============================================ WARNING: possible recursive locking detected 6.8.0-rc7-syzkaller-00142-g3aaa8ce7a335 #0 Not tainted -------------------------------------------- syz-executor.3/23559 is trying to acquire lock: ffff888053b4f218 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] ffff888053b4f218 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3806 [inline] ffff888053b4f218 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_queue_xmit+0x20af/0x3b10 net/core/dev.c:4317 but task is already holding lock: ffff888022098258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: spin_trylock include/linux/spinlock.h:361 [inline] ffff888022098258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:195 [inline] ffff888022098258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3763 [inline] ffff888022098258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_queue_xmit+0x1262/0x3b10 net/core/dev.c:4317 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(dev->qdisc_tx_busylock ?: &qdisc_tx_busylock); lock(dev->qdisc_tx_busylock ?: &qdisc_tx_busylock); *** DEADLOCK *** May be due to missing lock nesting notation 8 locks held by syz-executor.3/23559: #0: ffff88801f55e6b0 (sk_lock-AF_INET6){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1691 [inline] #0: ffff88801f55e6b0 (sk_lock-AF_INET6){+.+.}-{0:0}, at: rawv6_sendmsg+0x189c/0x23c0 net/ipv6/raw.c:912 #1: ffffffff8e130be0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:298 [inline] #1: ffffffff8e130be0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:750 [inline] #1: ffffffff8e130be0 (rcu_read_lock){....}-{1:2}, at: ip6_finish_output2+0x712/0x1660 net/ipv6/ip6_output.c:122 #2: ffffffff8e130c40 (rcu_read_lock_bh){....}-{1:2}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #2: ffffffff8e130c40 (rcu_read_lock_bh){....}-{1:2}, at: rcu_read_lock_bh include/linux/rcupdate.h:802 [inline] #2: ffffffff8e130c40 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x2c4/0x3b10 net/core/dev.c:4276 #3: ffff888022098258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: spin_trylock include/linux/spinlock.h:361 [inline] #3: ffff888022098258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:195 [inline] #3: ffff888022098258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3763 [inline] #3: ffff888022098258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_queue_xmit+0x1262/0x3b10 net/core/dev.c:4317 #4: ffff88802a4687f0 (k-slock-AF_INET6){+.-.}-{2:2}, at: spin_trylock include/linux/spinlock.h:361 [inline] #4: ffff88802a4687f0 (k-slock-AF_INET6){+.-.}-{2:2}, at: icmpv6_xmit_lock net/ipv6/icmp.c:108 [inline] #4: ffff88802a4687f0 (k-slock-AF_INET6){+.-.}-{2:2}, at: icmp6_send+0xc45/0x2070 net/ipv6/icmp.c:545 #5: ffffffff8e130be0 (rcu_read_lock){....}-{1:2}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #5: ffffffff8e130be0 (rcu_read_lock){....}-{1:2}, at: icmp6_send+0xba4/0x2070 net/ipv6/icmp.c:537 #6: ffffffff8e130be0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:298 [inline] #6: ffffffff8e130be0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:750 [inline] #6: ffffffff8e130be0 (rcu_read_lock){....}-{1:2}, at: ip6_finish_output2+0x712/0x1660 net/ipv6/ip6_output.c:122 #7: ffffffff8e130c40 (rcu_read_lock_bh){....}-{1:2}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #7: ffffffff8e130c40 (rcu_read_lock_bh){....}-{1:2}, at: rcu_read_lock_bh include/linux/rcupdate.h:802 [inline] #7: ffffffff8e130c40 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x2c4/0x3b10 net/core/dev.c:4276 stack backtrace: CPU: 1 PID: 23559 Comm: syz-executor.3 Not tainted 6.8.0-rc7-syzkaller-00142-g3aaa8ce7a335 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e7/0x2e0 lib/dump_stack.c:106 check_deadlock kernel/locking/lockdep.c:3062 [inline] validate_chain+0x15c0/0x58e0 kernel/locking/lockdep.c:3856 __lock_acquire+0x1345/0x1fd0 kernel/locking/lockdep.c:5137 lock_acquire+0x1e3/0x530 kernel/locking/lockdep.c:5754 __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] __dev_xmit_skb net/core/dev.c:3806 [inline] __dev_queue_xmit+0x20af/0x3b10 net/core/dev.c:4317 dev_queue_xmit include/linux/netdevice.h:3169 [inline] neigh_hh_output include/net/neighbour.h:526 [inline] neigh_output include/net/neighbour.h:540 [inline] ip6_finish_output2+0xfb5/0x1660 net/ipv6/ip6_output.c:137 ip6_finish_output+0x41e/0x810 net/ipv6/ip6_output.c:222 ip6_send_skb+0x112/0x230 net/ipv6/ip6_output.c:1955 icmp6_send+0x15fc/0x2070 net/ipv6/icmp.c:624 __icmpv6_send include/linux/icmpv6.h:28 [inline] icmpv6_send include/linux/icmpv6.h:49 [inline] ip6_link_failure+0x3c/0x4f0 net/ipv6/route.c:2787 ip_tunnel_xmit+0x162b/0x2940 net/ipv4/ip_tunnel.c:851 __gre_xmit net/ipv4/ip_gre.c:469 [inline] gre_tap_xmit+0x4ed/0x6e0 net/ipv4/ip_gre.c:748 __netdev_start_xmit include/linux/netdevice.h:4986 [inline] netdev_start_xmit include/linux/netdevice.h:5000 [inline] xmit_one net/core/dev.c:3547 [inline] dev_hard_start_xmit+0x242/0x770 net/core/dev.c:3563 sch_direct_xmit+0x2b6/0x5f0 net/sched/sch_generic.c:342 __dev_xmit_skb net/core/dev.c:3776 [inline] __dev_queue_xmit+0x1912/0x3b10 net/core/dev.c:4317 dev_queue_xmit include/linux/netdevice.h:3169 [inline] neigh_hh_output include/net/neighbour.h:526 [inline] neigh_output include/net/neighbour.h:540 [inline] ip6_finish_output2+0xfb5/0x1660 net/ipv6/ip6_output.c:137 ip6_fragment+0x139c/0x2290 net/ipv6/ip6_output.c:1020 __ip6_finish_output net/ipv6/ip6_output.c:209 [inline] ip6_finish_output+0x2b8/0x810 net/ipv6/ip6_output.c:222 ip6_send_skb+0x112/0x230 net/ipv6/ip6_output.c:1955 rawv6_push_pending_frames+0x75c/0x9e0 net/ipv6/raw.c:582 rawv6_sendmsg+0x19c7/0x23c0 net/ipv6/raw.c:920 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg+0x1a6/0x270 net/socket.c:745 sock_write_iter+0x2dd/0x400 net/socket.c:1160 do_iter_readv_writev+0x46c/0x640 vfs_writev+0x395/0xbb0 fs/read_write.c:971 do_writev+0x1b1/0x350 fs/read_write.c:1018 do_syscall_64+0xf9/0x240 entry_SYSCALL_64_after_hwframe+0x6f/0x77 RIP: 0033:0x7f63f4c7dda9 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:00007f63f59ec0c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000014 RAX: ffffffffffffffda RBX: 00007f63f4dabf80 RCX: 00007f63f4c7dda9 RDX: 0000000000000001 RSI: 00000000200000c0 RDI: 0000000000000003 RBP: 00007f63f4cca47a R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000000b R14: 00007f63f4dabf80 R15: 00007f63f4ecfa48