INFO: task khugepaged:37 blocked for more than 143 seconds. Not tainted 6.11.0-rc3-syzkaller-00010-g6b4aa469f049 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:khugepaged state:D stack:28168 pid:37 tgid:37 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5188 [inline] __schedule+0xe37/0x5490 kernel/sched/core.c:6529 __schedule_loop kernel/sched/core.c:6606 [inline] schedule+0xe7/0x350 kernel/sched/core.c:6621 schedule_timeout+0x258/0x2a0 kernel/time/timer.c:2557 do_wait_for_common kernel/sched/completion.c:95 [inline] __wait_for_common+0x3de/0x5f0 kernel/sched/completion.c:116 __flush_work+0x5bd/0xc60 kernel/workqueue.c:4208 __lru_add_drain_all+0x52c/0x740 mm/swap.c:920 khugepaged_do_scan mm/khugepaged.c:2501 [inline] khugepaged+0x108/0x1600 mm/khugepaged.c:2570 kthread+0x2c1/0x3a0 kernel/kthread.c:389 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 Showing all locks held in the system: 1 lock held by khungtaskd/30: #0: ffffffff8ddb5ce0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:326 [inline] #0: ffffffff8ddb5ce0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline] #0: ffffffff8ddb5ce0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x75/0x340 kernel/locking/lockdep.c:6626 1 lock held by khugepaged/37: #0: ffffffff8ded4cc8 (lock#3){+.+.}-{3:3}, at: __lru_add_drain_all+0x69/0x740 mm/swap.c:875 3 locks held by kworker/u8:3/52: #0: ffff88802b2f0148 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x1277/0x1b40 kernel/workqueue.c:3206 #1: ffffc90000bd7d80 ((work_completion)(&(&net->ipv6.addr_chk_work)->work)){+.+.}-{0:0}, at: process_one_work+0x921/0x1b40 kernel/workqueue.c:3207 #2: ffffffff8fa21e28 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_verify_work+0x12/0x30 net/ipv6/addrconf.c:4734 4 locks held by kworker/u8:7/1101: #0: ffff8880166e3148 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x1277/0x1b40 kernel/workqueue.c:3206 #1: ffffc90004247d80 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x921/0x1b40 kernel/workqueue.c:3207 #2: ffffffff8fa0c6d0 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0xbb/0xbf0 net/core/net_namespace.c:594 #3: ffffffff8fa21e28 (rtnl_mutex){+.+.}-{3:3}, at: wg_netns_pre_exit+0x1b/0x230 drivers/net/wireguard/device.c:414 3 locks held by kworker/u8:11/2528: #0: ffff888015889148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x1277/0x1b40 kernel/workqueue.c:3206 #1: ffffc900091d7d80 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x921/0x1b40 kernel/workqueue.c:3207 #2: ffffffff8fa21e28 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0x51/0xc0 net/core/link_watch.c:276 3 locks held by kworker/1:3/4690: #0: ffff888015881948 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: process_one_work+0x1277/0x1b40 kernel/workqueue.c:3206 #1: ffffc900020ffd80 ((reg_check_chans).work){+.+.}-{0:0}, at: process_one_work+0x921/0x1b40 kernel/workqueue.c:3207 #2: ffffffff8fa21e28 (rtnl_mutex){+.+.}-{3:3}, at: reg_check_chans_work+0x84/0x1140 net/wireless/reg.c:2480 2 locks held by getty/4980: #0: ffff88802b7a60a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc90002ef62f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0xfc8/0x1490 drivers/tty/n_tty.c:2211 5 locks held by kworker/0:3/5296: 2 locks held by kworker/0:7/8012: 6 locks held by syz.0.1178/10334: 1 lock held by syz.2.1179/10341: #0: ffffffff8fa21e28 (rtnl_mutex){+.+.}-{3:3}, at: tun_detach drivers/net/tun.c:698 [inline] #0: ffffffff8fa21e28 (rtnl_mutex){+.+.}-{3:3}, at: tun_chr_close+0x3e/0x250 drivers/net/tun.c:3510 1 lock held by syz.1.1180/10345: #0: ffffffff8fa21e28 (rtnl_mutex){+.+.}-{3:3}, at: tun_detach drivers/net/tun.c:698 [inline] #0: ffffffff8fa21e28 (rtnl_mutex){+.+.}-{3:3}, at: tun_chr_close+0x3e/0x250 drivers/net/tun.c:3510 2 locks held by syz.4.1182/10350: #0: ffffffff8fa21e28 (rtnl_mutex){+.+.}-{3:3}, at: tun_detach drivers/net/tun.c:698 [inline] #0: ffffffff8fa21e28 (rtnl_mutex){+.+.}-{3:3}, at: tun_chr_close+0x3e/0x250 drivers/net/tun.c:3510 #1: ffffffff8dc59a90 (cpu_hotplug_lock){++++}-{0:0}, at: flush_all_backlogs net/core/dev.c:6022 [inline] #1: ffffffff8dc59a90 (cpu_hotplug_lock){++++}-{0:0}, at: unregister_netdevice_many_notify+0x53b/0x1e40 net/core/dev.c:11326 1 lock held by syz-executor/10354: #0: ffffffff8fa21e28 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline] #0: ffffffff8fa21e28 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x372/0xea0 net/core/rtnetlink.c:6644 1 lock held by syz-executor/10359: #0: ffffffff8fa21e28 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline] #0: ffffffff8fa21e28 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x372/0xea0 net/core/rtnetlink.c:6644 1 lock held by syz-executor/10361: #0: ffffffff8fa21e28 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline] #0: ffffffff8fa21e28 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x372/0xea0 net/core/rtnetlink.c:6644 1 lock held by syz-executor/10363: #0: ffffffff8fa21e28 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline] #0: ffffffff8fa21e28 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x372/0xea0 net/core/rtnetlink.c:6644 1 lock held by syz-executor/10366: #0: ffffffff8fa21e28 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline] #0: ffffffff8fa21e28 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x372/0xea0 net/core/rtnetlink.c:6644 1 lock held by syz-executor/10376: #0: ffffffff8fa21e28 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline] #0: ffffffff8fa21e28 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x372/0xea0 net/core/rtnetlink.c:6644 1 lock held by syz-executor/10381: #0: ffffffff8fa21e28 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline] #0: ffffffff8fa21e28 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x372/0xea0 net/core/rtnetlink.c:6644 1 lock held by syz-executor/10383: #0: ffffffff8fa21e28 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline] #0: ffffffff8fa21e28 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x372/0xea0 net/core/rtnetlink.c:6644 1 lock held by syz-executor/10384: #0: ffffffff8fa21e28 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline] #0: ffffffff8fa21e28 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x372/0xea0 net/core/rtnetlink.c:6644 1 lock held by syz-executor/10389: #0: ffffffff8fa21e28 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline] #0: ffffffff8fa21e28 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x372/0xea0 net/core/rtnetlink.c:6644 1 lock held by syz-executor/10392: #0: ffffffff8fa21e28 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline] #0: ffffffff8fa21e28 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x372/0xea0 net/core/rtnetlink.c:6644 1 lock held by syz-executor/10395: #0: ffffffff8fa21e28 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline] #0: ffffffff8fa21e28 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x372/0xea0 net/core/rtnetlink.c:6644 1 lock held by syz-executor/10399: #0: ffffffff8fa21e28 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline] #0: ffffffff8fa21e28 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x372/0xea0 net/core/rtnetlink.c:6644 1 lock held by syz-executor/10401: #0: ffffffff8fa21e28 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline] #0: ffffffff8fa21e28 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x372/0xea0 net/core/rtnetlink.c:6644 1 lock held by syz-executor/10404: #0: ffffffff8fa21e28 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline] #0: ffffffff8fa21e28 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x372/0xea0 net/core/rtnetlink.c:6644 ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Not tainted 6.11.0-rc3-syzkaller-00010-g6b4aa469f049 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024 Call Trace: __dump_stack lib/dump_stack.c:93 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:119 nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x29c/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:223 [inline] watchdog+0xf4e/0x1280 kernel/hung_task.c:379 kthread+0x2c1/0x3a0 kernel/kthread.c:389 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 10334 Comm: syz.0.1178 Not tainted 6.11.0-rc3-syzkaller-00010-g6b4aa469f049 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024 RIP: 0010:__sanitizer_cov_trace_const_cmp8+0x0/0x20 kernel/kcov.c:319 Code: 0c 24 89 f2 89 fe bf 05 00 00 00 e9 2a fe ff ff 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 48 8b 0c 24 48 89 f2 48 89 fe bf 07 00 00 00 e9 f8 fd RSP: 0018:ffffc90000006a98 EFLAGS: 00000046 RAX: ffffffff8b11b45a RBX: ffffffff8b11b45a RCX: ffffffff813cd8b7 RDX: ffff88807a6bda00 RSI: ffffffff8b11b45a RDI: 0000000000000000 RBP: ffffc90000006b38 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: ffffc90000006aa8 R13: ffffffff81761520 R14: ffffc90000006b68 R15: ffff88807a6bda00 FS: 0000000000000000(0000) GS:ffff8880b9200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2dd0aff8 CR3: 000000000db7c000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: arch_stack_walk+0xce/0x170 arch/x86/kernel/stacktrace.c:27 stack_trace_save+0x95/0xd0 kernel/stacktrace.c:122 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:370 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:387 kmalloc_noprof include/linux/slab.h:681 [inline] dummy_urb_enqueue+0x8d/0x8a0 drivers/usb/gadget/udc/dummy_hcd.c:1271 usb_hcd_submit_urb+0x2d1/0x2090 drivers/usb/core/hcd.c:1533 usb_submit_urb+0x87c/0x1730 drivers/usb/core/urb.c:581 ath9k_hif_usb_rx_cb+0xb53/0x16a0 drivers/net/wireless/ath/ath9k/hif_usb.c:723 __usb_hcd_giveback_urb+0x389/0x6e0 drivers/usb/core/hcd.c:1650 usb_hcd_giveback_urb+0x396/0x450 drivers/usb/core/hcd.c:1734 dummy_timer+0x17c3/0x38d0 drivers/usb/gadget/udc/dummy_hcd.c:1987 __run_hrtimer kernel/time/hrtimer.c:1689 [inline] __hrtimer_run_queues+0x20c/0xcc0 kernel/time/hrtimer.c:1753 hrtimer_interrupt+0x31b/0x800 kernel/time/hrtimer.c:1815 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1032 [inline] __sysvec_apic_timer_interrupt+0x10f/0x450 arch/x86/kernel/apic/apic.c:1049 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline] sysvec_apic_timer_interrupt+0x43/0xb0 arch/x86/kernel/apic/apic.c:1043 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:in_softirq_really kernel/kcov.c:170 [inline] RIP: 0010:check_kcov_mode kernel/kcov.c:182 [inline] RIP: 0010:write_comp_data+0x24/0x90 kernel/kcov.c:245 Code: 90 90 90 90 90 90 49 89 d2 49 89 f8 49 89 f1 65 48 8b 15 2f 5e 79 7e 65 8b 05 30 5e 79 7e a9 00 01 ff 00 74 1d f6 c4 01 74 67 00 00 0f 00 75 60 a9 00 00 f0 00 75 59 8b 82 1c 16 00 00 85 c0 RSP: 0018:ffffc90000007718 EFLAGS: 00000202 RAX: 0000000000000101 RBX: ffffc900000077a0 RCX: ffffffff813cdf46 RDX: ffff88807a6bda00 RSI: 0000000000000000 RDI: 0000000000000005 RBP: 0000000000000001 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: ffffc900000077a0 R13: ffffffff81761520 R14: ffffc90000007860 R15: ffff88807a6bda00 unwind_next_frame+0x46/0x23a0 arch/x86/kernel/unwind_orc.c:475 arch_stack_walk+0x100/0x170 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x95/0xd0 kernel/stacktrace.c:122 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:579 poison_slab_object+0xf7/0x160 mm/kasan/common.c:240 __kasan_slab_free+0x32/0x50 mm/kasan/common.c:256 kasan_slab_free include/linux/kasan.h:184 [inline] slab_free_hook mm/slub.c:2252 [inline] slab_free mm/slub.c:4473 [inline] kmem_cache_free+0x12f/0x3a0 mm/slub.c:4548 skb_kfree_head net/core/skbuff.c:1082 [inline] skb_kfree_head net/core/skbuff.c:1079 [inline] skb_free_head+0x18a/0x1d0 net/core/skbuff.c:1096 skb_release_data+0x75c/0x980 net/core/skbuff.c:1123 skb_release_all net/core/skbuff.c:1188 [inline] __kfree_skb net/core/skbuff.c:1202 [inline] consume_skb net/core/skbuff.c:1426 [inline] consume_skb+0xd0/0x170 net/core/skbuff.c:1420 mac80211_hwsim_tx_frame+0x1f3/0x2a0 drivers/net/wireless/virtual/mac80211_hwsim.c:2216 __mac80211_hwsim_beacon_tx drivers/net/wireless/virtual/mac80211_hwsim.c:2232 [inline] mac80211_hwsim_beacon_tx+0x592/0xa00 drivers/net/wireless/virtual/mac80211_hwsim.c:2315 __iterate_interfaces+0x2d0/0x5d0 net/mac80211/util.c:772 ieee80211_iterate_active_interfaces_atomic+0x71/0x1b0 net/mac80211/util.c:808 mac80211_hwsim_beacon+0x105/0x200 drivers/net/wireless/virtual/mac80211_hwsim.c:2345 __run_hrtimer kernel/time/hrtimer.c:1689 [inline] __hrtimer_run_queues+0x20c/0xcc0 kernel/time/hrtimer.c:1753 hrtimer_run_softirq+0x17d/0x350 kernel/time/hrtimer.c:1770 handle_softirqs+0x216/0x8f0 kernel/softirq.c:554 __do_softirq kernel/softirq.c:588 [inline] invoke_softirq kernel/softirq.c:428 [inline] __irq_exit_rcu kernel/softirq.c:637 [inline] irq_exit_rcu+0xbb/0x120 kernel/softirq.c:649 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline] sysvec_apic_timer_interrupt+0x95/0xb0 arch/x86/kernel/apic/apic.c:1043 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:lock_release+0x170/0x6f0 kernel/locking/lockdep.c:5772 Code: f6 0f 85 8e 02 00 00 48 b8 00 00 00 00 00 fc ff df 4c 89 e2 48 c1 ea 03 80 3c 02 00 0f 85 fa 04 00 00 49 81 3c 24 a0 51 26 93 <0f> 84 65 02 00 00 9c 8f 04 24 fa 48 c7 c7 c0 c7 4c 8b e8 39 b5 a9 RSP: 0018:ffffc900032675c0 EFLAGS: 00000287 RAX: dffffc0000000000 RBX: 1ffff9200064ceba RCX: ffffffff81686999 RDX: 1ffff1100fd6399b RSI: 0000000000000000 RDI: ffff88807a6be4dc RBP: ffffffff90130ef8 R08: 0000000000000000 R09: fffffbfff2025bc3 R10: ffffffff9012de1f R11: 0000000000000000 R12: ffff88807eb1ccd8 R13: dffffc0000000000 R14: ffff88807a6bda00 R15: 00007f69965da000 __raw_spin_unlock include/linux/spinlock_api_smp.h:141 [inline] _raw_spin_unlock+0x16/0x50 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:391 [inline] zap_pte_range mm/memory.c:1688 [inline] zap_pmd_range mm/memory.c:1736 [inline] zap_pud_range mm/memory.c:1765 [inline] zap_p4d_range mm/memory.c:1786 [inline] unmap_page_range+0xbb8/0x3c10 mm/memory.c:1807 unmap_single_vma+0x194/0x2b0 mm/memory.c:1853 unmap_vmas+0x22f/0x490 mm/memory.c:1897 exit_mmap+0x1b8/0xb20 mm/mmap.c:3412 __mmput+0x12a/0x480 kernel/fork.c:1345 mmput+0x62/0x70 kernel/fork.c:1367 exit_mm kernel/exit.c:571 [inline] do_exit+0x9bf/0x2bb0 kernel/exit.c:869 do_group_exit+0xd3/0x2a0 kernel/exit.c:1031 get_signal+0x25fd/0x2770 kernel/signal.c:2917 arch_do_signal_or_restart+0x90/0x7e0 arch/x86/kernel/signal.c:310 exit_to_user_mode_loop kernel/entry/common.c:111 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0x150/0x2a0 kernel/entry/common.c:218 do_syscall_64+0xda/0x250 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f6997f79a33 Code: Unable to access opcode bytes at 0x7f6997f79a09. RSP: 002b:00007ffedaeb4d58 EFLAGS: 00000246 ORIG_RAX: 0000000000000009 RAX: 00007f69979df000 RBX: 00007f69962006c0 RCX: 00007f6997f79a33 RDX: 0000000000000000 RSI: 0000000000021000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 00000000ffffffff R09: 0000000000000000 R10: 0000000000020022 R11: 0000000000000246 R12: 00007ffedaeb4eb0 R13: ffffffffffffffc0 R14: 0000000000001000 R15: 0000000000000000