============================================ WARNING: possible recursive locking detected 5.14.0-syzkaller #0 Not tainted -------------------------------------------- syz-executor.0/19191 is trying to acquire lock: ffff8880213eb398 (_xmit_ETHER#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:363 [inline] ffff8880213eb398 (_xmit_ETHER#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4405 [inline] ffff8880213eb398 (_xmit_ETHER#2){+.-.}-{2:2}, at: sch_direct_xmit+0x30f/0xbb0 net/sched/sch_generic.c:340 but task is already holding lock: ffff888028244c98 (_xmit_ETHER#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:363 [inline] ffff888028244c98 (_xmit_ETHER#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4405 [inline] ffff888028244c98 (_xmit_ETHER#2){+.-.}-{2:2}, at: sch_direct_xmit+0x30f/0xbb0 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 7 locks held by syz-executor.0/19191: #0: ffffffff8b97f900 (rcu_read_lock_bh){....}-{1:2}, at: lwtunnel_xmit_redirect include/net/lwtunnel.h:95 [inline] #0: ffffffff8b97f900 (rcu_read_lock_bh){....}-{1:2}, at: ip_finish_output2+0x28b/0x2140 net/ipv4/ip_output.c:207 #1: ffffffff8b97f900 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x1da/0x3710 net/core/dev.c:4136 #2: ffff88807cbe4258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: spin_trylock include/linux/spinlock.h:373 [inline] #2: ffff88807cbe4258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:173 [inline] #2: ffff88807cbe4258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3790 [inline] #2: ffff88807cbe4258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_queue_xmit+0x125c/0x3710 net/core/dev.c:4170 #3: ffff888028244c98 (_xmit_ETHER#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:363 [inline] #3: ffff888028244c98 (_xmit_ETHER#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4405 [inline] #3: ffff888028244c98 (_xmit_ETHER#2){+.-.}-{2:2}, at: sch_direct_xmit+0x30f/0xbb0 net/sched/sch_generic.c:340 #4: ffffffff8b97f900 (rcu_read_lock_bh){....}-{1:2}, at: lwtunnel_xmit_redirect include/net/lwtunnel.h:95 [inline] #4: ffffffff8b97f900 (rcu_read_lock_bh){....}-{1:2}, at: ip_finish_output2+0x28b/0x2140 net/ipv4/ip_output.c:207 #5: ffffffff8b97f900 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x1da/0x3710 net/core/dev.c:4136 #6: ffff888035278258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: spin_trylock include/linux/spinlock.h:373 [inline] #6: ffff888035278258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:173 [inline] #6: ffff888035278258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3790 [inline] #6: ffff888035278258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_queue_xmit+0x125c/0x3710 net/core/dev.c:4170 stack backtrace: CPU: 1 PID: 19191 Comm: syz-executor.0 Not tainted 5.14.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:105 print_deadlock_bug kernel/locking/lockdep.c:2944 [inline] check_deadlock kernel/locking/lockdep.c:2987 [inline] validate_chain kernel/locking/lockdep.c:3776 [inline] __lock_acquire.cold+0x149/0x3ab kernel/locking/lockdep.c:5015 lock_acquire kernel/locking/lockdep.c:5625 [inline] lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5590 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:363 [inline] __netif_tx_lock include/linux/netdevice.h:4405 [inline] sch_direct_xmit+0x30f/0xbb0 net/sched/sch_generic.c:340 __dev_xmit_skb net/core/dev.c:3803 [inline] __dev_queue_xmit+0x14c3/0x3710 net/core/dev.c:4170 neigh_hh_output include/net/neighbour.h:499 [inline] neigh_output include/net/neighbour.h:508 [inline] ip_finish_output2+0xf01/0x2140 net/ipv4/ip_output.c:221 __ip_finish_output net/ipv4/ip_output.c:299 [inline] __ip_finish_output+0x396/0x640 net/ipv4/ip_output.c:281 ip_finish_output+0x32/0x200 net/ipv4/ip_output.c:309 NF_HOOK_COND include/linux/netfilter.h:296 [inline] ip_output+0x196/0x310 net/ipv4/ip_output.c:423 dst_output include/net/dst.h:450 [inline] ip_local_out+0xaf/0x1a0 net/ipv4/ip_output.c:126 iptunnel_xmit+0x628/0xa50 net/ipv4/ip_tunnel_core.c:82 ip_tunnel_xmit+0x10a6/0x2b60 net/ipv4/ip_tunnel.c:810 erspan_xmit+0x7e2/0x29c0 net/ipv4/ip_gre.c:709 __netdev_start_xmit include/linux/netdevice.h:4970 [inline] netdev_start_xmit include/linux/netdevice.h:4984 [inline] xmit_one net/core/dev.c:3576 [inline] dev_hard_start_xmit+0x1eb/0x920 net/core/dev.c:3592 sch_direct_xmit+0x19f/0xbb0 net/sched/sch_generic.c:342 __dev_xmit_skb net/core/dev.c:3803 [inline] __dev_queue_xmit+0x14c3/0x3710 net/core/dev.c:4170 neigh_resolve_output net/core/neighbour.c:1492 [inline] neigh_resolve_output+0x50e/0x820 net/core/neighbour.c:1472 neigh_output include/net/neighbour.h:510 [inline] ip_finish_output2+0x813/0x2140 net/ipv4/ip_output.c:221 ip_do_fragment+0x10f4/0x1430 net/ipv4/ip_output.c:841 ip_fragment.constprop.0+0x174/0x240 net/ipv4/ip_output.c:574 __ip_finish_output net/ipv4/ip_output.c:297 [inline] __ip_finish_output+0x2de/0x640 net/ipv4/ip_output.c:281 ip_finish_output+0x32/0x200 net/ipv4/ip_output.c:309 NF_HOOK_COND include/linux/netfilter.h:296 [inline] ip_output+0x196/0x310 net/ipv4/ip_output.c:423 dst_output include/net/dst.h:450 [inline] ip_local_out net/ipv4/ip_output.c:126 [inline] ip_send_skb+0xd4/0x260 net/ipv4/ip_output.c:1555 udp_send_skb+0x6cd/0x11a0 net/ipv4/udp.c:966 udp_sendmsg+0x1bad/0x2740 net/ipv4/udp.c:1253 udpv6_sendmsg+0x14f6/0x2c40 net/ipv6/udp.c:1359 inet6_sendmsg+0x99/0xe0 net/ipv6/af_inet6.c:643 sock_sendmsg_nosec net/socket.c:704 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:724 ____sys_sendmsg+0x331/0x810 net/socket.c:2409 ___sys_sendmsg+0xf3/0x170 net/socket.c:2463 __sys_sendmmsg+0x297/0x470 net/socket.c:2542 __compat_sys_sendmmsg net/compat.c:361 [inline] __do_compat_sys_sendmmsg net/compat.c:368 [inline] __se_compat_sys_sendmmsg net/compat.c:365 [inline] __ia32_compat_sys_sendmmsg+0x9b/0x100 net/compat.c:365 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline] __do_fast_syscall_32+0x65/0xf0 arch/x86/entry/common.c:178 do_fast_syscall_32+0x2f/0x70 arch/x86/entry/common.c:203 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c RIP: 0023:0xf7f2d549 Code: 03 74 c0 01 10 05 03 74 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 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:00000000f55275fc EFLAGS: 00000296 ORIG_RAX: 0000000000000159 RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000020004d80 RDX: 0000000000000132 RSI: 0000000004000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 ---------------- Code disassembly (best guess): 0: 03 74 c0 01 add 0x1(%rax,%rax,8),%esi 4: 10 05 03 74 b8 01 adc %al,0x1b87403(%rip) # 0x1b8740d a: 10 06 adc %al,(%rsi) c: 03 74 b4 01 add 0x1(%rsp,%rsi,4),%esi 10: 10 07 adc %al,(%rdi) 12: 03 74 b0 01 add 0x1(%rax,%rsi,4),%esi 16: 10 08 adc %cl,(%rax) 18: 03 74 d8 01 add 0x1(%rax,%rbx,8),%esi 1c: 00 00 add %al,(%rax) 1e: 00 00 add %al,(%rax) 20: 00 51 52 add %dl,0x52(%rcx) 23: 55 push %rbp 24: 89 e5 mov %esp,%ebp 26: 0f 34 sysenter 28: cd 80 int $0x80 * 2a: 5d pop %rbp <-- trapping instruction 2b: 5a pop %rdx 2c: 59 pop %rcx 2d: c3 retq 2e: 90 nop 2f: 90 nop 30: 90 nop 31: 90 nop 32: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi 39: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi