------------[ cut here ]------------
======================================================
WARNING: possible circular locking dependency detected
5.15.187-syzkaller #0 Not tainted
------------------------------------------------------
ksoftirqd/0/14 is trying to acquire lock:
ffffffff8c110d20 (console_owner){..-.}-{0:0}, at: console_lock_spinning_enable+0x2c/0x60 kernel/printk/printk.c:1802
but task is already holding lock:
ffff8880b9028098 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x123/0x270 kernel/time/timer.c:946
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #5 (&base->lock){-.-.}-{2:2}:
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0xa4/0xf0 kernel/locking/spinlock.c:162
lock_timer_base+0x123/0x270 kernel/time/timer.c:946
__mod_timer+0x117/0xd20 kernel/time/timer.c:1019
queue_delayed_work_on+0x126/0x1e0 kernel/workqueue.c:1715
psi_enqueue kernel/sched/stats.h:102 [inline]
enqueue_task+0x26d/0x2b0 kernel/sched/core.c:1973
activate_task kernel/sched/core.c:2005 [inline]
wake_up_new_task+0x442/0x9a0 kernel/sched/core.c:4522
kernel_clone+0x421/0x930 kernel/fork.c:2703
kernel_thread+0xc8/0x120 kernel/fork.c:2731
rest_init+0x21/0x330 init/main.c:706
start_kernel+0x486/0x530 init/main.c:1140
secondary_startup_64_no_verify+0xb1/0xbb
-> #4 (&rq->__lock){-.-.}-{2:2}:
_raw_spin_lock_nested+0x2e/0x40 kernel/locking/spinlock.c:368
raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:475
raw_spin_rq_lock kernel/sched/sched.h:1326 [inline]
rq_lock kernel/sched/sched.h:1621 [inline]
task_fork_fair+0x5c/0x350 kernel/sched/fair.c:11499
sched_cgroup_fork+0x2c6/0x320 kernel/sched/core.c:4466
copy_process+0x22d1/0x3e00 kernel/fork.c:2395
kernel_clone+0x219/0x930 kernel/fork.c:2679
kernel_thread+0xc8/0x120 kernel/fork.c:2731
rest_init+0x21/0x330 init/main.c:706
start_kernel+0x486/0x530 init/main.c:1140
secondary_startup_64_no_verify+0xb1/0xbb
-> #3 (&p->pi_lock){-.-.}-{2:2}:
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0xa4/0xf0 kernel/locking/spinlock.c:162
try_to_wake_up+0x5c/0x1050 kernel/sched/core.c:4030
__wake_up_common+0x2a4/0x4e0 kernel/sched/wait.c:108
__wake_up_common_lock kernel/sched/wait.c:138 [inline]
__wake_up+0x108/0x180 kernel/sched/wait.c:157
tty_port_default_wakeup+0xa5/0xf0 drivers/tty/tty_port.c:51
serial8250_tx_chars+0x629/0x830 drivers/tty/serial/8250/8250_port.c:1828
serial8250_handle_irq+0x519/0x610 drivers/tty/serial/8250/8250_port.c:1924
serial8250_default_handle_irq+0xb4/0x1a0 drivers/tty/serial/8250/8250_port.c:1941
serial8250_interrupt+0x9b/0x1c0 drivers/tty/serial/8250/8250_core.c:127
__handle_irq_event_percpu+0x291/0x9b0 kernel/irq/handle.c:156
handle_irq_event_percpu kernel/irq/handle.c:196 [inline]
handle_irq_event+0xa5/0x220 kernel/irq/handle.c:213
handle_edge_irq+0x243/0xb20 kernel/irq/chip.c:819
generic_handle_irq_desc include/linux/irqdesc.h:158 [inline]
handle_irq arch/x86/kernel/irq.c:233 [inline]
__common_interrupt+0xd7/0x1e0 arch/x86/kernel/irq.c:252
common_interrupt+0x59/0xd0 arch/x86/kernel/irq.c:242
asm_common_interrupt+0x22/0x40 arch/x86/include/asm/idtentry.h:667
ffs arch/x86/include/asm/bitops.h:297 [inline]
handle_softirqs+0x1a9/0x820 kernel/softirq.c:564
__do_softirq kernel/softirq.c:610 [inline]
invoke_softirq kernel/softirq.c:450 [inline]
__irq_exit_rcu+0x12f/0x220 kernel/softirq.c:659
irq_exit_rcu+0x5/0x20 kernel/softirq.c:671
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1108
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline]
arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
default_idle+0xb/0x10 arch/x86/kernel/process.c:728
default_idle_call+0x81/0xc0 kernel/sched/idle.c:112
cpuidle_idle_call kernel/sched/idle.c:194 [inline]
do_idle+0x21b/0x5b0 kernel/sched/idle.c:306
cpu_startup_entry+0x14/0x20 kernel/sched/idle.c:403
start_secondary+0x31f/0x430 arch/x86/kernel/smpboot.c:281
secondary_startup_64_no_verify+0xb1/0xbb
-> #2 (&tty->write_wait){-.-.}-{2:2}:
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0xa4/0xf0 kernel/locking/spinlock.c:162
__wake_up_common_lock kernel/sched/wait.c:137 [inline]
__wake_up+0xed/0x180 kernel/sched/wait.c:157
tty_port_default_wakeup+0xa5/0xf0 drivers/tty/tty_port.c:51
serial8250_tx_chars+0x629/0x830 drivers/tty/serial/8250/8250_port.c:1828
serial8250_handle_irq+0x519/0x610 drivers/tty/serial/8250/8250_port.c:1924
serial8250_default_handle_irq+0xb4/0x1a0 drivers/tty/serial/8250/8250_port.c:1941
serial8250_interrupt+0x9b/0x1c0 drivers/tty/serial/8250/8250_core.c:127
__handle_irq_event_percpu+0x291/0x9b0 kernel/irq/handle.c:156
handle_irq_event_percpu kernel/irq/handle.c:196 [inline]
handle_irq_event+0xa5/0x220 kernel/irq/handle.c:213
handle_edge_irq+0x243/0xb20 kernel/irq/chip.c:819
generic_handle_irq_desc include/linux/irqdesc.h:158 [inline]
handle_irq arch/x86/kernel/irq.c:233 [inline]
__common_interrupt+0xd7/0x1e0 arch/x86/kernel/irq.c:252
common_interrupt+0xb0/0xd0 arch/x86/kernel/irq.c:242
asm_common_interrupt+0x22/0x40 arch/x86/include/asm/idtentry.h:667
__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline]
_raw_spin_unlock_irqrestore+0xa5/0x100 kernel/locking/spinlock.c:194
spin_unlock_irqrestore include/linux/spinlock.h:418 [inline]
uart_write+0x62f/0x880 drivers/tty/serial/serial_core.c:592
process_output_block drivers/tty/n_tty.c:592 [inline]
n_tty_write+0xd21/0x1210 drivers/tty/n_tty.c:2339
do_tty_write drivers/tty/tty_io.c:1038 [inline]
file_tty_write+0x557/0x910 drivers/tty/tty_io.c:1110
call_write_iter include/linux/fs.h:2172 [inline]
new_sync_write fs/read_write.c:507 [inline]
vfs_write+0x712/0xd00 fs/read_write.c:594
ksys_write+0x14d/0x250 fs/read_write.c:647
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
-> #1 (&port_lock_key){-.-.}-{2:2}:
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0xa4/0xf0 kernel/locking/spinlock.c:162
serial8250_console_write+0x170/0xf80 drivers/tty/serial/8250/8250_port.c:3363
call_console_drivers kernel/printk/printk.c:-1 [inline]
console_unlock+0xc86/0x1200 kernel/printk/printk.c:2744
vprintk_emit+0xc0/0x150 kernel/printk/printk.c:2274
_printk+0xcc/0x110 kernel/printk/printk.c:2299
register_console+0x682/0x960 kernel/printk/printk.c:3107
univ8250_console_init+0x41/0x50 drivers/tty/serial/8250/8250_core.c:690
console_init+0x177/0x5d0 kernel/printk/printk.c:3207
start_kernel+0x2f9/0x530 init/main.c:1076
secondary_startup_64_no_verify+0xb1/0xbb
-> #0 (console_owner){..-.}-{0:0}:
check_prev_add kernel/locking/lockdep.c:3053 [inline]
check_prevs_add kernel/locking/lockdep.c:3172 [inline]
validate_chain kernel/locking/lockdep.c:3788 [inline]
__lock_acquire+0x2c33/0x7c60 kernel/locking/lockdep.c:5012
lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623
console_lock_spinning_enable+0x51/0x60 kernel/printk/printk.c:1805
console_unlock+0x9f8/0x1200 kernel/printk/printk.c:2741
vprintk_emit+0xc0/0x150 kernel/printk/printk.c:2274
_printk+0xcc/0x110 kernel/printk/printk.c:2299
report_bug+0x1e5/0x2e0 lib/bug.c:195
handle_bug+0x3a/0x70 arch/x86/kernel/traps.c:239
exc_invalid_op+0x16/0x40 arch/x86/kernel/traps.c:259
asm_exc_invalid_op+0x16/0x20 arch/x86/include/asm/idtentry.h:604
copy_from_user_nofault+0x160/0x1c0 mm/maccess.c:226
bpf_probe_read_user_common kernel/trace/bpf_trace.c:157 [inline]
____bpf_probe_read_user kernel/trace/bpf_trace.c:166 [inline]
bpf_probe_read_user+0x26/0x70 kernel/trace/bpf_trace.c:163
bpf_prog_02073d59a3c0f06f+0x3d/0x23c
bpf_dispatcher_nop_func include/linux/bpf.h:790 [inline]
__bpf_prog_run include/linux/filter.h:628 [inline]
bpf_prog_run include/linux/filter.h:635 [inline]
__bpf_trace_run kernel/trace/bpf_trace.c:1878 [inline]
bpf_trace_run3+0x17e/0x320 kernel/trace/bpf_trace.c:1916
trace_timer_start include/trace/events/timer.h:52 [inline]
enqueue_timer+0x394/0x520 kernel/time/timer.c:586
__mod_timer+0x88e/0xd20 kernel/time/timer.c:1060
sk_reset_timer+0x1f/0xb0 net/core/sock.c:3137
tcp_event_new_data_sent+0x20e/0x370 net/ipv4/tcp_output.c:81
tcp_write_xmit+0x192a/0x6590 net/ipv4/tcp_output.c:2714
__tcp_push_pending_frames+0x92/0x250 net/ipv4/tcp_output.c:2892
tcp_push_pending_frames include/net/tcp.h:1916 [inline]
tcp_data_snd_check net/ipv4/tcp_input.c:5571 [inline]
tcp_rcv_established+0xf25/0x1cb0 net/ipv4/tcp_input.c:5982
tcp_v4_do_rcv+0x44b/0x9b0 net/ipv4/tcp_ipv4.c:1731
tcp_v4_rcv+0x268f/0x2cb0 net/ipv4/tcp_ipv4.c:2143
ip_protocol_deliver_rcu+0x3ad/0x770 net/ipv4/ip_input.c:204
ip_local_deliver_finish+0x1d5/0x320 net/ipv4/ip_input.c:231
NF_HOOK+0x2d6/0x360 include/linux/netfilter.h:302
NF_HOOK+0x2d6/0x360 include/linux/netfilter.h:302
__netif_receive_skb_one_core net/core/dev.c:5525 [inline]
__netif_receive_skb+0xcc/0x290 net/core/dev.c:5639
process_backlog+0x364/0x780 net/core/dev.c:6516
__napi_poll+0xc0/0x430 net/core/dev.c:7075
napi_poll net/core/dev.c:7142 [inline]
net_rx_action+0x4a8/0x9c0 net/core/dev.c:7232
handle_softirqs+0x328/0x820 kernel/softirq.c:576
run_ksoftirqd+0x98/0xf0 kernel/softirq.c:943
smpboot_thread_fn+0x4f6/0x970 kernel/smpboot.c:164
kthread+0x436/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
other info that might help us debug this:
Chain exists of:
console_owner --> &rq->__lock --> &base->lock
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&base->lock);
lock(&rq->__lock);
lock(&base->lock);
lock(console_owner);
*** DEADLOCK ***
6 locks held by ksoftirqd/0/14:
#0: ffffffff8c11c2e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x9/0x30 include/linux/rcupdate.h:312
#1: ffffffff8c11c2e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:311
#2: ffff88807df918a0 (slock-AF_INET/1){+.-.}-{2:2}, at: tcp_v4_rcv+0x261d/0x2cb0 net/ipv4/tcp_ipv4.c:2137
#3: ffff8880b9028098 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x123/0x270 kernel/time/timer.c:946
#4: ffffffff8c11c2e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:311
#5: ffffffff8c110e00 (console_lock){+.+.}-{0:0}, at: vprintk_emit+0xa7/0x150 kernel/printk/printk.c:2273
stack backtrace:
CPU: 0 PID: 14 Comm: ksoftirqd/0 Not tainted 5.15.187-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
check_noncircular+0x274/0x310 kernel/locking/lockdep.c:2133
check_prev_add kernel/locking/lockdep.c:3053 [inline]
check_prevs_add kernel/locking/lockdep.c:3172 [inline]
validate_chain kernel/locking/lockdep.c:3788 [inline]
__lock_acquire+0x2c33/0x7c60 kernel/locking/lockdep.c:5012
lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623
console_lock_spinning_enable+0x51/0x60 kernel/printk/printk.c:1805
console_unlock+0x9f8/0x1200 kernel/printk/printk.c:2741
vprintk_emit+0xc0/0x150 kernel/printk/printk.c:2274
_printk+0xcc/0x110 kernel/printk/printk.c:2299
report_bug+0x1e5/0x2e0 lib/bug.c:195
handle_bug+0x3a/0x70 arch/x86/kernel/traps.c:239
exc_invalid_op+0x16/0x40 arch/x86/kernel/traps.c:259
asm_exc_invalid_op+0x16/0x20 arch/x86/include/asm/idtentry.h:604
RIP: 0010:copy_from_user_nofault+0x160/0x1c0 mm/maccess.c:226
Code: 24 45 31 f6 31 ff 89 de e8 2d e2 d7 ff 85 db 48 c7 c0 f2 ff ff ff 49 0f 44 c6 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 b0 de d7 ff <0f> 0b e9 1c ff ff ff 44 89 e1 80 e1 07 80 c1 03 38 c1 0f 8c ea fe
RSP: 0018:ffffc90000d36dc0 EFLAGS: 00010046
RAX: ffffffff819ff470 RBX: 0000000000000008 RCX: ffff88813fea9dc0
RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: dffffc0000000000 R09: fffffbfff1ff7619
R10: fffffbfff1ff7619 R11: 1ffffffff1ff7618 R12: ffff88813feab548
R13: 1ffff920001a6dc8 R14: ffffc90000d36e28 R15: 0000000000000000
bpf_probe_read_user_common kernel/trace/bpf_trace.c:157 [inline]
____bpf_probe_read_user kernel/trace/bpf_trace.c:166 [inline]
bpf_probe_read_user+0x26/0x70 kernel/trace/bpf_trace.c:163
bpf_prog_02073d59a3c0f06f+0x3d/0x23c
bpf_dispatcher_nop_func include/linux/bpf.h:790 [inline]
__bpf_prog_run include/linux/filter.h:628 [inline]
bpf_prog_run include/linux/filter.h:635 [inline]
__bpf_trace_run kernel/trace/bpf_trace.c:1878 [inline]
bpf_trace_run3+0x17e/0x320 kernel/trace/bpf_trace.c:1916
trace_timer_start include/trace/events/timer.h:52 [inline]
enqueue_timer+0x394/0x520 kernel/time/timer.c:586
__mod_timer+0x88e/0xd20 kernel/time/timer.c:1060
sk_reset_timer+0x1f/0xb0 net/core/sock.c:3137
tcp_event_new_data_sent+0x20e/0x370 net/ipv4/tcp_output.c:81
tcp_write_xmit+0x192a/0x6590 net/ipv4/tcp_output.c:2714
__tcp_push_pending_frames+0x92/0x250 net/ipv4/tcp_output.c:2892
tcp_push_pending_frames include/net/tcp.h:1916 [inline]
tcp_data_snd_check net/ipv4/tcp_input.c:5571 [inline]
tcp_rcv_established+0xf25/0x1cb0 net/ipv4/tcp_input.c:5982
tcp_v4_do_rcv+0x44b/0x9b0 net/ipv4/tcp_ipv4.c:1731
tcp_v4_rcv+0x268f/0x2cb0 net/ipv4/tcp_ipv4.c:2143
ip_protocol_deliver_rcu+0x3ad/0x770 net/ipv4/ip_input.c:204
ip_local_deliver_finish+0x1d5/0x320 net/ipv4/ip_input.c:231
NF_HOOK+0x2d6/0x360 include/linux/netfilter.h:302
NF_HOOK+0x2d6/0x360 include/linux/netfilter.h:302
__netif_receive_skb_one_core net/core/dev.c:5525 [inline]
__netif_receive_skb+0xcc/0x290 net/core/dev.c:5639
process_backlog+0x364/0x780 net/core/dev.c:6516
__napi_poll+0xc0/0x430 net/core/dev.c:7075
napi_poll net/core/dev.c:7142 [inline]
net_rx_action+0x4a8/0x9c0 net/core/dev.c:7232
handle_softirqs+0x328/0x820 kernel/softirq.c:576
run_ksoftirqd+0x98/0xf0 kernel/softirq.c:943
smpboot_thread_fn+0x4f6/0x970 kernel/smpboot.c:164
kthread+0x436/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
WARNING: CPU: 0 PID: 14 at mm/maccess.c:226 copy_from_user_nofault+0x160/0x1c0 mm/maccess.c:226
Modules linked in:
CPU: 0 PID: 14 Comm: ksoftirqd/0 Not tainted 5.15.187-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:copy_from_user_nofault+0x160/0x1c0 mm/maccess.c:226
Code: 24 45 31 f6 31 ff 89 de e8 2d e2 d7 ff 85 db 48 c7 c0 f2 ff ff ff 49 0f 44 c6 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 b0 de d7 ff <0f> 0b e9 1c ff ff ff 44 89 e1 80 e1 07 80 c1 03 38 c1 0f 8c ea fe
RSP: 0018:ffffc90000d36dc0 EFLAGS: 00010046
RAX: ffffffff819ff470 RBX: 0000000000000008 RCX: ffff88813fea9dc0
RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: dffffc0000000000 R09: fffffbfff1ff7619
R10: fffffbfff1ff7619 R11: 1ffffffff1ff7618 R12: ffff88813feab548
R13: 1ffff920001a6dc8 R14: ffffc90000d36e28 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055558cc8f808 CR3: 000000005d70a000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
bpf_probe_read_user_common kernel/trace/bpf_trace.c:157 [inline]
____bpf_probe_read_user kernel/trace/bpf_trace.c:166 [inline]
bpf_probe_read_user+0x26/0x70 kernel/trace/bpf_trace.c:163
bpf_prog_02073d59a3c0f06f+0x3d/0x23c
bpf_dispatcher_nop_func include/linux/bpf.h:790 [inline]
__bpf_prog_run include/linux/filter.h:628 [inline]
bpf_prog_run include/linux/filter.h:635 [inline]
__bpf_trace_run kernel/trace/bpf_trace.c:1878 [inline]
bpf_trace_run3+0x17e/0x320 kernel/trace/bpf_trace.c:1916
trace_timer_start include/trace/events/timer.h:52 [inline]
enqueue_timer+0x394/0x520 kernel/time/timer.c:586
__mod_timer+0x88e/0xd20 kernel/time/timer.c:1060
sk_reset_timer+0x1f/0xb0 net/core/sock.c:3137
tcp_event_new_data_sent+0x20e/0x370 net/ipv4/tcp_output.c:81
tcp_write_xmit+0x192a/0x6590 net/ipv4/tcp_output.c:2714
__tcp_push_pending_frames+0x92/0x250 net/ipv4/tcp_output.c:2892
tcp_push_pending_frames include/net/tcp.h:1916 [inline]
tcp_data_snd_check net/ipv4/tcp_input.c:5571 [inline]
tcp_rcv_established+0xf25/0x1cb0 net/ipv4/tcp_input.c:5982
tcp_v4_do_rcv+0x44b/0x9b0 net/ipv4/tcp_ipv4.c:1731
tcp_v4_rcv+0x268f/0x2cb0 net/ipv4/tcp_ipv4.c:2143
ip_protocol_deliver_rcu+0x3ad/0x770 net/ipv4/ip_input.c:204
ip_local_deliver_finish+0x1d5/0x320 net/ipv4/ip_input.c:231
NF_HOOK+0x2d6/0x360 include/linux/netfilter.h:302
NF_HOOK+0x2d6/0x360 include/linux/netfilter.h:302
__netif_receive_skb_one_core net/core/dev.c:5525 [inline]
__netif_receive_skb+0xcc/0x290 net/core/dev.c:5639
process_backlog+0x364/0x780 net/core/dev.c:6516
__napi_poll+0xc0/0x430 net/core/dev.c:7075
napi_poll net/core/dev.c:7142 [inline]
net_rx_action+0x4a8/0x9c0 net/core/dev.c:7232
handle_softirqs+0x328/0x820 kernel/softirq.c:576
run_ksoftirqd+0x98/0xf0 kernel/softirq.c:943
smpboot_thread_fn+0x4f6/0x970 kernel/smpboot.c:164
kthread+0x436/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287