======================================================== WARNING: possible irq lock inversion dependency detected 6.8.0-syzkaller-08951-gfe46a7dd189e #0 Not tainted -------------------------------------------------------- syz-executor.5/6103 just changed the state of lock: ffff888029b9b110 (&group->lock#2){..-.}-{2:2}, at: class_pcm_stream_lock_irqsave_constructor include/sound/pcm.h:669 [inline] ffff888029b9b110 (&group->lock#2){..-.}-{2:2}, at: snd_pcm_period_elapsed+0x21/0x50 sound/core/pcm_lib.c:1904 but this lock took another, SOFTIRQ-unsafe lock in the past: (&timer->lock){+.+.}-{2:2} and interrupts could create inverse lock ordering between them. other info that might help us debug this: Possible interrupt unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&timer->lock); local_irq_disable(); lock(&group->lock#2); lock(&timer->lock); lock(&group->lock#2); *** DEADLOCK *** 1 lock held by syz-executor.5/6103: #0: ffffffff8f38da88 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_set_dstaddr+0xd9/0x410 net/ipv6/addrconf.c:2960 the shortest dependencies between 2nd lock and 1st lock: -> (&timer->lock){+.+.}-{2:2} { HARDIRQ-ON-W at: lock_acquire+0x1e4/0x530 kernel/locking/lockdep.c:5754 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:351 [inline] class_spinlock_constructor include/linux/spinlock.h:561 [inline] snd_timer_close_locked+0x53/0x8d0 sound/core/timer.c:412 snd_timer_close+0xae/0x130 sound/core/timer.c:464 snd_seq_timer_close+0xa9/0xe0 sound/core/seq/seq_timer.c:302 queue_delete sound/core/seq/seq_queue.c:126 [inline] snd_seq_queue_delete+0x8f/0xf0 sound/core/seq/seq_queue.c:188 delete_seq_queue sound/core/seq/oss/seq_oss_init.c:371 [inline] snd_seq_oss_release+0x1d3/0x310 sound/core/seq/oss/seq_oss_init.c:416 odev_release+0x56/0x80 sound/core/seq/oss/seq_oss.c:144 __fput+0x42b/0x8a0 fs/file_table.c:422 __do_sys_close fs/open.c:1556 [inline] __se_sys_close fs/open.c:1541 [inline] __x64_sys_close+0x7f/0x110 fs/open.c:1541 do_syscall_64+0xfd/0x240 entry_SYSCALL_64_after_hwframe+0x6d/0x75 SOFTIRQ-ON-W at: lock_acquire+0x1e4/0x530 kernel/locking/lockdep.c:5754 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:351 [inline] class_spinlock_constructor include/linux/spinlock.h:561 [inline] snd_timer_close_locked+0x53/0x8d0 sound/core/timer.c:412 snd_timer_close+0xae/0x130 sound/core/timer.c:464 snd_seq_timer_close+0xa9/0xe0 sound/core/seq/seq_timer.c:302 queue_delete sound/core/seq/seq_queue.c:126 [inline] snd_seq_queue_delete+0x8f/0xf0 sound/core/seq/seq_queue.c:188 delete_seq_queue sound/core/seq/oss/seq_oss_init.c:371 [inline] snd_seq_oss_release+0x1d3/0x310 sound/core/seq/oss/seq_oss_init.c:416 odev_release+0x56/0x80 sound/core/seq/oss/seq_oss.c:144 __fput+0x42b/0x8a0 fs/file_table.c:422 __do_sys_close fs/open.c:1556 [inline] __se_sys_close fs/open.c:1541 [inline] __x64_sys_close+0x7f/0x110 fs/open.c:1541 do_syscall_64+0xfd/0x240 entry_SYSCALL_64_after_hwframe+0x6d/0x75 INITIAL USE at: lock_acquire+0x1e4/0x530 kernel/locking/lockdep.c:5754 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:351 [inline] class_spinlock_constructor include/linux/spinlock.h:561 [inline] snd_timer_close_locked+0x53/0x8d0 sound/core/timer.c:412 snd_timer_close+0xae/0x130 sound/core/timer.c:464 snd_seq_timer_close+0xa9/0xe0 sound/core/seq/seq_timer.c:302 queue_delete sound/core/seq/seq_queue.c:126 [inline] snd_seq_queue_delete+0x8f/0xf0 sound/core/seq/seq_queue.c:188 delete_seq_queue sound/core/seq/oss/seq_oss_init.c:371 [inline] snd_seq_oss_release+0x1d3/0x310 sound/core/seq/oss/seq_oss_init.c:416 odev_release+0x56/0x80 sound/core/seq/oss/seq_oss.c:144 __fput+0x42b/0x8a0 fs/file_table.c:422 __do_sys_close fs/open.c:1556 [inline] __se_sys_close fs/open.c:1541 [inline] __x64_sys_close+0x7f/0x110 fs/open.c:1541 do_syscall_64+0xfd/0x240 entry_SYSCALL_64_after_hwframe+0x6d/0x75 } ... key at: [] snd_timer_new.__key+0x0/0x20 ... acquired at: lock_acquire+0x1e4/0x530 kernel/locking/lockdep.c:5754 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162 class_spinlock_irqsave_constructor include/linux/spinlock.h:574 [inline] snd_timer_notify+0x103/0x3d0 sound/core/timer.c:1040 snd_pcm_timer_notify sound/core/pcm_native.c:622 [inline] snd_pcm_post_stop sound/core/pcm_native.c:1520 [inline] snd_pcm_action sound/core/pcm_native.c:1370 [inline] snd_pcm_stop+0x358/0x490 sound/core/pcm_native.c:1543 snd_pcm_drop+0x158/0x250 sound/core/pcm_native.c:2208 snd_pcm_oss_sync+0x202/0xc30 sound/core/oss/pcm_oss.c:1734 snd_pcm_oss_release+0x11e/0x280 sound/core/oss/pcm_oss.c:2575 __fput+0x42b/0x8a0 fs/file_table.c:422 task_work_run+0x251/0x310 kernel/task_work.c:180 exit_task_work include/linux/task_work.h:38 [inline] do_exit+0xa1b/0x27e0 kernel/exit.c:878 do_group_exit+0x207/0x2c0 kernel/exit.c:1027 get_signal+0x176e/0x1850 kernel/signal.c:2907 arch_do_signal_or_restart+0x96/0x860 arch/x86/kernel/signal.c:310 exit_to_user_mode_loop kernel/entry/common.c:105 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:201 [inline] syscall_exit_to_user_mode+0xc9/0x360 kernel/entry/common.c:212 do_syscall_64+0x10a/0x240 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x6d/0x75 -> (&group->lock#2){..-.}-{2:2} { IN-SOFTIRQ-W at: lock_acquire+0x1e4/0x530 kernel/locking/lockdep.c:5754 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162 class_pcm_stream_lock_irqsave_constructor include/sound/pcm.h:669 [inline] snd_pcm_period_elapsed+0x21/0x50 sound/core/pcm_lib.c:1904 dummy_hrtimer_callback+0x7f/0x180 sound/drivers/dummy.c:385 __run_hrtimer kernel/time/hrtimer.c:1692 [inline] __hrtimer_run_queues+0x597/0xd00 kernel/time/hrtimer.c:1756 hrtimer_run_softirq+0x19a/0x2c0 kernel/time/hrtimer.c:1773 __do_softirq+0x2be/0x943 kernel/softirq.c:554 invoke_softirq kernel/softirq.c:428 [inline] __irq_exit_rcu+0xf2/0x1c0 kernel/softirq.c:633 irq_exit_rcu+0x9/0x30 kernel/softirq.c:645 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1043 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 native_irq_enable arch/x86/include/asm/irqflags.h:42 [inline] arch_local_irq_enable arch/x86/include/asm/irqflags.h:77 [inline] raw_spin_rq_unlock_irq kernel/sched/sched.h:1397 [inline] finish_lock_switch kernel/sched/core.c:5163 [inline] finish_task_switch+0x1ea/0x870 kernel/sched/core.c:5281 context_switch kernel/sched/core.c:5412 [inline] __schedule+0x17db/0x4a20 kernel/sched/core.c:6736 preempt_schedule_irq+0xfb/0x1c0 kernel/sched/core.c:7058 irqentry_exit+0x5e/0x90 kernel/entry/common.c:348 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 preempt_schedule+0x4/0xf0 kernel/sched/core.c:6932 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:12 __local_bh_enable_ip+0x179/0x200 kernel/softirq.c:389 addrconf_notify+0xb29/0x1020 net/ipv6/addrconf.c:3744 notifier_call_chain+0x191/0x3b0 kernel/notifier.c:93 call_netdevice_notifiers_extack net/core/dev.c:1988 [inline] call_netdevice_notifiers net/core/dev.c:2002 [inline] dev_open+0x13a/0x1b0 net/core/dev.c:1471 addrconf_set_sit_dstaddr net/ipv6/addrconf.c:2941 [inline] addrconf_set_dstaddr+0x322/0x410 net/ipv6/addrconf.c:2963 inet6_ioctl+0x15d/0x280 net/ipv6/af_inet6.c:586 sock_do_ioctl+0x15a/0x460 net/socket.c:1222 sock_ioctl+0x629/0x8e0 net/socket.c:1341 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:904 [inline] __se_sys_ioctl+0xfe/0x170 fs/ioctl.c:890 do_syscall_64+0xfd/0x240 entry_SYSCALL_64_after_hwframe+0x6d/0x75 INITIAL USE at: lock_acquire+0x1e4/0x530 kernel/locking/lockdep.c:5754 __raw_spin_lock_irq include/linux/spinlock_api_smp.h:119 [inline] _raw_spin_lock_irq+0xd3/0x120 kernel/locking/spinlock.c:170 spin_lock_irq include/linux/spinlock.h:376 [inline] snd_pcm_group_lock_irq sound/core/pcm_native.c:97 [inline] snd_pcm_stream_lock_irq sound/core/pcm_native.c:136 [inline] class_pcm_stream_lock_irq_constructor include/sound/pcm.h:666 [inline] snd_pcm_hw_params+0x201/0x1ea0 sound/core/pcm_native.c:740 snd_pcm_oss_change_params_locked+0x20d5/0x3e00 sound/core/oss/pcm_oss.c:965 snd_pcm_oss_change_params sound/core/oss/pcm_oss.c:1105 [inline] snd_pcm_oss_make_ready+0x11d/0x350 sound/core/oss/pcm_oss.c:1164 snd_pcm_oss_sync+0x1bd/0xc30 sound/core/oss/pcm_oss.c:1730 snd_pcm_oss_release+0x11e/0x280 sound/core/oss/pcm_oss.c:2575 __fput+0x42b/0x8a0 fs/file_table.c:422 task_work_run+0x251/0x310 kernel/task_work.c:180 exit_task_work include/linux/task_work.h:38 [inline] do_exit+0xa1b/0x27e0 kernel/exit.c:878 do_group_exit+0x207/0x2c0 kernel/exit.c:1027 get_signal+0x176e/0x1850 kernel/signal.c:2907 arch_do_signal_or_restart+0x96/0x860 arch/x86/kernel/signal.c:310 exit_to_user_mode_loop kernel/entry/common.c:105 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:201 [inline] syscall_exit_to_user_mode+0xc9/0x360 kernel/entry/common.c:212 do_syscall_64+0x10a/0x240 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x6d/0x75 } ... key at: [] snd_pcm_group_init.__key+0x0/0x20 ... acquired at: mark_lock+0x223/0x350 kernel/locking/lockdep.c:4678 __lock_acquire+0xbcd/0x1fd0 kernel/locking/lockdep.c:5091 lock_acquire+0x1e4/0x530 kernel/locking/lockdep.c:5754 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162 class_pcm_stream_lock_irqsave_constructor include/sound/pcm.h:669 [inline] snd_pcm_period_elapsed+0x21/0x50 sound/core/pcm_lib.c:1904 dummy_hrtimer_callback+0x7f/0x180 sound/drivers/dummy.c:385 __run_hrtimer kernel/time/hrtimer.c:1692 [inline] __hrtimer_run_queues+0x597/0xd00 kernel/time/hrtimer.c:1756 hrtimer_run_softirq+0x19a/0x2c0 kernel/time/hrtimer.c:1773 __do_softirq+0x2be/0x943 kernel/softirq.c:554 invoke_softirq kernel/softirq.c:428 [inline] __irq_exit_rcu+0xf2/0x1c0 kernel/softirq.c:633 irq_exit_rcu+0x9/0x30 kernel/softirq.c:645 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1043 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 native_irq_enable arch/x86/include/asm/irqflags.h:42 [inline] arch_local_irq_enable arch/x86/include/asm/irqflags.h:77 [inline] raw_spin_rq_unlock_irq kernel/sched/sched.h:1397 [inline] finish_lock_switch kernel/sched/core.c:5163 [inline] finish_task_switch+0x1ea/0x870 kernel/sched/core.c:5281 context_switch kernel/sched/core.c:5412 [inline] __schedule+0x17db/0x4a20 kernel/sched/core.c:6736 preempt_schedule_irq+0xfb/0x1c0 kernel/sched/core.c:7058 irqentry_exit+0x5e/0x90 kernel/entry/common.c:348 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 preempt_schedule+0x4/0xf0 kernel/sched/core.c:6932 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:12 __local_bh_enable_ip+0x179/0x200 kernel/softirq.c:389 addrconf_notify+0xb29/0x1020 net/ipv6/addrconf.c:3744 notifier_call_chain+0x191/0x3b0 kernel/notifier.c:93 call_netdevice_notifiers_extack net/core/dev.c:1988 [inline] call_netdevice_notifiers net/core/dev.c:2002 [inline] dev_open+0x13a/0x1b0 net/core/dev.c:1471 addrconf_set_sit_dstaddr net/ipv6/addrconf.c:2941 [inline] addrconf_set_dstaddr+0x322/0x410 net/ipv6/addrconf.c:2963 inet6_ioctl+0x15d/0x280 net/ipv6/af_inet6.c:586 sock_do_ioctl+0x15a/0x460 net/socket.c:1222 sock_ioctl+0x629/0x8e0 net/socket.c:1341 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:904 [inline] __se_sys_ioctl+0xfe/0x170 fs/ioctl.c:890 do_syscall_64+0xfd/0x240 entry_SYSCALL_64_after_hwframe+0x6d/0x75 stack backtrace: CPU: 1 PID: 6103 Comm: syz-executor.5 Not tainted 6.8.0-syzkaller-08951-gfe46a7dd189e #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114 mark_lock_irq+0x80c/0xc20 kernel/locking/lockdep.c:4243 mark_lock+0x223/0x350 kernel/locking/lockdep.c:4678 __lock_acquire+0xbcd/0x1fd0 kernel/locking/lockdep.c:5091 lock_acquire+0x1e4/0x530 kernel/locking/lockdep.c:5754 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162 class_pcm_stream_lock_irqsave_constructor include/sound/pcm.h:669 [inline] snd_pcm_period_elapsed+0x21/0x50 sound/core/pcm_lib.c:1904 dummy_hrtimer_callback+0x7f/0x180 sound/drivers/dummy.c:385 __run_hrtimer kernel/time/hrtimer.c:1692 [inline] __hrtimer_run_queues+0x597/0xd00 kernel/time/hrtimer.c:1756 hrtimer_run_softirq+0x19a/0x2c0 kernel/time/hrtimer.c:1773 __do_softirq+0x2be/0x943 kernel/softirq.c:554 invoke_softirq kernel/softirq.c:428 [inline] __irq_exit_rcu+0xf2/0x1c0 kernel/softirq.c:633 irq_exit_rcu+0x9/0x30 kernel/softirq.c:645 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1043 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:finish_task_switch+0x1ea/0x870 kernel/sched/core.c:5283 Code: c9 50 e8 19 ae 0b 00 48 83 c4 08 4c 89 f7 e8 1d 38 00 00 0f 1f 44 00 00 4c 89 f7 e8 a0 1e 19 0a e8 8b 39 36 00 fb 48 8b 5d c0 <48> 8d bb f0 15 00 00 48 89 f8 48 c1 e8 03 49 be 00 00 00 00 00 fc RSP: 0018:ffffc900162f73a8 EFLAGS: 00000286 RAX: f8c2117145ac2700 RBX: ffff888027dc3c00 RCX: ffffffff81720c2a RDX: dffffc0000000000 RSI: ffffffff8baac1e0 RDI: ffffffff8bfed300 RBP: ffffc900162f73f0 R08: ffffffff92ce550f R09: 1ffffffff259caa1 R10: dffffc0000000000 R11: fffffbfff259caa2 R12: 1ffff110172a7e17 R13: dffffc0000000000 R14: ffff8880b953e340 R15: ffff8880b953f0b8 context_switch kernel/sched/core.c:5412 [inline] __schedule+0x17db/0x4a20 kernel/sched/core.c:6736 preempt_schedule_irq+0xfb/0x1c0 kernel/sched/core.c:7058 irqentry_exit+0x5e/0x90 kernel/entry/common.c:348 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:preempt_schedule+0x4/0xf0 kernel/sched/core.c:6932 Code: 71 e7 f5 e9 de d2 01 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa <55> 48 89 e5 41 57 41 56 41 54 53 48 83 e4 e0 48 83 ec 60 65 48 8b RSP: 0018:ffffc900162f77a0 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 1ffff92002c5ef04 RCX: ffffffff81720c2a RDX: dffffc0000000000 RSI: ffffffff8baac1e0 RDI: ffffffff8bfed300 RBP: ffffc900162f77f0 R08: ffffffff92ce550f R09: 1ffffffff259caa1 R10: dffffc0000000000 R11: fffffbfff259caa2 R12: dffffc0000000000 R13: 1ffff92002c5ef08 R14: ffffc900162f7840 R15: 0000000000000201 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:12 __local_bh_enable_ip+0x179/0x200 kernel/softirq.c:389 addrconf_notify+0xb29/0x1020 net/ipv6/addrconf.c:3744 notifier_call_chain+0x191/0x3b0 kernel/notifier.c:93 call_netdevice_notifiers_extack net/core/dev.c:1988 [inline] call_netdevice_notifiers net/core/dev.c:2002 [inline] dev_open+0x13a/0x1b0 net/core/dev.c:1471 addrconf_set_sit_dstaddr net/ipv6/addrconf.c:2941 [inline] addrconf_set_dstaddr+0x322/0x410 net/ipv6/addrconf.c:2963 inet6_ioctl+0x15d/0x280 net/ipv6/af_inet6.c:586 sock_do_ioctl+0x15a/0x460 net/socket.c:1222 sock_ioctl+0x629/0x8e0 net/socket.c:1341 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:904 [inline] __se_sys_ioctl+0xfe/0x170 fs/ioctl.c:890 do_syscall_64+0xfd/0x240 entry_SYSCALL_64_after_hwframe+0x6d/0x75 RIP: 0033:0x7fd53e07de69 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fd53edb60c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fd53e1ac050 RCX: 00007fd53e07de69 RDX: 0000000020000080 RSI: 0000000000008918 RDI: 0000000000000004 RBP: 00007fd53e0ca47a R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000006e R14: 00007fd53e1ac050 R15: 00007fff77ff35e8 TCP: request_sock_subflow_v4: Possible SYN flooding on port [::]:20002. Sending cookies. ---------------- Code disassembly (best guess): 0: c9 leave 1: 50 push %rax 2: e8 19 ae 0b 00 call 0xbae20 7: 48 83 c4 08 add $0x8,%rsp b: 4c 89 f7 mov %r14,%rdi e: e8 1d 38 00 00 call 0x3830 13: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) 18: 4c 89 f7 mov %r14,%rdi 1b: e8 a0 1e 19 0a call 0xa191ec0 20: e8 8b 39 36 00 call 0x3639b0 25: fb sti 26: 48 8b 5d c0 mov -0x40(%rbp),%rbx * 2a: 48 8d bb f0 15 00 00 lea 0x15f0(%rbx),%rdi <-- trapping instruction 31: 48 89 f8 mov %rdi,%rax 34: 48 c1 e8 03 shr $0x3,%rax 38: 49 rex.WB 39: be 00 00 00 00 mov $0x0,%esi 3e: 00 fc add %bh,%ah