============================================ WARNING: possible recursive locking detected 6.7.0-rc6-syzkaller-gaafe7ad77b91 #0 Not tainted -------------------------------------------- syz-executor.1/13338 is trying to acquire lock: ffff0000cce1b0d8 (_xmit_ETHER#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] ffff0000cce1b0d8 (_xmit_ETHER#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4403 [inline] ffff0000cce1b0d8 (_xmit_ETHER#2){+.-.}-{2:2}, at: __dev_queue_xmit+0x1128/0x31d8 net/core/dev.c:4342 but task is already holding lock: ffff0000d19448d8 (_xmit_ETHER#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] ffff0000d19448d8 (_xmit_ETHER#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4403 [inline] ffff0000d19448d8 (_xmit_ETHER#2){+.-.}-{2:2}, at: sch_direct_xmit+0x164/0x548 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 8 locks held by syz-executor.1/13338: #0: ffff80008e6c48c0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x18/0x54 include/linux/rcupdate.h:300 #1: ffff80008e6c4920 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x18/0x54 include/linux/rcupdate.h:300 #2: ffff80008e6c48c0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x10/0x4c include/linux/rcupdate.h:300 #3: ffff80008e6c4920 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x18/0x54 include/linux/rcupdate.h:300 #4: ffff00012eb93258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: spin_trylock include/linux/spinlock.h:361 [inline] #4: ffff00012eb93258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:194 [inline] #4: ffff00012eb93258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3759 [inline] #4: ffff00012eb93258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_queue_xmit+0xedc/0x31d8 net/core/dev.c:4312 #5: ffff0000d19448d8 (_xmit_ETHER#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] #5: ffff0000d19448d8 (_xmit_ETHER#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4403 [inline] #5: ffff0000d19448d8 (_xmit_ETHER#2){+.-.}-{2:2}, at: sch_direct_xmit+0x164/0x548 net/sched/sch_generic.c:340 #6: ffff80008e6c48c0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x10/0x4c include/linux/rcupdate.h:300 #7: ffff80008e6c4920 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x18/0x54 include/linux/rcupdate.h:300 stack backtrace: CPU: 0 PID: 13338 Comm: syz-executor.1 Not tainted 6.7.0-rc6-syzkaller-gaafe7ad77b91 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023 Call trace: dump_backtrace+0x1b8/0x1e4 arch/arm64/kernel/stacktrace.c:291 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:298 __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd0/0x124 lib/dump_stack.c:106 dump_stack+0x1c/0x28 lib/dump_stack.c:113 print_deadlock_bug+0x4e4/0x660 kernel/locking/lockdep.c:3012 check_deadlock kernel/locking/lockdep.c:3062 [inline] validate_chain kernel/locking/lockdep.c:3856 [inline] __lock_acquire+0x5fe4/0x763c kernel/locking/lockdep.c:5137 lock_acquire+0x23c/0x71c kernel/locking/lockdep.c:5754 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x48/0x60 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:351 [inline] __netif_tx_lock include/linux/netdevice.h:4403 [inline] __dev_queue_xmit+0x1128/0x31d8 net/core/dev.c:4342 dev_queue_xmit include/linux/netdevice.h:3134 [inline] neigh_resolve_output+0x518/0x618 net/core/neighbour.c:1563 neigh_output include/net/neighbour.h:542 [inline] ip_finish_output2+0xdf8/0x1394 net/ipv4/ip_output.c:235 __ip_finish_output+0x1b0/0x458 ip_finish_output+0x44/0x2e4 net/ipv4/ip_output.c:323 NF_HOOK_COND include/linux/netfilter.h:303 [inline] ip_output+0x1a8/0x21c net/ipv4/ip_output.c:433 dst_output include/net/dst.h:451 [inline] ip_local_out+0x120/0x160 net/ipv4/ip_output.c:129 iptunnel_xmit+0x428/0x940 net/ipv4/ip_tunnel_core.c:82 ip_tunnel_xmit+0x16cc/0x2654 net/ipv4/ip_tunnel.c:831 __gre_xmit+0x104/0x198 net/ipv4/ip_gre.c:469 erspan_xmit+0x928/0x13a0 net/ipv4/ip_gre.c:720 __netdev_start_xmit include/linux/netdevice.h:4940 [inline] netdev_start_xmit include/linux/netdevice.h:4954 [inline] xmit_one net/core/dev.c:3545 [inline] dev_hard_start_xmit+0x240/0x8ac net/core/dev.c:3561 sch_direct_xmit+0x234/0x548 net/sched/sch_generic.c:342 __dev_xmit_skb net/core/dev.c:3772 [inline] __dev_queue_xmit+0x1388/0x31d8 net/core/dev.c:4312 dev_queue_xmit include/linux/netdevice.h:3134 [inline] neigh_resolve_output+0x518/0x618 net/core/neighbour.c:1563 neigh_output include/net/neighbour.h:542 [inline] ip_finish_output2+0xdf8/0x1394 net/ipv4/ip_output.c:235 __ip_finish_output+0x1b0/0x458 ip_finish_output+0x44/0x2e4 net/ipv4/ip_output.c:323 NF_HOOK_COND include/linux/netfilter.h:303 [inline] ip_output+0x1a8/0x21c net/ipv4/ip_output.c:433 dst_output include/net/dst.h:451 [inline] ip_local_out+0x120/0x160 net/ipv4/ip_output.c:129 iptunnel_xmit+0x428/0x940 net/ipv4/ip_tunnel_core.c:82 ip_tunnel_xmit+0x16cc/0x2654 net/ipv4/ip_tunnel.c:831 __gre_xmit net/ipv4/ip_gre.c:469 [inline] ipgre_xmit+0x688/0xa30 net/ipv4/ip_gre.c:665 __netdev_start_xmit include/linux/netdevice.h:4940 [inline] netdev_start_xmit include/linux/netdevice.h:4954 [inline] xmit_one net/core/dev.c:3545 [inline] dev_hard_start_xmit+0x240/0x8ac net/core/dev.c:3561 __dev_queue_xmit+0x1570/0x31d8 net/core/dev.c:4346 dev_queue_xmit include/linux/netdevice.h:3134 [inline] __bpf_tx_skb+0x1a4/0x2c4 net/core/filter.c:2133 __bpf_redirect+0x590/0xb60 ____bpf_clone_redirect net/core/filter.c:2457 [inline] bpf_clone_redirect+0x1d0/0x2ec net/core/filter.c:2429 bpf_prog_208b094576c80b22+0x90/0xc8 bpf_dispatcher_nop_func include/linux/bpf.h:1196 [inline] __bpf_prog_run include/linux/filter.h:651 [inline] bpf_prog_run include/linux/filter.h:658 [inline] bpf_test_run+0x374/0x878 net/bpf/test_run.c:423 bpf_prog_test_run_skb+0x8d4/0x1090 net/bpf/test_run.c:1045 bpf_prog_test_run+0x2dc/0x364 kernel/bpf/syscall.c:4040 __sys_bpf+0x314/0x5dc kernel/bpf/syscall.c:5401 __do_sys_bpf kernel/bpf/syscall.c:5487 [inline] __se_sys_bpf kernel/bpf/syscall.c:5485 [inline] __arm64_sys_bpf+0x80/0x98 kernel/bpf/syscall.c:5485 __invoke_syscall arch/arm64/kernel/syscall.c:37 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:51 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:136 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:155 el0_svc+0x54/0x158 arch/arm64/kernel/entry-common.c:678 el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:696 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:595