INFO: task kworker/u8:13:15623 blocked for more than 145 seconds. Not tainted 6.15.0-rc3-syzkaller-00283-gf1a3944c860b #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u8:13 state:D stack:24232 pid:15623 tgid:15623 ppid:2 task_flags:0x4208060 flags:0x00004000 Workqueue: ipv6_addrconf addrconf_dad_work 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_preempt_disabled+0x13/0x30 kernel/sched/core.c:6917 __mutex_lock_common kernel/locking/mutex.c:678 [inline] __mutex_lock+0x724/0xe80 kernel/locking/mutex.c:746 rtnl_net_lock include/linux/rtnetlink.h:130 [inline] addrconf_dad_work+0x112/0x14b0 net/ipv6/addrconf.c:4195 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 Showing all locks held in the system: 2 locks held by kthreadd/2: 3 locks held by kworker/0:0/9: 4 locks held by kworker/u8:0/12: 4 locks held by kworker/u8:1/13: 1 lock held by khungtaskd/31: #0: ffffffff8df3b860 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8df3b860 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8df3b860 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6764 2 locks held by kworker/u8:2/36: #0: ffff88801eb6a948 ((wq_completion)iou_exit){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline] #0: ffff88801eb6a948 ((wq_completion)iou_exit){+.+.}-{0:0}, at: process_scheduled_works+0x9b1/0x17a0 kernel/workqueue.c:3319 #1: ffffc90000ad7c60 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline] #1: ffffc90000ad7c60 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ec/0x17a0 kernel/workqueue.c:3319 4 locks held by kworker/u8:3/54: #0: ffff88801aef6148 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline] #0: ffff88801aef6148 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x9b1/0x17a0 kernel/workqueue.c:3319 #1: ffffc9000120fc60 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline] #1: ffffc9000120fc60 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ec/0x17a0 kernel/workqueue.c:3319 #2: ffffffff8f2e6c90 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0x145/0xbd0 net/core/net_namespace.c:608 #3: ffffffff8f2f37c8 (rtnl_mutex){+.+.}-{4:4}, at: wg_netns_pre_exit+0x1c/0x1d0 drivers/net/wireguard/device.c:416 4 locks held by kworker/u8:4/63: #0: ffff8880282db148 ((wq_completion)wg-kex-wg2#21){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline] #0: ffff8880282db148 ((wq_completion)wg-kex-wg2#21){+.+.}-{0:0}, at: process_scheduled_works+0x9b1/0x17a0 kernel/workqueue.c:3319 #1: ffffc90001557c60 ((work_completion)(&peer->transmit_handshake_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline] #1: ffffc90001557c60 ((work_completion)(&peer->transmit_handshake_work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ec/0x17a0 kernel/workqueue.c:3319 #2: ffff888048cad308 (&wg->static_identity.lock){++++}-{4:4}, at: wg_noise_handshake_create_initiation+0x10a/0x7e0 drivers/net/wireguard/noise.c:529 #3: ffff888048174890 (&handshake->lock){++++}-{4:4}, at: wg_noise_handshake_create_initiation+0x11b/0x7e0 drivers/net/wireguard/noise.c:530 4 locks held by kworker/u8:5/797: 9 locks held by kworker/1:2/976: 2 locks held by kworker/R-bat_e/3398: 3 locks held by kworker/u8:6/3436: 3 locks held by kworker/u8:7/3463: 4 locks held by kworker/u8:8/3492: #0: ffff88806cc9f948 ((wq_completion)wg-kex-wg1#15){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline] #0: ffff88806cc9f948 ((wq_completion)wg-kex-wg1#15){+.+.}-{0:0}, at: process_scheduled_works+0x9b1/0x17a0 kernel/workqueue.c:3319 #1: ffffc9000d3a7c60 ((work_completion)(&peer->transmit_handshake_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline] #1: ffffc9000d3a7c60 ((work_completion)(&peer->transmit_handshake_work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ec/0x17a0 kernel/workqueue.c:3319 #2: ffff888051039308 (&wg->static_identity.lock){++++}-{4:4}, at: wg_noise_handshake_create_initiation+0x10a/0x7e0 drivers/net/wireguard/noise.c:529 #3: ffff888048170d20 (&handshake->lock){++++}-{4:4}, at: wg_noise_handshake_create_initiation+0x11b/0x7e0 drivers/net/wireguard/noise.c:530 3 locks held by kworker/u8:9/3508: 3 locks held by syslogd/5185: 2 locks held by klogd/5192: 3 locks held by udevd/5203: 2 locks held by dhcpcd/5496: 2 locks held by getty/5580: #0: ffff888030f0d0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc9000333b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222 3 locks held by syz-executor/5815: 6 locks held by kworker/1:4/5878: 3 locks held by kworker/0:3/5881: 3 locks held by kworker/0:5/5884: 3 locks held by kworker/0:6/5885: 3 locks held by kworker/0:7/5925: #0: ffff88801a080d48 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline] #0: ffff88801a080d48 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x9b1/0x17a0 kernel/workqueue.c:3319 #1: ffffc9000488fc60 (deferred_process_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline] #1: ffffc9000488fc60 (deferred_process_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ec/0x17a0 kernel/workqueue.c:3319 #2: ffffffff8f2f37c8 (rtnl_mutex){+.+.}-{4:4}, at: switchdev_deferred_process_work+0xe/0x20 net/switchdev/switchdev.c:104 3 locks held by kworker/0:8/5927: 3 locks held by syz-executor/7584: 4 locks held by kworker/0:9/10217: #0: ffff888047c1fd48 ((wq_completion)wg-kex-wg2#22){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline] #0: ffff888047c1fd48 ((wq_completion)wg-kex-wg2#22){+.+.}-{0:0}, at: process_scheduled_works+0x9b1/0x17a0 kernel/workqueue.c:3319 #1: ffffc90005bc7c60 ((work_completion)(&({ do { const void *__vpp_verify = (typeof((worker) + 0))((void *)0); (void)__vpp_verify; } while (0); ({ unsigned long __ptr; __ptr = (unsigned long) ((__typeof_unqual__(*((worker))) *)(( unsigned long)((worker)))); (typeof((__typeof_unqual__(*((worker))) *)(( unsigned long)((worker))))) (__ptr + (((__per_cpu_offset[(cpu)])))); }); })->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline] #1: ffffc90005bc7c60 ((work_completion)(&({ do { const void *__vpp_verify = (typeof((worker) + 0))((void *)0); (void)__vpp_verify; } while (0); ({ unsigned long __ptr; __ptr = (unsigned long) ((__typeof_unqual__(*((worker))) *)(( unsigned long)((worker)))); (typeof((__typeof_unqual__(*((worker))) *)(( unsigned long)((worker))))) (__ptr + (((__per_cpu_offset[(cpu)])))); }); })->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ec/0x17a0 kernel/workqueue.c:3319 #2: ffff888048cad308 (&wg->static_identity.lock){++++}-{4:4}, at: wg_noise_handshake_consume_initiation+0x150/0x900 drivers/net/wireguard/noise.c:598 #3: ffff888048174890 (&handshake->lock){++++}-{4:4}, at: wg_noise_handshake_consume_initiation+0x4de/0x900 drivers/net/wireguard/noise.c:632 5 locks held by kworker/1:10/10233: 3 locks held by kworker/1:11/10234: 3 locks held by kworker/1:12/10235: #0: ffff88801a081d48 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline] #0: ffff88801a081d48 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: process_scheduled_works+0x9b1/0x17a0 kernel/workqueue.c:3319 #1: ffffc90004b5fc60 ((reg_check_chans).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline] #1: ffffc90004b5fc60 ((reg_check_chans).work){+.+.}-{0:0}, at: process_scheduled_works+0x9ec/0x17a0 kernel/workqueue.c:3319 #2: ffffffff8f2f37c8 (rtnl_mutex){+.+.}-{4:4}, at: reg_check_chans_work+0x95/0xf00 net/wireless/reg.c:2483 4 locks held by kworker/1:13/10236: 4 locks held by kworker/1:14/10237: #0: ffff888047d57548 ((wq_completion)wg-kex-wg0#22){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline] #0: ffff888047d57548 ((wq_completion)wg-kex-wg0#22){+.+.}-{0:0}, at: process_scheduled_works+0x9b1/0x17a0 kernel/workqueue.c:3319 #1: ffffc90004b2fc60 ((work_completion)(&({ do { const void *__vpp_verify = (typeof((worker) + 0))((void *)0); (void)__vpp_verify; } while (0); ({ unsigned long __ptr; __ptr = (unsigned long) ((__typeof_unqual__(*((worker))) *)(( unsigned long)((worker)))); (typeof((__typeof_unqual__(*((worker))) *)(( unsigned long)((worker))))) (__ptr + (((__per_cpu_offset[(cpu)])))); }); })->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline] #1: ffffc90004b2fc60 ((work_completion)(&({ do { const void *__vpp_verify = (typeof((worker) + 0))((void *)0); (void)__vpp_verify; } while (0); ({ unsigned long __ptr; __ptr = (unsigned long) ((__typeof_unqual__(*((worker))) *)(( unsigned long)((worker)))); (typeof((__typeof_unqual__(*((worker))) *)(( unsigned long)((worker))))) (__ptr + (((__per_cpu_offset[(cpu)])))); }); })->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ec/0x17a0 kernel/workqueue.c:3319 #2: ffff8880698a9308 (&wg->static_identity.lock){++++}-{4:4}, at: wg_noise_handshake_consume_initiation+0x150/0x900 drivers/net/wireguard/noise.c:598 #3: ffff888048264890 (&handshake->lock){++++}-{4:4}, at: wg_noise_handshake_consume_initiation+0x4de/0x900 drivers/net/wireguard/noise.c:632 3 locks held by kworker/1:15/10238: #0: ffff88807de79548 ((wq_completion)wg-kex-wg1#16){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline] #0: ffff88807de79548 ((wq_completion)wg-kex-wg1#16){+.+.}-{0:0}, at: process_scheduled_works+0x9b1/0x17a0 kernel/workqueue.c:3319 #1: ffffc90004b1fc60 ((work_completion)(&({ do { const void *__vpp_verify = (typeof((worker) + 0))((void *)0); (void)__vpp_verify; } while (0); ({ unsigned long __ptr; __ptr = (unsigned long) ((__typeof_unqual__(*((worker))) *)(( unsigned long)((worker)))); (typeof((__typeof_unqual__(*((worker))) *)(( unsigned long)((worker))))) (__ptr + (((__per_cpu_offset[(cpu)])))); }); })->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline] #1: ffffc90004b1fc60 ((work_completion)(&({ do { const void *__vpp_verify = (typeof((worker) + 0))((void *)0); (void)__vpp_verify; } while (0); ({ unsigned long __ptr; __ptr = (unsigned long) ((__typeof_unqual__(*((worker))) *)(( unsigned long)((worker)))); (typeof((__typeof_unqual__(*((worker))) *)(( unsigned long)((worker))))) (__ptr + (((__per_cpu_offset[(cpu)])))); }); })->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ec/0x17a0 kernel/workqueue.c:3319 #2: ffff888048170d20 (&handshake->lock){++++}-{4:4}, at: wg_noise_handshake_begin_session+0x36/0xbd0 drivers/net/wireguard/noise.c:822 2 locks held by kworker/1:18/10241: 4 locks held by kworker/u8:10/13409: 4 locks held by kworker/u8:11/13410: 4 locks held by kworker/u8:12/13412: 3 locks held by kworker/u8:13/15623: #0: ffff88814cf31148 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline] #0: ffff88814cf31148 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0x9b1/0x17a0 kernel/workqueue.c:3319 #1: ffffc90004be7c60 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline] #1: ffffc90004be7c60 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ec/0x17a0 kernel/workqueue.c:3319 #2: ffffffff8f2f37c8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #2: ffffffff8f2f37c8 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_dad_work+0x112/0x14b0 net/ipv6/addrconf.c:4195 4 locks held by kworker/u8:14/15624: 6 locks held by kworker/u8:15/15625: 3 locks held by kworker/u8:16/15626: 4 locks held by kworker/u8:17/15627: 5 locks held by syz-executor/16603: 1 lock held by syz.6.2775/16639: 2 locks held by syz.4.3441/19056: 6 locks held by syz-executor/19121: 4 locks held by syz.3.3500/19302: 3 locks held by kworker/u8:18/19304: 2 locks held by kworker/0:2/19305: 1 lock held by kworker/u8:19/19306: ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.15.0-rc3-syzkaller-00283-gf1a3944c860b #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x17a/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+0xfee/0x1030 kernel/hung_task.c:437 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 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 15625 Comm: kworker/u8:15 Not tainted 6.15.0-rc3-syzkaller-00283-gf1a3944c860b #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025 Workqueue: wg-kex-wg2 wg_packet_handshake_send_worker RIP: 0010:check_preemption_disabled+0x1/0x120 lib/smp_processor_id.c:13 Code: 80 cd c1 8b 48 c7 c6 c0 cd c1 8b eb 1c 66 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 55 <41> 57 41 56 53 48 83 ec 10 65 48 8b 05 4e 8e 1f 07 48 89 44 24 08 RSP: 0018:ffffc90000a07658 EFLAGS: 00000046 RAX: 0000000000000008 RBX: 0000000000000000 RCX: 392dd590a2a8da00 RDX: 0000000000000100 RSI: ffffffff8d934029 RDI: ffffffff8bc1cde0 RBP: 00000000ffffffff R08: ffffc90000a079c0 R09: ffffc90000a079d0 R10: ffffc90000a07820 R11: fffff52000140f06 R12: 0000000000000246 R13: ffff888026fb1e00 R14: ffffffff8f2f37c8 R15: 0000000000000008 FS: 0000000000000000(0000) GS:ffff8881261cc000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000555565a435c8 CR3: 000000000dd36000 CR4: 00000000003526f0 DR0: 000000001000000d DR1: 00000000000000ff DR2: fffffffffffffff7 DR3: 3e00000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lockdep_recursion_finish kernel/locking/lockdep.c:472 [inline] lock_is_held_type+0xfe/0x190 kernel/locking/lockdep.c:5939 lock_is_held include/linux/lockdep.h:249 [inline] lockdep_rtnl_is_held+0x1b/0x40 net/core/rtnetlink.c:182 __in6_dev_get include/net/addrconf.h:347 [inline] ip6_ignore_linkdown include/net/addrconf.h:443 [inline] find_match+0xd0/0xc90 net/ipv6/route.c:781 __find_rr_leaf+0x23a/0x6d0 net/ipv6/route.c:869 find_rr_leaf net/ipv6/route.c:890 [inline] rt6_select net/ipv6/route.c:934 [inline] fib6_table_lookup+0x39f/0xa80 net/ipv6/route.c:2230 ip6_pol_route+0x222/0x1180 net/ipv6/route.c:2266 pol_lookup_func include/net/ip6_fib.h:616 [inline] fib6_rule_lookup+0x52f/0x6f0 net/ipv6/fib6_rules.c:120 ip6_route_input_lookup net/ipv6/route.c:2335 [inline] ip6_route_input+0x6ce/0xa50 net/ipv6/route.c:2631 ip6_rcv_finish+0x141/0x2d0 net/ipv6/ip6_input.c:77 ip_sabotage_in+0x1de/0x270 net/bridge/br_netfilter_hooks.c:993 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 __netif_receive_skb_one_core net/core/dev.c:5887 [inline] __netif_receive_skb+0xd3/0x380 net/core/dev.c:6000 netif_receive_skb_internal net/core/dev.c:6086 [inline] netif_receive_skb+0x1cb/0x790 net/core/dev.c:6145 NF_HOOK+0x9d/0x390 include/linux/netfilter.h:315 br_handle_frame_finish+0x1489/0x1950 net/bridge/br_input.c:-1 br_nf_hook_thresh+0x3bf/0x490 net/bridge/br_netfilter_hooks.c:-1 br_nf_pre_routing_finish_ipv6+0x948/0xd00 net/bridge/br_netfilter_ipv6.c:-1 NF_HOOK include/linux/netfilter.h:314 [inline] br_nf_pre_routing_ipv6+0x37e/0x6b0 net/bridge/br_netfilter_ipv6.c:184 nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline] nf_hook_bridge_pre net/bridge/br_input.c:282 [inline] br_handle_frame+0x97f/0x14c0 net/bridge/br_input.c:433 __netif_receive_skb_core+0x10de/0x4180 net/core/dev.c:5773 __netif_receive_skb_one_core net/core/dev.c:5885 [inline] __netif_receive_skb+0x72/0x380 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 local_bh_enable include/linux/bottom_half.h:33 [inline] fpregs_unlock arch/x86/include/asm/fpu/api.h:77 [inline] kernel_fpu_end+0xd2/0x120 arch/x86/kernel/fpu/core.c:460 blake2s_compress+0x5f/0xd0 arch/x86/crypto/blake2s-glue.c:49 blake2s_final+0x116/0x260 lib/crypto/blake2s.c:54 hmac+0x293/0x330 drivers/net/wireguard/noise.c:333 kdf+0x182/0x270 drivers/net/wireguard/noise.c:375 mix_precomputed_dh drivers/net/wireguard/noise.c:426 [inline] wg_noise_handshake_create_initiation+0x462/0x7e0 drivers/net/wireguard/noise.c:560 wg_packet_send_handshake_initiation drivers/net/wireguard/send.c:34 [inline] wg_packet_handshake_send_worker+0x163/0x320 drivers/net/wireguard/send.c:51 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