FAULT_INJECTION: forcing a failure.
name fail_usercopy, interval 1, probability 0, space 0, times 0
======================================================
WARNING: possible circular locking dependency detected
6.1.129-syzkaller #0 Not tainted
------------------------------------------------------
syz.4.581/6049 is trying to acquire lock:
ffffffff8d322840 (console_owner){-...}-{0:0}, at: console_lock_spinning_enable kernel/printk/printk.c:1818 [inline]
ffffffff8d322840 (console_owner){-...}-{0:0}, at: console_emit_next_record+0x74f/0xc30 kernel/printk/printk.c:2774
but task is already holding lock:
ffff8880b8e3a9d8 (&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:11886
sched_cgroup_fork+0x374/0x400 kernel/sched/core.c:4684
copy_process+0x2482/0x40a0 kernel/fork.c:2383
kernel_clone+0x222/0x920 kernel/fork.c:2681
user_mode_thread+0x140/0x1b0 kernel/fork.c:2757
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/0x1250 kernel/sched/core.c:4110
__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_is_held_type+0x137/0x180
lock_is_held include/linux/lockdep.h:283 [inline]
xa_entry include/linux/xarray.h:1198 [inline]
xas_reload+0xfd/0x470 include/linux/xarray.h:1583
next_uptodate_page+0x214/0xb70 mm/filemap.c:3390
next_map_page mm/filemap.c:3425 [inline]
filemap_map_pages+0xec2/0x12c0 mm/filemap.c:3497
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+0x19f/0x1a30 drivers/tty/serial/8250/8250_port.c:3433
call_console_driver kernel/printk/printk.c:1977 [inline]
console_emit_next_record+0x86d/0xc30 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+0x76c/0xc30 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_compat_str kernel/trace/bpf_trace.c:310 [inline]
bpf_probe_read_compat_str+0xe4/0x180 kernel/trace/bpf_trace.c:306
bpf_prog_c1796171ffc7efef+0x35/0x37
bpf_dispatcher_nop_func include/linux/bpf.h:1000 [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:2284 [inline]
bpf_trace_run4+0x253/0x470 kernel/trace/bpf_trace.c:2325
__traceiter_sched_switch+0x91/0xc0 include/trace/events/sched.h:222
trace_sched_switch include/trace/events/sched.h:222 [inline]
__schedule+0x2128/0x4570 kernel/sched/core.c:6557
preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6872
irqentry_exit+0x53/0x80 kernel/entry/common.c:439
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
memset_erms+0x9/0x10 arch/x86/lib/memset_64.S:63
slab_post_alloc_hook+0x71/0x3a0 mm/slab.h:739
slab_alloc_node mm/slub.c:3398 [inline]
slab_alloc mm/slub.c:3406 [inline]
__kmem_cache_alloc_lru mm/slub.c:3413 [inline]
kmem_cache_alloc+0x10c/0x2d0 mm/slub.c:3422
getname_flags+0xb8/0x4f0 fs/namei.c:139
do_sys_openat2+0xd2/0x4f0 fs/open.c:1312
do_sys_open fs/open.c:1334 [inline]
__do_sys_openat fs/open.c:1350 [inline]
__se_sys_openat fs/open.c:1345 [inline]
__x64_sys_openat+0x243/0x290 fs/open.c:1345
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
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 ***
3 locks held by syz.4.581/6049:
#0: ffff8880b8e3a9d8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:537
#1: ffffffff8d32e680 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
#1: ffffffff8d32e680 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
#1: ffffffff8d32e680 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2283 [inline]
#1: ffffffff8d32e680 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run4+0x16a/0x470 kernel/trace/bpf_trace.c:2325
#2: ffffffff8d20a5a0 (console_lock){+.+.}-{0:0}, at: _printk+0xd1/0x111 kernel/printk/printk.c:2328
stack backtrace:
CPU: 0 PID: 6049 Comm: syz.4.581 Not tainted 6.1.129-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
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+0x76c/0xc30 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_compat_str kernel/trace/bpf_trace.c:310 [inline]
bpf_probe_read_compat_str+0xe4/0x180 kernel/trace/bpf_trace.c:306
bpf_prog_c1796171ffc7efef+0x35/0x37
bpf_dispatcher_nop_func include/linux/bpf.h:1000 [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:2284 [inline]
bpf_trace_run4+0x253/0x470 kernel/trace/bpf_trace.c:2325
__traceiter_sched_switch+0x91/0xc0 include/trace/events/sched.h:222
trace_sched_switch include/trace/events/sched.h:222 [inline]
__schedule+0x2128/0x4570 kernel/sched/core.c:6557
preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6872
irqentry_exit+0x53/0x80 kernel/entry/common.c:439
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:memset_erms+0x9/0x10 arch/x86/lib/memset_64.S:64
Code: c1 e9 03 40 0f b6 f6 48 b8 01 01 01 01 01 01 01 01 48 0f af c6 f3 48 ab 89 d1 f3 aa 4c 89 c8 c3 90 49 89 f9 40 88 f0 48 89 d1 aa 4c 89 c8 c3 90 49 89 fa 40 0f b6 ce 48 b8 01 01 01 01 01 01
RSP: 0018:ffffc9000d0ffc28 EFLAGS: 00010246
RAX: ffff88807b1dd500 RBX: 0000000000000000 RCX: 0000000000000600
RDX: 0000000000001000 RSI: 0000000000000000 RDI: ffff88807b1ddf00
RBP: 0000000000000001 R08: 0000000000000009 R09: ffff88807b1dd500
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000001
R13: 0000000000000cc0 R14: 0000000000000001 R15: ffffc9000d0ffca0
slab_post_alloc_hook+0x71/0x3a0 mm/slab.h:739
slab_alloc_node mm/slub.c:3398 [inline]
slab_alloc mm/slub.c:3406 [inline]
__kmem_cache_alloc_lru mm/slub.c:3413 [inline]
kmem_cache_alloc+0x10c/0x2d0 mm/slub.c:3422
getname_flags+0xb8/0x4f0 fs/namei.c:139
do_sys_openat2+0xd2/0x4f0 fs/open.c:1312
do_sys_open fs/open.c:1334 [inline]
__do_sys_openat fs/open.c:1350 [inline]
__se_sys_openat fs/open.c:1345 [inline]
__x64_sys_openat+0x243/0x290 fs/open.c:1345
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f79d338d169
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f79d416e038 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f79d35a5fa0 RCX: 00007f79d338d169
RDX: 00000000000026e1 RSI: 0000400000000240 RDI: ffffffffffffff9c
RBP: 00007f79d416e090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 0000000000000000 R14: 00007f79d35a5fa0 R15: 00007fff24630c68
CPU: 0 PID: 6049 Comm: syz.4.581 Not tainted 6.1.129-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
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_compat_str kernel/trace/bpf_trace.c:310 [inline]
bpf_probe_read_compat_str+0xe4/0x180 kernel/trace/bpf_trace.c:306
bpf_prog_c1796171ffc7efef+0x35/0x37
bpf_dispatcher_nop_func include/linux/bpf.h:1000 [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:2284 [inline]
bpf_trace_run4+0x253/0x470 kernel/trace/bpf_trace.c:2325
__traceiter_sched_switch+0x91/0xc0 include/trace/events/sched.h:222
trace_sched_switch include/trace/events/sched.h:222 [inline]
__schedule+0x2128/0x4570 kernel/sched/core.c:6557
preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6872
irqentry_exit+0x53/0x80 kernel/entry/common.c:439
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:memset_erms+0x9/0x10 arch/x86/lib/memset_64.S:64
Code: c1 e9 03 40 0f b6 f6 48 b8 01 01 01 01 01 01 01 01 48 0f af c6 f3 48 ab 89 d1 f3 aa 4c 89 c8 c3 90 49 89 f9 40 88 f0 48 89 d1 aa 4c 89 c8 c3 90 49 89 fa 40 0f b6 ce 48 b8 01 01 01 01 01 01
RSP: 0018:ffffc9000d0ffc28 EFLAGS: 00010246
RAX: ffff88807b1dd500 RBX: 0000000000000000 RCX: 0000000000000600
RDX: 0000000000001000 RSI: 0000000000000000 RDI: ffff88807b1ddf00
RBP: 0000000000000001 R08: 0000000000000009 R09: ffff88807b1dd500
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000001
R13: 0000000000000cc0 R14: 0000000000000001 R15: ffffc9000d0ffca0
slab_post_alloc_hook+0x71/0x3a0 mm/slab.h:739
slab_alloc_node mm/slub.c:3398 [inline]
slab_alloc mm/slub.c:3406 [inline]
__kmem_cache_alloc_lru mm/slub.c:3413 [inline]
kmem_cache_alloc+0x10c/0x2d0 mm/slub.c:3422
getname_flags+0xb8/0x4f0 fs/namei.c:139
do_sys_openat2+0xd2/0x4f0 fs/open.c:1312
do_sys_open fs/open.c:1334 [inline]
__do_sys_openat fs/open.c:1350 [inline]
__se_sys_openat fs/open.c:1345 [inline]
__x64_sys_openat+0x243/0x290 fs/open.c:1345
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f79d338d169
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f79d416e038 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f79d35a5fa0 RCX: 00007f79d338d169
RDX: 00000000000026e1 RSI: 0000400000000240 RDI: ffffffffffffff9c
RBP: 00007f79d416e090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 0000000000000000 R14: 00007f79d35a5fa0 R15: 00007fff24630c68
----------------
Code disassembly (best guess):
0: c1 e9 03 shr $0x3,%ecx
3: 40 0f b6 f6 movzbl %sil,%esi
7: 48 b8 01 01 01 01 01 movabs $0x101010101010101,%rax
e: 01 01 01
11: 48 0f af c6 imul %rsi,%rax
15: f3 48 ab rep stos %rax,%es:(%rdi)
18: 89 d1 mov %edx,%ecx
1a: f3 aa rep stos %al,%es:(%rdi)
1c: 4c 89 c8 mov %r9,%rax
1f: c3 ret
20: 90 nop
21: 49 89 f9 mov %rdi,%r9
24: 40 88 f0 mov %sil,%al
27: 48 89 d1 mov %rdx,%rcx
* 2a: f3 aa rep stos %al,%es:(%rdi) <-- trapping instruction
2c: 4c 89 c8 mov %r9,%rax
2f: c3 ret
30: 90 nop
31: 49 89 fa mov %rdi,%r10
34: 40 0f b6 ce movzbl %sil,%ecx
38: 48 rex.W
39: b8 01 01 01 01 mov $0x1010101,%eax
3e: 01 01 add %eax,(%rcx)