INFO: task kworker/0:4:5875 blocked for more than 143 seconds. Not tainted 6.12.0-rc7-syzkaller-00042-gf1b785f4c787 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/0:4 state:D stack:17008 pid:5875 tgid:5875 ppid:2 flags:0x00004000 Workqueue: bcachefs_write_ref bch2_delete_dead_snapshots_work (bcachefs-delete-dead-snapshots/) Call Trace: context_switch kernel/sched/core.c:5328 [inline] __schedule+0x17fa/0x4bd0 kernel/sched/core.c:6693 __schedule_loop kernel/sched/core.c:6770 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6785 schedule_timeout+0x1be/0x310 kernel/time/timer.c:2615 __closure_sync_timeout+0x2d8/0x450 lib/closure.c:217 closure_sync_timeout include/linux/closure.h:206 [inline] __bch2_wait_on_allocator+0x11a/0x250 fs/bcachefs/alloc_foreground.c:1812 bch2_wait_on_allocator fs/bcachefs/alloc_foreground.h:239 [inline] bch2_btree_update_start+0x11a2/0x14e0 fs/bcachefs/btree_update_interior.c:1269 bch2_btree_split_leaf+0x123/0x840 fs/bcachefs/btree_update_interior.c:1856 bch2_trans_commit_error+0x212/0x1390 fs/bcachefs/btree_trans_commit.c:942 __bch2_trans_commit+0x7ead/0x93c0 fs/bcachefs/btree_trans_commit.c:1140 bch2_trans_commit fs/bcachefs/btree_update.h:184 [inline] bch2_delete_dead_snapshots+0x19b6/0x5ae0 fs/bcachefs/snapshot.c:1643 bch2_delete_dead_snapshots_work+0x34/0x40 fs/bcachefs/snapshot.c:1718 process_one_work kernel/workqueue.c:3229 [inline] process_scheduled_works+0xa63/0x1850 kernel/workqueue.c:3310 worker_thread+0x870/0xd30 kernel/workqueue.c:3391 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 INFO: task syz-executor:6468 blocked for more than 144 seconds. Not tainted 6.12.0-rc7-syzkaller-00042-gf1b785f4c787 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor state:D stack:20992 pid:6468 tgid:6468 ppid:1 flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:5328 [inline] __schedule+0x17fa/0x4bd0 kernel/sched/core.c:6693 __schedule_loop kernel/sched/core.c:6770 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6785 bch2_fs_read_only+0xa86/0x1200 fs/bcachefs/super.c:347 __bch2_fs_stop+0x105/0x5c0 fs/bcachefs/super.c:620 generic_shutdown_super+0x139/0x2d0 fs/super.c:642 bch2_kill_sb+0x41/0x50 fs/bcachefs/fs.c:2278 deactivate_locked_super+0xc4/0x130 fs/super.c:473 cleanup_mnt+0x41f/0x4b0 fs/namespace.c:1373 task_work_run+0x24f/0x310 kernel/task_work.c:239 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:328 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0x168/0x370 kernel/entry/common.c:218 do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f61bff7fa47 RSP: 002b:00007ffc43cc3bf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007f61bff7fa47 RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffc43cc3cb0 RBP: 00007ffc43cc3cb0 R08: 0000000000000000 R09: 0000000000000000 R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffc43cc4d30 R13: 00007f61bfff15fc R14: 0000000000020ddc R15: 00007ffc43cc4d70 INFO: task bch-reclaim/loo:7329 blocked for more than 144 seconds. Not tainted 6.12.0-rc7-syzkaller-00042-gf1b785f4c787 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:bch-reclaim/loo state:D stack:22768 pid:7329 tgid:7329 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5328 [inline] __schedule+0x17fa/0x4bd0 kernel/sched/core.c:6693 __schedule_loop kernel/sched/core.c:6770 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6785 schedule_timeout+0x1be/0x310 kernel/time/timer.c:2615 __closure_sync_timeout+0x2d8/0x450 lib/closure.c:217 closure_sync_timeout include/linux/closure.h:206 [inline] __bch2_wait_on_allocator+0x11a/0x250 fs/bcachefs/alloc_foreground.c:1812 bch2_wait_on_allocator fs/bcachefs/alloc_foreground.h:239 [inline] bch2_btree_update_start+0x11a2/0x14e0 fs/bcachefs/btree_update_interior.c:1269 bch2_btree_split_leaf+0x123/0x840 fs/bcachefs/btree_update_interior.c:1856 bch2_trans_commit_error+0x212/0x1390 fs/bcachefs/btree_trans_commit.c:942 __bch2_trans_commit+0x7ead/0x93c0 fs/bcachefs/btree_trans_commit.c:1140 bch2_trans_commit fs/bcachefs/btree_update.h:184 [inline] bch2_btree_write_buffer_flush_locked+0x4f03/0x59f0 fs/bcachefs/btree_write_buffer.c:429 btree_write_buffer_flush_seq+0x1a43/0x1bc0 fs/bcachefs/btree_write_buffer.c:510 bch2_btree_write_buffer_journal_flush+0x4e/0x80 fs/bcachefs/btree_write_buffer.c:525 journal_flush_pins+0x5f7/0xb20 fs/bcachefs/journal_reclaim.c:565 __bch2_journal_reclaim+0x789/0xdc0 fs/bcachefs/journal_reclaim.c:698 bch2_journal_reclaim_thread+0x174/0x560 fs/bcachefs/journal_reclaim.c:740 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 INFO: task bch-copygc/loop:7333 blocked for more than 144 seconds. Not tainted 6.12.0-rc7-syzkaller-00042-gf1b785f4c787 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:bch-copygc/loop state:D stack:20088 pid:7333 tgid:7333 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5328 [inline] __schedule+0x17fa/0x4bd0 kernel/sched/core.c:6693 __schedule_loop kernel/sched/core.c:6770 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6785 schedule_timeout+0x1be/0x310 kernel/time/timer.c:2615 __closure_sync_timeout+0x2d8/0x450 lib/closure.c:217 closure_sync_timeout include/linux/closure.h:206 [inline] __bch2_wait_on_allocator+0x11a/0x250 fs/bcachefs/alloc_foreground.c:1812 bch2_wait_on_allocator fs/bcachefs/alloc_foreground.h:239 [inline] __bch2_write+0x562a/0x5dd0 fs/bcachefs/io_write.c:1501 bch2_write+0x9b5/0x1760 fs/bcachefs/io_write.c:1631 closure_queue include/linux/closure.h:270 [inline] closure_call include/linux/closure.h:432 [inline] bch2_data_update_read_done+0x22e/0x330 fs/bcachefs/data_update.c:426 move_write fs/bcachefs/move.c:133 [inline] bch2_moving_ctxt_do_pending_writes+0x44c/0x8d0 fs/bcachefs/move.c:164 move_buckets_wait+0x182/0x1290 fs/bcachefs/movinggc.c:120 bch2_copygc_thread+0x83f/0xc20 fs/bcachefs/movinggc.c:392 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 INFO: task syz.6.169:7448 blocked for more than 145 seconds. Not tainted 6.12.0-rc7-syzkaller-00042-gf1b785f4c787 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.6.169 state:D stack:20312 pid:7448 tgid:7447 ppid:6410 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5328 [inline] __schedule+0x17fa/0x4bd0 kernel/sched/core.c:6693 __schedule_loop kernel/sched/core.c:6770 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6785 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6842 rwsem_down_read_slowpath kernel/locking/rwsem.c:1084 [inline] __down_read_common kernel/locking/rwsem.c:1248 [inline] __down_read kernel/locking/rwsem.c:1261 [inline] down_read+0x705/0xa40 kernel/locking/rwsem.c:1526 __super_lock fs/super.c:58 [inline] super_lock+0x27c/0x400 fs/super.c:120 super_lock_shared fs/super.c:139 [inline] iterate_supers+0x8c/0x190 fs/super.c:931 quota_sync_all fs/quota/quota.c:69 [inline] __do_sys_quotactl fs/quota/quota.c:938 [inline] __se_sys_quotactl+0x38e/0xa30 fs/quota/quota.c:917 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: 0033:0x7f0a95f7e719 RSP: 002b:00007f0a96dda038 EFLAGS: 00000246 ORIG_RAX: 00000000000000b3 RAX: ffffffffffffffda RBX: 00007f0a96135f80 RCX: 00007f0a95f7e719 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff80000100 RBP: 00007f0a95ff175e R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f0a96135f80 R15: 00007fff8bed6938 Showing all locks held in the system: 1 lock held by pool_workqueue_/3: #0: ffffffff8e93d338 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:329 [inline] #0: ffffffff8e93d338 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x451/0x830 kernel/rcu/tree_exp.h:976 1 lock held by khungtaskd/30: #0: ffffffff8e937da0 (rcu_read_lock){....}-{1:2} , at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] , at: rcu_read_lock include/linux/rcupdate.h:849 [inline] , at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6720 3 locks held by kworker/u8:5/1783: #0: ffff8880b863ea58 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:598 #1: ffffc90005077d00 ((work_completion)(&(&bat_priv->nc.work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline] #1: ffffc90005077d00 ((work_completion)(&(&bat_priv->nc.work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1850 kernel/workqueue.c:3310 #2: ffff8880b863ea58 (&rq->__lock){-.-.}-{2:2}, at: static_key_enable+0x12/0x20 kernel/jump_label.c:222 5 locks held by kworker/u8:7/3028: #0: ffff88801baeb148 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline] #0: ffff88801baeb148 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1850 kernel/workqueue.c:3310 #1: ffffc9000c7e7d00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline] #1: ffffc9000c7e7d00 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1850 kernel/workqueue.c:3310 #2: ffffffff8fcb4910 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x16a/0xcc0 net/core/net_namespace.c:580 #3: ffffffff8fcc1448 (rtnl_mutex){+.+.}-{3:3}, at: default_device_exit_batch+0xe9/0xaa0 net/core/dev.c:11938 #4: ffffffff8e93d338 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:329 [inline] #4: ffffffff8e93d338 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x451/0x830 kernel/rcu/tree_exp.h:976 1 lock held by dhcpcd/5496: #0: ffffffff8fcc1448 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline] #0: ffffffff8fcc1448 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x6e6/0xcf0 net/core/rtnetlink.c:6672 2 locks held by getty/5582: #0: ffff888031c9c0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc90002efe2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6a6/0x1e00 drivers/tty/n_tty.c:2211 4 locks held by kworker/0:4/5875: #0: ffff88802b9a4548 ((wq_completion)bcachefs_write_ref){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline] #0: ffff88802b9a4548 ((wq_completion)bcachefs_write_ref){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1850 kernel/workqueue.c:3310 #1: ffffc90004237d00 ((work_completion)(&c->snapshot_delete_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline] #1: ffffc90004237d00 ((work_completion)(&c->snapshot_delete_work)){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1850 kernel/workqueue.c:3310 #2: ffff888068d84398 (&c->btree_trans_barrier){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:151 [inline] #2: ffff888068d84398 (&c->btree_trans_barrier){.+.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:250 [inline] #2: ffff888068d84398 (&c->btree_trans_barrier){.+.+}-{0:0}, at: bch2_trans_srcu_lock+0x97/0x1a0 fs/bcachefs/btree_iter.c:3053 #3: ffff888068da66d0 (&c->gc_lock){++++}-{3:3}, at: bch2_btree_update_start+0x682/0x14e0 fs/bcachefs/btree_update_interior.c:1197 2 locks held by syz-executor/6468: #0: ffff88806cdbc0e0 (&type->s_umount_key#60){++++}-{3:3}, at: __super_lock fs/super.c:56 [inline] #0: ffff88806cdbc0e0 (&type->s_umount_key#60){++++}-{3:3}, at: __super_lock_excl fs/super.c:71 [inline] #0: ffff88806cdbc0e0 (&type->s_umount_key#60){++++}-{3:3}, at: deactivate_super+0xb5/0xf0 fs/super.c:505 #1: ffff888068d80278 (&c->state_lock){+.+.}-{3:3}, at: __bch2_fs_stop+0xfd/0x5c0 fs/bcachefs/super.c:619 3 locks held by kworker/u8:9/6685: #0: ffff88801ac89148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline] #0: ffff88801ac89148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1850 kernel/workqueue.c:3310 #1: ffffc90003037d00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline] #1: ffffc90003037d00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1850 kernel/workqueue.c:3310 #2: ffffffff8fcc1448 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:276 1 lock held by syz-executor/7257: #0: ffffffff8fcc1448 (rtnl_mutex){+.+.}-{3:3}, at: tun_detach drivers/net/tun.c:698 [inline] #0: ffffffff8fcc1448 (rtnl_mutex){+.+.}-{3:3}, at: tun_chr_close+0x3b/0x1b0 drivers/net/tun.c:3517 4 locks held by bch-reclaim/loo/7329: #0: ffff888068dcb0a8 (&j->reclaim_lock){+.+.}-{3:3}, at: bch2_journal_reclaim_thread+0x167/0x560 fs/bcachefs/journal_reclaim.c:739 #1: ffff888068d84398 (&c->btree_trans_barrier ){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:151 [inline] ){.+.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:250 [inline] ){.+.+}-{0:0}, at: __bch2_trans_get+0x7de/0xd20 fs/bcachefs/btree_iter.c:3228 #2: ffff888068d84740 (&wb->flushing.lock){+.+.}-{3:3}, at: btree_write_buffer_flush_seq+0x1a39/0x1bc0 fs/bcachefs/btree_write_buffer.c:509 #3: ffff888068da66d0 (&c->gc_lock){++++}-{3:3}, at: bch2_btree_update_start+0x682/0x14e0 fs/bcachefs/btree_update_interior.c:1197 1 lock held by syz.6.169/7448: #0: ffff88806cdbc0e0 (&type->s_umount_key#60){++++}-{3:3}, at: __super_lock fs/super.c:58 [inline] #0: ffff88806cdbc0e0 (&type->s_umount_key#60){++++}-{3:3}, at: super_lock+0x27c/0x400 fs/super.c:120 1 lock held by syz-executor/8367: #0: ffffffff8e93d338 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:329 [inline] #0: ffffffff8e93d338 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x451/0x830 kernel/rcu/tree_exp.h:976 1 lock held by syz.5.333/9291: #0: ffff88806cdbc0e0 (&type->s_umount_key#60){++++}-{3:3}, at: __super_lock fs/super.c:58 [inline] #0: ffff88806cdbc0e0 (&type->s_umount_key#60){++++}-{3:3}, at: super_lock+0x27c/0x400 fs/super.c:120 1 lock held by syz-executor/9715: #0: ffff88805f034420 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x3f/0x90 fs/namespace.c:515 1 lock held by syz-executor/10949: #0: ffffffff8fcc1448 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline] #0: ffffffff8fcc1448 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x6e6/0xcf0 net/core/rtnetlink.c:6672 ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Not tainted 6.12.0-rc7-syzkaller-00042-gf1b785f4c787 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 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 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 32 Comm: kworker/u8:2 Not tainted 6.12.0-rc7-syzkaller-00042-gf1b785f4c787 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024 Workqueue: events_unbound cfg80211_wiphy_work RIP: 0010:__mutex_lock+0x88/0xd70 kernel/locking/mutex.c:751 Code: 84 24 88 00 00 00 ff b2 08 8e 48 c7 84 24 90 00 00 00 40 88 c7 8b 48 8d 84 24 80 00 00 00 48 c1 e8 03 42 c7 04 20 f1 f1 f1 f1 <42> c7 44 20 09 f3 f3 f3 f3 66 42 c7 44 20 0d f3 f3 48 89 44 24 28 RSP: 0018:ffffc90000a87a00 EFLAGS: 00000a06 RAX: 1ffff92000150f50 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000002 RDI: ffffc90000a87aa0 RBP: ffffc90000a87b60 R08: ffffffff8b080809 R09: 1ffffffff2037bb5 R10: dffffc0000000000 R11: fffffbfff2037bb6 R12: dffffc0000000000 R13: ffff888052658700 R14: 0000000000000000 R15: ffff888052658660 FS: 0000000000000000(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffe0ab85ff8 CR3: 00000000796e8000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: wiphy_lock include/net/cfg80211.h:6014 [inline] cfg80211_wiphy_work+0xd9/0x490 net/wireless/core.c:426 process_one_work kernel/workqueue.c:3229 [inline] process_scheduled_works+0xa63/0x1850 kernel/workqueue.c:3310 worker_thread+0x870/0xd30 kernel/workqueue.c:3391 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