INFO: task syz.4.773:13427 blocked for more than 143 seconds. Not tainted 6.11.0-rc7-syzkaller-00039-g77f587896757 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.4.773 state:D stack:23872 pid:13427 tgid:13359 ppid:12899 flags:0x00000004 Call Trace: context_switch kernel/sched/core.c:5188 [inline] __schedule+0x17ae/0x4a10 kernel/sched/core.c:6529 __schedule_loop kernel/sched/core.c:6606 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6621 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6678 rwsem_down_write_slowpath+0xeeb/0x13b0 kernel/locking/rwsem.c:1178 __down_write_common kernel/locking/rwsem.c:1306 [inline] __down_write kernel/locking/rwsem.c:1315 [inline] down_write+0x1d7/0x220 kernel/locking/rwsem.c:1580 inode_lock include/linux/fs.h:800 [inline] do_lock_mount+0x112/0x3a0 fs/namespace.c:2580 lock_mount fs/namespace.c:2622 [inline] do_new_mount_fc fs/namespace.c:3409 [inline] do_new_mount+0x43d/0xb40 fs/namespace.c:3474 do_mount fs/namespace.c:3812 [inline] __do_sys_mount fs/namespace.c:4020 [inline] __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:3997 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f280577def9 RSP: 002b:00007f28065e5038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007f2805936130 RCX: 00007f280577def9 RDX: 0000000020000000 RSI: 00000000200001c0 RDI: 0000000000000000 RBP: 00007f28057f0b76 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f2805936130 R15: 00007ffc23f73e98 INFO: task syz.4.773:13428 blocked for more than 144 seconds. Not tainted 6.11.0-rc7-syzkaller-00039-g77f587896757 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.4.773 state:D stack:26360 pid:13428 tgid:13359 ppid:12899 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5188 [inline] __schedule+0x17ae/0x4a10 kernel/sched/core.c:6529 __schedule_loop kernel/sched/core.c:6606 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6621 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6678 rwsem_down_write_slowpath+0xeeb/0x13b0 kernel/locking/rwsem.c:1178 __down_write_common kernel/locking/rwsem.c:1306 [inline] __down_write kernel/locking/rwsem.c:1315 [inline] down_write+0x1d7/0x220 kernel/locking/rwsem.c:1580 inode_lock include/linux/fs.h:800 [inline] do_lock_mount+0x112/0x3a0 fs/namespace.c:2580 lock_mount fs/namespace.c:2622 [inline] do_new_mount_fc fs/namespace.c:3409 [inline] do_new_mount+0x43d/0xb40 fs/namespace.c:3474 do_mount fs/namespace.c:3812 [inline] __do_sys_mount fs/namespace.c:4020 [inline] __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:3997 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f280577f69a RSP: 002b:00007f28065c3e68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007f28065c3ef0 RCX: 00007f280577f69a RDX: 0000000020000080 RSI: 00000000200000c0 RDI: 0000000000000000 RBP: 0000000020000080 R08: 00007f28065c3ef0 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000200000c0 R13: 00007f28065c3eb0 R14: 0000000000000000 R15: 0000000020002280 INFO: task syz.4.773:13440 blocked for more than 144 seconds. Not tainted 6.11.0-rc7-syzkaller-00039-g77f587896757 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.4.773 state:D stack:26352 pid:13440 tgid:13359 ppid:12899 flags:0x00000004 Call Trace: context_switch kernel/sched/core.c:5188 [inline] __schedule+0x17ae/0x4a10 kernel/sched/core.c:6529 __schedule_loop kernel/sched/core.c:6606 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6621 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6678 rwsem_down_write_slowpath+0xeeb/0x13b0 kernel/locking/rwsem.c:1178 __down_write_common kernel/locking/rwsem.c:1306 [inline] __down_write kernel/locking/rwsem.c:1315 [inline] down_write+0x1d7/0x220 kernel/locking/rwsem.c:1580 inode_lock include/linux/fs.h:800 [inline] finish_preallocate_blocks fs/f2fs/file.c:561 [inline] f2fs_file_open+0x11b/0x3a0 fs/f2fs/file.c:614 do_dentry_open+0x970/0x1440 fs/open.c:959 vfs_open+0x3e/0x330 fs/open.c:1089 do_open fs/namei.c:3727 [inline] path_openat+0x2b3e/0x3470 fs/namei.c:3886 do_filp_open+0x235/0x490 fs/namei.c:3913 do_sys_openat2+0x13e/0x1d0 fs/open.c:1416 do_sys_open fs/open.c:1431 [inline] __do_sys_openat fs/open.c:1447 [inline] __se_sys_openat fs/open.c:1442 [inline] __x64_sys_openat+0x247/0x2a0 fs/open.c:1442 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f280577def9 RSP: 002b:00007f2806582038 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f28059363b8 RCX: 00007f280577def9 RDX: 0000000000000000 RSI: 0000000020000080 RDI: ffffffffffffff9c RBP: 00007f28057f0b76 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f28059363b8 R15: 00007ffc23f73e98 INFO: task syz.4.773:13442 blocked for more than 145 seconds. Not tainted 6.11.0-rc7-syzkaller-00039-g77f587896757 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.4.773 state:D stack:26672 pid:13442 tgid:13359 ppid:12899 flags:0x00000004 Call Trace: context_switch kernel/sched/core.c:5188 [inline] __schedule+0x17ae/0x4a10 kernel/sched/core.c:6529 __schedule_loop kernel/sched/core.c:6606 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6621 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6678 rwsem_down_write_slowpath+0xeeb/0x13b0 kernel/locking/rwsem.c:1178 __down_write_common kernel/locking/rwsem.c:1306 [inline] __down_write kernel/locking/rwsem.c:1315 [inline] down_write_nested+0x1e0/0x220 kernel/locking/rwsem.c:1696 vfs_rename+0x6a2/0xf00 fs/namei.c:4937 do_renameat2+0xd94/0x13f0 fs/namei.c:5123 __do_sys_rename fs/namei.c:5170 [inline] __se_sys_rename fs/namei.c:5168 [inline] __x64_sys_rename+0x82/0x90 fs/namei.c:5168 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f280577def9 RSP: 002b:00007f2806561038 EFLAGS: 00000246 ORIG_RAX: 0000000000000052 RAX: ffffffffffffffda RBX: 00007f2805936490 RCX: 00007f280577def9 RDX: 0000000000000000 RSI: 0000000020000f40 RDI: 00000000200003c0 RBP: 00007f28057f0b76 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f2805936490 R15: 00007ffc23f73e98 Showing all locks held in the system: 2 locks held by kworker/0:0/8: 1 lock held by khungtaskd/30: #0: ffffffff8e738320 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:326 [inline] #0: ffffffff8e738320 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline] #0: ffffffff8e738320 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6626 3 locks held by kworker/u8:2/35: #0: ffff88801d318948 ((wq_completion)cfg80211){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3206 [inline] #0: ffff88801d318948 ((wq_completion)cfg80211){+.+.}-{0:0}, at: process_scheduled_works+0x90a/0x1830 kernel/workqueue.c:3312 #1: ffffc90000ab7d00 ((work_completion)(&(&rdev->dfs_update_channels_wk)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3207 [inline] #1: ffffc90000ab7d00 ((work_completion)(&(&rdev->dfs_update_channels_wk)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x945/0x1830 kernel/workqueue.c:3312 #2: ffffffff8fa79e08 (rtnl_mutex){+.+.}-{3:3}, at: cfg80211_dfs_channels_update_work+0xbf/0x610 net/wireless/mlme.c:1021 2 locks held by kworker/u8:3/52: #0: ffff8880b893e998 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:560 #1: ffff8880b8928948 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x441/0x770 kernel/sched/psi.c:989 3 locks held by kworker/u8:5/80: #0: ffff8880b883e998 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:560 #1: ffff8880b8828948 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x441/0x770 kernel/sched/psi.c:989 #2: ffff8880648e0768 (&rdev->wiphy.mtx){+.+.}-{3:3}, at: wiphy_lock include/net/cfg80211.h:6014 [inline] #2: ffff8880648e0768 (&rdev->wiphy.mtx){+.+.}-{3:3}, at: cfg80211_wiphy_work+0xd9/0x490 net/wireless/core.c:426 3 locks held by kworker/u8:9/2934: #0: ffff88801a889148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3206 [inline] #0: ffff88801a889148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x90a/0x1830 kernel/workqueue.c:3312 #1: ffffc90009e77d00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3207 [inline] #1: ffffc90009e77d00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x945/0x1830 kernel/workqueue.c:3312 #2: ffffffff8fa79e08 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:276 6 locks held by kworker/u8:10/2954: #0: ffff88801b6e3148 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3206 [inline] #0: ffff88801b6e3148 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x90a/0x1830 kernel/workqueue.c:3312 #1: ffffc90009ff7d00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3207 [inline] #1: ffffc90009ff7d00 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x945/0x1830 kernel/workqueue.c:3312 #2: ffffffff8fa6d250 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x16a/0xcc0 net/core/net_namespace.c:594 #3: ffffffff8fa79e08 (rtnl_mutex){+.+.}-{3:3}, at: ieee80211_unregister_hw+0x55/0x2c0 net/mac80211/main.c:1662 #4: ffff88804b5b8768 (&rdev->wiphy.mtx){+.+.}-{3:3}, at: wiphy_lock include/net/cfg80211.h:6014 [inline] #4: ffff88804b5b8768 (&rdev->wiphy.mtx){+.+.}-{3:3}, at: ieee80211_remove_interfaces+0x12b/0x700 net/mac80211/iface.c:2262 #5: ffffffff8e73d6f8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:296 [inline] #5: ffffffff8e73d6f8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x381/0x830 kernel/rcu/tree_exp.h:958 4 locks held by kworker/u8:11/3992: #0: ffff888020a80948 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3206 [inline] #0: ffff888020a80948 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x90a/0x1830 kernel/workqueue.c:3312 #1: ffffc9000be37d00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3207 [inline] #1: ffffc9000be37d00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x945/0x1830 kernel/workqueue.c:3312 #2: ffff8880293120e0 (&type->s_umount_key#93){++++}-{3:3}, at: super_trylock_shared+0x22/0xf0 fs/super.c:562 #3: ffff8880721092a0 (&sbi->gc_lock){+.+.}-{3:3}, at: f2fs_down_write fs/f2fs/f2fs.h:2175 [inline] #3: ffff8880721092a0 (&sbi->gc_lock){+.+.}-{3:3}, at: f2fs_balance_fs+0x5b0/0x7a0 fs/f2fs/segment.c:440 1 lock held by dhcpcd/4892: #0: ffffffff8fa79e08 (rtnl_mutex){+.+.}-{3:3}, at: devinet_ioctl+0x2ce/0x1bc0 net/ipv4/devinet.c:1101 2 locks held by getty/4988: #0: ffff88803019d0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc900031332f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6ac/0x1e00 drivers/tty/n_tty.c:2211 5 locks held by syz.4.773/13425: 1 lock held by syz.4.773/13427: #0: ffff8880594712d8 (&sb->s_type->i_mutex_key#30){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:800 [inline] #0: ffff8880594712d8 (&sb->s_type->i_mutex_key#30){+.+.}-{3:3}, at: do_lock_mount+0x112/0x3a0 fs/namespace.c:2580 1 lock held by syz.4.773/13428: #0: ffff8880594712d8 (&sb->s_type->i_mutex_key#30){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:800 [inline] #0: ffff8880594712d8 (&sb->s_type->i_mutex_key#30){+.+.}-{3:3}, at: do_lock_mount+0x112/0x3a0 fs/namespace.c:2580 1 lock held by syz.4.773/13440: #0: ffff8880594712d8 (&sb->s_type->i_mutex_key#30){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:800 [inline] #0: ffff8880594712d8 (&sb->s_type->i_mutex_key#30){+.+.}-{3:3}, at: finish_preallocate_blocks fs/f2fs/file.c:561 [inline] #0: ffff8880594712d8 (&sb->s_type->i_mutex_key#30){+.+.}-{3:3}, at: f2fs_file_open+0x11b/0x3a0 fs/f2fs/file.c:614 3 locks held by syz.4.773/13442: #0: ffff888029312420 (sb_writers#23){.+.+}-{0:0}, at: mnt_want_write+0x3f/0x90 fs/namespace.c:515 #1: ffff888059472468 (&type->i_mutex_dir_key#17/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:835 [inline] #1: ffff888059472468 (&type->i_mutex_dir_key#17/1){+.+.}-{3:3}, at: lock_rename fs/namei.c:3147 [inline] #1: ffff888059472468 (&type->i_mutex_dir_key#17/1){+.+.}-{3:3}, at: do_renameat2+0x62c/0x13f0 fs/namei.c:5058 #2: ffff8880594712d8 (&sb->s_type->i_mutex_key#30/4){+.+.}-{3:3}, at: vfs_rename+0x6a2/0xf00 fs/namei.c:4937 2 locks held by syz.0.862/14248: #0: ffff8880293120e0 (&type->s_umount_key#93){++++}-{3:3}, at: __super_lock fs/super.c:58 [inline] #0: ffff8880293120e0 (&type->s_umount_key#93){++++}-{3:3}, at: super_lock+0x27c/0x400 fs/super.c:120 #1: ffff888025e187d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:388 [inline] #1: ffff888025e187d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0x274/0xb20 fs/fs-writeback.c:2790 1 lock held by syz.4.894/14499: #0: ffff8880293120e0 (&type->s_umount_key#93){++++}-{3:3}, at: __super_lock fs/super.c:56 [inline] #0: ffff8880293120e0 (&type->s_umount_key#93){++++}-{3:3}, at: super_lock+0x196/0x400 fs/super.c:120 1 lock held by syz.2.898/14518: #0: ffff8880293120e0 (&type->s_umount_key#93){++++}-{3:3}, at: __super_lock fs/super.c:58 [inline] #0: ffff8880293120e0 (&type->s_umount_key#93){++++}-{3:3}, at: super_lock+0x27c/0x400 fs/super.c:120 1 lock held by syz-executor/15084: #0: ffffffff8fa79e08 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline] #0: ffffffff8fa79e08 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x6e6/0xcf0 net/core/rtnetlink.c:6644 1 lock held by syz.3.953/15175: #0: ffff8880293120e0 (&type->s_umount_key#93){++++}-{3:3}, at: __super_lock fs/super.c:58 [inline] #0: ffff8880293120e0 (&type->s_umount_key#93){++++}-{3:3}, at: super_lock+0x27c/0x400 fs/super.c:120 ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 30 Comm: khungtaskd Not tainted 6.11.0-rc7-syzkaller-00039-g77f587896757 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024 Call Trace: __dump_stack lib/dump_stack.c:93 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:119 nmi_cpu_backtrace+0x49c/0x4d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x198/0x320 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+0xff4/0x1040 kernel/hung_task.c:379 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/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: 5320 Comm: kworker/1:9 Not tainted 6.11.0-rc7-syzkaller-00039-g77f587896757 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024 Workqueue: wg-crypt-wg0 wg_packet_encrypt_worker RIP: 0010:rcu_is_watching+0x44/0xb0 kernel/rcu/tree.c:726 Code: 73 7a 49 bf 00 00 00 00 00 fc ff df 4c 8d 34 dd 50 aa 08 8e 4c 89 f0 48 c1 e8 03 42 80 3c 38 00 74 08 4c 89 f7 e8 cc ec 7d 00 <48> c7 c3 78 7c 03 00 49 03 1e 48 89 d8 48 c1 e8 03 42 0f b6 04 38 RSP: 0018:ffffc90003f57468 EFLAGS: 00000046 RAX: 1ffffffff1c1154b RBX: 0000000000000001 RCX: ffff88802e368000 RDX: ffff88802e368000 RSI: ffffffff8c3fbae0 RDI: ffffffff8c3fbaa0 RBP: 0000000000000000 R08: ffffffff815cf7ee R09: 1ffffffff27f4d08 R10: dffffc0000000000 R11: fffffbfff27f4d09 R12: ffff88807c082800 R13: ffff88807c0829c0 R14: ffffffff8e08aa58 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff8880b8900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fe52c707ab8 CR3: 0000000012b74000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: rcu_read_lock include/linux/rcupdate.h:839 [inline] __queue_work+0x1dc/0xf50 kernel/workqueue.c:2261 queue_work_on+0x1c2/0x380 kernel/workqueue.c:2392 wg_queue_enqueue_per_peer_tx+0x21f/0x4a0 drivers/net/wireguard/queueing.h:188 wg_packet_encrypt_worker+0x1242/0x1610 drivers/net/wireguard/send.c:305 process_one_work kernel/workqueue.c:3231 [inline] process_scheduled_works+0xa2c/0x1830 kernel/workqueue.c:3312 worker_thread+0x86d/0xd10 kernel/workqueue.c:3389 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244