FAULT_INJECTION: forcing a failure.
name fail_usercopy, interval 1, probability 0, space 0, times 0
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.1.975/9699 is trying to acquire lock:
ffffffff8df31660 (console_owner){-...}-{0:0}, at: rcu_try_lock_acquire include/linux/rcupdate.h:336 [inline]
ffffffff8df31660 (console_owner){-...}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:335 [inline]
ffffffff8df31660 (console_owner){-...}-{0:0}, at: console_srcu_read_lock kernel/printk/printk.c:289 [inline]
ffffffff8df31660 (console_owner){-...}-{0:0}, at: console_flush_all+0x13a/0xb10 kernel/printk/printk.c:3176
but task is already holding lock:
ffff8880b883a218 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:638
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #4 (&rq->__lock){-.-.}-{2:2}:
lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
_raw_spin_lock_nested+0x32/0x50 kernel/locking/spinlock.c:378
raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:638
raw_spin_rq_lock kernel/sched/sched.h:1547 [inline]
task_rq_lock+0xbc/0x470 kernel/sched/core.c:738
cgroup_move_task+0x92/0x2a0 kernel/sched/psi.c:1170
css_set_move_task+0x658/0x9e0 kernel/cgroup/cgroup.c:951
cgroup_post_fork+0x1ef/0x790 kernel/cgroup/cgroup.c:6913
copy_process+0x3862/0x3c00 kernel/fork.c:2425
kernel_clone+0x21e/0x840 kernel/fork.c:2609
user_mode_thread+0xdd/0x140 kernel/fork.c:2685
rest_init+0x23/0x300 init/main.c:722
start_kernel+0x3ae/0x410 init/main.c:1111
x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310
x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291
common_startup_64+0x13e/0x147
-> #3 (&p->pi_lock){-.-.}-{2:2}:
lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0xa7/0xf0 kernel/locking/spinlock.c:162
class_raw_spinlock_irqsave_constructor include/linux/spinlock.h:557 [inline]
try_to_wake_up+0x67/0x12b0 kernel/sched/core.c:4181
__wake_up_common kernel/sched/wait.c:108 [inline]
__wake_up_common_lock+0x137/0x1f0 kernel/sched/wait.c:125
tty_port_default_wakeup+0xfb/0x170 drivers/tty/tty_port.c:67
serial8250_tx_chars+0x72e/0x970 drivers/tty/serial/8250/8250_port.c:1719
serial8250_handle_irq+0x633/0xbb0 drivers/tty/serial/8250/8250_port.c:1827
serial8250_default_handle_irq+0xbf/0x200 drivers/tty/serial/8250/8250_port.c:1846
serial8250_interrupt+0x8d/0x180 drivers/tty/serial/8250/8250_core.c:82
__handle_irq_event_percpu+0x295/0xab0 kernel/irq/handle.c:203
handle_irq_event_percpu kernel/irq/handle.c:240 [inline]
handle_irq_event+0x8b/0x1e0 kernel/irq/handle.c:257
handle_edge_irq+0x23b/0xa10 kernel/irq/chip.c:855
generic_handle_irq_desc include/linux/irqdesc.h:173 [inline]
handle_irq arch/x86/kernel/irq.c:254 [inline]
call_irq_handler arch/x86/kernel/irq.c:-1 [inline]
__common_interrupt+0x141/0x1f0 arch/x86/kernel/irq.c:325
common_interrupt+0xb6/0xe0 arch/x86/kernel/irq.c:318
asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:688
native_safe_halt arch/x86/include/asm/irqflags.h:48 [inline]
pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:81
arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
default_idle+0x13/0x20 arch/x86/kernel/process.c:767
default_idle_call+0x73/0xb0 kernel/sched/idle.c:122
cpuidle_idle_call kernel/sched/idle.c:190 [inline]
do_idle+0x1e7/0x510 kernel/sched/idle.c:330
cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:428
rest_init+0x2de/0x300 init/main.c:757
start_kernel+0x3ae/0x410 init/main.c:1111
x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310
x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291
common_startup_64+0x13e/0x147
-> #2 (&tty->write_wait){-.-.}-{3:3}:
lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0xa7/0xf0 kernel/locking/spinlock.c:162
__wake_up_common_lock+0x2f/0x1f0 kernel/sched/wait.c:124
tty_port_default_wakeup+0xfb/0x170 drivers/tty/tty_port.c:67
serial8250_tx_chars+0x72e/0x970 drivers/tty/serial/8250/8250_port.c:1719
serial8250_handle_irq+0x633/0xbb0 drivers/tty/serial/8250/8250_port.c:1827
serial8250_default_handle_irq+0xbf/0x200 drivers/tty/serial/8250/8250_port.c:1846
serial8250_interrupt+0x8d/0x180 drivers/tty/serial/8250/8250_core.c:82
__handle_irq_event_percpu+0x295/0xab0 kernel/irq/handle.c:203
handle_irq_event_percpu kernel/irq/handle.c:240 [inline]
handle_irq_event+0x8b/0x1e0 kernel/irq/handle.c:257
handle_edge_irq+0x23b/0xa10 kernel/irq/chip.c:855
generic_handle_irq_desc include/linux/irqdesc.h:173 [inline]
handle_irq arch/x86/kernel/irq.c:254 [inline]
call_irq_handler arch/x86/kernel/irq.c:-1 [inline]
__common_interrupt+0x141/0x1f0 arch/x86/kernel/irq.c:325
common_interrupt+0xb6/0xe0 arch/x86/kernel/irq.c:318
asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:688
native_safe_halt arch/x86/include/asm/irqflags.h:48 [inline]
pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:81
arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
default_idle+0x13/0x20 arch/x86/kernel/process.c:767
default_idle_call+0x73/0xb0 kernel/sched/idle.c:122
cpuidle_idle_call kernel/sched/idle.c:190 [inline]
do_idle+0x1e7/0x510 kernel/sched/idle.c:330
cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:428
rest_init+0x2de/0x300 init/main.c:757
start_kernel+0x3ae/0x410 init/main.c:1111
x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310
x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291
common_startup_64+0x13e/0x147
-> #1 (&port_lock_key){-.-.}-{3:3}:
lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0xa7/0xf0 kernel/locking/spinlock.c:162
uart_port_lock_irqsave include/linux/serial_core.h:717 [inline]
serial8250_console_write+0x17e/0x1ba0 drivers/tty/serial/8250/8250_port.c:3301
console_emit_next_record kernel/printk/printk.c:3111 [inline]
console_flush_all+0x6f3/0xb10 kernel/printk/printk.c:3199
__console_flush_and_unlock kernel/printk/printk.c:3258 [inline]
console_unlock+0xbb/0x190 kernel/printk/printk.c:3298
vprintk_emit+0x4c5/0x590 kernel/printk/printk.c:2423
_printk+0xcf/0x120 kernel/printk/printk.c:2448
register_console+0xa8b/0xf90 kernel/printk/printk.c:4099
univ8250_console_init+0x3a/0x70 drivers/tty/serial/8250/8250_core.c:511
console_init+0x10e/0x430 kernel/printk/printk.c:4298
start_kernel+0x254/0x410 init/main.c:1048
x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310
x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291
common_startup_64+0x13e/0x147
-> #0 (console_owner){-...}-{0:0}:
check_prev_add kernel/locking/lockdep.c:3165 [inline]
check_prevs_add kernel/locking/lockdep.c:3284 [inline]
validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3908
__lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237
lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
console_lock_spinning_enable kernel/printk/printk.c:1897 [inline]
console_emit_next_record kernel/printk/printk.c:3105 [inline]
console_flush_all+0x69c/0xb10 kernel/printk/printk.c:3199
__console_flush_and_unlock kernel/printk/printk.c:3258 [inline]
console_unlock+0xbb/0x190 kernel/printk/printk.c:3298
vprintk_emit+0x4c5/0x590 kernel/printk/printk.c:2423
_printk+0xcf/0x120 kernel/printk/printk.c:2448
fail_dump lib/fault-inject.c:66 [inline]
should_fail_ex+0x3f5/0x560 lib/fault-inject.c:174
strncpy_from_user+0x36/0x290 lib/strncpy_from_user.c:118
strncpy_from_user_nofault+0x72/0x150 mm/maccess.c:192
bpf_probe_read_user_str_common kernel/trace/bpf_trace.c:214 [inline]
____bpf_probe_read_compat_str kernel/trace/bpf_trace.c:309 [inline]
bpf_probe_read_compat_str+0xe2/0x180 kernel/trace/bpf_trace.c:305
bpf_prog_8667240c19f5840f+0x73/0x7b
bpf_dispatcher_nop_func include/linux/bpf.h:1350 [inline]
__bpf_prog_run include/linux/filter.h:721 [inline]
bpf_prog_run include/linux/filter.h:728 [inline]
__bpf_trace_run kernel/trace/bpf_trace.c:2075 [inline]
bpf_trace_run2+0x284/0x4b0 kernel/trace/bpf_trace.c:2116
__bpf_trace_tlb_flush+0xf5/0x150 include/trace/events/tlb.h:38
__do_trace_tlb_flush include/trace/events/tlb.h:38 [inline]
trace_tlb_flush+0x115/0x140 include/trace/events/tlb.h:38
switch_mm_irqs_off+0x54a/0x7b0 arch/x86/mm/tlb.c:-1
context_switch kernel/sched/core.c:5309 [inline]
__schedule+0x110e/0x4cc0 kernel/sched/core.c:6929
preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7256
irqentry_exit+0x6f/0x90 kernel/entry/common.c:211
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
syscall_enter_from_user_mode_work include/linux/entry-common.h:92 [inline]
syscall_enter_from_user_mode include/linux/entry-common.h:125 [inline]
do_syscall_64+0xc3/0xfa0 arch/x86/entry/syscall_64.c:90
entry_SYSCALL_64_after_hwframe+0x77/0x7f
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.1.975/9699:
#0: ffff8880b883a218 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:638
#1: ffffffff8df3d6e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#1: ffffffff8df3d6e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#1: ffffffff8df3d6e0 (rcu_read_lock){....}-{1:3}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2074 [inline]
#1: ffffffff8df3d6e0 (rcu_read_lock){....}-{1:3}, at: bpf_trace_run2+0x186/0x4b0 kernel/trace/bpf_trace.c:2116
#2: ffffffff8df316c0 (console_lock){+.+.}-{0:0}, at: _printk+0xcf/0x120 kernel/printk/printk.c:2448
#3: ffffffff8de18f90 (console_srcu){....}-{0:0}, at: rcu_try_lock_acquire include/linux/rcupdate.h:336 [inline]
#3: ffffffff8de18f90 (console_srcu){....}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:335 [inline]
#3: ffffffff8de18f90 (console_srcu){....}-{0:0}, at: console_srcu_read_lock kernel/printk/printk.c:289 [inline]
#3: ffffffff8de18f90 (console_srcu){....}-{0:0}, at: console_flush_all+0x13a/0xb10 kernel/printk/printk.c:3176
stack backtrace:
CPU: 0 UID: 0 PID: 9699 Comm: syz.1.975 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
print_circular_bug+0x2ee/0x310 kernel/locking/lockdep.c:2043
check_noncircular+0x134/0x160 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+0xb9b/0x2140 kernel/locking/lockdep.c:3908
__lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237
lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
console_lock_spinning_enable kernel/printk/printk.c:1897 [inline]
console_emit_next_record kernel/printk/printk.c:3105 [inline]
console_flush_all+0x69c/0xb10 kernel/printk/printk.c:3199
__console_flush_and_unlock kernel/printk/printk.c:3258 [inline]
console_unlock+0xbb/0x190 kernel/printk/printk.c:3298
vprintk_emit+0x4c5/0x590 kernel/printk/printk.c:2423
_printk+0xcf/0x120 kernel/printk/printk.c:2448
fail_dump lib/fault-inject.c:66 [inline]
should_fail_ex+0x3f5/0x560 lib/fault-inject.c:174
strncpy_from_user+0x36/0x290 lib/strncpy_from_user.c:118
strncpy_from_user_nofault+0x72/0x150 mm/maccess.c:192
bpf_probe_read_user_str_common kernel/trace/bpf_trace.c:214 [inline]
____bpf_probe_read_compat_str kernel/trace/bpf_trace.c:309 [inline]
bpf_probe_read_compat_str+0xe2/0x180 kernel/trace/bpf_trace.c:305
bpf_prog_8667240c19f5840f+0x73/0x7b
bpf_dispatcher_nop_func include/linux/bpf.h:1350 [inline]
__bpf_prog_run include/linux/filter.h:721 [inline]
bpf_prog_run include/linux/filter.h:728 [inline]
__bpf_trace_run kernel/trace/bpf_trace.c:2075 [inline]
bpf_trace_run2+0x284/0x4b0 kernel/trace/bpf_trace.c:2116
__bpf_trace_tlb_flush+0xf5/0x150 include/trace/events/tlb.h:38
__do_trace_tlb_flush include/trace/events/tlb.h:38 [inline]
trace_tlb_flush+0x115/0x140 include/trace/events/tlb.h:38
switch_mm_irqs_off+0x54a/0x7b0 arch/x86/mm/tlb.c:-1
context_switch kernel/sched/core.c:5309 [inline]
__schedule+0x110e/0x4cc0 kernel/sched/core.c:6929
preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7256
irqentry_exit+0x6f/0x90 kernel/entry/common.c:211
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:syscall_enter_from_user_mode_work include/linux/entry-common.h:94 [inline]
RIP: 0010:syscall_enter_from_user_mode include/linux/entry-common.h:125 [inline]
RIP: 0010:do_syscall_64+0xc3/0xfa0 arch/x86/entry/syscall_64.c:90
Code: 00 48 8b 7d 08 48 89 7b 18 e8 b9 72 00 00 0f 1f 44 00 00 0f 1f 44 00 00 90 e8 b9 91 80 f6 90 90 e8 62 91 80 f6 fb 49 8b 57 08 c2 3f 74 0e 4c 89 f7 4c 89 ee e8 6d 0a 63 f6 49 89 c4 90 90 41
RSP: 0018:ffffc9001ad7fee0 EFLAGS: 00000282
RAX: d9211d92eae6fa00 RBX: ffffc9001ad7fee0 RCX: d9211d92eae6fa00
RDX: 0000000000000000 RSI: ffffffff8d7117ce RDI: ffffffff8bbf08e0
RBP: ffffc9001ad7ff38 R08: ffffffff8f7d0477 R09: 1ffffffff1efa08e
R10: dffffc0000000000 R11: fffffbfff1efa08f R12: 0000000000000000
R13: 0000000000000000 R14: ffffc9001ad7ff48 R15: ffff88807a5d1e40
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f846d98e15c
Code: Unable to access opcode bytes at 0x7f846d98e132.
RSP: 002b:00007f846e800030 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007f846dbe5fa0 RCX: 00007f846d98e15c
RDX: 000000000000000f RSI: 00007f846e8000a0 RDI: 0000000000000005
RBP: 00007f846e800090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007f846dbe6038 R14: 00007f846dbe5fa0 R15: 00007ffdb503d6d8
CPU: 0 UID: 0 PID: 9699 Comm: syz.1.975 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
fail_dump lib/fault-inject.c:73 [inline]
should_fail_ex+0x414/0x560 lib/fault-inject.c:174
strncpy_from_user+0x36/0x290 lib/strncpy_from_user.c:118
strncpy_from_user_nofault+0x72/0x150 mm/maccess.c:192
bpf_probe_read_user_str_common kernel/trace/bpf_trace.c:214 [inline]
____bpf_probe_read_compat_str kernel/trace/bpf_trace.c:309 [inline]
bpf_probe_read_compat_str+0xe2/0x180 kernel/trace/bpf_trace.c:305
bpf_prog_8667240c19f5840f+0x73/0x7b
bpf_dispatcher_nop_func include/linux/bpf.h:1350 [inline]
__bpf_prog_run include/linux/filter.h:721 [inline]
bpf_prog_run include/linux/filter.h:728 [inline]
__bpf_trace_run kernel/trace/bpf_trace.c:2075 [inline]
bpf_trace_run2+0x284/0x4b0 kernel/trace/bpf_trace.c:2116
__bpf_trace_tlb_flush+0xf5/0x150 include/trace/events/tlb.h:38
__do_trace_tlb_flush include/trace/events/tlb.h:38 [inline]
trace_tlb_flush+0x115/0x140 include/trace/events/tlb.h:38
switch_mm_irqs_off+0x54a/0x7b0 arch/x86/mm/tlb.c:-1
context_switch kernel/sched/core.c:5309 [inline]
__schedule+0x110e/0x4cc0 kernel/sched/core.c:6929
preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7256
irqentry_exit+0x6f/0x90 kernel/entry/common.c:211
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:syscall_enter_from_user_mode_work include/linux/entry-common.h:94 [inline]
RIP: 0010:syscall_enter_from_user_mode include/linux/entry-common.h:125 [inline]
RIP: 0010:do_syscall_64+0xc3/0xfa0 arch/x86/entry/syscall_64.c:90
Code: 00 48 8b 7d 08 48 89 7b 18 e8 b9 72 00 00 0f 1f 44 00 00 0f 1f 44 00 00 90 e8 b9 91 80 f6 90 90 e8 62 91 80 f6 fb 49 8b 57 08 c2 3f 74 0e 4c 89 f7 4c 89 ee e8 6d 0a 63 f6 49 89 c4 90 90 41
RSP: 0018:ffffc9001ad7fee0 EFLAGS: 00000282
RAX: d9211d92eae6fa00 RBX: ffffc9001ad7fee0 RCX: d9211d92eae6fa00
RDX: 0000000000000000 RSI: ffffffff8d7117ce RDI: ffffffff8bbf08e0
RBP: ffffc9001ad7ff38 R08: ffffffff8f7d0477 R09: 1ffffffff1efa08e
R10: dffffc0000000000 R11: fffffbfff1efa08f R12: 0000000000000000
R13: 0000000000000000 R14: ffffc9001ad7ff48 R15: ffff88807a5d1e40
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f846d98e15c
Code: Unable to access opcode bytes at 0x7f846d98e132.
RSP: 002b:00007f846e800030 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007f846dbe5fa0 RCX: 00007f846d98e15c
RDX: 000000000000000f RSI: 00007f846e8000a0 RDI: 0000000000000005
RBP: 00007f846e800090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007f846dbe6038 R14: 00007f846dbe5fa0 R15: 00007ffdb503d6d8
----------------
Code disassembly (best guess):
0: 00 48 8b add %cl,-0x75(%rax)
3: 7d 08 jge 0xd
5: 48 89 7b 18 mov %rdi,0x18(%rbx)
9: e8 b9 72 00 00 call 0x72c7
e: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1)
13: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1)
18: 90 nop
19: e8 b9 91 80 f6 call 0xf68091d7
1e: 90 nop
1f: 90 nop
20: e8 62 91 80 f6 call 0xf6809187
25: fb sti
26: 49 8b 57 08 mov 0x8(%r15),%rdx
* 2a: f6 c2 3f test $0x3f,%dl <-- trapping instruction
2d: 74 0e je 0x3d
2f: 4c 89 f7 mov %r14,%rdi
32: 4c 89 ee mov %r13,%rsi
35: e8 6d 0a 63 f6 call 0xf6630aa7
3a: 49 89 c4 mov %rax,%r12
3d: 90 nop
3e: 90 nop
3f: 41 rex.B