INFO: task syz.0.2269:15321 blocked for more than 143 seconds.
Not tainted 6.11.0-rc1-syzkaller-00062-ge4fc196f5ba3 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.2269 state:D stack:26624 pid:15321 tgid:15321 ppid:15003 flags:0x00000004
Call Trace:
context_switch kernel/sched/core.c:5188 [inline]
__schedule+0x1800/0x4a60 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
__mutex_lock_common kernel/locking/mutex.c:684 [inline]
__mutex_lock+0x6a4/0xd70 kernel/locking/mutex.c:752
hugetlb_fault+0x575/0x3780 mm/hugetlb.c:6451
handle_mm_fault+0x173f/0x1980 mm/memory.c:5831
do_user_addr_fault arch/x86/mm/fault.c:1338 [inline]
handle_page_fault arch/x86/mm/fault.c:1481 [inline]
exc_page_fault+0x459/0x8c0 arch/x86/mm/fault.c:1539
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
RIP: 0033:0x7f2d4a33ee3c
RSP: 002b:00007f2d4a62fb98 EFLAGS: 00010246
RAX: 0000000020000000 RBX: 0000000000000004 RCX: 8000000000000010
RDX: 0000000000000010 RSI: 00007f2d49e006f9 RDI: 0000000020000000
RBP: 00007f2d4a62fc70 R08: 00007f2d4a200000 R09: 0000000000000001
R10: 0000000000000001 R11: 0000000000000009 R12: 0000000000000032
R13: 00007f2d4a62fc90 R14: 00007f2d4a62fcb0 R15: fffffffffffffffe
INFO: task syz.0.2269:15323 blocked for more than 143 seconds.
Not tainted 6.11.0-rc1-syzkaller-00062-ge4fc196f5ba3 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.2269 state:D stack:23680 pid:15323 tgid:15321 ppid:15003 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:5188 [inline]
__schedule+0x1800/0x4a60 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
__mutex_lock_common kernel/locking/mutex.c:684 [inline]
__mutex_lock+0x6a4/0xd70 kernel/locking/mutex.c:752
mfill_atomic_hugetlb mm/userfaultfd.c:578 [inline]
mfill_atomic mm/userfaultfd.c:769 [inline]
mfill_atomic_copy+0x12ed/0x1a50 mm/userfaultfd.c:865
userfaultfd_copy fs/userfaultfd.c:1729 [inline]
userfaultfd_ioctl+0x2896/0x70a0 fs/userfaultfd.c:2133
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:907 [inline]
__se_sys_ioctl+0xfc/0x170 fs/ioctl.c:893
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: 0033:0x7f2d4a3773b9
RSP: 002b:00007f2d49dff048 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f2d4a505f80 RCX: 00007f2d4a3773b9
RDX: 0000000020000000 RSI: 00000000c028aa03 RDI: 0000000000000006
RBP: 00007f2d4a3e48e6 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f2d4a505f80 R15: 00007f2d4a62fa38
INFO: task syz.0.2269:15324 blocked for more than 144 seconds.
Not tainted 6.11.0-rc1-syzkaller-00062-ge4fc196f5ba3 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.2269 state:D stack:25376 pid:15324 tgid:15321 ppid:15003 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:5188 [inline]
__schedule+0x1800/0x4a60 kernel/sched/core.c:6529
__schedule_loop kernel/sched/core.c:6606 [inline]
schedule+0x14b/0x320 kernel/sched/core.c:6621
io_schedule+0x8d/0x110 kernel/sched/core.c:7401
folio_wait_bit_common+0x882/0x12b0 mm/filemap.c:1307
__filemap_get_folio+0xb7/0xc10 mm/filemap.c:1898
hugetlb_fault+0x1b10/0x3780 mm/hugetlb.c:6531
handle_mm_fault+0x173f/0x1980 mm/memory.c:5831
do_user_addr_fault arch/x86/mm/fault.c:1389 [inline]
handle_page_fault arch/x86/mm/fault.c:1481 [inline]
exc_page_fault+0x2b9/0x8c0 arch/x86/mm/fault.c:1539
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
RIP: 0010:__put_user_4+0x11/0x20 arch/x86/lib/putuser.S:88
Code: 1f 84 00 00 00 00 00 66 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 48 89 cb 48 c1 fb 3f 48 09 d9 0f 01 cb <89> 01 31 c9 0f 01 ca c3 cc cc cc cc 0f 1f 00 90 90 90 90 90 90 90
RSP: 0018:ffffc900042ffdd8 EFLAGS: 00050202
RAX: 0000000000000009 RBX: 0000000000000000 RCX: 0000000020000640
RDX: 0000000000000000 RSI: ffffffff8c0ae6e0 RDI: ffffffff8c605bc0
RBP: ffffc900042ffed0 R08: ffffffff9017a4af R09: 1ffffffff202f495
R10: dffffc0000000000 R11: fffffbfff202f496 R12: 0000000000000000
R13: 1ffff9200085ffc4 R14: 1ffff9200085ffcc R15: 0000000020000640
__sys_socketpair+0x186/0x720 net/socket.c:1756
__do_sys_socketpair net/socket.c:1822 [inline]
__se_sys_socketpair net/socket.c:1819 [inline]
__x64_sys_socketpair+0x9b/0xb0 net/socket.c:1819
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: 0033:0x7f2d4a3773b9
RSP: 002b:00007f2d49dde048 EFLAGS: 00000246 ORIG_RAX: 0000000000000035
RAX: ffffffffffffffda RBX: 00007f2d4a506058 RCX: 00007f2d4a3773b9
RDX: 0000000000000000 RSI: 0000000000000005 RDI: 0000000000000001
RBP: 00007f2d4a3e48e6 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000020000640 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f2d4a506058 R15: 00007f2d4a62fa38
INFO: task syz.0.2269:15329 blocked for more than 144 seconds.
Not tainted 6.11.0-rc1-syzkaller-00062-ge4fc196f5ba3 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.2269 state:D stack:24344 pid:15329 tgid:15321 ppid:15003 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:5188 [inline]
__schedule+0x1800/0x4a60 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
__mutex_lock_common kernel/locking/mutex.c:684 [inline]
__mutex_lock+0x6a4/0xd70 kernel/locking/mutex.c:752
hugetlb_wp+0x104d/0x3a90 mm/hugetlb.c:6027
hugetlb_fault+0x26de/0x3780 mm/hugetlb.c:6579
handle_mm_fault+0x173f/0x1980 mm/memory.c:5831
do_user_addr_fault arch/x86/mm/fault.c:1389 [inline]
handle_page_fault arch/x86/mm/fault.c:1481 [inline]
exc_page_fault+0x2b9/0x8c0 arch/x86/mm/fault.c:1539
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
RIP: 0010:__put_user_4+0x11/0x20 arch/x86/lib/putuser.S:88
Code: 1f 84 00 00 00 00 00 66 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 48 89 cb 48 c1 fb 3f 48 09 d9 0f 01 cb <89> 01 31 c9 0f 01 ca c3 cc cc cc cc 0f 1f 00 90 90 90 90 90 90 90
RSP: 0018:ffffc90004477dd8 EFLAGS: 00050202
RAX: 0000000000000007 RBX: 0000000000000000 RCX: 0000000020000640
RDX: 0000000000000000 RSI: ffffffff8c0ae6e0 RDI: ffffffff8c605bc0
RBP: ffffc90004477ed0 R08: ffffffff9017a4af R09: 1ffffffff202f495
R10: dffffc0000000000 R11: fffffbfff202f496 R12: 0000000000000000
R13: 1ffff9200088efc4 R14: 1ffff9200088efcc R15: 0000000020000640
__sys_socketpair+0x186/0x720 net/socket.c:1756
__do_sys_socketpair net/socket.c:1822 [inline]
__se_sys_socketpair net/socket.c:1819 [inline]
__x64_sys_socketpair+0x9b/0xb0 net/socket.c:1819
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: 0033:0x7f2d4a3773b9
RSP: 002b:00007f2d49dbd048 EFLAGS: 00000246 ORIG_RAX: 0000000000000035
RAX: ffffffffffffffda RBX: 00007f2d4a506130 RCX: 00007f2d4a3773b9
RDX: 0000000000000000 RSI: 0000000000000005 RDI: 0000000000000001
RBP: 00007f2d4a3e48e6 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000020000640 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000006e R14: 00007f2d4a506130 R15: 00007f2d4a62fa38
Showing all locks held in the system:
3 locks held by kworker/1:0/25:
#0: ffff888015880948 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3206 [inline]
#0: ffff888015880948 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x90a/0x1830 kernel/workqueue.c:3312
#1: ffffc900001f7d00 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3207 [inline]
#1: ffffc900001f7d00 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_scheduled_works+0x945/0x1830 kernel/workqueue.c:3312
#2: ffff888066e00240 (&data->fib_lock){+.+.}-{3:3}, at: nsim_fib_event_work+0x2d1/0x4130 drivers/net/netdevsim/fib.c:1489
1 lock held by khungtaskd/30:
#0: ffffffff8e9377a0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:326 [inline]
#0: ffffffff8e9377a0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#0: ffffffff8e9377a0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6620
2 locks held by kworker/u8:7/2942:
1 lock held by klogd/4670:
2 locks held by dhcpcd/4894:
#0: ffffffff8fc64a88 (vlan_ioctl_mutex){+.+.}-{3:3}, at: sock_ioctl+0x664/0x8e0 net/socket.c:1303
#1: ffffffff8fc7fe48 (rtnl_mutex){+.+.}-{3:3}, at: vlan_ioctl_handler+0x112/0x9d0 net/8021q/vlan.c:553
2 locks held by getty/4988:
#0: ffff8880302910a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc900031232f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6b5/0x1e10 drivers/tty/n_tty.c:2211
3 locks held by kworker/u8:14/14116:
#0: ffff88802b2f9148 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3206 [inline]
#0: ffff88802b2f9148 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0x90a/0x1830 kernel/workqueue.c:3312
#1: ffffc900036cfd00 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3207 [inline]
#1: ffffc900036cfd00 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x945/0x1830 kernel/workqueue.c:3312
#2: ffffffff8fc7fe48 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_dad_work+0xd0/0x16f0 net/ipv6/addrconf.c:4194
4 locks held by kworker/u8:15/14119:
#0: ffff8880166e5948 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3206 [inline]
#0: ffff8880166e5948 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x90a/0x1830 kernel/workqueue.c:3312
#1: ffffc90004c3fd00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3207 [inline]
#1: ffffc90004c3fd00 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x945/0x1830 kernel/workqueue.c:3312
#2: ffffffff8fc732d0 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x16a/0xcc0 net/core/net_namespace.c:594
#3: ffffffff8fc7fe48 (rtnl_mutex){+.+.}-{3:3}, at: default_device_exit_batch+0xe9/0xa90 net/core/dev.c:11874
2 locks held by syz.0.2269/15321:
#0: ffff88805cbfd2f8 (&vma->vm_lock->lock){++++}-{3:3}, at: vma_start_read include/linux/mm.h:690 [inline]
#0: ffff88805cbfd2f8 (&vma->vm_lock->lock){++++}-{3:3}, at: lock_vma_under_rcu+0x2f9/0x6e0 mm/memory.c:5999
#1: ffff88801baaa578 (&hugetlb_fault_mutex_table[i]){+.+.}-{3:3}, at: hugetlb_fault+0x575/0x3780 mm/hugetlb.c:6451
3 locks held by syz.0.2269/15323:
#0: ffff88805cbfd730 (&vma->vm_lock->lock){++++}-{3:3}, at: vma_start_read include/linux/mm.h:690 [inline]
#0: ffff88805cbfd730 (&vma->vm_lock->lock){++++}-{3:3}, at: lock_vma_under_rcu+0x2f9/0x6e0 mm/memory.c:5999
#1: ffff88805f95eb38 (&ctx->map_changing_lock){.+.+}-{3:3}, at: mfill_atomic_hugetlb mm/userfaultfd.c:560 [inline]
#1: ffff88805f95eb38 (&ctx->map_changing_lock){.+.+}-{3:3}, at: mfill_atomic mm/userfaultfd.c:769 [inline]
#1: ffff88805f95eb38 (&ctx->map_changing_lock){.+.+}-{3:3}, at: mfill_atomic_copy+0x117e/0x1a50 mm/userfaultfd.c:865
#2: ffff88801baaa578 (&hugetlb_fault_mutex_table[i]){+.+.}-{3:3}, at: mfill_atomic_hugetlb mm/userfaultfd.c:578 [inline]
#2: ffff88801baaa578 (&hugetlb_fault_mutex_table[i]){+.+.}-{3:3}, at: mfill_atomic mm/userfaultfd.c:769 [inline]
#2: ffff88801baaa578 (&hugetlb_fault_mutex_table[i]){+.+.}-{3:3}, at: mfill_atomic_copy+0x12ed/0x1a50 mm/userfaultfd.c:865
3 locks held by syz.0.2269/15324:
#0: ffff88807d330b18 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:163 [inline]
#0: ffff88807d330b18 (&mm->mmap_lock){++++}-{3:3}, at: get_mmap_lock_carefully mm/memory.c:5870 [inline]
#0: ffff88807d330b18 (&mm->mmap_lock){++++}-{3:3}, at: lock_mm_and_find_vma+0x32/0x2f0 mm/memory.c:5930
#1: ffff88801baaa578 (&hugetlb_fault_mutex_table[i]){+.+.}-{3:3}, at: hugetlb_fault+0x575/0x3780 mm/hugetlb.c:6451
#2: ffff88807cca44e8 (&resv_map->rw_sema){++++}-{3:3}, at: hugetlb_fault+0x67b/0x3780 mm/hugetlb.c:6458
2 locks held by syz.0.2269/15329:
#0: ffff88807d330b18 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:163 [inline]
#0: ffff88807d330b18 (&mm->mmap_lock){++++}-{3:3}, at: get_mmap_lock_carefully mm/memory.c:5870 [inline]
#0: ffff88807d330b18 (&mm->mmap_lock){++++}-{3:3}, at: lock_mm_and_find_vma+0x32/0x2f0 mm/memory.c:5930
#1: ffff88801baaa578 (&hugetlb_fault_mutex_table[i]){+.+.}-{3:3}, at: hugetlb_wp+0x104d/0x3a90 mm/hugetlb.c:6027
1 lock held by syz-executor/17254:
#0: ffffffff8e93cb78 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:328 [inline]
#0: ffffffff8e93cb78 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x451/0x830 kernel/rcu/tree_exp.h:958
2 locks held by syz-executor/17256:
#0: ffff88805bdf4d80 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_close net/bluetooth/hci_core.c:488 [inline]
#0: ffff88805bdf4d80 (&hdev->req_lock){+.+.}-{3:3}, at: hci_unregister_dev+0x203/0x510 net/bluetooth/hci_core.c:2699
#1: ffff88805bdf4078 (&hdev->lock){+.+.}-{3:3}, at: hci_dev_close_sync+0x572/0x11a0 net/bluetooth/hci_sync.c:5110
1 lock held by syz-executor/17435:
#0: ffffffff8e93cb78 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:328 [inline]
#0: ffffffff8e93cb78 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x451/0x830 kernel/rcu/tree_exp.h:958
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Not tainted 6.11.0-rc1-syzkaller-00062-ge4fc196f5ba3 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024
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+0xfee/0x1030 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: 2942 Comm: kworker/u8:7 Not tainted 6.11.0-rc1-syzkaller-00062-ge4fc196f5ba3 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024
Workqueue: bat_events batadv_nc_worker
RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:26 [inline]
RIP: 0010:__local_bh_disable_ip+0x163/0x220 kernel/softirq.c:325
Code: 24 40 42 80 3c 23 00 74 05 e8 19 67 a3 00 f6 44 24 41 02 0f 85 ac 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 65 8b 05 a5 9e ac 7e <25> ff ff ff 7f 44 39 f8 75 43 4c 8b 75 08 4c 89 f7 e8 57 c2 19 00
RSP: 0018:ffffc900098e79c0 EFLAGS: 00000206
RAX: 0000000080000201 RBX: 1ffff9200131cf40 RCX: ffffffff94f21903
RDX: 1ffff110057ed9f9 RSI: 0000000000000201 RDI: ffffc900098e7a00
RBP: ffffc900098e7a98 R08: ffffffff937298df R09: 1ffffffff26e531b
R10: dffffc0000000000 R11: fffffbfff26e531c R12: dffffc0000000000
R13: 1ffff9200131cf3c R14: 0000000000000246 R15: 0000000000000201
FS: 0000000000000000(0000) GS:ffff8880b9200000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffd79a2bf98 CR3: 000000000e734000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
__raw_spin_lock_bh include/linux/spinlock_api_smp.h:125 [inline]
_raw_spin_lock_bh+0x1c/0x50 kernel/locking/spinlock.c:178
spin_lock_bh include/linux/spinlock.h:356 [inline]
batadv_nc_purge_paths+0xe8/0x3b0 net/batman-adv/network-coding.c:442
batadv_nc_worker+0x365/0x610 net/batman-adv/network-coding.c:722
process_one_work kernel/workqueue.c:3231 [inline]
process_scheduled_works+0xa2c/0x1830 kernel/workqueue.c:3312
worker_thread+0x86d/0xd40 kernel/workqueue.c:3390
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