============================================ WARNING: possible recursive locking detected 6.6.0-rc2-next-20230921-syzkaller-06975-g940fcc189c51 #0 Not tainted -------------------------------------------- syz-executor.0/5150 is trying to acquire lock: ffff8880752c20d8 (_xmit_ETHER#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] ffff8880752c20d8 (_xmit_ETHER#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4374 [inline] ffff8880752c20d8 (_xmit_ETHER#2){+.-.}-{2:2}, at: __dev_queue_xmit+0x1ab3/0x3d60 net/core/dev.c:4336 but task is already holding lock: ffff888029bcb0d8 (_xmit_ETHER#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] ffff888029bcb0d8 (_xmit_ETHER#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4374 [inline] ffff888029bcb0d8 (_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 9 locks held by syz-executor.0/5150: #0: ffffffff8cbaada0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:303 [inline] #0: ffffffff8cbaada0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:749 [inline] #0: ffffffff8cbaada0 (rcu_read_lock){....}-{1:2}, at: rawv6_send_hdrinc net/ipv6/raw.c:653 [inline] #0: ffffffff8cbaada0 (rcu_read_lock){....}-{1:2}, at: rawv6_sendmsg+0x20b8/0x40a0 net/ipv6/raw.c:908 #1: ffffffff8cbaada0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:303 [inline] #1: ffffffff8cbaada0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:749 [inline] #1: ffffffff8cbaada0 (rcu_read_lock){....}-{1:2}, at: ip6_finish_output2+0x2cc/0x1700 net/ipv6/ip6_output.c:120 #2: ffffffff8cbaad40 (rcu_read_lock_bh){....}-{1:2}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #2: ffffffff8cbaad40 (rcu_read_lock_bh){....}-{1:2}, at: rcu_read_lock_bh include/linux/rcupdate.h:801 [inline] #2: ffffffff8cbaad40 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x244/0x3d60 net/core/dev.c:4265 #3: ffff88802655a258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: spin_trylock include/linux/spinlock.h:361 [inline] #3: ffff88802655a258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:194 [inline] #3: ffff88802655a258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:191 [inline] #3: ffff88802655a258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3758 [inline] #3: ffff88802655a258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_queue_xmit+0x104a/0x3d60 net/core/dev.c:4306 #4: ffff888029bcb0d8 (_xmit_ETHER#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] #4: ffff888029bcb0d8 (_xmit_ETHER#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4374 [inline] #4: ffff888029bcb0d8 (_xmit_ETHER#2){+.-.}-{2:2}, at: sch_direct_xmit+0x333/0xc20 net/sched/sch_generic.c:340 #5: ffff888025f700b0 (k-slock-AF_INET6){+...}-{2:2}, at: spin_trylock include/linux/spinlock.h:361 [inline] #5: ffff888025f700b0 (k-slock-AF_INET6){+...}-{2:2}, at: icmpv6_xmit_lock net/ipv6/icmp.c:108 [inline] #5: ffff888025f700b0 (k-slock-AF_INET6){+...}-{2:2}, at: icmp6_send+0xcdf/0x2740 net/ipv6/icmp.c:545 #6: ffffffff8cbaada0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:303 [inline] #6: ffffffff8cbaada0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:749 [inline] #6: ffffffff8cbaada0 (rcu_read_lock){....}-{1:2}, at: icmp6_send+0x13d1/0x2740 net/ipv6/icmp.c:613 #7: ffffffff8cbaada0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:303 [inline] #7: ffffffff8cbaada0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:749 [inline] #7: ffffffff8cbaada0 (rcu_read_lock){....}-{1:2}, at: ip6_finish_output2+0x2cc/0x1700 net/ipv6/ip6_output.c:120 #8: ffffffff8cbaad40 (rcu_read_lock_bh){....}-{1:2}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #8: ffffffff8cbaad40 (rcu_read_lock_bh){....}-{1:2}, at: rcu_read_lock_bh include/linux/rcupdate.h:801 [inline] #8: ffffffff8cbaad40 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x244/0x3d60 net/core/dev.c:4265 stack backtrace: CPU: 0 PID: 5150 Comm: syz-executor.0 Not tainted 6.6.0-rc2-next-20230921-syzkaller-06975-g940fcc189c51 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/04/2023 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:4374 [inline] __dev_queue_xmit+0x1ab3/0x3d60 net/core/dev.c:4336 dev_queue_xmit include/linux/netdevice.h:3092 [inline] neigh_resolve_output net/core/neighbour.c:1552 [inline] neigh_resolve_output+0x58c/0x900 net/core/neighbour.c:1532 neigh_output include/net/neighbour.h:542 [inline] ip6_finish_output2+0x581/0x1700 net/ipv6/ip6_output.c:135 __ip6_finish_output net/ipv6/ip6_output.c:196 [inline] ip6_finish_output+0x485/0x1250 net/ipv6/ip6_output.c:207 NF_HOOK_COND include/linux/netfilter.h:293 [inline] ip6_output+0x1e2/0x530 net/ipv6/ip6_output.c:228 dst_output include/net/dst.h:458 [inline] ip6_local_out+0xaf/0x190 net/ipv6/output_core.c:155 ip6_send_skb+0xb7/0x330 net/ipv6/ip6_output.c:2017 ip6_push_pending_frames+0xe0/0x100 net/ipv6/ip6_output.c:2037 icmpv6_push_pending_frames+0x2da/0x460 net/ipv6/icmp.c:307 icmp6_send+0x1c1c/0x2740 net/ipv6/icmp.c:624 __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:2787 dst_link_failure include/net/dst.h:437 [inline] ip_tunnel_xmit+0x2d43/0x3370 net/ipv4/ip_tunnel.c:837 erspan_xmit+0x52b/0x1f90 net/ipv4/ip_gre.c:717 __netdev_start_xmit include/linux/netdevice.h:4911 [inline] netdev_start_xmit include/linux/netdevice.h:4925 [inline] xmit_one net/core/dev.c:3544 [inline] dev_hard_start_xmit+0x13d/0x6c0 net/core/dev.c:3560 sch_direct_xmit+0x1ac/0xc20 net/sched/sch_generic.c:342 __dev_xmit_skb net/core/dev.c:3771 [inline] __dev_queue_xmit+0x126e/0x3d60 net/core/dev.c:4306 dev_queue_xmit include/linux/netdevice.h:3092 [inline] neigh_resolve_output net/core/neighbour.c:1552 [inline] neigh_resolve_output+0x58c/0x900 net/core/neighbour.c:1532 neigh_output include/net/neighbour.h:542 [inline] ip6_finish_output2+0x581/0x1700 net/ipv6/ip6_output.c:135 __ip6_finish_output net/ipv6/ip6_output.c:196 [inline] ip6_finish_output+0x485/0x1250 net/ipv6/ip6_output.c:207 NF_HOOK_COND include/linux/netfilter.h:293 [inline] ip6_output+0x1e2/0x530 net/ipv6/ip6_output.c:228 dst_output include/net/dst.h:458 [inline] NF_HOOK include/linux/netfilter.h:304 [inline] rawv6_send_hdrinc net/ipv6/raw.c:655 [inline] rawv6_sendmsg+0x22ba/0x40a0 net/ipv6/raw.c:908 inet_sendmsg+0x9d/0xe0 net/ipv4/af_inet.c:840 sock_sendmsg_nosec net/socket.c:730 [inline] sock_sendmsg+0xd9/0x180 net/socket.c:753 sock_write_iter+0x29b/0x3d0 net/socket.c:1141 call_write_iter include/linux/fs.h:1957 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x650/0xe40 fs/read_write.c:584 ksys_write+0x1f0/0x250 fs/read_write.c:637 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x4548a9 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:00007ffad531c0d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 000000000054bf00 RCX: 00000000004548a9 RDX: 0000000000000028 RSI: 0000000020000140 RDI: 0000000000000005 RBP: 00000000004a05f4 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000049f7f4 R13: 000000000000000b R14: 000000000054bf00 R15: 00007ffc20613708