FAULT_INJECTION: forcing a failure. name fail_usercopy, interval 1, probability 0, space 0, times 1 ====================================================== WARNING: possible circular locking dependency detected 6.1.115-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor373/4468 is trying to acquire lock: ffffffff8d31f4c0 (console_owner){....}-{0:0}, at: console_lock_spinning_enable kernel/printk/printk.c:1818 [inline] ffffffff8d31f4c0 (console_owner){....}-{0:0}, at: console_emit_next_record+0xa9c/0x1000 kernel/printk/printk.c:2774 but task is already holding lock: ffff8880b8f3a9d8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:537 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #4 (&rq->__lock){-.-.}-{2:2}: lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 _raw_spin_lock_nested+0x2d/0x40 kernel/locking/spinlock.c:378 raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:537 raw_spin_rq_lock kernel/sched/sched.h:1355 [inline] rq_lock kernel/sched/sched.h:1645 [inline] task_fork_fair+0x5d/0x350 kernel/sched/fair.c:11877 sched_cgroup_fork+0x374/0x400 kernel/sched/core.c:4682 copy_process+0x2442/0x4060 kernel/fork.c:2381 kernel_clone+0x222/0x920 kernel/fork.c:2679 user_mode_thread+0x12e/0x190 kernel/fork.c:2755 rest_init+0x23/0x300 init/main.c:698 start_kernel+0x0/0x53f init/main.c:893 start_kernel+0x496/0x53f init/main.c:1140 secondary_startup_64_no_verify+0xcf/0xdb -> #3 (&p->pi_lock){-.-.}-{2:2}: lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd1/0x120 kernel/locking/spinlock.c:162 try_to_wake_up+0xad/0x12e0 kernel/sched/core.c:4108 __wake_up_common+0x2a0/0x4e0 kernel/sched/wait.c:107 __wake_up_common_lock kernel/sched/wait.c:138 [inline] __wake_up+0x11a/0x1c0 kernel/sched/wait.c:160 tty_port_default_wakeup+0xa2/0xf0 drivers/tty/tty_port.c:71 serial8250_tx_chars+0x60d/0x800 drivers/tty/serial/8250/8250_port.c:1854 serial8250_handle_irq+0x4ff/0x6a0 drivers/tty/serial/8250/8250_port.c:1961 serial8250_default_handle_irq+0xc8/0x1e0 drivers/tty/serial/8250/8250_port.c:1981 serial8250_interrupt+0xa1/0x1e0 drivers/tty/serial/8250/8250_core.c:126 __handle_irq_event_percpu+0x2a8/0xb20 kernel/irq/handle.c:158 handle_irq_event_percpu kernel/irq/handle.c:193 [inline] handle_irq_event+0x85/0x1e0 kernel/irq/handle.c:210 handle_edge_irq+0x245/0xbf0 kernel/irq/chip.c:819 generic_handle_irq_desc include/linux/irqdesc.h:158 [inline] handle_irq arch/x86/kernel/irq.c:231 [inline] __common_interrupt+0xd7/0x1f0 arch/x86/kernel/irq.c:250 common_interrupt+0xae/0xd0 arch/x86/kernel/irq.c:240 asm_common_interrupt+0x22/0x40 arch/x86/include/asm/idtentry.h:682 lock_acquire+0x26f/0x5a0 kernel/locking/lockdep.c:5666 rcu_lock_acquire include/linux/rcupdate.h:350 [inline] rcu_read_lock_sched include/linux/rcupdate.h:883 [inline] pfn_valid+0x113/0x440 include/linux/mmzone.h:1857 page_table_check_set+0x25/0x6d0 mm/page_table_check.c:108 page_table_check_pte_set include/linux/page_table_check.h:83 [inline] set_pte_at arch/x86/include/asm/pgtable.h:1009 [inline] do_set_pte+0x584/0x590 mm/memory.c:4424 filemap_map_pages+0xc7c/0x12c0 mm/filemap.c:3480 do_fault_around mm/memory.c:4598 [inline] do_read_fault mm/memory.c:4624 [inline] do_fault mm/memory.c:4758 [inline] handle_pte_fault mm/memory.c:5029 [inline] __handle_mm_fault mm/memory.c:5171 [inline] handle_mm_fault+0x33e0/0x5340 mm/memory.c:5292 do_user_addr_fault arch/x86/mm/fault.c:1340 [inline] handle_page_fault arch/x86/mm/fault.c:1431 [inline] exc_page_fault+0x26f/0x620 arch/x86/mm/fault.c:1487 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:608 -> #2 (&tty->write_wait){-...}-{2:2}: lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd1/0x120 kernel/locking/spinlock.c:162 __wake_up_common_lock kernel/sched/wait.c:137 [inline] __wake_up+0xfd/0x1c0 kernel/sched/wait.c:160 tty_port_default_wakeup+0xa2/0xf0 drivers/tty/tty_port.c:71 serial8250_tx_chars+0x60d/0x800 drivers/tty/serial/8250/8250_port.c:1854 serial8250_handle_irq+0x4ff/0x6a0 drivers/tty/serial/8250/8250_port.c:1961 serial8250_default_handle_irq+0xc8/0x1e0 drivers/tty/serial/8250/8250_port.c:1981 serial8250_interrupt+0xa1/0x1e0 drivers/tty/serial/8250/8250_core.c:126 __handle_irq_event_percpu+0x2a8/0xb20 kernel/irq/handle.c:158 handle_irq_event_percpu kernel/irq/handle.c:193 [inline] handle_irq_event+0x85/0x1e0 kernel/irq/handle.c:210 handle_edge_irq+0x245/0xbf0 kernel/irq/chip.c:819 generic_handle_irq_desc include/linux/irqdesc.h:158 [inline] handle_irq arch/x86/kernel/irq.c:231 [inline] __common_interrupt+0xd7/0x1f0 arch/x86/kernel/irq.c:250 common_interrupt+0xae/0xd0 arch/x86/kernel/irq.c:240 asm_common_interrupt+0x22/0x40 arch/x86/include/asm/idtentry.h:682 native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline] arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline] acpi_safe_halt drivers/acpi/processor_idle.c:111 [inline] acpi_idle_do_entry+0x10f/0x340 drivers/acpi/processor_idle.c:567 acpi_idle_enter+0x352/0x4f0 drivers/acpi/processor_idle.c:704 cpuidle_enter_state+0x516/0xf80 drivers/cpuidle/cpuidle.c:239 cpuidle_enter+0x59/0x90 drivers/cpuidle/cpuidle.c:356 call_cpuidle kernel/sched/idle.c:155 [inline] cpuidle_idle_call kernel/sched/idle.c:236 [inline] do_idle+0x3ce/0x680 kernel/sched/idle.c:303 cpu_startup_entry+0x3d/0x60 kernel/sched/idle.c:401 rest_init+0x2da/0x300 init/main.c:733 start_kernel+0x0/0x53f init/main.c:893 start_kernel+0x496/0x53f init/main.c:1140 secondary_startup_64_no_verify+0xcf/0xdb -> #1 (&port_lock_key){-...}-{2:2}: lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd1/0x120 kernel/locking/spinlock.c:162 serial8250_console_write+0x19d/0x1750 drivers/tty/serial/8250/8250_port.c:3404 call_console_driver kernel/printk/printk.c:1977 [inline] console_emit_next_record+0xbb4/0x1000 kernel/printk/printk.c:2777 console_unlock+0x278/0x7c0 kernel/printk/printk.c:2906 vprintk_emit+0x523/0x740 kernel/printk/printk.c:2303 _printk+0xd1/0x111 kernel/printk/printk.c:2328 register_console+0x6b9/0x9a0 kernel/printk/printk.c:3269 univ8250_console_init+0x41/0x43 drivers/tty/serial/8250/8250_core.c:687 console_init+0x1d6/0x7f3 kernel/printk/printk.c:3359 start_kernel+0x30b/0x53f init/main.c:1076 secondary_startup_64_no_verify+0xcf/0xdb -> #0 (console_owner){....}-{0:0}: check_prev_add kernel/locking/lockdep.c:3090 [inline] check_prevs_add kernel/locking/lockdep.c:3209 [inline] validate_chain+0x1661/0x5950 kernel/locking/lockdep.c:3825 __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5049 lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 console_lock_spinning_enable kernel/printk/printk.c:1818 [inline] console_emit_next_record+0xabd/0x1000 kernel/printk/printk.c:2774 console_unlock+0x278/0x7c0 kernel/printk/printk.c:2906 vprintk_emit+0x523/0x740 kernel/printk/printk.c:2303 _printk+0xd1/0x111 kernel/printk/printk.c:2328 fail_dump lib/fault-inject.c:45 [inline] should_fail_ex+0x387/0x4d0 lib/fault-inject.c:147 strncpy_from_user+0x32/0x360 lib/strncpy_from_user.c:118 strncpy_from_user_nofault+0x6c/0x130 mm/maccess.c:186 bpf_probe_read_user_str_common kernel/trace/bpf_trace.c:204 [inline] ____bpf_probe_read_user_str kernel/trace/bpf_trace.c:213 [inline] bpf_probe_read_user_str+0x26/0x70 kernel/trace/bpf_trace.c:210 bpf_prog_bc7c5c6b9645592f+0x35/0x37 bpf_dispatcher_nop_func include/linux/bpf.h:989 [inline] __bpf_prog_run include/linux/filter.h:603 [inline] bpf_prog_run include/linux/filter.h:610 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2271 [inline] bpf_trace_run4+0x253/0x470 kernel/trace/bpf_trace.c:2312 trace_sched_switch include/trace/events/sched.h:222 [inline] __schedule+0x2128/0x4570 kernel/sched/core.c:6555 preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6870 irqentry_exit+0x53/0x80 kernel/entry/common.c:439 asm_sysvec_reschedule_ipi+0x16/0x20 arch/x86/include/asm/idtentry.h:696 lock_acquire+0x26f/0x5a0 kernel/locking/lockdep.c:5666 __might_fault+0xbd/0x110 mm/memory.c:5851 clear_rseq_cs kernel/rseq.c:228 [inline] rseq_ip_fixup kernel/rseq.c:262 [inline] __rseq_handle_notify_resume+0x5ba/0x1500 kernel/rseq.c:300 rseq_handle_notify_resume include/linux/sched.h:2329 [inline] resume_user_mode_work include/linux/resume_user_mode.h:61 [inline] exit_to_user_mode_loop+0xb4/0x100 kernel/entry/common.c:177 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline] syscall_exit_to_user_mode+0x60/0x270 kernel/entry/common.c:303 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:87 entry_SYSCALL_64_after_hwframe+0x68/0xd2 other info that might help us debug this: Chain exists of: console_owner --> &p->pi_lock --> &rq->__lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&rq->__lock); lock(&p->pi_lock); lock(&rq->__lock); lock(console_owner); *** DEADLOCK *** 4 locks held by syz-executor373/4468: #0: ffff888074e508d8 (&mm->mmap_lock){++++}-{3:3}, at: __might_fault+0xa1/0x110 mm/memory.c:5851 #1: ffff8880b8f3a9d8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:537 #2: ffffffff8d32b000 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #2: ffffffff8d32b000 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #2: ffffffff8d32b000 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2270 [inline] #2: ffffffff8d32b000 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run4+0x16a/0x470 kernel/trace/bpf_trace.c:2312 #3: ffffffff8d207220 (console_lock){+.+.}-{0:0}, at: _printk+0xd1/0x111 kernel/printk/printk.c:2328 stack backtrace: CPU: 1 PID: 4468 Comm: syz-executor373 Not tainted 6.1.115-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106 check_noncircular+0x2fa/0x3b0 kernel/locking/lockdep.c:2170 check_prev_add kernel/locking/lockdep.c:3090 [inline] check_prevs_add kernel/locking/lockdep.c:3209 [inline] validate_chain+0x1661/0x5950 kernel/locking/lockdep.c:3825 __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5049 lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 console_lock_spinning_enable kernel/printk/printk.c:1818 [inline] console_emit_next_record+0xabd/0x1000 kernel/printk/printk.c:2774 console_unlock+0x278/0x7c0 kernel/printk/printk.c:2906 vprintk_emit+0x523/0x740 kernel/printk/printk.c:2303 _printk+0xd1/0x111 kernel/printk/printk.c:2328 fail_dump lib/fault-inject.c:45 [inline] should_fail_ex+0x387/0x4d0 lib/fault-inject.c:147 strncpy_from_user+0x32/0x360 lib/strncpy_from_user.c:118 strncpy_from_user_nofault+0x6c/0x130 mm/maccess.c:186 bpf_probe_read_user_str_common kernel/trace/bpf_trace.c:204 [inline] ____bpf_probe_read_user_str kernel/trace/bpf_trace.c:213 [inline] bpf_probe_read_user_str+0x26/0x70 kernel/trace/bpf_trace.c:210 bpf_prog_bc7c5c6b9645592f+0x35/0x37 bpf_dispatcher_nop_func include/linux/bpf.h:989 [inline] __bpf_prog_run include/linux/filter.h:603 [inline] bpf_prog_run include/linux/filter.h:610 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2271 [inline] bpf_trace_run4+0x253/0x470 kernel/trace/bpf_trace.c:2312 trace_sched_switch include/trace/events/sched.h:222 [inline] __schedule+0x2128/0x4570 kernel/sched/core.c:6555 preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6870 irqentry_exit+0x53/0x80 kernel/entry/common.c:439 asm_sysvec_reschedule_ipi+0x16/0x20 arch/x86/include/asm/idtentry.h:696 RIP: 0010:lock_acquire+0x26f/0x5a0 kernel/locking/lockdep.c:5666 Code: 2b 00 74 08 4c 89 f7 e8 6f 7b 77 00 f6 44 24 61 02 0f 85 84 01 00 00 41 f7 c7 00 02 00 00 74 01 fb 48 c7 44 24 40 0e 36 e0 45 <4b> c7 44 25 00 00 00 00 00 43 c7 44 25 09 00 00 00 00 43 c7 44 25 RSP: 0018:ffffc9000410fbe0 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 1ffff92000821f88 RCX: ffffffff816b55e2 RDX: dffffc0000000000 RSI: ffffffff8b0c1440 RDI: ffffffff8b5d7540 RBP: ffffc9000410fd38 R08: dffffc0000000000 R09: fffffbfff2246053 R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff92000821f84 R13: dffffc0000000000 R14: ffffc9000410fc40 R15: 0000000000000246 __might_fault+0xbd/0x110 mm/memory.c:5851 clear_rseq_cs kernel/rseq.c:228 [inline] rseq_ip_fixup kernel/rseq.c:262 [inline] __rseq_handle_notify_resume+0x5ba/0x1500 kernel/rseq.c:300 rseq_handle_notify_resume include/linux/sched.h:2329 [inline] resume_user_mode_work include/linux/resume_user_mode.h:61 [inline] exit_to_user_mode_loop+0xb4/0x100 kernel/entry/common.c:177 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline] syscall_exit_to_user_mode+0x60/0x270 kernel/entry/common.c:303 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:87 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7faa24b9c20f Code: 89 54 24 18 48 89 74 24 10 89 7c 24 08 e8 a9 82 02 00 48 8b 54 24 18 48 8b 74 24 10 41 89 c0 8b 7c 24 08 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 31 44 89 c7 48 89 44 24 08 e8 fc 82 02 00 48 RSP: 002b:00007faa24b0f1e0 EFLAGS: 00000293 ORIG_RAX: 0000000000000001 RAX: 0000000000000001 RBX: 00007faa24c21428 RCX: 00007faa24b9c20f RDX: 0000000000000001 RSI: 00007faa24b0f210 RDI: 0000000000000007 RBP: 00007faa24c21420 R08: 0000000000000000 R09: 00007faa24b0efa7 R10: 0000000000000000 R11: 0000000000000293 R12: 00007faa24bed854 R13: 00007faa24b0f210 R14: 0000000000000007 R15: 77735f6465686373 CPU: 1 PID: 4468 Comm: syz-executor373 Not tainted 6.1.115-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106 fail_dump lib/fault-inject.c:52 [inline] should_fail_ex+0x3a6/0x4d0 lib/fault-inject.c:147 strncpy_from_user+0x32/0x360 lib/strncpy_from_user.c:118 strncpy_from_user_nofault+0x6c/0x130 mm/maccess.c:186 bpf_probe_read_user_str_common kernel/trace/bpf_trace.c:204 [inline] ____bpf_probe_read_user_str kernel/trace/bpf_trace.c:213 [inline] bpf_probe_read_user_str+0x26/0x70 kernel/trace/bpf_trace.c:210 bpf_prog_bc7c5c6b9645592f+0x35/0x37 bpf_dispatcher_nop_func include/linux/bpf.h:989 [inline] __bpf_prog_run include/linux/filter.h:603 [inline] bpf_prog_run include/linux/filter.h:610 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2271 [inline] bpf_trace_run4+0x253/0x470 kernel/trace/bpf_trace.c:2312 trace_sched_switch include/trace/events/sched.h:222 [inline] __schedule+0x2128/0x4570 kernel/sched/core.c:6555 preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6870 irqentry_exit+0x53/0x80 kernel/entry/common.c:439 asm_sysvec_reschedule_ipi+0x16/0x20 arch/x86/include/asm/idtentry.h:696 RIP: 0010:lock_acquire+0x26f/0x5a0 kernel/locking/lockdep.c:5666 Code: 2b 00 74 08 4c 89 f7 e8 6f 7b 77 00 f6 44 24 61 02 0f 85 84 01 00 00 41 f7 c7 00 02 00 00 74 01 fb 48 c7 44 24 40 0e 36 e0 45 <4b> c7 44 25 00 00 00 00 00 43 c7 44 25 09 00 00 00 00 43 c7 44 25 RSP: 0018:ffffc9000410fbe0 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 1ffff92000821f88 RCX: ffffffff816b55e2 RDX: dffffc0000000000 RSI: ffffffff8b0c1440 RDI: ffffffff8b5d7540 RBP: ffffc9000410fd38 R08: dffffc0000000000 R09: fffffbfff2246053 R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff92000821f84 R13: dffffc0000000000 R14: ffffc9000410fc40 R15: 0000000000000246 __might_fault+0xbd/0x110 mm/memory.c:5851 clear_rseq_cs kernel/rseq.c:228 [inline] rseq_ip_fixup kernel/rseq.c:262 [inline] __rseq_handle_notify_resume+0x5ba/0x1500 kernel/rseq.c:300 rseq_handle_notify_resume include/linux/sched.h:2329 [inline] resume_user_mode_work include/linux/resume_user_mode.h:61 [inline] exit_to_user_mode_loop+0xb4/0x100 kernel/entry/common.c:177 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline] syscall_exit_to_user_mode+0x60/0x270 kernel/entry/common.c:303 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:87 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7faa24b9c20f Code: 89 54 24 18 48 89 74 24 10 89 7c 24 08 e8 a9 82 02 00 48 8b 54 24 18 48 8b 74 24 10 41 89 c0 8b 7c 24 08 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 31 44 89 c7 48 89 44 24 08 e8 fc 82 02 00 48 RSP: 002b:00007faa24b0f1e0 EFLAGS: 00000293 ORIG_RAX: 0000000000000001 RAX: 0000000000000001 RBX: 00007faa24c21428 RCX: 00007faa24b9c20f RDX: 0000000000000001 RSI: 00007faa24b0f210 RDI: 0000000000000007 RBP: 00007faa24c21420 R08: 0000000000000000 R09: 00007faa24b0efa7 R10: 0000000000000000 R11: 0000000000000293 R12: 00007faa24bed854 R13: 00007faa24b0f210 R14: 0000000000000007 R15: 77735f6465686373 ---------------- Code disassembly (best guess): 0: 2b 00 sub (%rax),%eax 2: 74 08 je 0xc 4: 4c 89 f7 mov %r14,%rdi 7: e8 6f 7b 77 00 call 0x777b7b c: f6 44 24 61 02 testb $0x2,0x61(%rsp) 11: 0f 85 84 01 00 00 jne 0x19b 17: 41 f7 c7 00 02 00 00 test $0x200,%r15d 1e: 74 01 je 0x21 20: fb sti 21: 48 c7 44 24 40 0e 36 movq $0x45e0360e,0x40(%rsp) 28: e0 45 * 2a: 4b c7 44 25 00 00 00 movq $0x0,0x0(%r13,%r12,1) <-- trapping instruction 31: 00 00 33: 43 c7 44 25 09 00 00 movl $0x0,0x9(%r13,%r12,1) 3a: 00 00 3c: 43 rex.XB 3d: c7 .byte 0xc7 3e: 44 rex.R 3f: 25 .byte 0x25