BTRFS info (device loop0): using free space tree BTRFS info (device loop0): has skinny extents BTRFS info (device loop0): enabling ssd optimizations ============================================ WARNING: possible recursive locking detected 5.15.165-syzkaller #0 Not tainted -------------------------------------------- syz.0.325/5037 is trying to acquire lock: ffff0000daa00498 (_xmit_TUNNEL6#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:363 [inline] ffff0000daa00498 (_xmit_TUNNEL6#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4429 [inline] ffff0000daa00498 (_xmit_TUNNEL6#2){+.-.}-{2:2}, at: sch_direct_xmit+0x15c/0x484 net/sched/sch_generic.c:340 but task is already holding lock: ffff0000daa00498 (_xmit_TUNNEL6#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:363 [inline] ffff0000daa00498 (_xmit_TUNNEL6#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4429 [inline] ffff0000daa00498 (_xmit_TUNNEL6#2){+.-.}-{2:2}, at: generic_xdp_tx+0xa0/0x59c net/core/dev.c:4877 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(_xmit_TUNNEL6#2); lock(_xmit_TUNNEL6#2); *** DEADLOCK *** May be due to missing lock nesting notation 8 locks held by syz.0.325/5037: #0: ffff800014c817a0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x10/0x4c include/linux/rcupdate.h:311 #1: ffff800014c817a0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x18/0x54 include/linux/rcupdate.h:311 #2: ffff0000daa00498 (_xmit_TUNNEL6#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:363 [inline] #2: ffff0000daa00498 (_xmit_TUNNEL6#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4429 [inline] #2: ffff0000daa00498 (_xmit_TUNNEL6#2){+.-.}-{2:2}, at: generic_xdp_tx+0xa0/0x59c net/core/dev.c:4877 #3: ffff0000c1459660 (k-slock-AF_INET6){+.-.}-{2:2}, at: spin_trylock include/linux/spinlock.h:373 [inline] #3: ffff0000c1459660 (k-slock-AF_INET6){+.-.}-{2:2}, at: icmpv6_xmit_lock+0x100/0x188 net/ipv6/icmp.c:118 #4: ffff800014c817a0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x10/0x4c include/linux/rcupdate.h:311 #5: ffff800014c81800 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x18/0x54 include/linux/rcupdate.h:311 #6: ffff800014c81800 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x18/0x54 include/linux/rcupdate.h:311 #7: ffff0000dbb7b948 (dev->qdisc_running_key ?: &qdisc_running_key){+...}-{0:0}, at: __dev_xmit_skb net/core/dev.c:3897 [inline] #7: ffff0000dbb7b948 (dev->qdisc_running_key ?: &qdisc_running_key){+...}-{0:0}, at: __dev_queue_xmit+0x1054/0x2a6c net/core/dev.c:4213 stack backtrace: CPU: 1 PID: 5037 Comm: syz.0.325 Not tainted 5.15.165-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024 Call trace: dump_backtrace+0x0/0x530 arch/arm64/kernel/stacktrace.c:152 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:216 __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x108/0x170 lib/dump_stack.c:106 dump_stack+0x1c/0x58 lib/dump_stack.c:113 __lock_acquire+0x62bc/0x7638 kernel/locking/lockdep.c:5012 lock_acquire+0x240/0x77c kernel/locking/lockdep.c:5623 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0xb0/0x10c kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:363 [inline] __netif_tx_lock include/linux/netdevice.h:4429 [inline] sch_direct_xmit+0x15c/0x484 net/sched/sch_generic.c:340 qdisc_restart net/sched/sch_generic.c:407 [inline] __qdisc_run+0x878/0x1fc0 net/sched/sch_generic.c:415 __dev_xmit_skb net/core/dev.c:3902 [inline] __dev_queue_xmit+0x1068/0x2a6c net/core/dev.c:4213 dev_queue_xmit+0x24/0x34 net/core/dev.c:4281 neigh_connected_output+0x334/0x378 net/core/neighbour.c:1533 neigh_output include/net/neighbour.h:509 [inline] ip6_finish_output2+0x1348/0x1c4c net/ipv6/ip6_output.c:126 __ip6_finish_output+0x580/0x6ec net/ipv6/ip6_output.c:197 ip6_finish_output+0x40/0x218 net/ipv6/ip6_output.c:207 NF_HOOK_COND include/linux/netfilter.h:291 [inline] ip6_output+0x274/0x594 net/ipv6/ip6_output.c:230 dst_output include/net/dst.h:443 [inline] ip6_local_out+0x120/0x160 net/ipv6/output_core.c:161 ip6_send_skb+0x118/0x428 net/ipv6/ip6_output.c:1943 ip6_push_pending_frames+0xd0/0x118 net/ipv6/ip6_output.c:1963 icmpv6_push_pending_frames+0x244/0x398 net/ipv6/icmp.c:311 icmp6_send+0x11a4/0x1b18 net/ipv6/icmp.c:630 __icmpv6_send include/linux/icmpv6.h:28 [inline] icmpv6_send include/linux/icmpv6.h:49 [inline] ip6_link_failure+0x44/0x4a8 net/ipv6/route.c:2794 dst_link_failure include/net/dst.h:422 [inline] vti6_xmit net/ipv6/ip6_vti.c:548 [inline] vti6_tnl_xmit+0xed4/0x1888 net/ipv6/ip6_vti.c:587 __netdev_start_xmit include/linux/netdevice.h:5019 [inline] netdev_start_xmit include/linux/netdevice.h:5033 [inline] generic_xdp_tx+0x25c/0x59c net/core/dev.c:4879 dev_map_generic_redirect+0x340/0x7b8 kernel/bpf/devmap.c:676 dev_map_redirect_multi+0x6b8/0x840 kernel/bpf/devmap.c:770 xdp_do_generic_redirect_map net/core/filter.c:4149 [inline] xdp_do_generic_redirect+0x668/0xe2c net/core/filter.c:4211 do_xdp_generic+0x3b8/0x8a8 net/core/dev.c:4903 __netif_receive_skb_core+0x15c4/0x341c net/core/dev.c:5308 __netif_receive_skb_one_core net/core/dev.c:5483 [inline] __netif_receive_skb+0x114/0x400 net/core/dev.c:5599 netif_receive_skb_internal net/core/dev.c:5685 [inline] netif_receive_skb+0x1e0/0x8c4 net/core/dev.c:5744 tun_rx_batched+0x568/0x6e4 tun_get_user+0x2320/0x3774 drivers/net/tun.c:1989 tun_chr_write_iter+0xfc/0x20c drivers/net/tun.c:2019 call_write_iter include/linux/fs.h:2172 [inline] new_sync_write fs/read_write.c:507 [inline] vfs_write+0x884/0xb44 fs/read_write.c:594 ksys_write+0x15c/0x26c fs/read_write.c:647 __do_sys_write fs/read_write.c:659 [inline] __se_sys_write fs/read_write.c:656 [inline] __arm64_sys_write+0x7c/0x90 fs/read_write.c:656 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181 el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584