg+0x2fa/0x420 net/socket.c:2709 __compat_sys_sendmmsg net/compat.c:360 [inline] __do_compat_sys_sendmmsg net/compat.c:367 [inline] __se_compat_sys_sendmmsg net/compat.c:364 [inline] __ia32_compat_sys_sendmmsg+0x9d/0x100 net/compat.c:364 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline] __do_fast_syscall_32+0x73/0x120 arch/x86/entry/common.c:387 do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:412 entry_SYSENTER_compat_after_hwframe+0x84/0x8e 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#3); lock(&qdisc_xmit_lock_key#3); lock(dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#3); *** DEADLOCK *** 10 locks held by syz.2.23080/22314: #0: ffff888026a85598 (sk_lock-AF_INET6){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1624 [inline] #0: ffff888026a85598 (sk_lock-AF_INET6){+.+.}-{0:0}, at: sctp_sendmsg+0xda6/0x1eb0 net/sctp/socket.c:1970 #1: ffffffff8e1bd140 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #1: ffffffff8e1bd140 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #1: ffffffff8e1bd140 (rcu_read_lock){....}-{1:3}, at: sctp_v6_xmit+0xba9/0x1180 net/sctp/ipv6.c:247 #2: ffffffff8e1bd140 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #2: ffffffff8e1bd140 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #2: ffffffff8e1bd140 (rcu_read_lock){....}-{1:3}, at: ip6_finish_output2+0x3db/0x20a0 net/ipv6/ip6_output.c:126 #3: ffffffff8e1bd0e0 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #3: ffffffff8e1bd0e0 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:901 [inline] #3: ffffffff8e1bd0e0 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x277/0x43e0 net/core/dev.c:4577 #4: ffff888068cccd18 (&qdisc_xmit_lock_key#3){+.-.}-{3:3}, at: spin_lock include/linux/spinlock.h:351 [inline] #4: ffff888068cccd18 (&qdisc_xmit_lock_key#3){+.-.}-{3:3}, at: __netif_tx_lock include/linux/netdevice.h:4591 [inline] #4: ffff888068cccd18 (&qdisc_xmit_lock_key#3){+.-.}-{3:3}, at: sch_direct_xmit+0x340/0xc30 net/sched/sch_generic.c:341 #5: ffffffff8e1bd140 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #5: ffffffff8e1bd140 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #5: ffffffff8e1bd140 (rcu_read_lock){....}-{1:3}, at: icmp6_send+0x27d/0x2bb0 net/ipv6/icmp.c:477 #6: ffff88804a3f01d8 (k-slock-AF_INET6){+.-.}-{3:3}, at: spin_trylock include/linux/spinlock.h:361 [inline] #6: ffff88804a3f01d8 (k-slock-AF_INET6){+.-.}-{3:3}, at: icmpv6_xmit_lock net/ipv6/icmp.c:108 [inline] #6: ffff88804a3f01d8 (k-slock-AF_INET6){+.-.}-{3:3}, at: icmp6_send+0x8dc/0x2bb0 net/ipv6/icmp.c:554 #7: ffffffff8e1bd140 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #7: ffffffff8e1bd140 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #7: ffffffff8e1bd140 (rcu_read_lock){....}-{1:3}, at: ip6_send_skb+0xc4/0x460 net/ipv6/ip6_output.c:1979 #8: ffffffff8e1bd140 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #8: ffffffff8e1bd140 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #8: ffffffff8e1bd140 (rcu_read_lock){....}-{1:3}, at: ip6_finish_output2+0x3db/0x20a0 net/ipv6/ip6_output.c:126 #9: ffffffff8e1bd0e0 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #9: ffffffff8e1bd0e0 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:901 [inline] #9: ffffffff8e1bd0e0 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x277/0x43e0 net/core/dev.c:4577 stack backtrace: CPU: 0 UID: 0 PID: 22314 Comm: syz.2.23080 Not tainted 6.14.0-rc7-syzkaller-00050-gfc444ada1310 #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 print_circular_bug+0x490/0x760 kernel/locking/lockdep.c:2076 check_noncircular+0x31a/0x400 kernel/locking/lockdep.c:2208 check_prev_add kernel/locking/lockdep.c:3163 [inline] check_prevs_add kernel/locking/lockdep.c:3282 [inline] validate_chain kernel/locking/lockdep.c:3906 [inline] __lock_acquire+0x249e/0x3c40 kernel/locking/lockdep.c:5228 lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5851 __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:4076 [inline] __dev_queue_xmit+0x3343/0x43e0 net/core/dev.c:4618 dev_queue_xmit include/linux/netdevice.h:3313 [inline] neigh_hh_output include/net/neighbour.h:523 [inline] neigh_output include/net/neighbour.h:537 [inline] ip6_finish_output2+0xed9/0x20a0 net/ipv6/ip6_output.c:141 __ip6_finish_output net/ipv6/ip6_output.c:215 [inline] ip6_finish_output+0x3f9/0x1360 net/ipv6/ip6_output.c:226 NF_HOOK_COND include/linux/netfilter.h:303 [inline] ip6_output+0x1f8/0x540 net/ipv6/ip6_output.c:247 dst_output include/net/dst.h:459 [inline] ip6_local_out+0xcd/0x4a0 net/ipv6/output_core.c:155 ip6_send_skb+0x112/0x460 net/ipv6/ip6_output.c:1980 ip6_push_pending_frames+0xe0/0x110 net/ipv6/ip6_output.c:2001 icmpv6_push_pending_frames+0x2dc/0x460 net/ipv6/icmp.c:311 icmp6_send+0x1e90/0x2bb0 net/ipv6/icmp.c:632 __icmpv6_send include/linux/icmpv6.h:28 [inline] icmpv6_send include/linux/icmpv6.h:49 [inline] ip6_link_failure+0x31/0x5a0 net/ipv6/route.c:2799 dst_link_failure include/net/dst.h:429 [inline] ip_tunnel_xmit+0x2fdb/0x37a0 net/ipv4/ip_tunnel.c:864 __gre_xmit+0x8bc/0xc00 net/ipv4/ip_gre.c:484 erspan_xmit+0x570/0x25b0 net/ipv4/ip_gre.c:743 __netdev_start_xmit include/linux/netdevice.h:5151 [inline] netdev_start_xmit include/linux/netdevice.h:5160 [inline] xmit_one net/core/dev.c:3800 [inline] dev_hard_start_xmit+0x9a/0x7b0 net/core/dev.c:3816 sch_direct_xmit+0x1ae/0xc30 net/sched/sch_generic.c:343 qdisc_restart net/sched/sch_generic.c:408 [inline] __qdisc_run+0x53f/0x1a10 net/sched/sch_generic.c:416 __dev_xmit_skb net/core/dev.c:4111 [inline] __dev_queue_xmit+0x2aa4/0x43e0 net/core/dev.c:4618 dev_queue_xmit include/linux/netdevice.h:3313 [inline] neigh_resolve_output net/core/neighbour.c:1514 [inline] neigh_resolve_output+0x53a/0x940 net/core/neighbour.c:1494 neigh_output include/net/neighbour.h:539 [inline] ip6_finish_output2+0xb20/0x20a0 net/ipv6/ip6_output.c:141 __ip6_finish_output net/ipv6/ip6_output.c:215 [inline] ip6_finish_output+0x3f9/0x1360 net/ipv6/ip6_output.c:226 NF_HOOK_COND include/linux/netfilter.h:303 [inline] ip6_output+0x1f8/0x540 net/ipv6/ip6_output.c:247 dst_output include/net/dst.h:459 [inline] NF_HOOK include/linux/netfilter.h:314 [inline] NF_HOOK include/linux/netfilter.h:308 [inline] ip6_xmit+0x12d2/0x2300 net/ipv6/ip6_output.c:366 sctp_v6_xmit+0xc9a/0x1180 net/sctp/ipv6.c:248 sctp_packet_transmit+0x1e89/0x2fd0 net/sctp/output.c:653 sctp_packet_singleton+0x19f/0x370 net/sctp/outqueue.c:783 sctp_outq_flush_ctrl net/sctp/outqueue.c:914 [inline] sctp_outq_flush+0x54d/0x3380 net/sctp/outqueue.c:1212 sctp_cmd_interpreter net/sctp/sm_sideeffect.c:1818 [inline] sctp_side_effects net/sctp/sm_sideeffect.c:1198 [inline] sctp_do_sm+0x179c/0x5c90 net/sctp/sm_sideeffect.c:1169 sctp_primitive_ASSOCIATE+0x9c/0xd0 net/sctp/primitive.c:73 sctp_sendmsg_to_asoc+0xa4d/0x1ad0 net/sctp/socket.c:1841 sctp_sendmsg+0xf0a/0x1eb0 net/sctp/socket.c:2031 inet_sendmsg+0x119/0x140 net/ipv4/af_inet.c:851 sock_sendmsg_nosec net/socket.c:718 [inline] __sock_sendmsg net/socket.c:733 [inline] ____sys_sendmsg+0x98c/0xc90 net/socket.c:2573 ___sys_sendmsg+0x135/0x1e0 net/socket.c:2627 __sys_sendmmsg+0x2fa/0x420 net/socket.c:2709 __compat_sys_sendmmsg net/compat.c:360 [inline] __do_compat_sys_sendmmsg net/compat.c:367 [inline] __se_compat_sys_sendmmsg net/compat.c:364 [inline] __ia32_compat_sys_sendmmsg+0x9d/0x100 net/compat.c:364 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline] __do_fast_syscall_32+0x73/0x120 arch/x86/entry/common.c:387 do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:412 entry_SYSENTER_compat_after_hwframe+0x84/0x8e RIP: 0023:0xf7f81579 Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00 RSP: 002b:00000000f50a655c EFLAGS: 00000296 ORIG_RAX: 0000000000000159 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000080002700 RDX: 0000000000000001 RSI: 000000002000c8c4 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000296 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 syz.2.23080 (22314) used greatest stack depth: 18832 bytes left ---------------- Code disassembly (best guess), 2 bytes skipped: 0: 10 06 adc %al,(%rsi) 2: 03 74 b4 01 add 0x1(%rsp,%rsi,4),%esi 6: 10 07 adc %al,(%rdi) 8: 03 74 b0 01 add 0x1(%rax,%rsi,4),%esi c: 10 08 adc %cl,(%rax) e: 03 74 d8 01 add 0x1(%rax,%rbx,8),%esi 1e: 00 51 52 add %dl,0x52(%rcx) 21: 55 push %rbp 22: 89 e5 mov %esp,%ebp 24: 0f 34 sysenter 26: cd 80 int $0x80 * 28: 5d pop %rbp <-- trapping instruction 29: 5a pop %rdx 2a: 59 pop %rcx 2b: c3 ret 2c: 90 nop 2d: 90 nop 2e: 90 nop 2f: 90 nop 30: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi 37: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi