rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P3936/1:b..l P63/1:b..l P30131/1:b..l P30132/1:b..l P29832/1:b..l
rcu: (detected by 0, t=10502 jiffies, g=259597, q=768 ncpus=2)
task:udevd state:R running task stack:23000 pid:29832 tgid:29832 ppid:5202 task_flags:0x400140 flags:0x00000002
Call Trace:
context_switch kernel/sched/core.c:5382 [inline]
__schedule+0x16e2/0x4cd0 kernel/sched/core.c:6767
preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7090
irqentry_exit+0x6f/0x90 kernel/entry/common.c:354
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:lock_acquire+0x175/0x360 kernel/locking/lockdep.c:5870
Code: 00 00 00 00 9c 8f 44 24 30 f7 44 24 30 00 02 00 00 0f 85 cd 00 00 00 f7 44 24 08 00 02 00 00 74 01 fb 65 48 8b 05 8b 51 d7 10 <48> 3b 44 24 58 0f 85 f2 00 00 00 48 83 c4 60 5b 41 5c 41 5d 41 5e
RSP: 0018:ffffc900047177f8 EFLAGS: 00000206
RAX: 74d30435f279cf00 RBX: 0000000000000000 RCX: 74d30435f279cf00
RDX: 0000000000000000 RSI: ffffffff8d93622d RDI: ffffffff8bc1d2e0
RBP: ffffffff8171a9f5 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: ffffffff8171a9f5 R12: 0000000000000002
R13: ffffffff8df3d860 R14: 0000000000000000 R15: 0000000000000246
rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
rcu_read_lock include/linux/rcupdate.h:841 [inline]
class_rcu_constructor include/linux/rcupdate.h:1155 [inline]
unwind_next_frame+0xc2/0x2390 arch/x86/kernel/unwind_orc.c:479
arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
save_stack+0xf7/0x1f0 mm/page_owner.c:156
__reset_page_owner+0x71/0x1f0 mm/page_owner.c:308
reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1262 [inline]
__free_frozen_pages+0xb0e/0xcd0 mm/page_alloc.c:2725
discard_slab mm/slub.c:2716 [inline]
__put_partials+0x161/0x1c0 mm/slub.c:3185
put_cpu_partial+0x17c/0x250 mm/slub.c:3260
__slab_free+0x2f7/0x400 mm/slub.c:4512
qlink_free mm/kasan/quarantine.c:163 [inline]
qlist_free_all+0x9a/0x140 mm/kasan/quarantine.c:179
kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
__kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:329
kasan_slab_alloc include/linux/kasan.h:250 [inline]
slab_post_alloc_hook mm/slub.c:4147 [inline]
slab_alloc_node mm/slub.c:4196 [inline]
kmem_cache_alloc_noprof+0x1c1/0x3c0 mm/slub.c:4203
getname_flags+0xb8/0x540 fs/namei.c:146
getname include/linux/fs.h:2852 [inline]
__do_sys_mkdir fs/namei.c:4414 [inline]
__se_sys_mkdir fs/namei.c:4412 [inline]
__x64_sys_mkdir+0x5d/0x80 fs/namei.c:4412
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f767d514c37
RSP: 002b:00007ffcfa61c798 EFLAGS: 00000246 ORIG_RAX: 0000000000000053
RAX: ffffffffffffffda RBX: 00007ffcfa61e4df RCX: 00007f767d514c37
RDX: 000000000000004e RSI: 00000000000001ed RDI: 00007ffcfa61c7a0
RBP: 00007ffcfa61d860 R08: 00007ffcfa61e4d0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffcfa61e490
R13: 0000000000000000 R14: 000055bb196097d4 R15: 000000000000004e
task:udevd state:R running task stack:24920 pid:30132 tgid:30132 ppid:5202 task_flags:0x400140 flags:0x00000002
Call Trace:
context_switch kernel/sched/core.c:5382 [inline]
__schedule+0x16e2/0x4cd0 kernel/sched/core.c:6767
preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7090
irqentry_exit+0x6f/0x90 kernel/entry/common.c:354
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:lockdep_enabled kernel/locking/lockdep.c:121 [inline]
RIP: 0010:lock_release+0x69/0x3e0 kernel/locking/lockdep.c:5879
Code: 05 dc c7 e0 0d 73 16 e8 c5 c8 08 00 84 c0 75 0d f6 05 ff bd ca 0d 01 0f 84 ad 02 00 00 83 3d 9d f6 e0 0d 00 0f 84 44 02 00 00 <65> 8b 05 80 7d d7 10 85 c0 0f 85 35 02 00 00 65 4c 8b 3c 25 08 70
RSP: 0018:ffffc90003867550 EFLAGS: 00000202
RAX: 0000000000000001 RBX: ffffffff9011ca01 RCX: 976ab2b7cf2ad400
RDX: ffffc90003867601 RSI: ffffffff8bc1d2c0 RDI: ffffffff8bc1d280
RBP: dffffc0000000000 R08: ffffc900038677b0 R09: 0000000000000000
R10: ffffc900038676d8 R11: fffff5200070cedd R12: ffffc900038677c0
R13: ffffffff8171a9f5 R14: ffffffff8df3d860 R15: ffffffff8171a9f5
rcu_lock_release include/linux/rcupdate.h:341 [inline]
rcu_read_unlock include/linux/rcupdate.h:871 [inline]
class_rcu_destructor include/linux/rcupdate.h:1155 [inline]
unwind_next_frame+0x19a9/0x2390 arch/x86/kernel/unwind_orc.c:680
arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
save_stack+0xf7/0x1f0 mm/page_owner.c:156
__reset_page_owner+0x71/0x1f0 mm/page_owner.c:308
reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1262 [inline]
__free_frozen_pages+0xb0e/0xcd0 mm/page_alloc.c:2725
discard_slab mm/slub.c:2716 [inline]
__put_partials+0x161/0x1c0 mm/slub.c:3185
put_cpu_partial+0x17c/0x250 mm/slub.c:3260
__slab_free+0x2f7/0x400 mm/slub.c:4512
qlink_free mm/kasan/quarantine.c:163 [inline]
qlist_free_all+0x9a/0x140 mm/kasan/quarantine.c:179
kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
__kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:329
kasan_slab_alloc include/linux/kasan.h:250 [inline]
slab_post_alloc_hook mm/slub.c:4147 [inline]
slab_alloc_node mm/slub.c:4196 [inline]
__do_kmalloc_node mm/slub.c:4326 [inline]
__kvmalloc_node_noprof+0x2b7/0x5e0 mm/slub.c:5012
seq_buf_alloc fs/seq_file.c:38 [inline]
seq_read_iter+0x1fd/0xe10 fs/seq_file.c:210
new_sync_read fs/read_write.c:489 [inline]
vfs_read+0x4cd/0x980 fs/read_write.c:570
ksys_read+0x145/0x250 fs/read_write.c:713
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f767d4a7407
RSP: 002b:00007ffcfa61abd0 EFLAGS: 00000202 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007f767dbdd880 RCX: 00007f767d4a7407
RDX: 0000000000001000 RSI: 000055bb29bc28f0 RDI: 0000000000000008
RBP: 00007f767d5efff0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 000000000000000a
R13: 00007f767d5efea0 R14: 0000000000000000 R15: 000055bb29bbb0a0
task:udevd state:R running task stack:23000 pid:30131 tgid:30131 ppid:5202 task_flags:0x400140 flags:0x00004002
Call Trace:
context_switch kernel/sched/core.c:5382 [inline]
__schedule+0x16e2/0x4cd0 kernel/sched/core.c:6767
preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7090
irqentry_exit+0x6f/0x90 kernel/entry/common.c:354
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:unwind_next_frame+0xc9c/0x2390 arch/x86/kernel/unwind_orc.c:-1
Code: 4c 8b 6c 24 50 4c 8b 64 24 10 74 08 48 89 df e8 3a 0f b0 00 4c 89 23 ba 10 00 00 00 4c 89 ef 31 f6 e8 08 11 b0 00 48 8b 14 24 c5 04 00 00 4c 89 7c 24 28 48 89 5c 24 78 4d 8d 66 08 4d 89 e5
RSP: 0018:ffffc90003a66f98 EFLAGS: 00000246
RAX: ffffc90003a670b8 RBX: ffffc90003a670a0 RCX: 0000000000000000
RDX: ffffffff9019d08a RSI: 0000000000000000 RDI: ffffc90003a670c8
RBP: dffffc0000000000 R08: ffffc90003a670c7 R09: 0000000000000000
R10: ffffc90003a670b8 R11: fffff5200074ce19 R12: ffffc90003a673d8
R13: ffffc90003a670b8 R14: ffffc90003a67068 R15: ffffc90003a670b0
arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
save_stack+0xf7/0x1f0 mm/page_owner.c:156
__reset_page_owner+0x71/0x1f0 mm/page_owner.c:308
reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1262 [inline]
__free_frozen_pages+0xb0e/0xcd0 mm/page_alloc.c:2725
discard_slab mm/slub.c:2716 [inline]
__put_partials+0x161/0x1c0 mm/slub.c:3185
put_cpu_partial+0x17c/0x250 mm/slub.c:3260
__slab_free+0x2f7/0x400 mm/slub.c:4512
qlink_free mm/kasan/quarantine.c:163 [inline]
qlist_free_all+0x9a/0x140 mm/kasan/quarantine.c:179
kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
__kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:329
kasan_slab_alloc include/linux/kasan.h:250 [inline]
slab_post_alloc_hook mm/slub.c:4147 [inline]
slab_alloc_node mm/slub.c:4196 [inline]
__do_kmalloc_node mm/slub.c:4326 [inline]
__kmalloc_noprof+0x224/0x4f0 mm/slub.c:4339
kmalloc_noprof include/linux/slab.h:909 [inline]
tomoyo_realpath_from_path+0xe3/0x5d0 security/tomoyo/realpath.c:251
tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
tomoyo_check_open_permission+0x1c1/0x3b0 security/tomoyo/file.c:771
security_file_open+0xb1/0x270 security/security.c:3114
do_dentry_open+0x35e/0x1970 fs/open.c:933
vfs_open+0x3b/0x340 fs/open.c:1086
do_open fs/namei.c:3880 [inline]
path_openat+0x2ee5/0x3830 fs/namei.c:4039
do_filp_open+0x1fa/0x410 fs/namei.c:4066
do_sys_openat2+0x121/0x1c0 fs/open.c:1429
do_sys_open fs/open.c:1444 [inline]
__do_sys_openat fs/open.c:1460 [inline]
__se_sys_openat fs/open.c:1455 [inline]
__x64_sys_openat+0x138/0x170 fs/open.c:1455
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f767d515c3a
RSP: 002b:00007ffcfa61d858 EFLAGS: 00000206 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007ffcfa61d890 RCX: 00007f767d515c3a
RDX: 0000000000090800 RSI: 00007ffcfa61dc90 RDI: 00000000ffffff9c
RBP: 0000000000000007 R08: 000055bb29bb0690 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 000055bb29bb7ec0
R13: 00007ffcfa61e490 R14: 00007ffcfa61e090 R15: 00007ffcfa61dc90
task:kworker/u8:4 state:R running task stack:21400 pid:63 tgid:63 ppid:2 task_flags:0x24248060 flags:0x00004000
Workqueue: writeback wb_workfn (flush-8:0)
Call Trace:
context_switch kernel/sched/core.c:5382 [inline]
__schedule+0x16e2/0x4cd0 kernel/sched/core.c:6767
preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7090
irqentry_exit+0x6f/0x90 kernel/entry/common.c:354
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:lock_acquire+0x175/0x360 kernel/locking/lockdep.c:5870
Code: 00 00 00 00 9c 8f 44 24 30 f7 44 24 30 00 02 00 00 0f 85 cd 00 00 00 f7 44 24 08 00 02 00 00 74 01 fb 65 48 8b 05 8b 51 d7 10 <48> 3b 44 24 58 0f 85 f2 00 00 00 48 83 c4 60 5b 41 5c 41 5d 41 5e
RSP: 0018:ffffc90001556598 EFLAGS: 00000206
RAX: 6e2a3b42aa872300 RBX: 0000000000000000 RCX: 6e2a3b42aa872300
RDX: 0000000000000000 RSI: ffffffff8d93622d RDI: ffffffff8bc1d2e0
RBP: ffffffff8171a9f5 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: ffffffff8171a9f5 R12: 0000000000000002
R13: ffffffff8df3d860 R14: 0000000000000000 R15: 0000000000000246
rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
rcu_read_lock include/linux/rcupdate.h:841 [inline]
class_rcu_constructor include/linux/rcupdate.h:1155 [inline]
unwind_next_frame+0xc2/0x2390 arch/x86/kernel/unwind_orc.c:479
arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
save_stack+0xf7/0x1f0 mm/page_owner.c:156
__reset_page_owner+0x71/0x1f0 mm/page_owner.c:308
reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1262 [inline]
__free_frozen_pages+0xb0e/0xcd0 mm/page_alloc.c:2725
discard_slab mm/slub.c:2716 [inline]
__put_partials+0x161/0x1c0 mm/slub.c:3185
put_cpu_partial+0x17c/0x250 mm/slub.c:3260
__slab_free+0x2f7/0x400 mm/slub.c:4512
qlink_free mm/kasan/quarantine.c:163 [inline]
qlist_free_all+0x9a/0x140 mm/kasan/quarantine.c:179
kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
__kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:329
kasan_slab_alloc include/linux/kasan.h:250 [inline]
slab_post_alloc_hook mm/slub.c:4147 [inline]
slab_alloc_node mm/slub.c:4196 [inline]
kmem_cache_alloc_noprof+0x1c1/0x3c0 mm/slub.c:4203
ext4_init_io_end+0x29/0x130 fs/ext4/page-io.c:307
ext4_do_writepages+0xb85/0x3e50 fs/ext4/inode.c:2687
ext4_writepages+0x203/0x350 fs/ext4/inode.c:2829
do_writepages+0x3ae/0x7b0 mm/page-writeback.c:2656
__writeback_single_inode+0x145/0xff0 fs/fs-writeback.c:1680
writeback_sb_inodes+0x6b5/0x1000 fs/fs-writeback.c:1976
__writeback_inodes_wb+0x111/0x240 fs/fs-writeback.c:2047
wb_writeback+0x44f/0xaf0 fs/fs-writeback.c:2158
wb_check_old_data_flush fs/fs-writeback.c:2262 [inline]
wb_do_writeback fs/fs-writeback.c:2315 [inline]
wb_workfn+0xaef/0xef0 fs/fs-writeback.c:2343
process_one_work kernel/workqueue.c:3238 [inline]
process_scheduled_works+0xadb/0x17a0 kernel/workqueue.c:3319
worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400
kthread+0x70e/0x8a0 kernel/kthread.c:464
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
task:syz.2.7425 state:R running task stack:24552 pid:3936 tgid:3932 ppid:29823 task_flags:0x40044c flags:0x00004006
Call Trace:
rcu: rcu_preempt kthread starved for 9804 jiffies! g259597 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt state:I stack:27496 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5382 [inline]
__schedule+0x16e2/0x4cd0 kernel/sched/core.c:6767
__schedule_loop kernel/sched/core.c:6845 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6860
schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2046
rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2248
kthread+0x70e/0x8a0 kernel/kthread.c:464
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 16649 Comm: kworker/u8:3 Not tainted 6.15.0-rc6-syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: events_unbound nsim_dev_trap_report_work
RIP: 0010:check_kcov_mode kernel/kcov.c:183 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x2f/0x70 kernel/kcov.c:217
Code: 8b 04 24 65 48 8b 0c 25 08 70 75 92 65 8b 15 a8 a0 b5 10 81 e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 35 83 b9 3c 16 00 00 00 <74> 2c 8b 91 18 16 00 00 83 fa 02 75 21 48 8b 91 20 16 00 00 48 8b
RSP: 0018:ffffc90000a07f78 EFLAGS: 00000246
RAX: ffffffff89c9e7f5 RBX: dffffc0000000000 RCX: ffff88801bee1e00
RDX: 0000000000000100 RSI: 00000000aa1414ac RDI: ffff888056266000
RBP: ffffc90000a08030 R08: ffff88801bee1e00 R09: 0000000000000002
R10: 000000000000000a R11: 0000000000000100 R12: ffff88802a092f00
R13: ffff888056266000 R14: ffff88819068e1d0 R15: 00000000aa1414ac
FS: 0000000000000000(0000) GS:ffff8881261c9000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000404030 CR3: 00000000279f0000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 000000000000000e DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
ip_neigh_gw4+0x75/0x3b0 include/net/route.h:399
ip_neigh_for_gw include/net/route.h:-1 [inline]
ip_finish_output2+0x57a/0x1160 net/ipv4/ip_output.c:229
synproxy_send_client_synack+0x8bb/0xe20 net/netfilter/nf_synproxy_core.c:484
nft_synproxy_eval_v4+0x36e/0x560 net/netfilter/nft_synproxy.c:59
nft_synproxy_do_eval+0x345/0x570 net/netfilter/nft_synproxy.c:141
expr_call_ops_eval net/netfilter/nf_tables_core.c:237 [inline]
nft_do_chain+0x409/0x1920 net/netfilter/nf_tables_core.c:285
nft_do_chain_inet+0x25d/0x340 net/netfilter/nft_chain_filter.c:161
nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline]
nf_hook_slow+0xc2/0x220 net/netfilter/core.c:626
nf_hook include/linux/netfilter.h:269 [inline]
NF_HOOK+0x206/0x3a0 include/linux/netfilter.h:312
NF_HOOK+0x309/0x3a0 include/linux/netfilter.h:314
__netif_receive_skb_one_core net/core/dev.c:5887 [inline]
__netif_receive_skb+0x143/0x380 net/core/dev.c:6000
process_backlog+0x60e/0x14f0 net/core/dev.c:6352
__napi_poll+0xc4/0x480 net/core/dev.c:7324
napi_poll net/core/dev.c:7388 [inline]
net_rx_action+0x6ea/0xdf0 net/core/dev.c:7510
handle_softirqs+0x283/0x870 kernel/softirq.c:579
do_softirq+0xec/0x180 kernel/softirq.c:480
__local_bh_enable_ip+0x17d/0x1c0 kernel/softirq.c:407
spin_unlock_bh include/linux/spinlock.h:396 [inline]
nsim_dev_trap_report drivers/net/netdevsim/dev.c:820 [inline]
nsim_dev_trap_report_work+0x7c7/0xb80 drivers/net/netdevsim/dev.c:851
process_one_work kernel/workqueue.c:3238 [inline]
process_scheduled_works+0xadb/0x17a0 kernel/workqueue.c:3319
worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400
kthread+0x70e/0x8a0 kernel/kthread.c:464
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245