======================================================== WARNING: possible irq lock inversion dependency detected 6.8.0-syzkaller-08951-gfe46a7dd189e #0 Not tainted -------------------------------------------------------- syz-executor290/5064 just changed the state of lock: ffff8880299f1110 (&group->lock#2){..-.}-{2:2}, at: _snd_pcm_stream_lock_irqsave+0xa0/0xd0 sound/core/pcm_native.c:170 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-executor290/5064: #0: ffff888065646a20 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock include/linux/mmap_lock.h:108 [inline] #0: ffff888065646a20 (&mm->mmap_lock){++++}-{3:3}, at: exit_mmap+0x203/0xb60 mm/mmap.c:3295 the shortest dependencies between 2nd lock and 1st lock: -> (&timer->lock){+.+.}-{2:2} { HARDIRQ-ON-W at: lock_acquire kernel/locking/lockdep.c:5754 [inline] lock_acquire+0x1b1/0x540 kernel/locking/lockdep.c:5719 __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+0x65/0xbd0 sound/core/timer.c:412 snd_timer_close+0x8b/0xf0 sound/core/timer.c:464 snd_timer_user_release+0x91/0x260 sound/core/timer.c:1468 __fput+0x270/0xb80 fs/file_table.c:422 task_work_run+0x14e/0x250 kernel/task_work.c:180 exit_task_work include/linux/task_work.h:38 [inline] do_exit+0xa7d/0x2be0 kernel/exit.c:878 do_group_exit+0xd3/0x2a0 kernel/exit.c:1027 __do_sys_exit_group kernel/exit.c:1038 [inline] __se_sys_exit_group kernel/exit.c:1036 [inline] __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1036 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xd2/0x260 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x6d/0x75 SOFTIRQ-ON-W at: lock_acquire kernel/locking/lockdep.c:5754 [inline] lock_acquire+0x1b1/0x540 kernel/locking/lockdep.c:5719 __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+0x65/0xbd0 sound/core/timer.c:412 snd_timer_close+0x8b/0xf0 sound/core/timer.c:464 snd_timer_user_release+0x91/0x260 sound/core/timer.c:1468 __fput+0x270/0xb80 fs/file_table.c:422 task_work_run+0x14e/0x250 kernel/task_work.c:180 exit_task_work include/linux/task_work.h:38 [inline] do_exit+0xa7d/0x2be0 kernel/exit.c:878 do_group_exit+0xd3/0x2a0 kernel/exit.c:1027 __do_sys_exit_group kernel/exit.c:1038 [inline] __se_sys_exit_group kernel/exit.c:1036 [inline] __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1036 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xd2/0x260 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x6d/0x75 INITIAL USE at: lock_acquire kernel/locking/lockdep.c:5754 [inline] lock_acquire+0x1b1/0x540 kernel/locking/lockdep.c:5719 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162 class_spinlock_irqsave_constructor include/linux/spinlock.h:574 [inline] snd_timer_notify+0x111/0x3e0 sound/core/timer.c:1040 snd_pcm_timer_notify sound/core/pcm_native.c:622 [inline] snd_pcm_post_start+0x272/0x350 sound/core/pcm_native.c:1459 snd_pcm_action_single+0x10a/0x150 sound/core/pcm_native.c:1289 snd_pcm_action+0x70/0x90 sound/core/pcm_native.c:1370 __snd_pcm_lib_xfer+0x175b/0x1ea0 sound/core/pcm_lib.c:2301 snd_pcm_oss_read3+0x18e/0x2d0 sound/core/oss/pcm_oss.c:1281 snd_pcm_oss_read2+0x309/0x3d0 sound/core/oss/pcm_oss.c:1492 snd_pcm_oss_read1 sound/core/oss/pcm_oss.c:1520 [inline] snd_pcm_oss_read+0x46e/0x760 sound/core/oss/pcm_oss.c:2773 vfs_read+0x1d4/0xb80 fs/read_write.c:474 ksys_read+0x12f/0x260 fs/read_write.c:619 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xd2/0x260 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x6d/0x75 } ... key at: [] __key.6+0x0/0x40 ... acquired at: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162 class_spinlock_irqsave_constructor include/linux/spinlock.h:574 [inline] snd_timer_notify+0x111/0x3e0 sound/core/timer.c:1040 snd_pcm_timer_notify sound/core/pcm_native.c:622 [inline] snd_pcm_post_start+0x272/0x350 sound/core/pcm_native.c:1459 snd_pcm_action_single+0x10a/0x150 sound/core/pcm_native.c:1289 snd_pcm_action+0x70/0x90 sound/core/pcm_native.c:1370 __snd_pcm_lib_xfer+0x175b/0x1ea0 sound/core/pcm_lib.c:2301 snd_pcm_oss_read3+0x18e/0x2d0 sound/core/oss/pcm_oss.c:1281 snd_pcm_oss_read2+0x309/0x3d0 sound/core/oss/pcm_oss.c:1492 snd_pcm_oss_read1 sound/core/oss/pcm_oss.c:1520 [inline] snd_pcm_oss_read+0x46e/0x760 sound/core/oss/pcm_oss.c:2773 vfs_read+0x1d4/0xb80 fs/read_write.c:474 ksys_read+0x12f/0x260 fs/read_write.c:619 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xd2/0x260 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x6d/0x75 -> (&group->lock#2){..-.}-{2:2} { IN-SOFTIRQ-W at: lock_acquire kernel/locking/lockdep.c:5754 [inline] lock_acquire+0x1b1/0x540 kernel/locking/lockdep.c:5719 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162 _snd_pcm_stream_lock_irqsave+0xa0/0xd0 sound/core/pcm_native.c:170 class_pcm_stream_lock_irqsave_constructor include/sound/pcm.h:669 [inline] snd_pcm_period_elapsed+0x20/0x50 sound/core/pcm_lib.c:1904 dummy_hrtimer_callback+0x9d/0x1c0 sound/drivers/dummy.c:385 __run_hrtimer kernel/time/hrtimer.c:1692 [inline] __hrtimer_run_queues+0x20c/0xc20 kernel/time/hrtimer.c:1756 hrtimer_run_softirq+0x17d/0x350 kernel/time/hrtimer.c:1773 __do_softirq+0x218/0x8de kernel/softirq.c:554 invoke_softirq kernel/softirq.c:428 [inline] __irq_exit_rcu kernel/softirq.c:633 [inline] irq_exit_rcu+0xb9/0x120 kernel/softirq.c:645 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 preempt_latency_start kernel/sched/core.c:5854 [inline] preempt_latency_start kernel/sched/core.c:5849 [inline] preempt_count_add+0xa4/0x150 kernel/sched/core.c:5877 unwind_next_frame+0xce/0x23a0 arch/x86/kernel/unwind_orc.c:479 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 mm/kasan/common.c:240 [inline] __kasan_slab_free+0x11d/0x1a0 mm/kasan/common.c:256 kasan_slab_free include/linux/kasan.h:184 [inline] slab_free_hook mm/slub.c:2106 [inline] slab_free mm/slub.c:4280 [inline] kmem_cache_free+0x12e/0x360 mm/slub.c:4344 pmd_ptlock_free include/linux/mm.h:3014 [inline] pagetable_pmd_dtor include/linux/mm.h:3055 [inline] ___pmd_free_tlb+0x74/0x2f0 arch/x86/mm/pgtable.c:72 __pmd_free_tlb arch/x86/include/asm/pgalloc.h:93 [inline] free_pmd_range mm/memory.c:226 [inline] free_pud_range mm/memory.c:244 [inline] free_p4d_range mm/memory.c:278 [inline] free_pgd_range+0x9ca/0xbc0 mm/memory.c:358 free_pgtables+0x154/0x860 mm/memory.c:405 exit_mmap+0x3d2/0xb60 mm/mmap.c:3298 __mmput+0x12a/0x4d0 kernel/fork.c:1345 mmput+0x62/0x70 kernel/fork.c:1367 exit_mm kernel/exit.c:569 [inline] do_exit+0x999/0x2be0 kernel/exit.c:865 do_group_exit+0xd3/0x2a0 kernel/exit.c:1027 __do_sys_exit_group kernel/exit.c:1038 [inline] __se_sys_exit_group kernel/exit.c:1036 [inline] __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1036 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xd2/0x260 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x6d/0x75 INITIAL USE at: lock_acquire kernel/locking/lockdep.c:5754 [inline] lock_acquire+0x1b1/0x540 kernel/locking/lockdep.c:5719 __raw_spin_lock_irq include/linux/spinlock_api_smp.h:119 [inline] _raw_spin_lock_irq+0x36/0x50 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+0x151/0x1a30 sound/core/pcm_native.c:740 snd_pcm_kernel_ioctl+0x147/0x2d0 sound/core/pcm_native.c:3434 snd_pcm_oss_change_params_locked+0x146c/0x3aa0 sound/core/oss/pcm_oss.c:965 snd_pcm_oss_make_ready_locked+0xb7/0x130 sound/core/oss/pcm_oss.c:1187 snd_pcm_oss_read1 sound/core/oss/pcm_oss.c:1515 [inline] snd_pcm_oss_read+0x3a2/0x760 sound/core/oss/pcm_oss.c:2773 vfs_read+0x1d4/0xb80 fs/read_write.c:474 ksys_read+0x12f/0x260 fs/read_write.c:619 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xd2/0x260 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x6d/0x75 } ... key at: [] __key.5+0x0/0x40 ... acquired at: mark_usage kernel/locking/lockdep.c:4567 [inline] __lock_acquire+0x13d4/0x3b30 kernel/locking/lockdep.c:5091 lock_acquire kernel/locking/lockdep.c:5754 [inline] lock_acquire+0x1b1/0x540 kernel/locking/lockdep.c:5719 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162 _snd_pcm_stream_lock_irqsave+0xa0/0xd0 sound/core/pcm_native.c:170 class_pcm_stream_lock_irqsave_constructor include/sound/pcm.h:669 [inline] snd_pcm_period_elapsed+0x20/0x50 sound/core/pcm_lib.c:1904 dummy_hrtimer_callback+0x9d/0x1c0 sound/drivers/dummy.c:385 __run_hrtimer kernel/time/hrtimer.c:1692 [inline] __hrtimer_run_queues+0x20c/0xc20 kernel/time/hrtimer.c:1756 hrtimer_run_softirq+0x17d/0x350 kernel/time/hrtimer.c:1773 __do_softirq+0x218/0x8de kernel/softirq.c:554 invoke_softirq kernel/softirq.c:428 [inline] __irq_exit_rcu kernel/softirq.c:633 [inline] irq_exit_rcu+0xb9/0x120 kernel/softirq.c:645 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 preempt_latency_start kernel/sched/core.c:5854 [inline] preempt_latency_start kernel/sched/core.c:5849 [inline] preempt_count_add+0xa4/0x150 kernel/sched/core.c:5877 unwind_next_frame+0xce/0x23a0 arch/x86/kernel/unwind_orc.c:479 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 mm/kasan/common.c:240 [inline] __kasan_slab_free+0x11d/0x1a0 mm/kasan/common.c:256 kasan_slab_free include/linux/kasan.h:184 [inline] slab_free_hook mm/slub.c:2106 [inline] slab_free mm/slub.c:4280 [inline] kmem_cache_free+0x12e/0x360 mm/slub.c:4344 pmd_ptlock_free include/linux/mm.h:3014 [inline] pagetable_pmd_dtor include/linux/mm.h:3055 [inline] ___pmd_free_tlb+0x74/0x2f0 arch/x86/mm/pgtable.c:72 __pmd_free_tlb arch/x86/include/asm/pgalloc.h:93 [inline] free_pmd_range mm/memory.c:226 [inline] free_pud_range mm/memory.c:244 [inline] free_p4d_range mm/memory.c:278 [inline] free_pgd_range+0x9ca/0xbc0 mm/memory.c:358 free_pgtables+0x154/0x860 mm/memory.c:405 exit_mmap+0x3d2/0xb60 mm/mmap.c:3298 __mmput+0x12a/0x4d0 kernel/fork.c:1345 mmput+0x62/0x70 kernel/fork.c:1367 exit_mm kernel/exit.c:569 [inline] do_exit+0x999/0x2be0 kernel/exit.c:865 do_group_exit+0xd3/0x2a0 kernel/exit.c:1027 __do_sys_exit_group kernel/exit.c:1038 [inline] __se_sys_exit_group kernel/exit.c:1036 [inline] __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1036 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xd2/0x260 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x6d/0x75 stack backtrace: CPU: 1 PID: 5064 Comm: syz-executor290 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+0x116/0x1f0 lib/dump_stack.c:114 print_irq_inversion_bug.part.0+0x3e9/0x5a0 kernel/locking/lockdep.c:4080 print_irq_inversion_bug kernel/locking/lockdep.c:4033 [inline] check_usage_forwards kernel/locking/lockdep.c:4111 [inline] mark_lock_irq kernel/locking/lockdep.c:4243 [inline] mark_lock+0x574/0xc60 kernel/locking/lockdep.c:4678 mark_usage kernel/locking/lockdep.c:4567 [inline] __lock_acquire+0x13d4/0x3b30 kernel/locking/lockdep.c:5091 lock_acquire kernel/locking/lockdep.c:5754 [inline] lock_acquire+0x1b1/0x540 kernel/locking/lockdep.c:5719 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162 _snd_pcm_stream_lock_irqsave+0xa0/0xd0 sound/core/pcm_native.c:170 class_pcm_stream_lock_irqsave_constructor include/sound/pcm.h:669 [inline] snd_pcm_period_elapsed+0x20/0x50 sound/core/pcm_lib.c:1904 dummy_hrtimer_callback+0x9d/0x1c0 sound/drivers/dummy.c:385 __run_hrtimer kernel/time/hrtimer.c:1692 [inline] __hrtimer_run_queues+0x20c/0xc20 kernel/time/hrtimer.c:1756 hrtimer_run_softirq+0x17d/0x350 kernel/time/hrtimer.c:1773 __do_softirq+0x218/0x8de kernel/softirq.c:554 invoke_softirq kernel/softirq.c:428 [inline] __irq_exit_rcu kernel/softirq.c:633 [inline] irq_exit_rcu+0xb9/0x120 kernel/softirq.c:645 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:preempt_latency_start kernel/sched/core.c:5854 [inline] RIP: 0010:preempt_latency_start kernel/sched/core.c:5849 [inline] RIP: 0010:preempt_count_add+0xa4/0x150 kernel/sched/core.c:5877 Code: 65 48 8b 2d 3e 75 a6 7e 48 8d bd c0 14 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 87 00 00 00 <48> 89 9d c0 14 00 00 5b 5d c3 cc cc cc cc 31 ff 31 db e8 45 40 0e RSP: 0018:ffffc9000340f638 EFLAGS: 00000246 RAX: dffffc0000000000 RBX: ffffffff813c979e RCX: 1ffffffff28d0b54 RDX: 1ffff11004b7e658 RSI: ffffffff813c973b RDI: ffff888025bf32c0 RBP: ffff888025bf1e00 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000001 R12: ffffc9000340f6d0 R13: ffffffff8178d3a0 R14: ffffc9000340f790 R15: ffff888025bf1e00 unwind_next_frame+0xce/0x23a0 arch/x86/kernel/unwind_orc.c:479 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 mm/kasan/common.c:240 [inline] __kasan_slab_free+0x11d/0x1a0 mm/kasan/common.c:256 kasan_slab_free include/linux/kasan.h:184 [inline] slab_free_hook mm/slub.c:2106 [inline] slab_free mm/slub.c:4280 [inline] kmem_cache_free+0x12e/0x360 mm/slub.c:4344 pmd_ptlock_free include/linux/mm.h:3014 [inline] pagetable_pmd_dtor include/linux/mm.h:3055 [inline] ___pmd_free_tlb+0x74/0x2f0 arch/x86/mm/pgtable.c:72 __pmd_free_tlb arch/x86/include/asm/pgalloc.h:93 [inline] free_pmd_range mm/memory.c:226 [inline] free_pud_range mm/memory.c:244 [inline] free_p4d_range mm/memory.c:278 [inline] free_pgd_range+0x9ca/0xbc0 mm/memory.c:358 free_pgtables+0x154/0x860 mm/memory.c:405 exit_mmap+0x3d2/0xb60 mm/mmap.c:3298 __mmput+0x12a/0x4d0 kernel/fork.c:1345 mmput+0x62/0x70 kernel/fork.c:1367 exit_mm kernel/exit.c:569 [inline] do_exit+0x999/0x2be0 kernel/exit.c:865 do_group_exit+0xd3/0x2a0 kernel/exit.c:1027 __do_sys_exit_group kernel/exit.c:1038 [inline] __se_sys_exit_group kernel/exit.c:1036 [inline] __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1036 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xd2/0x260 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x6d/0x75 RIP: 0033:0x7fbca38e4d39 Code: Unable to access opcode bytes at 0x7fbca38e4d0f. RSP: 002b:00007fffe23f0778 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fbca38e4d39 RDX: 000000000000003c RSI: 00000000000000e7 RDI: 0000000000000000 RBP: 00007fbca395f2b0 R08: ffffffffffffffb8 R09: 00000000000000a0 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fbca395f2b0 R13: 0000000000000000 R14: 00007fbca395fd20 R15: 00007fbca38b5ec0 ---------------- Code disassembly (best guess): 0: 65 48 8b 2d 3e 75 a6 mov %gs:0x7ea6753e(%rip),%rbp # 0x7ea67546 7: 7e 8: 48 8d bd c0 14 00 00 lea 0x14c0(%rbp),%rdi f: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax 16: fc ff df 19: 48 89 fa mov %rdi,%rdx 1c: 48 c1 ea 03 shr $0x3,%rdx 20: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) 24: 0f 85 87 00 00 00 jne 0xb1 * 2a: 48 89 9d c0 14 00 00 mov %rbx,0x14c0(%rbp) <-- trapping instruction 31: 5b pop %rbx 32: 5d pop %rbp 33: c3 ret 34: cc int3 35: cc int3 36: cc int3 37: cc int3 38: 31 ff xor %edi,%edi 3a: 31 db xor %ebx,%ebx 3c: e8 .byte 0xe8 3d: 45 rex.RB 3e: 40 0e rex (bad)