============================================ WARNING: possible recursive locking detected 6.1.138-syzkaller #0 Not tainted -------------------------------------------- syz.3.445/5857 is trying to acquire lock: ffff888018e89a18 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] ffff888018e89a18 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3925 [inline] ffff888018e89a18 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_queue_xmit+0x208f/0x3760 net/core/dev.c:4300 but task is already holding lock: ffff888027c9a258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: spin_trylock include/linux/spinlock.h:361 [inline] ffff888027c9a258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:195 [inline] ffff888027c9a258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3882 [inline] ffff888027c9a258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_queue_xmit+0x129a/0x3760 net/core/dev.c:4300 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 11 locks held by syz.3.445/5857: #0: ffff88805a2956a0 (&xs->mutex){+.+.}-{3:3}, at: xsk_setsockopt+0x5b2/0x790 net/xdp/xsk.c:1106 #1: ffff8880779c97d8 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_lock include/linux/mmap_lock.h:117 [inline] #1: ffff8880779c97d8 (&mm->mmap_lock){++++}-{3:3}, at: xdp_umem_pin_pages+0xc5/0x330 net/xdp/xdp_umem.c:104 #2: ffffc90000007bc0 ((&ndev->rs_timer)){+.-.}-{0:0}, at: call_timer_fn+0xc1/0x670 kernel/time/timer.c:1501 #3: ffffffff8c92a960 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #3: ffffffff8c92a960 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #3: ffffffff8c92a960 (rcu_read_lock){....}-{1:2}, at: ndisc_send_skb+0x1f2/0x1510 net/ipv6/ndisc.c:484 #4: ffffffff8c92a960 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #4: ffffffff8c92a960 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #4: ffffffff8c92a960 (rcu_read_lock){....}-{1:2}, at: ip6_finish_output2+0x593/0x1590 net/ipv6/ip6_output.c:123 #5: ffffffff8c92a9c0 (rcu_read_lock_bh){....}-{1:2}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #5: ffffffff8c92a9c0 (rcu_read_lock_bh){....}-{1:2}, at: rcu_read_lock_bh include/linux/rcupdate.h:843 [inline] #5: ffffffff8c92a9c0 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x26f/0x3760 net/core/dev.c:4257 #6: ffffffff8c92a960 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #6: ffffffff8c92a960 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #6: ffffffff8c92a960 (rcu_read_lock){....}-{1:2}, at: bond_start_xmit+0xfe/0x1b90 drivers/net/bonding/bond_main.c:5523 #7: ffffffff8c92a9c0 (rcu_read_lock_bh){....}-{1:2}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #7: ffffffff8c92a9c0 (rcu_read_lock_bh){....}-{1:2}, at: rcu_read_lock_bh include/linux/rcupdate.h:843 [inline] #7: ffffffff8c92a9c0 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x26f/0x3760 net/core/dev.c:4257 #8: ffff888027c9a258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: spin_trylock include/linux/spinlock.h:361 [inline] #8: ffff888027c9a258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:195 [inline] #8: ffff888027c9a258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3882 [inline] #8: ffff888027c9a258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_queue_xmit+0x129a/0x3760 net/core/dev.c:4300 #9: ffffffff8c92a960 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #9: ffffffff8c92a960 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #9: ffffffff8c92a960 (rcu_read_lock){....}-{1:2}, at: ip_finish_output2+0x3e8/0x11b0 net/ipv4/ip_output.c:221 #10: ffffffff8c92a9c0 (rcu_read_lock_bh){....}-{1:2}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #10: ffffffff8c92a9c0 (rcu_read_lock_bh){....}-{1:2}, at: rcu_read_lock_bh include/linux/rcupdate.h:843 [inline] #10: ffffffff8c92a9c0 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x26f/0x3760 net/core/dev.c:4257 stack backtrace: CPU: 0 PID: 5857 Comm: syz.3.445 Not tainted 6.1.138-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025 Call Trace: dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106 __lock_acquire+0x122f/0x7c50 kernel/locking/lockdep.c:-1 lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:351 [inline] __dev_xmit_skb net/core/dev.c:3925 [inline] __dev_queue_xmit+0x208f/0x3760 net/core/dev.c:4300 dev_queue_xmit include/linux/netdevice.h:3051 [inline] neigh_hh_output include/net/neighbour.h:528 [inline] neigh_output include/net/neighbour.h:542 [inline] ip_finish_output2+0xbe8/0x11b0 net/ipv4/ip_output.c:228 iptunnel_xmit+0x525/0x930 net/ipv4/ip_tunnel_core.c:82 ip_tunnel_xmit+0x1c39/0x2360 net/ipv4/ip_tunnel.c:858 __gre_xmit net/ipv4/ip_gre.c:474 [inline] gre_tap_xmit+0x50b/0x700 net/ipv4/ip_gre.c:751 __netdev_start_xmit include/linux/netdevice.h:4896 [inline] netdev_start_xmit include/linux/netdevice.h:4910 [inline] xmit_one net/core/dev.c:3658 [inline] dev_hard_start_xmit+0x262/0x870 net/core/dev.c:3674 sch_direct_xmit+0x24e/0x4a0 net/sched/sch_generic.c:342 __dev_xmit_skb net/core/dev.c:3895 [inline] __dev_queue_xmit+0x18cd/0x3760 net/core/dev.c:4300 dev_queue_xmit include/linux/netdevice.h:3051 [inline] bond_dev_queue_xmit+0x108/0x1e0 drivers/net/bonding/bond_main.c:307 __bond_start_xmit drivers/net/bonding/bond_main.c:5503 [inline] bond_start_xmit+0xced/0x1b90 drivers/net/bonding/bond_main.c:5525 __netdev_start_xmit include/linux/netdevice.h:4896 [inline] netdev_start_xmit include/linux/netdevice.h:4910 [inline] xmit_one net/core/dev.c:3658 [inline] dev_hard_start_xmit+0x262/0x870 net/core/dev.c:3674 __dev_queue_xmit+0x1bf1/0x3760 net/core/dev.c:4334 dev_queue_xmit include/linux/netdevice.h:3051 [inline] neigh_hh_output include/net/neighbour.h:528 [inline] neigh_output include/net/neighbour.h:542 [inline] ip6_finish_output2+0xd6b/0x1590 net/ipv6/ip6_output.c:138 __ip6_finish_output net/ipv6/ip6_output.c:205 [inline] ip6_finish_output+0x5d3/0xa60 net/ipv6/ip6_output.c:216 dst_output include/net/dst.h:453 [inline] NF_HOOK include/linux/netfilter.h:302 [inline] ndisc_send_skb+0xbfb/0x1510 net/ipv6/ndisc.c:513 addrconf_rs_timer+0x2b8/0x600 net/ipv6/addrconf.c:3982 call_timer_fn+0x1a0/0x670 kernel/time/timer.c:1504 expire_timers kernel/time/timer.c:1549 [inline] __run_timers+0x525/0x7c0 kernel/time/timer.c:1820 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1833 handle_softirqs+0x2a1/0x920 kernel/softirq.c:578 __do_softirq kernel/softirq.c:612 [inline] invoke_softirq kernel/softirq.c:452 [inline] __irq_exit_rcu+0x12f/0x220 kernel/softirq.c:661 irq_exit_rcu+0x5/0x20 kernel/softirq.c:673 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline] sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1118 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691 RIP: 0010:lock_acquire+0x80/0x490 kernel/locking/lockdep.c:5630 Code: 48 c7 44 24 68 12 fe 1a 8c 48 c7 44 24 70 a0 e5 62 81 4c 8d 6c 24 60 49 c1 ed 03 48 b8 f1 f1 f1 f1 00 f2 f2 f2 4b 89 44 3d 00 <66> 43 c7 44 3d 09 f3 f3 43 c6 44 3d 0b f3 0f 1f 44 00 00 65 44 8b RSP: 0018:ffffc9000344f580 EFLAGS: 00000a02 RAX: f2f2f200f1f1f1f1 RBX: 0000000000000000 RCX: 0000000000000002 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8c92a960 RBP: ffffc9000344f690 R08: 0000000000000000 R09: 0000000000000000 R10: fffffbfff1bfd046 R11: 1ffffffff1bfd045 R12: ffff88802ef60000 R13: 1ffff92000689ebc R14: ffff8880779c9680 R15: dffffc0000000000 rcu_lock_acquire include/linux/rcupdate.h:350 [inline] rcu_read_lock include/linux/rcupdate.h:791 [inline] get_mem_cgroup_from_mm+0x50/0x290 mm/memcontrol.c:1036 __mem_cgroup_charge+0x11/0x80 mm/memcontrol.c:6945 mem_cgroup_charge include/linux/memcontrol.h:672 [inline] do_anonymous_page mm/memory.c:4195 [inline] handle_pte_fault mm/memory.c:5029 [inline] __handle_mm_fault mm/memory.c:5173 [inline] handle_mm_fault+0x22dc/0x3e70 mm/memory.c:5294 faultin_page mm/gup.c:1026 [inline] __get_user_pages+0x3ff/0xeb0 mm/gup.c:1250 __get_user_pages_locked mm/gup.c:1454 [inline] __gup_longterm_locked+0x24b/0x1740 mm/gup.c:2143 xdp_umem_pin_pages+0x119/0x330 net/xdp/xdp_umem.c:105 xdp_umem_reg net/xdp/xdp_umem.c:218 [inline] xdp_umem_create+0x5bb/0x7e0 net/xdp/xdp_umem.c:251 xsk_setsockopt+0x635/0x790 net/xdp/xsk.c:1112 __sys_setsockopt+0x3d6/0x660 net/socket.c:2288 __do_sys_setsockopt net/socket.c:2299 [inline] __se_sys_setsockopt net/socket.c:2296 [inline] __x64_sys_setsockopt+0xb1/0xc0 net/socket.c:2296 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7effda18e969 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007effdafab038 EFLAGS: 00000246 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 00007effda3b5fa0 RCX: 00007effda18e969 RDX: 0000000000000004 RSI: 000000000000011b RDI: 0000000000000005 RBP: 00007effda210ab1 R08: 000000000000001c R09: 0000000000000000 R10: 00002000000000c0 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007effda3b5fa0 R15: 00007ffef3735f58 ---------------- Code disassembly (best guess): 0: 48 c7 44 24 68 12 fe movq $0xffffffff8c1afe12,0x68(%rsp) 7: 1a 8c 9: 48 c7 44 24 70 a0 e5 movq $0xffffffff8162e5a0,0x70(%rsp) 10: 62 81 12: 4c 8d 6c 24 60 lea 0x60(%rsp),%r13 17: 49 c1 ed 03 shr $0x3,%r13 1b: 48 b8 f1 f1 f1 f1 00 movabs $0xf2f2f200f1f1f1f1,%rax 22: f2 f2 f2 25: 4b 89 44 3d 00 mov %rax,0x0(%r13,%r15,1) * 2a: 66 43 c7 44 3d 09 f3 movw $0xf3f3,0x9(%r13,%r15,1) <-- trapping instruction 31: f3 32: 43 c6 44 3d 0b f3 movb $0xf3,0xb(%r13,%r15,1) 38: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) 3d: 65 gs 3e: 44 rex.R 3f: 8b .byte 0x8b