============================================ WARNING: possible recursive locking detected 6.9.0-rc5-syzkaller-01160-g2bd87951de65 #0 Not tainted -------------------------------------------- syz-executor.1/14884 is trying to acquire lock: ffff88804edc53e0 (&br->multicast_lock){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] ffff88804edc53e0 (&br->multicast_lock){+.-.}-{2:2}, at: br_ip6_multicast_query net/bridge/br_multicast.c:3523 [inline] ffff88804edc53e0 (&br->multicast_lock){+.-.}-{2:2}, at: br_multicast_ipv6_rcv net/bridge/br_multicast.c:3919 [inline] ffff88804edc53e0 (&br->multicast_lock){+.-.}-{2:2}, at: br_multicast_rcv+0x30e2/0x8180 net/bridge/br_multicast.c:3974 but task is already holding lock: ffff8880673353e0 (&br->multicast_lock){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] ffff8880673353e0 (&br->multicast_lock){+.-.}-{2:2}, at: br_multicast_port_query_expired+0x64/0x3b0 net/bridge/br_multicast.c:1905 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&br->multicast_lock); lock(&br->multicast_lock); *** DEADLOCK *** May be due to missing lock nesting notation 7 locks held by syz-executor.1/14884: #0: ffffffff8f5a7dc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline] #0: ffffffff8f5a7dc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x842/0x10d0 net/core/rtnetlink.c:6591 #1: ffffffff8e334d20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline] #1: ffffffff8e334d20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:781 [inline] #1: ffffffff8e334d20 (rcu_read_lock){....}-{1:2}, at: br_multicast_dump_querier_state+0x2cc/0xd30 net/bridge/br_multicast.c:3140 #2: ffffc90000007c00 ((&pmctx->ip6_own_query.timer)){+.-.}-{0:0}, at: call_timer_fn+0xc0/0x650 kernel/time/timer.c:1790 #3: ffff8880673353e0 (&br->multicast_lock){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] #3: ffff8880673353e0 (&br->multicast_lock){+.-.}-{2:2}, at: br_multicast_port_query_expired+0x64/0x3b0 net/bridge/br_multicast.c:1905 #4: ffffffff8e334d80 (rcu_read_lock_bh){....}-{1:2}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #4: ffffffff8e334d80 (rcu_read_lock_bh){....}-{1:2}, at: rcu_read_lock_bh include/linux/rcupdate.h:833 [inline] #4: ffffffff8e334d80 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x2c7/0x3ca0 net/core/dev.c:4304 #5: ffffffff8e334d80 (rcu_read_lock_bh){....}-{1:2}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #5: ffffffff8e334d80 (rcu_read_lock_bh){....}-{1:2}, at: rcu_read_lock_bh include/linux/rcupdate.h:833 [inline] #5: ffffffff8e334d80 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x2c7/0x3ca0 net/core/dev.c:4304 #6: ffffffff8e334d20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline] #6: ffffffff8e334d20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:781 [inline] #6: ffffffff8e334d20 (rcu_read_lock){....}-{1:2}, at: br_dev_xmit+0x1b9/0x1a10 net/bridge/br_device.c:44 stack backtrace: CPU: 0 PID: 14884 Comm: syz-executor.1 Not tainted 6.9.0-rc5-syzkaller-01160-g2bd87951de65 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114 check_deadlock kernel/locking/lockdep.c:3062 [inline] validate_chain+0x15c1/0x58e0 kernel/locking/lockdep.c:3856 __lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137 lock_acquire+0x1ed/0x550 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] br_ip6_multicast_query net/bridge/br_multicast.c:3523 [inline] br_multicast_ipv6_rcv net/bridge/br_multicast.c:3919 [inline] br_multicast_rcv+0x30e2/0x8180 net/bridge/br_multicast.c:3974 br_dev_xmit+0xb17/0x1a10 net/bridge/br_device.c:90 __netdev_start_xmit include/linux/netdevice.h:4880 [inline] netdev_start_xmit include/linux/netdevice.h:4894 [inline] xmit_one net/core/dev.c:3564 [inline] dev_hard_start_xmit+0x27a/0x7e0 net/core/dev.c:3580 __dev_queue_xmit+0x1ad1/0x3ca0 net/core/dev.c:4379 dev_queue_xmit include/linux/netdevice.h:3094 [inline] vlan_dev_hard_start_xmit+0x36c/0x5f0 net/8021q/vlan_dev.c:125 __netdev_start_xmit include/linux/netdevice.h:4880 [inline] netdev_start_xmit include/linux/netdevice.h:4894 [inline] xmit_one net/core/dev.c:3564 [inline] dev_hard_start_xmit+0x27a/0x7e0 net/core/dev.c:3580 __dev_queue_xmit+0x1ad1/0x3ca0 net/core/dev.c:4379 dev_queue_xmit include/linux/netdevice.h:3094 [inline] br_dev_queue_push_xmit+0x701/0x8d0 net/bridge/br_forward.c:53 NF_HOOK include/linux/netfilter.h:314 [inline] __br_multicast_send_query+0x2ecb/0x4750 net/bridge/br_multicast.c:1809 br_multicast_send_query+0x4ee/0x6b0 net/bridge/br_multicast.c:1888 br_multicast_port_query_expired+0x2d4/0x3b0 net/bridge/br_multicast.c:1913 call_timer_fn+0x18e/0x650 kernel/time/timer.c:1793 expire_timers kernel/time/timer.c:1844 [inline] __run_timers kernel/time/timer.c:2418 [inline] __run_timer_base+0x66a/0x8e0 kernel/time/timer.c:2429 run_timer_base kernel/time/timer.c:2438 [inline] run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2448 __do_softirq+0x2c6/0x980 kernel/softirq.c:554 invoke_softirq kernel/softirq.c:428 [inline] __irq_exit_rcu+0xf2/0x1c0 kernel/softirq.c:633 irq_exit_rcu+0x9/0x30 kernel/softirq.c:645 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1043 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:__seqprop_spinlock_sequence include/linux/seqlock.h:227 [inline] RIP: 0010:br_multicast_read_querier+0x262/0x410 net/bridge/br_multicast.c:1832 Code: 85 e4 75 16 e8 7f dd 47 f7 eb 15 e8 78 dd 47 f7 e8 33 ca 32 01 4d 85 e4 74 ea e8 69 dd 47 f7 fb 49 bc 00 00 00 00 00 fc ff df <43> 0f b6 04 27 84 c0 0f 85 cc 00 00 00 41 8b 5d 00 89 de 83 e6 01 RSP: 0018:ffffc9000b9fe000 EFLAGS: 00000293 RAX: ffffffff8a4e23d7 RBX: 0000000000000000 RCX: ffff88801e220000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc9000b9fe0f0 R08: ffffffff8a4e23a8 R09: 1ffffffff25e76a1 R10: dffffc0000000000 R11: fffffbfff25e76a2 R12: dffffc0000000000 R13: ffff888067335380 R14: ffff88806733537c R15: 1ffff1100ce66a70 br_multicast_dump_querier_state+0x697/0xd30 net/bridge/br_multicast.c:3168 br_fill_info+0x1725/0x2020 net/bridge/br_netlink.c:1718 rtnl_link_info_fill net/core/rtnetlink.c:699 [inline] rtnl_link_fill+0x257/0x790 net/core/rtnetlink.c:720 rtnl_fill_ifinfo+0x1bab/0x2260 net/core/rtnetlink.c:1908 rtmsg_ifinfo_build_skb+0x1ab/0x290 net/core/rtnetlink.c:4057 rtmsg_ifinfo_event net/core/rtnetlink.c:4091 [inline] rtmsg_ifinfo+0x91/0x1b0 net/core/rtnetlink.c:4100 netdev_state_change+0x139/0x1a0 net/core/dev.c:1362 do_setlink+0x3e3/0x41f0 net/core/rtnetlink.c:3124 __rtnl_newlink net/core/rtnetlink.c:3680 [inline] rtnl_newlink+0x180b/0x20a0 net/core/rtnetlink.c:3727 rtnetlink_rcv_msg+0x89b/0x10d0 net/core/rtnetlink.c:6594 netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2564 netlink_unicast_kernel net/netlink/af_netlink.c:1335 [inline] netlink_unicast+0x7ea/0x980 net/netlink/af_netlink.c:1361 netlink_sendmsg+0x8e1/0xcb0 net/netlink/af_netlink.c:1905 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg+0x221/0x270 net/socket.c:745 ____sys_sendmsg+0x525/0x7d0 net/socket.c:2584 ___sys_sendmsg net/socket.c:2638 [inline] __sys_sendmsg+0x2b0/0x3a0 net/socket.c:2667 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f7747a7dea9 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:00007f77488980c8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f7747babf80 RCX: 00007f7747a7dea9 RDX: 0000000000000000 RSI: 0000000020000280 RDI: 0000000000000004 RBP: 00007f7747aca4a4 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000000b R14: 00007f7747babf80 R15: 00007ffebb4c77a8 ---------------- Code disassembly (best guess): 0: 85 e4 test %esp,%esp 2: 75 16 jne 0x1a 4: e8 7f dd 47 f7 call 0xf747dd88 9: eb 15 jmp 0x20 b: e8 78 dd 47 f7 call 0xf747dd88 10: e8 33 ca 32 01 call 0x132ca48 15: 4d 85 e4 test %r12,%r12 18: 74 ea je 0x4 1a: e8 69 dd 47 f7 call 0xf747dd88 1f: fb sti 20: 49 bc 00 00 00 00 00 movabs $0xdffffc0000000000,%r12 27: fc ff df * 2a: 43 0f b6 04 27 movzbl (%r15,%r12,1),%eax <-- trapping instruction 2f: 84 c0 test %al,%al 31: 0f 85 cc 00 00 00 jne 0x103 37: 41 8b 5d 00 mov 0x0(%r13),%ebx 3b: 89 de mov %ebx,%esi 3d: 83 e6 01 and $0x1,%esi