INFO: task syz.3.1660:13420 blocked for more than 144 seconds. Not tainted 6.12.0-rc2-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.3.1660 state:D stack:26096 pid:13420 tgid:13419 ppid:13002 flags:0x00000004 Call Trace: context_switch kernel/sched/core.c:5315 [inline] __schedule+0xef5/0x5750 kernel/sched/core.c:6675 __schedule_loop kernel/sched/core.c:6752 [inline] schedule+0xe7/0x350 kernel/sched/core.c:6767 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6824 __mutex_lock_common kernel/locking/mutex.c:684 [inline] __mutex_lock+0x5b8/0x9c0 kernel/locking/mutex.c:752 nfsd_nl_threads_set_doit+0x694/0xbe0 fs/nfsd/nfsctl.c:1671 genl_family_rcv_msg_doit+0x202/0x2f0 net/netlink/genetlink.c:1115 genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline] genl_rcv_msg+0x565/0x800 net/netlink/genetlink.c:1210 netlink_rcv_skb+0x165/0x410 net/netlink/af_netlink.c:2550 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219 netlink_unicast_kernel net/netlink/af_netlink.c:1331 [inline] netlink_unicast+0x53c/0x7f0 net/netlink/af_netlink.c:1357 netlink_sendmsg+0x8b8/0xd70 net/netlink/af_netlink.c:1901 sock_sendmsg_nosec net/socket.c:729 [inline] __sock_sendmsg net/socket.c:744 [inline] ____sys_sendmsg+0x9ae/0xb40 net/socket.c:2602 ___sys_sendmsg+0x135/0x1e0 net/socket.c:2656 __sys_sendmsg+0x117/0x1f0 net/socket.c:2685 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f91ab97dff9 RSP: 002b:00007f91ac7d2038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f91abb35f80 RCX: 00007f91ab97dff9 RDX: 0000000000008004 RSI: 0000000020000140 RDI: 0000000000000009 RBP: 00007f91ab9f0296 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f91abb35f80 R15: 00007ffc8a7f2748 INFO: task syz.1.1661:13426 blocked for more than 145 seconds. Not tainted 6.12.0-rc2-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.1.1661 state:D stack:26096 pid:13426 tgid:13423 ppid:12864 flags:0x00000004 Call Trace: context_switch kernel/sched/core.c:5315 [inline] __schedule+0xef5/0x5750 kernel/sched/core.c:6675 __schedule_loop kernel/sched/core.c:6752 [inline] schedule+0xe7/0x350 kernel/sched/core.c:6767 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6824 __mutex_lock_common kernel/locking/mutex.c:684 [inline] __mutex_lock+0x5b8/0x9c0 kernel/locking/mutex.c:752 nfsd_nl_threads_set_doit+0x694/0xbe0 fs/nfsd/nfsctl.c:1671 genl_family_rcv_msg_doit+0x202/0x2f0 net/netlink/genetlink.c:1115 genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline] genl_rcv_msg+0x565/0x800 net/netlink/genetlink.c:1210 netlink_rcv_skb+0x165/0x410 net/netlink/af_netlink.c:2550 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219 netlink_unicast_kernel net/netlink/af_netlink.c:1331 [inline] netlink_unicast+0x53c/0x7f0 net/netlink/af_netlink.c:1357 netlink_sendmsg+0x8b8/0xd70 net/netlink/af_netlink.c:1901 sock_sendmsg_nosec net/socket.c:729 [inline] __sock_sendmsg net/socket.c:744 [inline] ____sys_sendmsg+0x9ae/0xb40 net/socket.c:2602 ___sys_sendmsg+0x135/0x1e0 net/socket.c:2656 __sys_sendmsg+0x117/0x1f0 net/socket.c:2685 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f37d497dff9 RSP: 002b:00007f37d57bb038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f37d4b35f80 RCX: 00007f37d497dff9 RDX: 0000000000008004 RSI: 0000000020000140 RDI: 0000000000000009 RBP: 00007f37d49f0296 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f37d4b35f80 R15: 00007ffeff1a10d8 Showing all locks held in the system: 1 lock held by khungtaskd/30: #0: ffffffff8ddb7800 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #0: ffffffff8ddb7800 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #0: ffffffff8ddb7800 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x7f/0x390 kernel/locking/lockdep.c:6720 2 locks held by getty/4985: #0: ffff88802ea6e0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc900031332f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0xfba/0x1480 drivers/tty/n_tty.c:2211 2 locks held by kworker/0:3/5269: 2 locks held by kworker/u8:13/5546: 2 locks held by kworker/u8:21/5554: #0: ffff888021eed948 ((wq_completion)iou_exit){+.+.}-{0:0}, at: process_one_work+0x1212/0x1b30 kernel/workqueue.c:3204 #1: ffffc90004c1fd80 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_one_work+0x8bb/0x1b30 kernel/workqueue.c:3205 3 locks held by kworker/u8:26/6026: #0: ffff88802ddd7148 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x1212/0x1b30 kernel/workqueue.c:3204 #1: ffffc90003e67d80 ((work_completion)(&(&net->ipv6.addr_chk_work)->work)){+.+.}-{0:0}, at: process_one_work+0x8bb/0x1b30 kernel/workqueue.c:3205 #2: ffffffff8fac3128 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_verify_work+0x12/0x30 net/ipv6/addrconf.c:4736 3 locks held by kworker/u8:34/6127: #0: ffff88801ac89148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x1212/0x1b30 kernel/workqueue.c:3204 #1: ffffc9000355fd80 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x8bb/0x1b30 kernel/workqueue.c:3205 #2: ffffffff8fac3128 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0x51/0xc0 net/core/link_watch.c:276 1 lock held by syz.3.590/8154: 2 locks held by syz.2.1466/12438: #0: ffffffff8fb61190 (cb_lock){++++}-{3:3}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218 #1: ffffffff8e1d1868 (nfsd_mutex){+.+.}-{3:3}, at: nfsd_nl_threads_set_doit+0x694/0xbe0 fs/nfsd/nfsctl.c:1671 1 lock held by syz.3.1540/12892: 2 locks held by syz.3.1660/13420: #0: ffffffff8fb61190 (cb_lock){++++}-{3:3}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218 #1: ffffffff8e1d1868 (nfsd_mutex){+.+.}-{3:3}, at: nfsd_nl_threads_set_doit+0x694/0xbe0 fs/nfsd/nfsctl.c:1671 2 locks held by syz.1.1661/13426: #0: ffffffff8fb61190 (cb_lock){++++}-{3:3}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218 #1: ffffffff8e1d1868 (nfsd_mutex){+.+.}-{3:3}, at: nfsd_nl_threads_set_doit+0x694/0xbe0 fs/nfsd/nfsctl.c:1671 2 locks held by kworker/1:4/13698: #0: ffff88801ac80948 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x1212/0x1b30 kernel/workqueue.c:3204 #1: ffffc90008ee7d80 (free_ipc_work){+.+.}-{0:0}, at: process_one_work+0x8bb/0x1b30 kernel/workqueue.c:3205 2 locks held by syz.1.1703/13732: #0: ffffffff8fb61190 (cb_lock){++++}-{3:3}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218 #1: ffffffff8e1d1868 (nfsd_mutex){+.+.}-{3:3}, at: nfsd_nl_threads_set_doit+0x694/0xbe0 fs/nfsd/nfsctl.c:1671 2 locks held by syz.2.1713/13767: #0: ffffffff8fb61190 (cb_lock){++++}-{3:3}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218 #1: ffffffff8e1d1868 (nfsd_mutex){+.+.}-{3:3}, at: nfsd_nl_threads_set_doit+0x694/0xbe0 fs/nfsd/nfsctl.c:1671 2 locks held by syz.0.1724/13805: #0: ffffffff8fb61190 (cb_lock){++++}-{3:3}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218 #1: ffffffff8e1d1868 (nfsd_mutex){+.+.}-{3:3}, at: nfsd_nl_threads_set_doit+0x694/0xbe0 fs/nfsd/nfsctl.c:1671 2 locks held by syz-executor/13818: #0: ffff888088e380e0 (&type->s_umount_key#49){++++}-{3:3}, at: __super_lock fs/super.c:56 [inline] #0: ffff888088e380e0 (&type->s_umount_key#49){++++}-{3:3}, at: __super_lock_excl fs/super.c:71 [inline] #0: ffff888088e380e0 (&type->s_umount_key#49){++++}-{3:3}, at: deactivate_super+0xd6/0x100 fs/super.c:505 #1: ffffffff8e1d1868 (nfsd_mutex){+.+.}-{3:3}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:625 2 locks held by syz.3.1730/13837: #0: ffffffff8fb61190 (cb_lock){++++}-{3:3}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218 #1: ffffffff8e1d1868 (nfsd_mutex){+.+.}-{3:3}, at: nfsd_nl_threads_set_doit+0x694/0xbe0 fs/nfsd/nfsctl.c:1671 2 locks held by syz-executor/13844: #0: ffff888091e020e0 (&type->s_umount_key#49){++++}-{3:3}, at: __super_lock fs/super.c:56 [inline] #0: ffff888091e020e0 (&type->s_umount_key#49){++++}-{3:3}, at: __super_lock_excl fs/super.c:71 [inline] #0: ffff888091e020e0 (&type->s_umount_key#49){++++}-{3:3}, at: deactivate_super+0xd6/0x100 fs/super.c:505 #1: ffffffff8e1d1868 (nfsd_mutex){+.+.}-{3:3}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:625 2 locks held by syz-executor/13893: #0: ffff888067dd20e0 (&type->s_umount_key#49){++++}-{3:3}, at: __super_lock fs/super.c:56 [inline] #0: ffff888067dd20e0 (&type->s_umount_key#49){++++}-{3:3}, at: __super_lock_excl fs/super.c:71 [inline] #0: ffff888067dd20e0 (&type->s_umount_key#49){++++}-{3:3}, at: deactivate_super+0xd6/0x100 fs/super.c:505 #1: ffffffff8e1d1868 (nfsd_mutex){+.+.}-{3:3}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:625 2 locks held by syz-executor/13933: #0: ffff8881433e40e0 (&type->s_umount_key#49){++++}-{3:3}, at: __super_lock fs/super.c:56 [inline] #0: ffff8881433e40e0 (&type->s_umount_key#49){++++}-{3:3}, at: __super_lock_excl fs/super.c:71 [inline] #0: ffff8881433e40e0 (&type->s_umount_key#49){++++}-{3:3}, at: deactivate_super+0xd6/0x100 fs/super.c:505 #1: ffffffff8e1d1868 (nfsd_mutex){+.+.}-{3:3}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:625 2 locks held by syz.0.1865/14462: #0: ffffffff8fb61190 (cb_lock){++++}-{3:3}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218 #1: ffffffff8e1d1868 (nfsd_mutex){+.+.}-{3:3}, at: nfsd_nl_threads_set_doit+0x694/0xbe0 fs/nfsd/nfsctl.c:1671 2 locks held by syz.1.1899/14625: #0: ffff88803a57a0e0 (&type->s_umount_key#49){++++}-{3:3}, at: __super_lock fs/super.c:56 [inline] #0: ffff88803a57a0e0 (&type->s_umount_key#49){++++}-{3:3}, at: __super_lock_excl fs/super.c:71 [inline] #0: ffff88803a57a0e0 (&type->s_umount_key#49){++++}-{3:3}, at: deactivate_super+0xd6/0x100 fs/super.c:505 #1: ffffffff8e1d1868 (nfsd_mutex){+.+.}-{3:3}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:625 2 locks held by syz.2.1922/14718: #0: ffffffff8fb61190 (cb_lock){++++}-{3:3}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218 #1: ffffffff8e1d1868 (nfsd_mutex){+.+.}-{3:3}, at: nfsd_nl_threads_set_doit+0x694/0xbe0 fs/nfsd/nfsctl.c:1671 2 locks held by syz-executor/14741: #0: ffff88803904c0e0 (&type->s_umount_key#49){++++}-{3:3}, at: __super_lock fs/super.c:56 [inline] #0: ffff88803904c0e0 (&type->s_umount_key#49){++++}-{3:3}, at: __super_lock_excl fs/super.c:71 [inline] #0: ffff88803904c0e0 (&type->s_umount_key#49){++++}-{3:3}, at: deactivate_super+0xd6/0x100 fs/super.c:505 #1: ffffffff8e1d1868 (nfsd_mutex){+.+.}-{3:3}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:625 3 locks held by syz-executor/14869: #0: ffff88809501cd80 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_close+0x26/0x90 net/bluetooth/hci_core.c:481 #1: ffff88809501c078 (&hdev->lock){+.+.}-{3:3}, at: hci_dev_close_sync+0x2ef/0x11d0 net/bluetooth/hci_sync.c:5183 #2: ffffffff8ddc30f8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock+0x1a4/0x3b0 kernel/rcu/tree_exp.h:329 1 lock held by syz.0.1971/14968: 1 lock held by syz.0.1971/14973: 2 locks held by syz.0.1989/15070: #0: ffffffff8fb61190 (cb_lock){++++}-{3:3}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218 #1: ffffffff8e1d1868 (nfsd_mutex){+.+.}-{3:3}, at: nfsd_nl_threads_set_doit+0x694/0xbe0 fs/nfsd/nfsctl.c:1671 2 locks held by syz.3.2003/15143: #0: ffffffff8fb61190 (cb_lock){++++}-{3:3}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218 #1: ffffffff8e1d1868 (nfsd_mutex){+.+.}-{3:3}, at: nfsd_nl_threads_set_doit+0x694/0xbe0 fs/nfsd/nfsctl.c:1671 2 locks held by syz-executor/15160: #0: ffffffff8fac3128 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline] #0: ffffffff8fac3128 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x372/0xea0 net/core/rtnetlink.c:6643 #1: ffffffff8ddc30f8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock+0x1a4/0x3b0 kernel/rcu/tree_exp.h:329 2 locks held by syz.2.2010/15171: #0: ffffffff8faad510 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x292/0x6b0 net/core/net_namespace.c:490 #1: ffffffff8fac3128 (rtnl_mutex){+.+.}-{3:3}, at: ip_tunnel_init_net+0x1b0/0x6e0 net/ipv4/ip_tunnel.c:1159 3 locks held by syz.2.2010/15195: #0: ffff88805fc5cd80 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_close+0x26/0x90 net/bluetooth/hci_core.c:481 #1: ffff88805fc5c078 (&hdev->lock){+.+.}-{3:3}, at: hci_dev_close_sync+0x2ef/0x11d0 net/bluetooth/hci_sync.c:5183 #2: ffffffff8fd28c88 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:1972 [inline] #2: ffffffff8fd28c88 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_conn_hash_flush+0xc4/0x260 net/bluetooth/hci_conn.c:2589 3 locks held by syz.1.2011/15199: #0: ffff88805cf18d80 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_close+0x26/0x90 net/bluetooth/hci_core.c:481 #1: ffff88805cf18078 (&hdev->lock){+.+.}-{3:3}, at: hci_dev_close_sync+0x2ef/0x11d0 net/bluetooth/hci_sync.c:5183 #2: ffffffff8fd28c88 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:1972 [inline] #2: ffffffff8fd28c88 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_conn_hash_flush+0xc4/0x260 net/bluetooth/hci_conn.c:2589 ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 30 Comm: khungtaskd Not tainted 6.12.0-rc2-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x29c/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:223 [inline] watchdog+0xf0c/0x1240 kernel/hung_task.c:379 kthread+0x2c1/0x3a0 kernel/kthread.c:389 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 13698 Comm: kworker/1:4 Not tainted 6.12.0-rc2-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Workqueue: events free_obj_work RIP: 0010:__orc_find+0x5a/0xf0 arch/x86/kernel/unwind_orc.c:100 Code: 00 00 fc ff df 49 89 ff 48 89 fd eb 0c 48 8d 6b 04 49 89 df 49 39 ec 72 4e 4c 89 e2 48 29 ea 48 89 d6 48 c1 ea 3f 48 c1 fe 02 <48> 01 f2 48 d1 fa 48 8d 5c 95 00 48 89 da 48 c1 ea 03 0f b6 34 0a RSP: 0018:ffffc90008ee7728 EFLAGS: 00000206 RAX: ffffffff90ab94c2 RBX: 0000000000000001 RCX: dffffc0000000000 RDX: 0000000000000000 RSI: 0000000000000006 RDI: ffffffff902bf428 RBP: ffffffff902bf428 R08: ffffffff90ab94ec R09: ffffffff90ac885c R10: ffffc90008ee7828 R11: 0000000000003435 R12: ffffffff902bf440 R13: ffffffff81343573 R14: ffffffff902bf428 R15: ffffffff902bf428 FS: 0000000000000000(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055dbd81c5030 CR3: 000000000db7c000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: orc_find arch/x86/kernel/unwind_orc.c:227 [inline] unwind_next_frame+0x2be/0x20c0 arch/x86/kernel/unwind_orc.c:494 __unwind_start arch/x86/kernel/unwind_orc.c:760 [inline] __unwind_start+0x437/0x7c0 arch/x86/kernel/unwind_orc.c:685 unwind_start arch/x86/include/asm/unwind.h:64 [inline] arch_stack_walk+0x74/0x100 arch/x86/kernel/stacktrace.c:24 stack_trace_save+0x95/0xd0 kernel/stacktrace.c:122 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:579 poison_slab_object mm/kasan/common.c:247 [inline] __kasan_slab_free+0x51/0x70 mm/kasan/common.c:264 kasan_slab_free include/linux/kasan.h:230 [inline] slab_free_hook mm/slub.c:2342 [inline] slab_free mm/slub.c:4579 [inline] kmem_cache_free+0x152/0x4b0 mm/slub.c:4681 free_obj_work+0x341/0x630 lib/debugobjects.c:331 process_one_work+0x958/0x1b30 kernel/workqueue.c:3229 process_scheduled_works kernel/workqueue.c:3310 [inline] worker_thread+0x6c8/0xf00 kernel/workqueue.c:3391 kthread+0x2c1/0x3a0 kernel/kthread.c:389 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244