x_tables: ip6_tables: rpfilter match: used from hooks OUTPUT, but only valid from PREROUTING ============================================ WARNING: possible recursive locking detected 5.15.152-syzkaller #0 Not tainted -------------------------------------------- syz-executor.1/13191 is trying to acquire lock: ffff8880777f0898 (_xmit_ETHER#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:363 [inline] ffff8880777f0898 (_xmit_ETHER#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4429 [inline] ffff8880777f0898 (_xmit_ETHER#2){+.-.}-{2:2}, at: __dev_queue_xmit+0x15be/0x3230 net/core/dev.c:4244 but task is already holding lock: ffff88809925ac98 (_xmit_ETHER#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:363 [inline] ffff88809925ac98 (_xmit_ETHER#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4429 [inline] ffff88809925ac98 (_xmit_ETHER#2){+.-.}-{2:2}, at: sch_direct_xmit+0x1c0/0x5e0 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 6 locks held by syz-executor.1/13191: #0: ffffffff8c91f780 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x9/0x30 include/linux/rcupdate.h:269 #1: ffffffff8c91f780 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x9/0x30 include/linux/rcupdate.h:269 #2: ffff8880983db258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: spin_trylock include/linux/spinlock.h:373 [inline] #2: ffff8880983db258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:173 [inline] #2: ffff8880983db258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3831 [inline] #2: ffff8880983db258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_queue_xmit+0x11f2/0x3230 net/core/dev.c:4213 #3: ffff88809925ac98 (_xmit_ETHER#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:363 [inline] #3: ffff88809925ac98 (_xmit_ETHER#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4429 [inline] #3: ffff88809925ac98 (_xmit_ETHER#2){+.-.}-{2:2}, at: sch_direct_xmit+0x1c0/0x5e0 net/sched/sch_generic.c:340 #4: ffffffff8c91f780 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x9/0x30 include/linux/rcupdate.h:269 #5: ffffffff8c91f780 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x9/0x30 include/linux/rcupdate.h:269 stack backtrace: CPU: 0 PID: 13191 Comm: syz-executor.1 Not tainted 5.15.152-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106 print_deadlock_bug kernel/locking/lockdep.c:2946 [inline] check_deadlock kernel/locking/lockdep.c:2989 [inline] validate_chain+0x46d2/0x5930 kernel/locking/lockdep.c:3775 __lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5012 lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623 __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:4429 [inline] __dev_queue_xmit+0x15be/0x3230 net/core/dev.c:4244 neigh_output include/net/neighbour.h:509 [inline] ip_finish_output2+0xd0c/0x11a0 net/ipv4/ip_output.c:228 iptunnel_xmit+0x513/0x950 net/ipv4/ip_tunnel_core.c:82 ip_tunnel_xmit+0x198c/0x27b0 net/ipv4/ip_tunnel.c:824 __gre_xmit net/ipv4/ip_gre.c:469 [inline] erspan_xmit+0xa9c/0x1530 net/ipv4/ip_gre.c:718 __netdev_start_xmit include/linux/netdevice.h:5019 [inline] netdev_start_xmit include/linux/netdevice.h:5033 [inline] xmit_one net/core/dev.c:3617 [inline] dev_hard_start_xmit+0x298/0x7a0 net/core/dev.c:3633 sch_direct_xmit+0x2b2/0x5e0 net/sched/sch_generic.c:342 __dev_xmit_skb net/core/dev.c:3844 [inline] __dev_queue_xmit+0x18ee/0x3230 net/core/dev.c:4213 neigh_output include/net/neighbour.h:509 [inline] ip_finish_output2+0xd0c/0x11a0 net/ipv4/ip_output.c:228 dst_output include/net/dst.h:443 [inline] ip_local_out net/ipv4/ip_output.c:126 [inline] ip_send_skb+0x113/0x1a0 net/ipv4/ip_output.c:1581 udp_send_skb+0x900/0x11f0 net/ipv4/udp.c:979 udp_sendmsg+0x1f3d/0x2d90 net/ipv4/udp.c:1266 udpv6_sendmsg+0xbec/0x3190 net/ipv6/udp.c:1392 sock_sendmsg_nosec net/socket.c:704 [inline] __sock_sendmsg net/socket.c:716 [inline] ____sys_sendmsg+0x59e/0x8f0 net/socket.c:2431 ___sys_sendmsg+0x252/0x2e0 net/socket.c:2485 __sys_sendmmsg+0x2bf/0x560 net/socket.c:2571 __do_sys_sendmmsg net/socket.c:2600 [inline] __se_sys_sendmmsg net/socket.c:2597 [inline] __x64_sys_sendmmsg+0x9c/0xb0 net/socket.c:2597 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x61/0xcb RIP: 0033:0x7f77c66cdda9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 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 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f77c4c4e0c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000133 RAX: ffffffffffffffda RBX: 00007f77c67fbf80 RCX: 00007f77c66cdda9 RDX: 0000000000006c00 RSI: 0000000020007e40 RDI: 0000000000000008 RBP: 00007f77c671a47a R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000000b R14: 00007f77c67fbf80 R15: 00007ffed1daea78