============================================ WARNING: possible recursive locking detected 6.1.41-syzkaller #0 Not tainted -------------------------------------------- segctord/26746 is trying to acquire lock: ffff88808c425338 (&br->multicast_lock){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:350 [inline] ffff88808c425338 (&br->multicast_lock){+.-.}-{2:2}, at: br_ip6_multicast_query net/bridge/br_multicast.c:3345 [inline] ffff88808c425338 (&br->multicast_lock){+.-.}-{2:2}, at: br_multicast_ipv6_rcv net/bridge/br_multicast.c:3741 [inline] ffff88808c425338 (&br->multicast_lock){+.-.}-{2:2}, at: br_multicast_rcv+0x1072/0x7590 net/bridge/br_multicast.c:3796 but task is already holding lock: ffff888084eb9338 (&br->multicast_lock){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:350 [inline] ffff888084eb9338 (&br->multicast_lock){+.-.}-{2:2}, at: br_multicast_port_query_expired+0x64/0x3b0 net/bridge/br_multicast.c:1746 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 6 locks held by segctord/26746: #0: ffffffff8ce058a0 (console_lock){+.+.}-{0:0}, at: vprintk_emit+0xb8/0x1f0 kernel/printk/printk.c:2267 #1: ffffc90000007bc0 ((&pmctx->ip6_own_query.timer)){+.-.}-{0:0}, at: lockdep_copy_map include/linux/lockdep.h:41 [inline] #1: ffffc90000007bc0 ((&pmctx->ip6_own_query.timer)){+.-.}-{0:0}, at: call_timer_fn+0xbd/0x6b0 kernel/time/timer.c:1464 #2: ffff888084eb9338 (&br->multicast_lock){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:350 [inline] #2: ffff888084eb9338 (&br->multicast_lock){+.-.}-{2:2}, at: br_multicast_port_query_expired+0x64/0x3b0 net/bridge/br_multicast.c:1746 #3: ffffffff8cf29740 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x9/0x30 include/linux/rcupdate.h:306 #4: ffffffff8cf29740 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x9/0x30 include/linux/rcupdate.h:306 #5: ffffffff8cf296e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:305 stack backtrace: CPU: 0 PID: 26746 Comm: segctord Not tainted 6.1.41-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2023 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:2991 [inline] check_deadlock kernel/locking/lockdep.c:3034 [inline] validate_chain+0x4726/0x58e0 kernel/locking/lockdep.c:3819 __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5056 lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5669 __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:350 [inline] br_ip6_multicast_query net/bridge/br_multicast.c:3345 [inline] br_multicast_ipv6_rcv net/bridge/br_multicast.c:3741 [inline] br_multicast_rcv+0x1072/0x7590 net/bridge/br_multicast.c:3796 br_dev_xmit+0xad5/0x1840 net/bridge/br_device.c:89 __netdev_start_xmit include/linux/netdevice.h:4853 [inline] netdev_start_xmit include/linux/netdevice.h:4867 [inline] xmit_one net/core/dev.c:3595 [inline] dev_hard_start_xmit+0x261/0x8c0 net/core/dev.c:3611 __dev_queue_xmit+0x1b97/0x3c90 net/core/dev.c:4261 dev_queue_xmit include/linux/netdevice.h:3021 [inline] vlan_dev_hard_start_xmit+0x3da/0x6b0 net/8021q/vlan_dev.c:124 __netdev_start_xmit include/linux/netdevice.h:4853 [inline] netdev_start_xmit include/linux/netdevice.h:4867 [inline] xmit_one net/core/dev.c:3595 [inline] dev_hard_start_xmit+0x261/0x8c0 net/core/dev.c:3611 __dev_queue_xmit+0x1b97/0x3c90 net/core/dev.c:4261 dev_queue_xmit include/linux/netdevice.h:3021 [inline] br_dev_queue_push_xmit+0x6e6/0x8a0 net/bridge/br_forward.c:53 NF_HOOK include/linux/netfilter.h:302 [inline] __br_multicast_send_query+0x2e36/0x46a0 net/bridge/br_multicast.c:1650 br_multicast_send_query+0x502/0x6d0 net/bridge/br_multicast.c:1729 br_multicast_port_query_expired+0x2d4/0x3b0 net/bridge/br_multicast.c:1754 call_timer_fn+0x19e/0x6b0 kernel/time/timer.c:1474 expire_timers kernel/time/timer.c:1519 [inline] __run_timers+0x67c/0x890 kernel/time/timer.c:1790 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1803 __do_softirq+0x2e9/0xa4c kernel/softirq.c:571 invoke_softirq kernel/softirq.c:445 [inline] __irq_exit_rcu+0x155/0x240 kernel/softirq.c:650 irq_exit_rcu+0x5/0x20 kernel/softirq.c:662 sysvec_apic_timer_interrupt+0x91/0xb0 arch/x86/kernel/apic/apic.c:1106 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:649 RIP: 0010:console_emit_next_record+0xb70/0xda0 kernel/printk/printk.c:2740 Code: 00 48 8b 5c 24 68 44 0f b6 74 24 1f 4d 85 e4 75 07 e8 c4 0b 1c 00 eb 06 e8 bd 0b 1c 00 fb 48 c7 84 24 a0 00 00 00 0e 36 e0 45 <41> c7 44 1d 00 00 00 00 00 49 c7 44 1d 0a 00 00 00 00 49 c7 44 1d RSP: 0018:ffffc900155ef6c0 EFLAGS: 00000293 RAX: ffffffff816dcf33 RBX: 1ffff92002abdeec RCX: ffff8880752c5940 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc900155ef970 R08: ffffffff816dcf09 R09: fffffbfff2052c45 R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000200 R13: dffffc0000000000 R14: 0000000000000001 R15: ffffc900155ef9e0 console_unlock+0x278/0x6e0 kernel/printk/printk.c:2860 vprintk_emit+0xd1/0x1f0 kernel/printk/printk.c:2268 _printk+0xd1/0x111 kernel/printk/printk.c:2289 __nilfs_msg+0x2a9/0x330 fs/nilfs2/super.c:78 nilfs_segctor_thread+0x27a/0x1130 fs/nilfs2/segment.c:2580 kthread+0x26e/0x300 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306 ---------------- Code disassembly (best guess): 0: 00 48 8b add %cl,-0x75(%rax) 3: 5c pop %rsp 4: 24 68 and $0x68,%al 6: 44 0f b6 74 24 1f movzbl 0x1f(%rsp),%r14d c: 4d 85 e4 test %r12,%r12 f: 75 07 jne 0x18 11: e8 c4 0b 1c 00 call 0x1c0bda 16: eb 06 jmp 0x1e 18: e8 bd 0b 1c 00 call 0x1c0bda 1d: fb sti 1e: 48 c7 84 24 a0 00 00 movq $0x45e0360e,0xa0(%rsp) 25: 00 0e 36 e0 45 * 2a: 41 c7 44 1d 00 00 00 movl $0x0,0x0(%r13,%rbx,1) <-- trapping instruction 31: 00 00 33: 49 c7 44 1d 0a 00 00 movq $0x0,0xa(%r13,%rbx,1) 3a: 00 00 3c: 49 rex.WB 3d: c7 .byte 0xc7 3e: 44 rex.R 3f: 1d .byte 0x1d