====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.4.3616/19306 is trying to acquire lock: ffffffff8e883760 (fs_reclaim){+.+.}-{0:0}, at: might_alloc include/linux/sched/mm.h:317 [inline] ffffffff8e883760 (fs_reclaim){+.+.}-{0:0}, at: prepare_alloc_pages+0x152/0x650 mm/page_alloc.c:5018 but task is already holding lock: ffff88806d156540 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_trylock include/linux/mmap_lock.h:611 [inline] ffff88806d156540 (&mm->mmap_lock){++++}-{4:4}, at: get_mmap_lock_carefully mm/mmap_lock.c:441 [inline] ffff88806d156540 (&mm->mmap_lock){++++}-{4:4}, at: lock_mm_and_find_vma+0x36/0x340 mm/mmap_lock.c:501 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #7 (&mm->mmap_lock){++++}-{4:4}: __might_fault+0xcb/0x130 mm/memory.c:7230 _inline_copy_from_user include/linux/uaccess.h:169 [inline] _copy_from_user+0x28/0xb0 lib/usercopy.c:18 copy_from_user include/linux/uaccess.h:223 [inline] csum_and_copy_from_user include/net/checksum.h:31 [inline] copy_from_user_iter_csum net/core/skbuff.c:7419 [inline] iterate_ubuf include/linux/iov_iter.h:30 [inline] iterate_and_advance2 include/linux/iov_iter.h:302 [inline] csum_and_copy_from_iter_full+0x1e7/0x1f00 net/core/skbuff.c:7431 ip_generic_getfrag+0x149/0x2d0 net/ipv4/ip_output.c:942 __ip6_append_data+0x39e4/0x3f70 net/ipv6/ip6_output.c:1733 ip6_append_data+0x10f/0x280 net/ipv6/ip6_output.c:1886 rawv6_sendmsg+0x12d3/0x18e0 net/ipv6/raw.c:912 sock_sendmsg_nosec net/socket.c:721 [inline] __sock_sendmsg net/socket.c:736 [inline] ____sys_sendmsg+0x80a/0x9f0 net/socket.c:2585 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2639 __sys_sendmsg net/socket.c:2671 [inline] __do_sys_sendmsg net/socket.c:2676 [inline] __se_sys_sendmsg net/socket.c:2674 [inline] __x64_sys_sendmsg+0x1bd/0x2a0 net/socket.c:2674 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #6 (sk_lock-AF_INET6){+.+.}-{0:0}: lock_sock_nested+0x41/0x100 net/core/sock.c:3781 lock_sock include/net/sock.h:1713 [inline] inet_shutdown+0x6a/0x390 net/ipv4/af_inet.c:915 nbd_mark_nsock_dead+0x2e9/0x560 drivers/block/nbd.c:318 recv_work+0x1c7f/0x1d90 drivers/block/nbd.c:1021 process_one_work kernel/workqueue.c:3276 [inline] process_scheduled_works+0xb6e/0x18c0 kernel/workqueue.c:3359 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3440 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 -> #5 (&nsock->tx_lock){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:614 [inline] __mutex_lock+0x19f/0x1300 kernel/locking/mutex.c:776 nbd_handle_cmd drivers/block/nbd.c:1143 [inline] nbd_queue_rq+0x37b/0x1100 drivers/block/nbd.c:1207 blk_mq_dispatch_rq_list+0xa70/0x1910 block/blk-mq.c:2148 __blk_mq_do_dispatch_sched block/blk-mq-sched.c:168 [inline] blk_mq_do_dispatch_sched block/blk-mq-sched.c:182 [inline] __blk_mq_sched_dispatch_requests+0xdcc/0x1600 block/blk-mq-sched.c:307 blk_mq_sched_dispatch_requests+0xd7/0x190 block/blk-mq-sched.c:329 blk_mq_run_hw_queue+0x348/0x4f0 block/blk-mq.c:2386 blk_mq_dispatch_list+0xd16/0xe10 include/linux/spinlock.h:-1 blk_mq_flush_plug_list+0x48d/0x570 block/blk-mq.c:2997 __blk_flush_plug+0x3ed/0x4d0 block/blk-core.c:1230 blk_finish_plug block/blk-core.c:1257 [inline] __submit_bio+0x28d/0x580 block/blk-core.c:649 __submit_bio_noacct_mq block/blk-core.c:722 [inline] submit_bio_noacct_nocheck+0x2f4/0xa70 block/blk-core.c:753 submit_bh fs/buffer.c:2826 [inline] block_read_full_folio+0x599/0x830 fs/buffer.c:2444 filemap_read_folio+0x137/0x3b0 mm/filemap.c:2501 do_read_cache_folio+0x358/0x590 mm/filemap.c:4106 read_mapping_folio include/linux/pagemap.h:1017 [inline] read_part_sector+0xb6/0x2b0 block/partitions/core.c:723 adfspart_check_ICS+0xa5/0xa40 block/partitions/acorn.c:360 check_partition block/partitions/core.c:142 [inline] blk_add_partitions block/partitions/core.c:590 [inline] bdev_disk_changed+0x7ba/0x1550 block/partitions/core.c:694 blkdev_get_whole+0x380/0x510 block/bdev.c:764 bdev_open+0x31e/0xd30 block/bdev.c:973 blkdev_open+0x470/0x610 block/fops.c:697 do_dentry_open+0x785/0x14e0 fs/open.c:949 vfs_open+0x3b/0x340 fs/open.c:1081 do_open fs/namei.c:4677 [inline] path_openat+0x2e08/0x3860 fs/namei.c:4836 do_file_open+0x23e/0x4a0 fs/namei.c:4865 do_sys_openat2+0x113/0x200 fs/open.c:1366 do_sys_open fs/open.c:1372 [inline] __do_sys_openat fs/open.c:1388 [inline] __se_sys_openat fs/open.c:1383 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1383 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #4 (&cmd->lock){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:614 [inline] __mutex_lock+0x19f/0x1300 kernel/locking/mutex.c:776 nbd_queue_rq+0xc6/0x1100 drivers/block/nbd.c:1199 blk_mq_dispatch_rq_list+0xa70/0x1910 block/blk-mq.c:2148 __blk_mq_do_dispatch_sched block/blk-mq-sched.c:168 [inline] blk_mq_do_dispatch_sched block/blk-mq-sched.c:182 [inline] __blk_mq_sched_dispatch_requests+0xdcc/0x1600 block/blk-mq-sched.c:307 blk_mq_sched_dispatch_requests+0xd7/0x190 block/blk-mq-sched.c:329 blk_mq_run_hw_queue+0x348/0x4f0 block/blk-mq.c:2386 blk_mq_dispatch_list+0xd16/0xe10 include/linux/spinlock.h:-1 blk_mq_flush_plug_list+0x48d/0x570 block/blk-mq.c:2997 __blk_flush_plug+0x3ed/0x4d0 block/blk-core.c:1230 blk_finish_plug block/blk-core.c:1257 [inline] __submit_bio+0x28d/0x580 block/blk-core.c:649 __submit_bio_noacct_mq block/blk-core.c:722 [inline] submit_bio_noacct_nocheck+0x2f4/0xa70 block/blk-core.c:753 submit_bh fs/buffer.c:2826 [inline] block_read_full_folio+0x599/0x830 fs/buffer.c:2444 filemap_read_folio+0x137/0x3b0 mm/filemap.c:2501 do_read_cache_folio+0x358/0x590 mm/filemap.c:4106 read_mapping_folio include/linux/pagemap.h:1017 [inline] read_part_sector+0xb6/0x2b0 block/partitions/core.c:723 adfspart_check_ICS+0xa5/0xa40 block/partitions/acorn.c:360 check_partition block/partitions/core.c:142 [inline] blk_add_partitions block/partitions/core.c:590 [inline] bdev_disk_changed+0x7ba/0x1550 block/partitions/core.c:694 blkdev_get_whole+0x380/0x510 block/bdev.c:764 bdev_open+0x31e/0xd30 block/bdev.c:973 blkdev_open+0x470/0x610 block/fops.c:697 do_dentry_open+0x785/0x14e0 fs/open.c:949 vfs_open+0x3b/0x340 fs/open.c:1081 do_open fs/namei.c:4677 [inline] path_openat+0x2e08/0x3860 fs/namei.c:4836 do_file_open+0x23e/0x4a0 fs/namei.c:4865 do_sys_openat2+0x113/0x200 fs/open.c:1366 do_sys_open fs/open.c:1372 [inline] __do_sys_openat fs/open.c:1388 [inline] __se_sys_openat fs/open.c:1383 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1383 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #3 (set->srcu){.+.+}-{0:0}: srcu_lock_sync include/linux/srcu.h:199 [inline] __synchronize_srcu+0xca/0x300 kernel/rcu/srcutree.c:1481 elevator_switch+0x1e8/0x7a0 block/elevator.c:576 elevator_change+0x2cc/0x450 block/elevator.c:681 elevator_set_default+0x36c/0x430 block/elevator.c:754 blk_register_queue+0x366/0x430 block/blk-sysfs.c:946 __add_disk+0x677/0xd50 block/genhd.c:528 add_disk_fwnode+0xfb/0x480 block/genhd.c:597 add_disk include/linux/blkdev.h:785 [inline] nbd_dev_add+0x72c/0xb50 drivers/block/nbd.c:1984 nbd_init+0x168/0x1f0 drivers/block/nbd.c:2692 do_one_initcall+0x250/0x8d0 init/main.c:1382 do_initcall_level+0x104/0x190 init/main.c:1444 do_initcalls+0x59/0xa0 init/main.c:1460 kernel_init_freeable+0x2a6/0x3e0 init/main.c:1692 kernel_init+0x1d/0x1d0 init/main.c:1582 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 -> #2 (&q->elevator_lock){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:614 [inline] __mutex_lock+0x19f/0x1300 kernel/locking/mutex.c:776 elevator_change+0x1b3/0x450 block/elevator.c:679 elevator_set_none+0xb5/0x140 block/elevator.c:769 blk_mq_elv_switch_none block/blk-mq.c:5110 [inline] __blk_mq_update_nr_hw_queues block/blk-mq.c:5155 [inline] blk_mq_update_nr_hw_queues+0x5e7/0x1a60 block/blk-mq.c:5220 nbd_start_device+0x17f/0xb10 drivers/block/nbd.c:1489 nbd_genl_connect+0x165b/0x1cf0 drivers/block/nbd.c:2239 genl_family_rcv_msg_doit+0x22a/0x330 net/netlink/genetlink.c:1114 genl_family_rcv_msg net/netlink/genetlink.c:1194 [inline] genl_rcv_msg+0x61c/0x7a0 net/netlink/genetlink.c:1209 netlink_rcv_skb+0x232/0x4b0 net/netlink/af_netlink.c:2550 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x80f/0x9b0 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec net/socket.c:721 [inline] __sock_sendmsg net/socket.c:736 [inline] ____sys_sendmsg+0x972/0x9f0 net/socket.c:2585 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2639 __sys_sendmsg net/socket.c:2671 [inline] __do_sys_sendmsg net/socket.c:2676 [inline] __se_sys_sendmsg net/socket.c:2674 [inline] __x64_sys_sendmsg+0x1bd/0x2a0 net/socket.c:2674 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #1 (&q->q_usage_counter(io)#49){++++}-{0:0}: blk_alloc_queue+0x546/0x680 block/blk-core.c:461 blk_mq_alloc_queue block/blk-mq.c:4429 [inline] __blk_mq_alloc_disk+0x197/0x390 block/blk-mq.c:4476 nbd_dev_add+0x499/0xb50 drivers/block/nbd.c:1954 nbd_init+0x168/0x1f0 drivers/block/nbd.c:2692 do_one_initcall+0x250/0x8d0 init/main.c:1382 do_initcall_level+0x104/0x190 init/main.c:1444 do_initcalls+0x59/0xa0 init/main.c:1460 kernel_init_freeable+0x2a6/0x3e0 init/main.c:1692 kernel_init+0x1d/0x1d0 init/main.c:1582 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 -> #0 (fs_reclaim){+.+.}-{0:0}: check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x15a5/0x2cf0 kernel/locking/lockdep.c:5237 lock_acquire+0xf0/0x2e0 kernel/locking/lockdep.c:5868 __fs_reclaim_acquire mm/page_alloc.c:4348 [inline] fs_reclaim_acquire+0x71/0x100 mm/page_alloc.c:4362 might_alloc include/linux/sched/mm.h:317 [inline] prepare_alloc_pages+0x152/0x650 mm/page_alloc.c:5018 __alloc_frozen_pages_noprof+0x12f/0x380 mm/page_alloc.c:5239 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2490 folio_alloc_mpol_noprof+0x39/0x70 mm/mempolicy.c:2509 shmem_alloc_folio mm/shmem.c:1930 [inline] shmem_alloc_and_add_folio+0x445/0xf80 mm/shmem.c:1972 shmem_get_folio_gfp+0x5a9/0x1670 mm/shmem.c:2567 shmem_fault+0x179/0x390 mm/shmem.c:2768 __do_fault+0x138/0x390 mm/memory.c:5364 do_shared_fault mm/memory.c:5863 [inline] do_fault mm/memory.c:5937 [inline] do_pte_missing+0x5c4/0x3490 mm/memory.c:4477 handle_pte_fault mm/memory.c:6317 [inline] __handle_mm_fault mm/memory.c:6455 [inline] handle_mm_fault+0x1bec/0x3310 mm/memory.c:6624 do_user_addr_fault+0x75b/0x1340 arch/x86/mm/fault.c:1385 handle_page_fault arch/x86/mm/fault.c:1474 [inline] exc_page_fault+0x6a/0xc0 arch/x86/mm/fault.c:1527 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618 stac arch/x86/include/asm/uaccess_64.h:67 [inline] epoll_put_uevent include/linux/eventpoll.h:85 [inline] ep_send_events fs/eventpoll.c:1822 [inline] ep_try_send_events+0x79f/0xf10 fs/eventpoll.c:1905 ep_poll fs/eventpoll.c:1970 [inline] do_epoll_wait+0x5cf/0xf60 fs/eventpoll.c:2462 __do_sys_epoll_wait fs/eventpoll.c:2470 [inline] __se_sys_epoll_wait fs/eventpoll.c:2465 [inline] __x64_sys_epoll_wait+0x1d7/0x230 fs/eventpoll.c:2465 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f other info that might help us debug this: Chain exists of: fs_reclaim --> sk_lock-AF_INET6 --> &mm->mmap_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- rlock(&mm->mmap_lock); lock(sk_lock-AF_INET6); lock(&mm->mmap_lock); lock(fs_reclaim); *** DEADLOCK *** 2 locks held by syz.4.3616/19306: #0: ffff88806ce9a468 (&ep->mtx){+.+.}-{4:4}, at: ep_send_events fs/eventpoll.c:1781 [inline] #0: ffff88806ce9a468 (&ep->mtx){+.+.}-{4:4}, at: ep_try_send_events+0x19d/0xf10 fs/eventpoll.c:1905 #1: ffff88806d156540 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_trylock include/linux/mmap_lock.h:611 [inline] #1: ffff88806d156540 (&mm->mmap_lock){++++}-{4:4}, at: get_mmap_lock_carefully mm/mmap_lock.c:441 [inline] #1: ffff88806d156540 (&mm->mmap_lock){++++}-{4:4}, at: lock_mm_and_find_vma+0x36/0x340 mm/mmap_lock.c:501 stack backtrace: CPU: 0 UID: 0 PID: 19306 Comm: syz.4.3616 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_circular_bug+0x2e1/0x300 kernel/locking/lockdep.c:2043 check_noncircular+0x12e/0x150 kernel/locking/lockdep.c:2175 check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x15a5/0x2cf0 kernel/locking/lockdep.c:5237 lock_acquire+0xf0/0x2e0 kernel/locking/lockdep.c:5868 __fs_reclaim_acquire mm/page_alloc.c:4348 [inline] fs_reclaim_acquire+0x71/0x100 mm/page_alloc.c:4362 might_alloc include/linux/sched/mm.h:317 [inline] prepare_alloc_pages+0x152/0x650 mm/page_alloc.c:5018 __alloc_frozen_pages_noprof+0x12f/0x380 mm/page_alloc.c:5239 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2490 folio_alloc_mpol_noprof+0x39/0x70 mm/mempolicy.c:2509 shmem_alloc_folio mm/shmem.c:1930 [inline] shmem_alloc_and_add_folio+0x445/0xf80 mm/shmem.c:1972 shmem_get_folio_gfp+0x5a9/0x1670 mm/shmem.c:2567 shmem_fault+0x179/0x390 mm/shmem.c:2768 __do_fault+0x138/0x390 mm/memory.c:5364 do_shared_fault mm/memory.c:5863 [inline] do_fault mm/memory.c:5937 [inline] do_pte_missing+0x5c4/0x3490 mm/memory.c:4477 handle_pte_fault mm/memory.c:6317 [inline] __handle_mm_fault mm/memory.c:6455 [inline] handle_mm_fault+0x1bec/0x3310 mm/memory.c:6624 do_user_addr_fault+0x75b/0x1340 arch/x86/mm/fault.c:1385 handle_page_fault arch/x86/mm/fault.c:1474 [inline] exc_page_fault+0x6a/0xc0 arch/x86/mm/fault.c:1527 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618 RIP: 0010:epoll_put_uevent include/linux/eventpoll.h:86 [inline] RIP: 0010:ep_send_events fs/eventpoll.c:1822 [inline] RIP: 0010:ep_try_send_events+0x79f/0xf10 fs/eventpoll.c:1905 Code: b6 04 28 84 c0 0f 85 d4 03 00 00 49 8b 07 48 ba 00 f0 ff ff ff 7f 00 00 48 8b 74 24 68 48 89 f1 48 39 d1 48 0f 47 ca 0f 01 cb <44> 89 31 48 89 41 04 0f 01 ca 48 83 c6 0c 44 8b 74 24 14 0f 84 13 RSP: 0018:ffffc9000cc27ac0 EFLAGS: 00050283 RAX: 0000000000000000 RBX: ffff8880341da798 RCX: 000020000000affb RDX: 00007ffffffff000 RSI: 000020000000affb RDI: ffff8880341da7f3 RBP: ffffc9000cc27bf0 R08: ffff8880359826a7 R09: 1ffff11006b304d4 R10: dffffc0000000000 R11: ffffed1006b304d5 R12: 1ffff1100683b4fd R13: dffffc0000000000 R14: 0000000000000004 R15: ffff8880341da7ec ep_poll fs/eventpoll.c:1970 [inline] do_epoll_wait+0x5cf/0xf60 fs/eventpoll.c:2462 __do_sys_epoll_wait fs/eventpoll.c:2470 [inline] __se_sys_epoll_wait fs/eventpoll.c:2465 [inline] __x64_sys_epoll_wait+0x1d7/0x230 fs/eventpoll.c:2465 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f9aadf9c819 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f9aaedb4028 EFLAGS: 00000246 ORIG_RAX: 00000000000000e8 RAX: ffffffffffffffda RBX: 00007f9aae215fa0 RCX: 00007f9aadf9c819 RDX: 0000000000000001 RSI: 000020000000affb RDI: 0000000000000004 RBP: 00007f9aae032c91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000007fff R11: 0000000000000246 R12: 0000000000000000 R13: 00007f9aae216038 R14: 00007f9aae215fa0 R15: 00007ffc2aff6f18 ---------------- Code disassembly (best guess): 0: b6 04 mov $0x4,%dh 2: 28 84 c0 0f 85 d4 03 sub %al,0x3d4850f(%rax,%rax,8) 9: 00 00 add %al,(%rax) b: 49 8b 07 mov (%r15),%rax e: 48 ba 00 f0 ff ff ff movabs $0x7ffffffff000,%rdx 15: 7f 00 00 18: 48 8b 74 24 68 mov 0x68(%rsp),%rsi 1d: 48 89 f1 mov %rsi,%rcx 20: 48 39 d1 cmp %rdx,%rcx 23: 48 0f 47 ca cmova %rdx,%rcx 27: 0f 01 cb stac * 2a: 44 89 31 mov %r14d,(%rcx) <-- trapping instruction 2d: 48 89 41 04 mov %rax,0x4(%rcx) 31: 0f 01 ca clac 34: 48 83 c6 0c add $0xc,%rsi 38: 44 8b 74 24 14 mov 0x14(%rsp),%r14d 3d: 0f .byte 0xf 3e: 84 13 test %dl,(%rbx)