================================ WARNING: inconsistent lock state 6.0.0-syzkaller-02734-g0326074ff465 #0 Not tainted -------------------------------- inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage. syz-executor.3/17809 [HC0[0]:SC1[1]:HE1:SE0] takes: ffffffff8c0c3aa0 (fs_reclaim){+.?.}-{0:0}, at: might_alloc include/linux/sched/mm.h:271 [inline] ffffffff8c0c3aa0 (fs_reclaim){+.?.}-{0:0}, at: slab_pre_alloc_hook mm/slab.h:700 [inline] ffffffff8c0c3aa0 (fs_reclaim){+.?.}-{0:0}, at: slab_alloc_node mm/slub.c:3162 [inline] ffffffff8c0c3aa0 (fs_reclaim){+.?.}-{0:0}, at: slab_alloc mm/slub.c:3256 [inline] ffffffff8c0c3aa0 (fs_reclaim){+.?.}-{0:0}, at: kmem_cache_alloc_trace+0x40/0x3e0 mm/slub.c:3287 {SOFTIRQ-ON-W} state was registered at: lock_acquire kernel/locking/lockdep.c:5666 [inline] lock_acquire+0x1ab/0x570 kernel/locking/lockdep.c:5631 __fs_reclaim_acquire mm/page_alloc.c:4674 [inline] fs_reclaim_acquire+0x115/0x160 mm/page_alloc.c:4688 might_alloc include/linux/sched/mm.h:271 [inline] slab_pre_alloc_hook mm/slab.h:700 [inline] slab_alloc_node mm/slub.c:3162 [inline] slab_alloc mm/slub.c:3256 [inline] kmem_cache_alloc_trace+0x40/0x3e0 mm/slub.c:3287 kmalloc include/linux/slab.h:600 [inline] kzalloc include/linux/slab.h:733 [inline] alloc_workqueue_attrs+0x39/0xc0 kernel/workqueue.c:3394 wq_numa_init kernel/workqueue.c:5964 [inline] workqueue_init+0x12f/0x8ae kernel/workqueue.c:6091 kernel_init_freeable+0x3fb/0x73a init/main.c:1607 kernel_init+0x1a/0x1d0 init/main.c:1512 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306 irq event stamp: 946 hardirqs last enabled at (946): [] __local_bh_enable_ip+0xa0/0x120 kernel/softirq.c:401 hardirqs last disabled at (945): [] __local_bh_enable_ip+0xc3/0x120 kernel/softirq.c:378 softirqs last enabled at (866): [] tcp_sendmsg+0x36/0x40 net/ipv4/tcp.c:1483 softirqs last disabled at (873): [] invoke_softirq kernel/softirq.c:445 [inline] softirqs last disabled at (873): [] __irq_exit_rcu+0x123/0x180 kernel/softirq.c:650 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(fs_reclaim); lock(fs_reclaim); *** DEADLOCK *** 5 locks held by syz-executor.3/17809: #0: ffffc90000a3e220 (&futex_queues[i].lock){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:349 [inline] #0: ffffc90000a3e220 (&futex_queues[i].lock){+.+.}-{2:2}, at: futex_wake+0x1b5/0x490 kernel/futex/waitwake.c:164 #1: ffffffff8bf86740 (rcu_read_lock){....}-{1:2}, at: __skb_unlink include/linux/skbuff.h:2322 [inline] #1: ffffffff8bf86740 (rcu_read_lock){....}-{1:2}, at: __skb_dequeue include/linux/skbuff.h:2337 [inline] #1: ffffffff8bf86740 (rcu_read_lock){....}-{1:2}, at: process_backlog+0x34b/0x7c0 net/core/dev.c:5925 #2: ffffffff8bf86740 (rcu_read_lock){....}-{1:2}, at: __skb_pull include/linux/skbuff.h:2607 [inline] #2: ffffffff8bf86740 (rcu_read_lock){....}-{1:2}, at: ip_local_deliver_finish+0x206/0x4c0 net/ipv4/ip_input.c:230 #3: ffff88807e9a30b0 (slock-AF_INET/1){+.-.}-{2:2}, at: tcp_v4_rcv+0x3019/0x38c0 net/ipv4/tcp_ipv4.c:2096 #4: ffffffff8bf86740 (rcu_read_lock){....}-{1:2}, at: __refcount_add include/linux/refcount.h:200 [inline] #4: ffffffff8bf86740 (rcu_read_lock){....}-{1:2}, at: __refcount_inc include/linux/refcount.h:250 [inline] #4: ffffffff8bf86740 (rcu_read_lock){....}-{1:2}, at: refcount_inc include/linux/refcount.h:267 [inline] #4: ffffffff8bf86740 (rcu_read_lock){....}-{1:2}, at: skb_get include/linux/skbuff.h:1847 [inline] #4: ffffffff8bf86740 (rcu_read_lock){....}-{1:2}, at: sk_psock_verdict_recv+0xa3/0x750 net/core/skmsg.c:1183 stack backtrace: CPU: 1 PID: 17809 Comm: syz-executor.3 Not tainted 6.0.0-syzkaller-02734-g0326074ff465 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/22/2022 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_usage_bug kernel/locking/lockdep.c:3961 [inline] valid_state kernel/locking/lockdep.c:3973 [inline] mark_lock_irq kernel/locking/lockdep.c:4176 [inline] mark_lock.part.0.cold+0x18/0xd8 kernel/locking/lockdep.c:4632 mark_lock kernel/locking/lockdep.c:4596 [inline] mark_usage kernel/locking/lockdep.c:4527 [inline] __lock_acquire+0x11d9/0x56d0 kernel/locking/lockdep.c:5007 lock_acquire kernel/locking/lockdep.c:5666 [inline] lock_acquire+0x1ab/0x570 kernel/locking/lockdep.c:5631 __fs_reclaim_acquire mm/page_alloc.c:4674 [inline] fs_reclaim_acquire+0x115/0x160 mm/page_alloc.c:4688 might_alloc include/linux/sched/mm.h:271 [inline] slab_pre_alloc_hook mm/slab.h:700 [inline] slab_alloc_node mm/slub.c:3162 [inline] slab_alloc mm/slub.c:3256 [inline] kmem_cache_alloc_trace+0x40/0x3e0 mm/slub.c:3287 kmalloc include/linux/slab.h:600 [inline] kzalloc include/linux/slab.h:733 [inline] alloc_sk_msg+0x38/0xa0 net/core/skmsg.c:507 sk_psock_skb_ingress_self+0x25/0x320 net/core/skmsg.c:600 sk_psock_verdict_apply+0x429/0x540 net/core/skmsg.c:1014 sk_psock_verdict_recv+0x3a3/0x750 net/core/skmsg.c:1201 tcp_read_skb+0x173/0x670 net/ipv4/tcp.c:1770 sk_psock_verdict_data_ready+0x9d/0xc0 net/core/skmsg.c:1215 tcp_data_ready+0x106/0x520 net/ipv4/tcp_input.c:5004 tcp_rcv_established+0x1a9f/0x20e0 net/ipv4/tcp_input.c:5971 tcp_v4_do_rcv+0x66c/0x9b0 net/ipv4/tcp_ipv4.c:1681 tcp_v4_rcv+0x329d/0x38c0 net/ipv4/tcp_ipv4.c:2100 ip_protocol_deliver_rcu+0x9b/0x7c0 net/ipv4/ip_input.c:205 ip_local_deliver_finish+0x2e8/0x4c0 net/ipv4/ip_input.c:233 NF_HOOK include/linux/netfilter.h:302 [inline] NF_HOOK include/linux/netfilter.h:296 [inline] ip_local_deliver+0x1aa/0x200 net/ipv4/ip_input.c:254 dst_input include/net/dst.h:455 [inline] ip_rcv_finish+0x1cb/0x2f0 net/ipv4/ip_input.c:444 NF_HOOK include/linux/netfilter.h:302 [inline] NF_HOOK include/linux/netfilter.h:296 [inline] ip_rcv+0xaa/0xd0 net/ipv4/ip_input.c:564 __netif_receive_skb_one_core+0x114/0x180 net/core/dev.c:5485 __netif_receive_skb+0x1f/0x1c0 net/core/dev.c:5599 process_backlog+0x3a0/0x7c0 net/core/dev.c:5927 __napi_poll+0xb3/0x6d0 net/core/dev.c:6494 napi_poll net/core/dev.c:6561 [inline] net_rx_action+0x9c1/0xd90 net/core/dev.c:6672 __do_softirq+0x1d0/0x9c8 kernel/softirq.c:571 invoke_softirq kernel/softirq.c:445 [inline] __irq_exit_rcu+0x123/0x180 kernel/softirq.c:650 irq_exit_rcu+0x5/0x20 kernel/softirq.c:662 sysvec_apic_timer_interrupt+0x93/0xc0 arch/x86/kernel/apic/apic.c:1107 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:649 RIP: 0010:lock_acquire+0x1ef/0x570 kernel/locking/lockdep.c:5634 Code: f6 a3 7e 83 f8 01 0f 85 e8 02 00 00 9c 58 f6 c4 02 0f 85 fb 02 00 00 48 83 7c 24 08 00 74 01 fb 48 b8 00 00 00 00 00 fc ff df <48> 01 c3 48 c7 03 00 00 00 00 48 c7 43 08 00 00 00 00 48 8b 84 24 RSP: 0018:ffffc90014ed7ba8 EFLAGS: 00000206 RAX: dffffc0000000000 RBX: 1ffff920029daf77 RCX: ffffffff815e2cde RDX: 1ffff1100f4bf14e RSI: 0000000000000001 RDI: 0000000000000000 RBP: 0000000000000001 R08: 0000000000000000 R09: ffffffff90903a0f R10: fffffbfff2120741 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: ffffc90000a3e220 R15: 0000000000000000 __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:349 [inline] futex_wake+0x1b5/0x490 kernel/futex/waitwake.c:164 do_futex+0x266/0x300 kernel/futex/syscalls.c:111 __do_sys_futex kernel/futex/syscalls.c:183 [inline] __se_sys_futex kernel/futex/syscalls.c:164 [inline] __x64_sys_futex+0x1b0/0x4a0 kernel/futex/syscalls.c:164 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f845668b5a9 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 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f8457823218 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: ffffffffffffffda RBX: 00007f84567ac058 RCX: 00007f845668b5a9 RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007f84567ac05c RBP: 00007f84567ac050 R08: 00007ffd35db1080 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000246 R12: 00007f84567ac05c R13: 00007ffd35d7eb5f R14: 00007f8457823300 R15: 0000000000022000 BUG: sleeping function called from invalid context at include/linux/sched/mm.h:274 in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 17809, name: syz-executor.3 preempt_count: 102, expected: 0 RCU nest depth: 3, expected: 0 INFO: lockdep is turned off. Preemption disabled at: [<0000000000000000>] 0x0 CPU: 1 PID: 17809 Comm: syz-executor.3 Not tainted 6.0.0-syzkaller-02734-g0326074ff465 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/22/2022 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 __might_resched.cold+0x222/0x26b kernel/sched/core.c:9893 might_alloc include/linux/sched/mm.h:274 [inline] slab_pre_alloc_hook mm/slab.h:700 [inline] slab_alloc_node mm/slub.c:3162 [inline] slab_alloc mm/slub.c:3256 [inline] kmem_cache_alloc_trace+0x2f9/0x3e0 mm/slub.c:3287 kmalloc include/linux/slab.h:600 [inline] kzalloc include/linux/slab.h:733 [inline] alloc_sk_msg+0x38/0xa0 net/core/skmsg.c:507 sk_psock_skb_ingress_self+0x25/0x320 net/core/skmsg.c:600 sk_psock_verdict_apply+0x429/0x540 net/core/skmsg.c:1014 sk_psock_verdict_recv+0x3a3/0x750 net/core/skmsg.c:1201 tcp_read_skb+0x173/0x670 net/ipv4/tcp.c:1770 sk_psock_verdict_data_ready+0x9d/0xc0 net/core/skmsg.c:1215 tcp_data_ready+0x106/0x520 net/ipv4/tcp_input.c:5004 tcp_rcv_established+0x1a9f/0x20e0 net/ipv4/tcp_input.c:5971 tcp_v4_do_rcv+0x66c/0x9b0 net/ipv4/tcp_ipv4.c:1681 tcp_v4_rcv+0x329d/0x38c0 net/ipv4/tcp_ipv4.c:2100 ip_protocol_deliver_rcu+0x9b/0x7c0 net/ipv4/ip_input.c:205 ip_local_deliver_finish+0x2e8/0x4c0 net/ipv4/ip_input.c:233 NF_HOOK include/linux/netfilter.h:302 [inline] NF_HOOK include/linux/netfilter.h:296 [inline] ip_local_deliver+0x1aa/0x200 net/ipv4/ip_input.c:254 dst_input include/net/dst.h:455 [inline] ip_rcv_finish+0x1cb/0x2f0 net/ipv4/ip_input.c:444 NF_HOOK include/linux/netfilter.h:302 [inline] NF_HOOK include/linux/netfilter.h:296 [inline] ip_rcv+0xaa/0xd0 net/ipv4/ip_input.c:564 __netif_receive_skb_one_core+0x114/0x180 net/core/dev.c:5485 __netif_receive_skb+0x1f/0x1c0 net/core/dev.c:5599 process_backlog+0x3a0/0x7c0 net/core/dev.c:5927 __napi_poll+0xb3/0x6d0 net/core/dev.c:6494 napi_poll net/core/dev.c:6561 [inline] net_rx_action+0x9c1/0xd90 net/core/dev.c:6672 __do_softirq+0x1d0/0x9c8 kernel/softirq.c:571 invoke_softirq kernel/softirq.c:445 [inline] __irq_exit_rcu+0x123/0x180 kernel/softirq.c:650 irq_exit_rcu+0x5/0x20 kernel/softirq.c:662 sysvec_apic_timer_interrupt+0x93/0xc0 arch/x86/kernel/apic/apic.c:1107 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:649 RIP: 0010:lock_acquire+0x1ef/0x570 kernel/locking/lockdep.c:5634 Code: f6 a3 7e 83 f8 01 0f 85 e8 02 00 00 9c 58 f6 c4 02 0f 85 fb 02 00 00 48 83 7c 24 08 00 74 01 fb 48 b8 00 00 00 00 00 fc ff df <48> 01 c3 48 c7 03 00 00 00 00 48 c7 43 08 00 00 00 00 48 8b 84 24 RSP: 0018:ffffc90014ed7ba8 EFLAGS: 00000206 RAX: dffffc0000000000 RBX: 1ffff920029daf77 RCX: ffffffff815e2cde RDX: 1ffff1100f4bf14e RSI: 0000000000000001 RDI: 0000000000000000 RBP: 0000000000000001 R08: 0000000000000000 R09: ffffffff90903a0f R10: fffffbfff2120741 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: ffffc90000a3e220 R15: 0000000000000000 __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:349 [inline] futex_wake+0x1b5/0x490 kernel/futex/waitwake.c:164 do_futex+0x266/0x300 kernel/futex/syscalls.c:111 __do_sys_futex kernel/futex/syscalls.c:183 [inline] __se_sys_futex kernel/futex/syscalls.c:164 [inline] __x64_sys_futex+0x1b0/0x4a0 kernel/futex/syscalls.c:164 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f845668b5a9 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 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f8457823218 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: ffffffffffffffda RBX: 00007f84567ac058 RCX: 00007f845668b5a9 RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007f84567ac05c RBP: 00007f84567ac050 R08: 00007ffd35db1080 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000246 R12: 00007f84567ac05c R13: 00007ffd35d7eb5f R14: 00007f8457823300 R15: 0000000000022000 BUG: sleeping function called from invalid context at include/linux/sched/mm.h:274 in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 17868, name: syz-executor.3 preempt_count: 101, expected: 0 RCU nest depth: 3, expected: 0 INFO: lockdep is turned off. Preemption disabled at: [] softirq_handle_begin kernel/softirq.c:409 [inline] [] __do_softirq+0xe1/0x9c8 kernel/softirq.c:547 CPU: 1 PID: 17868 Comm: syz-executor.3 Tainted: G W 6.0.0-syzkaller-02734-g0326074ff465 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/22/2022 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 __might_resched.cold+0x222/0x26b kernel/sched/core.c:9893 might_alloc include/linux/sched/mm.h:274 [inline] slab_pre_alloc_hook mm/slab.h:700 [inline] slab_alloc_node mm/slub.c:3162 [inline] slab_alloc mm/slub.c:3256 [inline] kmem_cache_alloc_trace+0x2f9/0x3e0 mm/slub.c:3287 kmalloc include/linux/slab.h:600 [inline] kzalloc include/linux/slab.h:733 [inline] alloc_sk_msg+0x38/0xa0 net/core/skmsg.c:507 sk_psock_skb_ingress_self+0x25/0x320 net/core/skmsg.c:600 sk_psock_verdict_apply+0x429/0x540 net/core/skmsg.c:1014 sk_psock_verdict_recv+0x3a3/0x750 net/core/skmsg.c:1201 tcp_read_skb+0x173/0x670 net/ipv4/tcp.c:1770 sk_psock_verdict_data_ready+0x9d/0xc0 net/core/skmsg.c:1215 tcp_data_ready+0x106/0x520 net/ipv4/tcp_input.c:5004 tcp_rcv_established+0x1a9f/0x20e0 net/ipv4/tcp_input.c:5971 tcp_v4_do_rcv+0x66c/0x9b0 net/ipv4/tcp_ipv4.c:1681 tcp_v4_rcv+0x329d/0x38c0 net/ipv4/tcp_ipv4.c:2100 ip_protocol_deliver_rcu+0x9b/0x7c0 net/ipv4/ip_input.c:205 ip_local_deliver_finish+0x2e8/0x4c0 net/ipv4/ip_input.c:233 NF_HOOK include/linux/netfilter.h:302 [inline] NF_HOOK include/linux/netfilter.h:296 [inline] ip_local_deliver+0x1aa/0x200 net/ipv4/ip_input.c:254 dst_input include/net/dst.h:455 [inline] ip_rcv_finish+0x1cb/0x2f0 net/ipv4/ip_input.c:444 NF_HOOK include/linux/netfilter.h:302 [inline] NF_HOOK include/linux/netfilter.h:296 [inline] ip_rcv+0xaa/0xd0 net/ipv4/ip_input.c:564 __netif_receive_skb_one_core+0x114/0x180 net/core/dev.c:5485 __netif_receive_skb+0x1f/0x1c0 net/core/dev.c:5599 process_backlog+0x3a0/0x7c0 net/core/dev.c:5927 __napi_poll+0xb3/0x6d0 net/core/dev.c:6494 napi_poll net/core/dev.c:6561 [inline] net_rx_action+0x9c1/0xd90 net/core/dev.c:6672 __do_softirq+0x1d0/0x9c8 kernel/softirq.c:571 invoke_softirq kernel/softirq.c:445 [inline] __irq_exit_rcu+0x123/0x180 kernel/softirq.c:650 irq_exit_rcu+0x5/0x20 kernel/softirq.c:662 sysvec_apic_timer_interrupt+0x45/0xc0 arch/x86/kernel/apic/apic.c:1107 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:649 RIP: 0033:0x7f8456638771 Code: c7 44 24 08 00 00 00 00 41 89 ed 4c 8d 25 a7 78 16 00 eb 24 0f 1f 44 00 00 4c 89 ff e8 98 11 ff ff 41 08 c5 0f 85 f7 01 00 00 <41> 83 c6 01 44 39 73 04 0f 86 b7 00 00 00 48 8b 04 24 44 89 f7 48 RSP: 002b:00007ffd35d7eaf0 EFLAGS: 00000246 RAX: 00000000df4f814c RBX: 00007f84567ac0e8 RCX: 0000001b2f320000 RDX: 00000000df4f814b RSI: 0000001b2f32adec RDI: 000000000906e424 RBP: 00000000df4f814b R08: 000000000000014c R09: 00000000df4f814f R10: 00007ffd35d7ecc0 R11: 0000000000000246 R12: 00007f84567a0000 R13: 0000000000000001 R14: 000000000000018c R15: ffffffff81d3dd9c net_ratelimit: 3 callbacks suppressed TCP: request_sock_TCPv6: Possible SYN flooding on port 20002. Sending cookies. Check SNMP counters. ---------------- Code disassembly (best guess): 0: f6 a3 7e 83 f8 01 mulb 0x1f8837e(%rbx) 6: 0f 85 e8 02 00 00 jne 0x2f4 c: 9c pushfq d: 58 pop %rax e: f6 c4 02 test $0x2,%ah 11: 0f 85 fb 02 00 00 jne 0x312 17: 48 83 7c 24 08 00 cmpq $0x0,0x8(%rsp) 1d: 74 01 je 0x20 1f: fb sti 20: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax 27: fc ff df * 2a: 48 01 c3 add %rax,%rbx <-- trapping instruction 2d: 48 c7 03 00 00 00 00 movq $0x0,(%rbx) 34: 48 c7 43 08 00 00 00 movq $0x0,0x8(%rbx) 3b: 00 3c: 48 rex.W 3d: 8b .byte 0x8b 3e: 84 .byte 0x84 3f: 24 .byte 0x24