============================================ WARNING: possible recursive locking detected 5.7.0-rc2-syzkaller #0 Not tainted -------------------------------------------- syz-executor.0/8519 is trying to acquire lock: ffff8880909d0498 (_xmit_ETHER){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:353 [inline] ffff8880909d0498 (_xmit_ETHER){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4068 [inline] ffff8880909d0498 (_xmit_ETHER){+.-.}-{2:2}, at: __dev_queue_xmit+0x20d2/0x2990 net/core/dev.c:4116 but task is already holding lock: ffff88809e079498 (_xmit_ETHER){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:353 [inline] ffff88809e079498 (_xmit_ETHER){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4068 [inline] ffff88809e079498 (_xmit_ETHER){+.-.}-{2:2}, at: sch_direct_xmit+0x1f3/0xff0 net/sched/sch_generic.c:311 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(_xmit_ETHER); lock(_xmit_ETHER); *** DEADLOCK *** May be due to missing lock nesting notation 11 locks held by syz-executor.0/8519: #0: ffffffff88db7800 (rcu_read_lock){....}-{1:2}, at: l3mdev_l3_out include/net/l3mdev.h:179 [inline] #0: ffffffff88db7800 (rcu_read_lock){....}-{1:2}, at: l3mdev_ip6_out include/net/l3mdev.h:200 [inline] #0: ffffffff88db7800 (rcu_read_lock){....}-{1:2}, at: rawv6_send_hdrinc net/ipv6/raw.c:677 [inline] #0: ffffffff88db7800 (rcu_read_lock){....}-{1:2}, at: rawv6_sendmsg+0x179b/0x3100 net/ipv6/raw.c:944 #1: ffffffff88db77a0 (rcu_read_lock_bh){....}-{1:2}, at: lwtunnel_xmit_redirect include/net/lwtunnel.h:92 [inline] #1: ffffffff88db77a0 (rcu_read_lock_bh){....}-{1:2}, at: ip6_finish_output2+0x1c1/0x2340 net/ipv6/ip6_output.c:103 #2: ffffffff88db77a0 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x205/0x2990 net/core/dev.c:4055 #3: ffff8880a40d1258 (&sch->seqlock){+...}-{2:2}, at: spin_trylock include/linux/spinlock.h:363 [inline] #3: ffff8880a40d1258 (&sch->seqlock){+...}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:159 [inline] #3: ffff8880a40d1258 (&sch->seqlock){+...}-{2:2}, at: qdisc_run include/net/pkt_sched.h:128 [inline] #3: ffff8880a40d1258 (&sch->seqlock){+...}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3736 [inline] #3: ffff8880a40d1258 (&sch->seqlock){+...}-{2:2}, at: __dev_queue_xmit+0x1fcc/0x2990 net/core/dev.c:4089 #4: ffff8880a40d1148 (dev->qdisc_running_key ?: &qdisc_running_key){+...}-{0:0}, at: neigh_hh_output include/net/neighbour.h:499 [inline] #4: ffff8880a40d1148 (dev->qdisc_running_key ?: &qdisc_running_key){+...}-{0:0}, at: neigh_output include/net/neighbour.h:508 [inline] #4: ffff8880a40d1148 (dev->qdisc_running_key ?: &qdisc_running_key){+...}-{0:0}, at: ip6_finish_output2+0xc90/0x2340 net/ipv6/ip6_output.c:117 #5: ffff88809e079498 (_xmit_ETHER){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:353 [inline] #5: ffff88809e079498 (_xmit_ETHER){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4068 [inline] #5: ffff88809e079498 (_xmit_ETHER){+.-.}-{2:2}, at: sch_direct_xmit+0x1f3/0xff0 net/sched/sch_generic.c:311 #6: ffffffff88db7800 (rcu_read_lock){....}-{1:2}, at: icmpv6_send+0x0/0x150 net/ipv6/ip6_icmp.c:31 #7: ffff8880928570e0 (k-slock-AF_INET6){+...}-{2:2}, at: spin_trylock include/linux/spinlock.h:363 [inline] #7: ffff8880928570e0 (k-slock-AF_INET6){+...}-{2:2}, at: icmpv6_xmit_lock net/ipv6/icmp.c:117 [inline] #7: ffff8880928570e0 (k-slock-AF_INET6){+...}-{2:2}, at: icmp6_send+0xa91/0x1e80 net/ipv6/icmp.c:538 #8: ffffffff88db7800 (rcu_read_lock){....}-{1:2}, at: icmp6_send+0xfa5/0x1e80 net/ipv6/icmp.c:598 #9: ffffffff88db77a0 (rcu_read_lock_bh){....}-{1:2}, at: lwtunnel_xmit_redirect include/net/lwtunnel.h:92 [inline] #9: ffffffff88db77a0 (rcu_read_lock_bh){....}-{1:2}, at: ip6_finish_output2+0x1c1/0x2340 net/ipv6/ip6_output.c:103 #10: ffffffff88db77a0 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x205/0x2990 net/core/dev.c:4055 stack backtrace: CPU: 1 PID: 8519 Comm: syz-executor.0 Not tainted 5.7.0-rc2-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x128/0x182 lib/dump_stack.c:118 print_deadlock_bug kernel/locking/lockdep.c:2410 [inline] check_deadlock kernel/locking/lockdep.c:2451 [inline] validate_chain kernel/locking/lockdep.c:3221 [inline] __lock_acquire.cold.67+0x148/0x3da kernel/locking/lockdep.c:4355 lock_acquire+0x1e3/0x970 kernel/locking/lockdep.c:4934 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:353 [inline] __netif_tx_lock include/linux/netdevice.h:4068 [inline] __dev_queue_xmit+0x20d2/0x2990 net/core/dev.c:4116 neigh_output include/net/neighbour.h:510 [inline] ip6_finish_output2+0xcc4/0x2340 net/ipv6/ip6_output.c:117 NF_HOOK_COND include/linux/netfilter.h:296 [inline] ip6_output+0x200/0x700 net/ipv6/ip6_output.c:176 ip6_send_skb+0x8d/0x2e0 net/ipv6/ip6_output.c:1865 icmp6_send+0x1677/0x1e80 net/ipv6/icmp.c:617 icmpv6_send+0x89/0x150 net/ipv6/ip6_icmp.c:43 ip6_link_failure+0x1d/0x3a0 net/ipv6/route.c:2640 dst_link_failure include/net/dst.h:418 [inline] ip_tunnel_xmit+0x1273/0x27e1 net/ipv4/ip_tunnel.c:820 erspan_xmit+0x815/0x2f00 net/ipv4/ip_gre.c:683 __netdev_start_xmit include/linux/netdevice.h:4587 [inline] netdev_start_xmit include/linux/netdevice.h:4601 [inline] xmit_one net/core/dev.c:3545 [inline] dev_hard_start_xmit+0x167/0x790 net/core/dev.c:3561 sch_direct_xmit+0x27a/0xff0 net/sched/sch_generic.c:313 qdisc_restart net/sched/sch_generic.c:376 [inline] __qdisc_run+0x3f0/0x1750 net/sched/sch_generic.c:384 qdisc_run include/net/pkt_sched.h:134 [inline] __dev_xmit_skb net/core/dev.c:3736 [inline] __dev_queue_xmit+0x19ba/0x2990 net/core/dev.c:4089 neigh_hh_output include/net/neighbour.h:499 [inline] neigh_output include/net/neighbour.h:508 [inline] ip6_finish_output2+0xc90/0x2340 net/ipv6/ip6_output.c:117 NF_HOOK_COND include/linux/netfilter.h:296 [inline] ip6_output+0x200/0x700 net/ipv6/ip6_output.c:176 dst_output include/net/dst.h:435 [inline] NF_HOOK include/linux/netfilter.h:307 [inline] rawv6_send_hdrinc net/ipv6/raw.c:687 [inline] rawv6_sendmsg+0x1960/0x3100 net/ipv6/raw.c:944 sock_sendmsg_nosec net/socket.c:652 [inline] sock_sendmsg+0xac/0xe0 net/socket.c:672 sock_write_iter+0x218/0x380 net/socket.c:1004 call_write_iter include/linux/fs.h:1907 [inline] new_sync_write+0x531/0x6c0 fs/read_write.c:484 vfs_write+0x18b/0x490 fs/read_write.c:559 ksys_write+0x180/0x1c0 fs/read_write.c:612 do_syscall_64+0xc6/0x620 arch/x86/entry/common.c:295 entry_SYSCALL_64_after_hwframe+0x49/0xb3 RIP: 0033:0x45cc79 Code: 2d b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 fb b5 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f6046831c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00000000000358c0 RCX: 000000000045cc79 RDX: 0000000000000028 RSI: 0000000020000140 RDI: 0000000000000005 RBP: 000000000078bfe0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000078bfac R13: 00007ffd74c70c6f R14: 00007f60468329c0 R15: 000000000078bfac