================================================================== BUG: KASAN: use-after-free in __hlist_del include/linux/list.h:886 [inline] BUG: KASAN: use-after-free in detach_timer kernel/time/timer.c:886 [inline] BUG: KASAN: use-after-free in expire_timers kernel/time/timer.c:1544 [inline] BUG: KASAN: use-after-free in __run_timers+0x669/0xa10 kernel/time/timer.c:1826 Write of size 8 at addr ffff888113a40a00 by task kworker/u4:2/43 CPU: 1 PID: 43 Comm: kworker/u4:2 Not tainted 6.1.118-syzkaller-00074-g3e3f2b9e9fca #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/25/2024 Workqueue: events_unbound bpf_map_free_deferred Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x151/0x1b7 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:316 [inline] print_report+0x158/0x4e0 mm/kasan/report.c:427 kasan_report+0x13c/0x170 mm/kasan/report.c:531 __asan_report_store8_noabort+0x17/0x20 mm/kasan/report_generic.c:356 __hlist_del include/linux/list.h:886 [inline] detach_timer kernel/time/timer.c:886 [inline] expire_timers kernel/time/timer.c:1544 [inline] __run_timers+0x669/0xa10 kernel/time/timer.c:1826 run_timer_softirq+0x69/0xf0 kernel/time/timer.c:1839 handle_softirqs+0x1db/0x650 kernel/softirq.c:617 __do_softirq kernel/softirq.c:655 [inline] invoke_softirq kernel/softirq.c:472 [inline] __irq_exit_rcu+0x52/0xf0 kernel/softirq.c:704 irq_exit_rcu+0x9/0x10 kernel/softirq.c:716 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline] sysvec_apic_timer_interrupt+0xa9/0xc0 arch/x86/kernel/apic/apic.c:1118 asm_sysvec_apic_timer_interrupt+0x1b/0x20 arch/x86/include/asm/idtentry.h:691 RIP: 0010:memset_erms+0x9/0x10 arch/x86/lib/memset_64.S:64 Code: c1 e9 03 40 0f b6 f6 48 b8 01 01 01 01 01 01 01 01 48 0f af c6 f3 48 ab 89 d1 f3 aa 4c 89 c8 c3 90 49 89 f9 40 88 f0 48 89 d1 aa 4c 89 c8 c3 90 49 89 fa 40 0f b6 ce 48 b8 01 01 01 01 01 01 RSP: 0018:ffffc900002cfb58 EFLAGS: 00010207 RAX: dffffc00000000f8 RBX: 0000000000002600 RCX: 0000000000001840 RDX: 0000000000002600 RSI: 00000000000000f8 RDI: fffff5200204a3c0 RBP: ffffc900002cfb70 R08: ffffffff81b678bd R09: fffff52002049600 R10: ffffffffffffffff R11: dffffc0000000001 R12: ffff88811689b700 R13: 0000000000013000 R14: ffffc9001024b000 R15: ffff88811689b708 kasan_poison_vmalloc include/linux/kasan.h:432 [inline] __vunmap+0x29e/0xb60 mm/vmalloc.c:2708 vunmap+0x41/0x60 mm/vmalloc.c:2825 bpf_ringbuf_free kernel/bpf/ringbuf.c:227 [inline] ringbuf_map_free+0x83/0x120 kernel/bpf/ringbuf.c:238 bpf_map_free_deferred+0xf7/0x1b0 kernel/bpf/syscall.c:637 process_one_work+0x73d/0xcb0 kernel/workqueue.c:2299 worker_thread+0xa60/0x1260 kernel/workqueue.c:2446 kthread+0x26d/0x300 kernel/kthread.c:386 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Allocated by task 326: kasan_save_stack mm/kasan/common.c:45 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:52 kasan_save_alloc_info+0x1f/0x30 mm/kasan/generic.c:505 ____kasan_kmalloc mm/kasan/common.c:379 [inline] __kasan_kmalloc+0x9c/0xb0 mm/kasan/common.c:388 kasan_kmalloc include/linux/kasan.h:212 [inline] __do_kmalloc_node mm/slab_common.c:938 [inline] __kmalloc+0xb4/0x1e0 mm/slab_common.c:951 kmalloc include/linux/slab.h:562 [inline] kzalloc include/linux/slab.h:693 [inline] hci_alloc_dev_priv+0x27/0x1c00 net/bluetooth/hci_core.c:2435 hci_alloc_dev include/net/bluetooth/hci_core.h:1484 [inline] hci_uart_register_dev drivers/bluetooth/hci_ldisc.c:636 [inline] hci_uart_set_proto drivers/bluetooth/hci_ldisc.c:712 [inline] hci_uart_tty_ioctl+0x401/0xa70 drivers/bluetooth/hci_ldisc.c:765 tty_ioctl+0x903/0xc50 drivers/tty/tty_io.c:2785 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl+0x114/0x190 fs/ioctl.c:856 __x64_sys_ioctl+0x7b/0x90 fs/ioctl.c:856 x64_sys_call+0x98/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:17 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 Freed by task 375: kasan_save_stack mm/kasan/common.c:45 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:52 kasan_save_free_info+0x2b/0x40 mm/kasan/generic.c:516 ____kasan_slab_free+0x131/0x180 mm/kasan/common.c:241 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:249 kasan_slab_free include/linux/kasan.h:178 [inline] slab_free_hook mm/slub.c:1745 [inline] slab_free_freelist_hook mm/slub.c:1771 [inline] slab_free mm/slub.c:3686 [inline] __kmem_cache_free+0x21d/0x410 mm/slub.c:3702 kfree+0x7a/0xf0 mm/slab_common.c:990 hci_release_dev+0x14d3/0x1640 net/bluetooth/hci_core.c:2763 bt_host_release+0x83/0xa0 net/bluetooth/hci_sysfs.c:92 device_release+0x95/0x1c0 kobject_cleanup lib/kobject.c:681 [inline] kobject_release lib/kobject.c:712 [inline] kref_put include/linux/kref.h:65 [inline] kobject_put+0x178/0x260 lib/kobject.c:729 put_device+0x1f/0x30 drivers/base/core.c:3805 hci_dev_put include/net/bluetooth/hci_core.h:1444 [inline] hci_dev_cmd+0x2be/0x9b0 net/bluetooth/hci_core.c:795 hci_sock_ioctl+0x415/0x7f0 net/bluetooth/hci_sock.c:1096 sock_do_ioctl+0x152/0x450 net/socket.c:1194 sock_ioctl+0x455/0x740 net/socket.c:1311 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl+0x114/0x190 fs/ioctl.c:856 __x64_sys_ioctl+0x7b/0x90 fs/ioctl.c:856 x64_sys_call+0x98/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:17 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 Last potentially related work creation: kasan_save_stack+0x3b/0x60 mm/kasan/common.c:45 __kasan_record_aux_stack+0xb4/0xc0 mm/kasan/generic.c:486 kasan_record_aux_stack_noalloc+0xb/0x10 mm/kasan/generic.c:496 insert_work+0x56/0x310 kernel/workqueue.c:1368 __queue_work+0x9b6/0xd70 kernel/workqueue.c:1527 queue_work_on+0x105/0x170 kernel/workqueue.c:1555 queue_work include/linux/workqueue.h:510 [inline] hci_cmd_sync_run net/bluetooth/hci_sync.c:140 [inline] __hci_cmd_sync_sk+0xc2a/0xf70 net/bluetooth/hci_sync.c:162 __hci_cmd_sync_status_sk net/bluetooth/hci_sync.c:253 [inline] __hci_cmd_sync_status net/bluetooth/hci_sync.c:277 [inline] hci_cmd_sync_status+0x52/0x130 net/bluetooth/hci_sync.c:288 hci_dev_cmd+0x39e/0x9b0 net/bluetooth/hci_core.c:749 hci_sock_ioctl+0x415/0x7f0 net/bluetooth/hci_sock.c:1096 sock_do_ioctl+0x152/0x450 net/socket.c:1194 sock_ioctl+0x455/0x740 net/socket.c:1311 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl+0x114/0x190 fs/ioctl.c:856 __x64_sys_ioctl+0x7b/0x90 fs/ioctl.c:856 x64_sys_call+0x98/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:17 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 Second to last potentially related work creation: kasan_save_stack+0x3b/0x60 mm/kasan/common.c:45 __kasan_record_aux_stack+0xb4/0xc0 mm/kasan/generic.c:486 kasan_record_aux_stack_noalloc+0xb/0x10 mm/kasan/generic.c:496 insert_work+0x56/0x310 kernel/workqueue.c:1368 __queue_work+0x9b6/0xd70 kernel/workqueue.c:1527 queue_work_on+0x105/0x170 kernel/workqueue.c:1555 queue_work include/linux/workqueue.h:510 [inline] hci_cmd_sync_run net/bluetooth/hci_sync.c:140 [inline] __hci_cmd_sync_sk+0xc2a/0xf70 net/bluetooth/hci_sync.c:162 __hci_cmd_sync_status_sk net/bluetooth/hci_sync.c:253 [inline] __hci_cmd_sync_status net/bluetooth/hci_sync.c:277 [inline] hci_cmd_sync_status+0x52/0x130 net/bluetooth/hci_sync.c:288 hci_dev_cmd+0x39e/0x9b0 net/bluetooth/hci_core.c:749 hci_sock_ioctl+0x415/0x7f0 net/bluetooth/hci_sock.c:1096 sock_do_ioctl+0x152/0x450 net/socket.c:1194 sock_ioctl+0x455/0x740 net/socket.c:1311 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl+0x114/0x190 fs/ioctl.c:856 __x64_sys_ioctl+0x7b/0x90 fs/ioctl.c:856 x64_sys_call+0x98/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:17 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 The buggy address belongs to the object at ffff888113a40000 which belongs to the cache kmalloc-8k of size 8192 The buggy address is located 2560 bytes inside of 8192-byte region [ffff888113a40000, ffff888113a42000) The buggy address belongs to the physical page: page:ffffea00044e9000 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x113a40 head:ffffea00044e9000 order:3 compound_mapcount:0 compound_pincount:0 flags: 0x4000000000010200(slab|head|zone=1) raw: 4000000000010200 0000000000000000 dead000000000122 ffff888100043500 raw: 0000000000000000 0000000000020002 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 3, migratetype Unmovable, gfp_mask 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 326, tgid 318 (syz.1.2), ts 24354088435, free_ts 24342399516 set_page_owner include/linux/page_owner.h:33 [inline] post_alloc_hook+0x213/0x220 mm/page_alloc.c:2590 prep_new_page+0x1b/0x110 mm/page_alloc.c:2597 get_page_from_freelist+0x2f41/0x2fc0 mm/page_alloc.c:4462 __alloc_pages+0x234/0x610 mm/page_alloc.c:5759 alloc_slab_page+0x6c/0xf0 allocate_slab mm/slub.c:1962 [inline] new_slab+0x90/0x3e0 mm/slub.c:2015 ___slab_alloc+0x6f9/0xb80 mm/slub.c:3203 __slab_alloc+0x5d/0xa0 mm/slub.c:3302 slab_alloc_node mm/slub.c:3387 [inline] __kmem_cache_alloc_node+0x207/0x2a0 mm/slub.c:3462 __do_kmalloc_node mm/slab_common.c:937 [inline] __kmalloc+0xa3/0x1e0 mm/slab_common.c:951 kmalloc include/linux/slab.h:562 [inline] kzalloc include/linux/slab.h:693 [inline] hci_alloc_dev_priv+0x27/0x1c00 net/bluetooth/hci_core.c:2435 hci_alloc_dev include/net/bluetooth/hci_core.h:1484 [inline] hci_uart_register_dev drivers/bluetooth/hci_ldisc.c:636 [inline] hci_uart_set_proto drivers/bluetooth/hci_ldisc.c:712 [inline] hci_uart_tty_ioctl+0x401/0xa70 drivers/bluetooth/hci_ldisc.c:765 tty_ioctl+0x903/0xc50 drivers/tty/tty_io.c:2785 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl+0x114/0x190 fs/ioctl.c:856 __x64_sys_ioctl+0x7b/0x90 fs/ioctl.c:856 x64_sys_call+0x98/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:17 page last free stack trace: reset_page_owner include/linux/page_owner.h:26 [inline] free_pages_prepare mm/page_alloc.c:1498 [inline] free_pcp_prepare mm/page_alloc.c:1572 [inline] free_unref_page_prepare+0x83d/0x850 mm/page_alloc.c:3511 free_unref_page+0xb2/0x5c0 mm/page_alloc.c:3607 free_the_page mm/page_alloc.c:798 [inline] __free_pages+0x61/0xf0 mm/page_alloc.c:5848 __free_slab+0xce/0x1a0 mm/slub.c:2039 free_slab mm/slub.c:2054 [inline] discard_slab mm/slub.c:2060 [inline] __unfreeze_partials+0x165/0x1a0 mm/slub.c:2609 put_cpu_partial+0xa9/0x100 mm/slub.c:2685 __slab_free+0x1c8/0x280 mm/slub.c:3563 do_slab_free mm/slub.c:3640 [inline] ___cache_free+0xc6/0xd0 mm/slub.c:3696 qlink_free mm/kasan/quarantine.c:168 [inline] qlist_free_all+0xc5/0x140 mm/kasan/quarantine.c:187 kasan_quarantine_reduce+0x15a/0x180 mm/kasan/quarantine.c:294 __kasan_slab_alloc+0x24/0x80 mm/kasan/common.c:310 kasan_slab_alloc include/linux/kasan.h:202 [inline] slab_post_alloc_hook+0x53/0x2c0 mm/slab.h:768 slab_alloc_node mm/slub.c:3421 [inline] slab_alloc mm/slub.c:3431 [inline] __kmem_cache_alloc_lru mm/slub.c:3438 [inline] kmem_cache_alloc+0x175/0x320 mm/slub.c:3447 mt_alloc_one lib/maple_tree.c:155 [inline] mas_alloc_nodes+0x267/0x7d0 lib/maple_tree.c:1282 mas_node_count_gfp lib/maple_tree.c:1364 [inline] mas_preallocate+0xef2/0x1bd0 lib/maple_tree.c:5659 vma_expand+0x2f2/0xa10 mm/mmap.c:560 Memory state around the buggy address: ffff888113a40900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888113a40980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888113a40a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888113a40a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888113a40b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] CPU: 1 PID: 43 Comm: kworker/u4:2 Tainted: G B 6.1.118-syzkaller-00074-g3e3f2b9e9fca #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/25/2024 Workqueue: events_unbound bpf_map_free_deferred RIP: 0010:__queue_work+0x4f1/0xd70 Code: 39 03 0f 84 40 01 00 00 e8 fc 6b 2a 00 4c 89 e7 e8 e4 d3 d6 03 49 bd 00 00 00 00 00 fc ff df 4c 8b 65 d0 4c 89 f0 48 c1 e8 03 <42> 80 3c 28 00 74 08 4c 89 f7 e8 30 df 71 00 49 8b 3e e8 98 cc d6 RSP: 0018:ffffc900001b0c78 EFLAGS: 00010046 RAX: 0000000000000000 RBX: 000000007fffffff RCX: ffff888100896540 RDX: 0000000000000100 RSI: 000000007fffffff RDI: 000000007fffffff RBP: ffffc900001b0d00 R08: ffffffff814b186b R09: 0000000000000007 R10: ffffffffffffffff R11: dffffc0000000001 R12: ffff888113a409c8 R13: dffffc0000000000 R14: 0000000000000000 R15: ffff888113a409e0 FS: 0000000000000000(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055c06228e978 CR3: 0000000135857000 CR4: 00000000003506a0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: delayed_work_timer_fn+0x61/0x80 kernel/workqueue.c:1653 call_timer_fn+0x3b/0x2d0 kernel/time/timer.c:1510 expire_timers kernel/time/timer.c:1550 [inline] __run_timers+0x756/0xa10 kernel/time/timer.c:1826 run_timer_softirq+0x69/0xf0 kernel/time/timer.c:1839 handle_softirqs+0x1db/0x650 kernel/softirq.c:617 __do_softirq kernel/softirq.c:655 [inline] invoke_softirq kernel/softirq.c:472 [inline] __irq_exit_rcu+0x52/0xf0 kernel/softirq.c:704 irq_exit_rcu+0x9/0x10 kernel/softirq.c:716 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline] sysvec_apic_timer_interrupt+0xa9/0xc0 arch/x86/kernel/apic/apic.c:1118 asm_sysvec_apic_timer_interrupt+0x1b/0x20 arch/x86/include/asm/idtentry.h:691 RIP: 0010:memset_erms+0x9/0x10 arch/x86/lib/memset_64.S:64 Code: c1 e9 03 40 0f b6 f6 48 b8 01 01 01 01 01 01 01 01 48 0f af c6 f3 48 ab 89 d1 f3 aa 4c 89 c8 c3 90 49 89 f9 40 88 f0 48 89 d1 aa 4c 89 c8 c3 90 49 89 fa 40 0f b6 ce 48 b8 01 01 01 01 01 01 RSP: 0018:ffffc900002cfb58 EFLAGS: 00010207 RAX: dffffc00000000f8 RBX: 0000000000002600 RCX: 0000000000001840 RDX: 0000000000002600 RSI: 00000000000000f8 RDI: fffff5200204a3c0 RBP: ffffc900002cfb70 R08: ffffffff81b678bd R09: fffff52002049600 R10: ffffffffffffffff R11: dffffc0000000001 R12: ffff88811689b700 R13: 0000000000013000 R14: ffffc9001024b000 R15: ffff88811689b708 kasan_poison_vmalloc include/linux/kasan.h:432 [inline] __vunmap+0x29e/0xb60 mm/vmalloc.c:2708 vunmap+0x41/0x60 mm/vmalloc.c:2825 bpf_ringbuf_free kernel/bpf/ringbuf.c:227 [inline] ringbuf_map_free+0x83/0x120 kernel/bpf/ringbuf.c:238 bpf_map_free_deferred+0xf7/0x1b0 kernel/bpf/syscall.c:637 process_one_work+0x73d/0xcb0 kernel/workqueue.c:2299 worker_thread+0xa60/0x1260 kernel/workqueue.c:2446 kthread+0x26d/0x300 kernel/kthread.c:386 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:__queue_work+0x4f1/0xd70 Code: 39 03 0f 84 40 01 00 00 e8 fc 6b 2a 00 4c 89 e7 e8 e4 d3 d6 03 49 bd 00 00 00 00 00 fc ff df 4c 8b 65 d0 4c 89 f0 48 c1 e8 03 <42> 80 3c 28 00 74 08 4c 89 f7 e8 30 df 71 00 49 8b 3e e8 98 cc d6 RSP: 0018:ffffc900001b0c78 EFLAGS: 00010046 RAX: 0000000000000000 RBX: 000000007fffffff RCX: ffff888100896540 RDX: 0000000000000100 RSI: 000000007fffffff RDI: 000000007fffffff RBP: ffffc900001b0d00 R08: ffffffff814b186b R09: 0000000000000007 R10: ffffffffffffffff R11: dffffc0000000001 R12: ffff888113a409c8 R13: dffffc0000000000 R14: 0000000000000000 R15: ffff888113a409e0 FS: 0000000000000000(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055c06228e978 CR3: 0000000135857000 CR4: 00000000003506a0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 ---------------- Code disassembly (best guess): 0: c1 e9 03 shr $0x3,%ecx 3: 40 0f b6 f6 movzbl %sil,%esi 7: 48 b8 01 01 01 01 01 movabs $0x101010101010101,%rax e: 01 01 01 11: 48 0f af c6 imul %rsi,%rax 15: f3 48 ab rep stos %rax,%es:(%rdi) 18: 89 d1 mov %edx,%ecx 1a: f3 aa rep stos %al,%es:(%rdi) 1c: 4c 89 c8 mov %r9,%rax 1f: c3 ret 20: 90 nop 21: 49 89 f9 mov %rdi,%r9 24: 40 88 f0 mov %sil,%al 27: 48 89 d1 mov %rdx,%rcx * 2a: f3 aa rep stos %al,%es:(%rdi) <-- trapping instruction 2c: 4c 89 c8 mov %r9,%rax 2f: c3 ret 30: 90 nop 31: 49 89 fa mov %rdi,%r10 34: 40 0f b6 ce movzbl %sil,%ecx 38: 48 rex.W 39: b8 01 01 01 01 mov $0x1010101,%eax 3e: 01 01 add %eax,(%rcx)