INFO: task syz-executor:5834 blocked for more than 163 seconds. Tainted: G U 6.15.0-rc6-syzkaller-00051-g405e6c37c89e #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor state:D stack:23496 pid:5834 tgid:5834 ppid:1 task_flags:0x400140 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x116f/0x5de0 kernel/sched/core.c:6767 __schedule_loop kernel/sched/core.c:6845 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6860 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6917 __mutex_lock_common kernel/locking/mutex.c:678 [inline] __mutex_lock+0x6c7/0xb90 kernel/locking/mutex.c:746 nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:596 nfsd_umount+0x48/0xe0 fs/nfsd/nfsctl.c:1386 deactivate_locked_super+0xc1/0x1a0 fs/super.c:473 deactivate_super fs/super.c:506 [inline] deactivate_super+0xde/0x100 fs/super.c:502 cleanup_mnt+0x225/0x450 fs/namespace.c:1431 task_work_run+0x14d/0x240 kernel/task_work.c:227 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] exit_to_user_mode_loop kernel/entry/common.c:114 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0x27b/0x2a0 kernel/entry/common.c:218 do_syscall_64+0xda/0x230 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f5909b8fc97 RSP: 002b:00007ffe1dbf17a8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 00007f5909c1089d RCX: 00007f5909b8fc97 RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffe1dbf1860 RBP: 00007ffe1dbf1860 R08: 0000000000000000 R09: 0000000000000000 R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffe1dbf28f0 R13: 00007f5909c1089d R14: 0000000000085e8a R15: 00007ffe1dbf2930 INFO: task syz.4.1488:12668 blocked for more than 163 seconds. Tainted: G U 6.15.0-rc6-syzkaller-00051-g405e6c37c89e #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.4.1488 state:D stack:27704 pid:12668 tgid:12666 ppid:12477 task_flags:0x400140 flags:0x00000004 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x116f/0x5de0 kernel/sched/core.c:6767 __schedule_loop kernel/sched/core.c:6845 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6860 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6917 __mutex_lock_common kernel/locking/mutex.c:678 [inline] __mutex_lock+0x6c7/0xb90 kernel/locking/mutex.c:746 nfsd_nl_threads_set_doit+0x698/0xbf0 fs/nfsd/nfsctl.c:1629 genl_family_rcv_msg_doit+0x206/0x2f0 net/netlink/genetlink.c:1115 genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline] genl_rcv_msg+0x55c/0x800 net/netlink/genetlink.c:1210 netlink_rcv_skb+0x16d/0x440 net/netlink/af_netlink.c:2534 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219 netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline] netlink_unicast+0x53a/0x7f0 net/netlink/af_netlink.c:1339 netlink_sendmsg+0x8d1/0xdd0 net/netlink/af_netlink.c:1883 sock_sendmsg_nosec net/socket.c:712 [inline] __sock_sendmsg net/socket.c:727 [inline] ____sys_sendmsg+0xa98/0xc70 net/socket.c:2566 ___sys_sendmsg+0x134/0x1d0 net/socket.c:2620 __sys_sendmsg+0x16d/0x220 net/socket.c:2652 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x230 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f0f90f8e969 RSP: 002b:00007f0f91e9d038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f0f911b5fa0 RCX: 00007f0f90f8e969 RDX: 0000000000040010 RSI: 00002000000000c0 RDI: 0000000000000003 RBP: 00007f0f91010ab1 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f0f911b5fa0 R15: 00007fffb5488a28 INFO: task syz-executor:12684 blocked for more than 144 seconds. Tainted: G U 6.15.0-rc6-syzkaller-00051-g405e6c37c89e #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor state:D stack:23848 pid:12684 tgid:12684 ppid:1 task_flags:0x400140 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x116f/0x5de0 kernel/sched/core.c:6767 __schedule_loop kernel/sched/core.c:6845 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6860 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6917 __mutex_lock_common kernel/locking/mutex.c:678 [inline] __mutex_lock+0x6c7/0xb90 kernel/locking/mutex.c:746 nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:596 nfsd_umount+0x48/0xe0 fs/nfsd/nfsctl.c:1386 deactivate_locked_super+0xc1/0x1a0 fs/super.c:473 deactivate_super fs/super.c:506 [inline] deactivate_super+0xde/0x100 fs/super.c:502 cleanup_mnt+0x225/0x450 fs/namespace.c:1431 task_work_run+0x14d/0x240 kernel/task_work.c:227 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] exit_to_user_mode_loop kernel/entry/common.c:114 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0x27b/0x2a0 kernel/entry/common.c:218 do_syscall_64+0xda/0x230 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f344498fc97 RSP: 002b:00007ffd2955b358 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 00007f3444a1089d RCX: 00007f344498fc97 RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffd2955b410 RBP: 00007ffd2955b410 R08: 0000000000000000 R09: 0000000000000000 R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffd2955c4a0 R13: 00007f3444a1089d R14: 000000000008cff9 R15: 00007ffd2955c4e0 INFO: task syz.2.1505:12742 blocked for more than 144 seconds. Tainted: G U 6.15.0-rc6-syzkaller-00051-g405e6c37c89e #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.2.1505 state:D stack:27032 pid:12742 tgid:12740 ppid:5829 task_flags:0x400140 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x116f/0x5de0 kernel/sched/core.c:6767 __schedule_loop kernel/sched/core.c:6845 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6860 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6917 __mutex_lock_common kernel/locking/mutex.c:678 [inline] __mutex_lock+0x6c7/0xb90 kernel/locking/mutex.c:746 expkey_flush+0x20/0x90 fs/nfsd/export.c:252 write_flush.constprop.0+0x2af/0x3d0 net/sunrpc/cache.c:1549 pde_write fs/proc/inode.c:330 [inline] proc_reg_write+0x240/0x330 fs/proc/inode.c:342 do_loop_readv_writev fs/read_write.c:848 [inline] do_loop_readv_writev fs/read_write.c:833 [inline] vfs_writev+0x6c7/0xdc0 fs/read_write.c:1057 do_writev+0x132/0x330 fs/read_write.c:1101 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x230 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fc778b8e969 RSP: 002b:00007fc779a03038 EFLAGS: 00000246 ORIG_RAX: 0000000000000014 RAX: ffffffffffffffda RBX: 00007fc778db5fa0 RCX: 00007fc778b8e969 RDX: 000000000000000a RSI: 0000200000000200 RDI: 0000000000000007 RBP: 00007fc778c10ab1 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fc778db5fa0 R15: 00007fffac824028 Showing all locks held in the system: 1 lock held by pool_workqueue_/3: 1 lock held by khungtaskd/31: #0: ffffffff8e3bfa80 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8e3bfa80 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8e3bfa80 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6764 4 locks held by kworker/u8:2/36: #0: ffff88801c2f6148 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3213 #1: ffffc90000ad7d18 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3214 #2: ffffffff90111890 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xc9/0xb30 net/core/net_namespace.c:608 #3: ffffffff90127728 (rtnl_mutex){+.+.}-{4:4}, at: wg_netns_pre_exit+0x1b/0x230 drivers/net/wireguard/device.c:416 3 locks held by kworker/u8:3/53: 3 locks held by kworker/u8:8/1150: #0: ffff88801b489148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3213 #1: ffffc90003ea7d18 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3214 #2: ffffffff90127728 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0x51/0xc0 net/core/link_watch.c:303 2 locks held by syz-executor/5834: #0: ffff888012f700e0 (&type->s_umount_key#50){++++}-{4:4}, at: __super_lock fs/super.c:56 [inline] #0: ffff888012f700e0 (&type->s_umount_key#50){++++}-{4:4}, at: __super_lock_excl fs/super.c:71 [inline] #0: ffff888012f700e0 (&type->s_umount_key#50){++++}-{4:4}, at: deactivate_super fs/super.c:505 [inline] #0: ffff888012f700e0 (&type->s_umount_key#50){++++}-{4:4}, at: deactivate_super+0xd6/0x100 fs/super.c:502 #1: ffffffff8e7cc728 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:596 2 locks held by syz.3.1393/12258: #0: ffffffff901c97d0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218 #1: ffffffff8e7cc728 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_set_doit+0x698/0xbf0 fs/nfsd/nfsctl.c:1629 2 locks held by syz.4.1488/12668: #0: ffffffff901c97d0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218 #1: ffffffff8e7cc728 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_set_doit+0x698/0xbf0 fs/nfsd/nfsctl.c:1629 2 locks held by syz-executor/12684: #0: ffff8880744920e0 (&type->s_umount_key#50){++++}-{4:4}, at: __super_lock fs/super.c:56 [inline] #0: ffff8880744920e0 (&type->s_umount_key#50){++++}-{4:4}, at: __super_lock_excl fs/super.c:71 [inline] #0: ffff8880744920e0 (&type->s_umount_key#50){++++}-{4:4}, at: deactivate_super fs/super.c:505 [inline] #0: ffff8880744920e0 (&type->s_umount_key#50){++++}-{4:4}, at: deactivate_super+0xd6/0x100 fs/super.c:502 #1: ffffffff8e7cc728 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:596 3 locks held by syz.2.1505/12742: #0: ffff8880334537b8 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x2a2/0x370 fs/file.c:1213 #1: ffff88805957c420 (sb_writers#3){.+.+}-{0:0}, at: do_writev+0x132/0x330 fs/read_write.c:1101 #2: ffffffff8e7cc728 (nfsd_mutex){+.+.}-{4:4}, at: expkey_flush+0x20/0x90 fs/nfsd/export.c:252 3 locks held by kworker/1:1/12766: #0: ffff88801b480d48 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3213 #1: ffffc900043d7d18 (free_ipc_work){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3214 #2: ffffffff8e3cafb8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x1a3/0x3c0 kernel/rcu/tree_exp.h:336 2 locks held by syz-executor/12878: #0: ffff88804a6f00e0 (&type->s_umount_key#50){++++}-{4:4}, at: __super_lock fs/super.c:56 [inline] #0: ffff88804a6f00e0 (&type->s_umount_key#50){++++}-{4:4}, at: __super_lock_excl fs/super.c:71 [inline] #0: ffff88804a6f00e0 (&type->s_umount_key#50){++++}-{4:4}, at: deactivate_super fs/super.c:505 [inline] #0: ffff88804a6f00e0 (&type->s_umount_key#50){++++}-{4:4}, at: deactivate_super+0xd6/0x100 fs/super.c:502 #1: ffffffff8e7cc728 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:596 2 locks held by syz-executor/13028: #0: ffffffff90127728 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:633 [inline] #0: ffffffff90127728 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x38/0x230 drivers/net/tun.c:3390 #1: ffffffff8e3cafb8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x1a3/0x3c0 kernel/rcu/tree_exp.h:336 3 locks held by syz.1.1728/13832: #0: ffff888033210478 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x2a2/0x370 fs/file.c:1213 #1: ffff888028f5c420 (sb_writers#3){.+.+}-{0:0}, at: do_writev+0x132/0x330 fs/read_write.c:1101 #2: ffffffff8e7cc728 (nfsd_mutex){+.+.}-{4:4}, at: expkey_flush+0x20/0x90 fs/nfsd/export.c:252 2 locks held by getty/14140: #0: ffff8880319ad0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc9000b74e2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x41b/0x14f0 drivers/tty/n_tty.c:2222 1 lock held by syz.6.1904/14559: #0: ffffffff90127728 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:633 [inline] #0: ffffffff90127728 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x38/0x230 drivers/net/tun.c:3390 1 lock held by syz.3.1918/14577: #0: ffffffff90127728 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:633 [inline] #0: ffffffff90127728 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x38/0x230 drivers/net/tun.c:3390 1 lock held by syz.9.1922/14618: #0: ffffffff90127728 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:633 [inline] #0: ffffffff90127728 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x38/0x230 drivers/net/tun.c:3390 2 locks held by syz.8.1923/14623: #0: ffffffff90111890 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x286/0x5f0 net/core/net_namespace.c:514 #1: ffffffff90127728 (rtnl_mutex){+.+.}-{4:4}, at: setup_net+0x3f9/0x850 net/core/net_namespace.c:386 ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Tainted: G U 6.15.0-rc6-syzkaller-00051-g405e6c37c89e #0 PREEMPT(full) Tainted: [U]=USER Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 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:158 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:274 [inline] watchdog+0xf70/0x12c0 kernel/hung_task.c:437 kthread+0x3c5/0x780 kernel/kthread.c:464 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 1142 Comm: kworker/u8:7 Tainted: G U 6.15.0-rc6-syzkaller-00051-g405e6c37c89e #0 PREEMPT(full) Tainted: [U]=USER Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Workqueue: events_unbound cfg80211_wiphy_work RIP: 0010:__lock_acquire+0x4a7/0x1ba0 kernel/locking/lockdep.c:5205 Code: ef f2 ff ff 85 c0 0f 84 88 02 00 00 ba 08 00 00 00 48 89 de 4c 89 f7 e8 d7 f2 ff ff 85 c0 0f 84 70 02 00 00 8b 15 99 35 1b 19 <85> d2 0f 84 36 02 00 00 8b 44 24 08 49 8b 8e e0 0a 00 00 85 c0 0f RSP: 0018:ffffc90003e271d0 EFLAGS: 00000002 RAX: 0000000000000001 RBX: ffff888027ad2968 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffff888027ad2968 RDI: ffff888027ad1e00 RBP: ffff888027ad28f0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: ffffffff8e3bfa80 R12: 0000000000000004 R13: 0000000000000001 R14: ffff888027ad1e00 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888124aea000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f5f0ce35990 CR3: 000000000e180000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_acquire kernel/locking/lockdep.c:5866 [inline] lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5823 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+0xd1/0x20a0 arch/x86/kernel/unwind_orc.c:479 arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:377 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:394 kasan_kmalloc include/linux/kasan.h:260 [inline] __do_kmalloc_node mm/slub.c:4327 [inline] __kmalloc_noprof+0x223/0x510 mm/slub.c:4339 kmalloc_noprof include/linux/slab.h:909 [inline] kzalloc_noprof include/linux/slab.h:1039 [inline] ieee802_11_parse_elems_full+0x1d7/0x3780 net/mac80211/parse.c:1013 ieee802_11_parse_elems_crc net/mac80211/ieee80211_i.h:2402 [inline] ieee802_11_parse_elems net/mac80211/ieee80211_i.h:2409 [inline] ieee80211_rx_mgmt_probe_beacon net/mac80211/ibss.c:1577 [inline] ieee80211_ibss_rx_queued_mgmt+0xc69/0x2fd0 net/mac80211/ibss.c:1608 ieee80211_iface_process_skb net/mac80211/iface.c:1625 [inline] ieee80211_iface_work+0xbf4/0x1020 net/mac80211/iface.c:1679 cfg80211_wiphy_work+0x3dc/0x550 net/wireless/core.c:435 process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3238 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400 kthread+0x3c5/0x780 kernel/kthread.c:464 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245