syzbot

INFO: task syz.3.1445:10776 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.1445      state:D stack:24360 pid:10776 tgid:10774 ppid:5800   task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5298 [inline]
 __schedule+0x1553/0x5240 kernel/sched/core.c:6911
 __schedule_loop kernel/sched/core.c:6993 [inline]
 schedule+0x164/0x360 kernel/sched/core.c:7008
 io_schedule+0x80/0xe0 kernel/sched/core.c:7835
 folio_wait_bit_common+0x6dd/0xbc0 mm/filemap.c:1323
 folio_lock include/linux/pagemap.h:1159 [inline]
 migrate_folio_unmap mm/migrate.c:1250 [inline]
 migrate_pages_batch+0x1864/0x4090 mm/migrate.c:1890
 migrate_pages_sync mm/migrate.c:2034 [inline]
 migrate_pages+0x20c5/0x2a50 mm/migrate.c:2116
 compact_zone+0x26ec/0x4890 mm/compaction.c:2647
 compact_node mm/compaction.c:2916 [inline]
 compact_nodes mm/compaction.c:2938 [inline]
 sysctl_compaction_handler+0x3f3/0x870 mm/compaction.c:2989
 proc_sys_call_handler+0x4c9/0x830 fs/proc/proc_sysctl.c:600
 iter_file_splice_write+0x9a6/0x10f0 fs/splice.c:736
 do_splice_from fs/splice.c:936 [inline]
 direct_splice_actor+0x104/0x160 fs/splice.c:1159
 splice_direct_to_actor+0x545/0xc80 fs/splice.c:1103
 do_splice_direct_actor fs/splice.c:1202 [inline]
 do_splice_direct+0x19b/0x2a0 fs/splice.c:1228
 do_sendfile+0x547/0x7e0 fs/read_write.c:1372
 __do_sys_sendfile64 fs/read_write.c:1427 [inline]
 __se_sys_sendfile64+0xdf/0x1a0 fs/read_write.c:1419
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2d0130c819
RSP: 002b:00007f2cff566028 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007f2d01585fa0 RCX: 00007f2d0130c819
RDX: 00002000000000c0 RSI: 0000000000000004 RDI: 0000000000000005
RBP: 00007f2d013a2c91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000005 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f2d01586038 R14: 00007f2d01585fa0 R15: 00007ffe19612c98
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/38:
 #0: ffffffff8ddcb9c0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
 #0: ffffffff8ddcb9c0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
 #0: ffffffff8ddcb9c0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
2 locks held by kworker/1:2/933:
6 locks held by kworker/u8:12/1454:
 #0: ffff888019c44138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline]
 #0: ffff888019c44138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0xa52/0x18c0 kernel/workqueue.c:3359
 #1: ffffc9000638fc40 ((work_completion)(&(&nsim_dev->trap_data->trap_report_dw)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3252 [inline]
 #1: ffffc9000638fc40 ((work_completion)(&(&nsim_dev->trap_data->trap_report_dw)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa8d/0x18c0 kernel/workqueue.c:3359
 #2: ffff88805e254300 (&devlink->lock_key#5){+.+.}-{4:4}, at: nsim_dev_trap_report_work+0x57/0xbc0 drivers/net/netdevsim/dev.c:909
 #3: ffff88805e1a1920 (&nsim_trap_data->trap_lock){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
 #3: ffff88805e1a1920 (&nsim_trap_data->trap_lock){+.+.}-{3:3}, at: nsim_dev_trap_report drivers/net/netdevsim/dev.c:862 [inline]
 #3: ffff88805e1a1920 (&nsim_trap_data->trap_lock){+.+.}-{3:3}, at: nsim_dev_trap_report_work+0x1ad/0xbc0 drivers/net/netdevsim/dev.c:922
 #4: ffffffff8ddcb9c0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
 #4: ffffffff8ddcb9c0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
 #4: ffffffff8ddcb9c0 (rcu_read_lock){....}-{1:3}, at: __rt_spin_lock kernel/locking/spinlock_rt.c:50 [inline]
 #4: ffffffff8ddcb9c0 (rcu_read_lock){....}-{1:3}, at: rt_spin_lock+0x1e0/0x400 kernel/locking/spinlock_rt.c:57
 #5: ffff88801ded5958 (&n->list_lock){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
 #5: ffff88801ded5958 (&n->list_lock){+.+.}-{3:3}, at: get_partial_node_bulk mm/slub.c:3750 [inline]
 #5: ffff88801ded5958 (&n->list_lock){+.+.}-{3:3}, at: __refill_objects_node+0x87/0x560 mm/slub.c:7027
4 locks held by kworker/u8:13/1860:
6 locks held by kworker/u8:15/4144:
2 locks held by kworker/u8:16/4614:
 #0: ffff888019c44138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline]
 #0: ffff888019c44138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0xa52/0x18c0 kernel/workqueue.c:3359
 #1: ffffc90010fdfc40 ((reaper_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3252 [inline]
 #1: ffffc90010fdfc40 ((reaper_work).work){+.+.}-{0:0}, at: process_scheduled_works+0xa8d/0x18c0 kernel/workqueue.c:3359
2 locks held by getty/5558:
 #0: ffff888036c990a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc90003e8b2e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x462/0x13c0 drivers/tty/n_tty.c:2211
1 lock held by udevd/6845:
 #0: ffff8880269004c8 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xcc0 block/bdev.c:961
3 locks held by kworker/u8:20/9113:
 #0: ffff888031b74938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline]
 #0: ffff888031b74938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0xa52/0x18c0 kernel/workqueue.c:3359
 #1: ffffc90006b1fc40 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3252 [inline]
 #1: ffffc90006b1fc40 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa8d/0x18c0 kernel/workqueue.c:3359
 #2: ffffffff8f15cc78 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
 #2: ffffffff8f15cc78 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_dad_work+0x124/0x1680 net/ipv6/addrconf.c:4198
2 locks held by kworker/1:1/9487:
 #0: ffff888019c07938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline]
 #0: ffff888019c07938 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0xa52/0x18c0 kernel/workqueue.c:3359
 #1: ffffc900066bfc40 (key_gc_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3252 [inline]
 #1: ffffc900066bfc40 (key_gc_work){+.+.}-{0:0}, at: process_scheduled_works+0xa8d/0x18c0 kernel/workqueue.c:3359
1 lock held by syz.3.1445/10776:
 #0: ffff88802d230480 (sb_writers#3){.+.+}-{0:0}, at: direct_splice_actor+0x49/0x160 fs/splice.c:1158
6 locks held by kworker/1:9/10797:
 #0: ffff888021e8d138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline]
 #0: ffff888021e8d138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0xa52/0x18c0 kernel/workqueue.c:3359
 #1: ffffc90006b5fc40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3252 [inline]
 #1: ffffc90006b5fc40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0xa8d/0x18c0 kernel/workqueue.c:3359
 #2: ffff888029c52210 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:949 [inline]
 #2: ffff888029c52210 (&dev->mutex){....}-{4:4}, at: hub_event+0x17c/0x4f60 drivers/usb/core/hub.c:5899
 #3: ffff888029d51640 (&port_dev->status_lock){+.+.}-{4:4}, at: usb_lock_port drivers/usb/core/hub.c:3252 [inline]
 #3: ffff888029d51640 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5464 [inline]
 #3: ffff888029d51640 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5707 [inline]
 #3: ffff888029d51640 (&port_dev->status_lock){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5871 [inline]
 #3: ffff888029d51640 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_event+0x21b0/0x4f60 drivers/usb/core/hub.c:5953
 #4: ffff888026effe58 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5465 [inline]
 #4: ffff888026effe58 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5707 [inline]
 #4: ffff888026effe58 (hcd->address0_mutex){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5871 [inline]
 #4: ffff888026effe58 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_event+0x21e0/0x4f60 drivers/usb/core/hub.c:5953
 #5: ffffffff8e9fc7a0 (ehci_cf_port_reset_rwsem){.+.+}-{4:4}, at: hub_port_reset+0x14e/0x1820 drivers/usb/core/hub.c:3067
2 locks held by syz-executor/11422:
 #0: ffffffff8f15cc78 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
 #0: ffffffff8f15cc78 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x404/0x1ad0 net/ipv4/devinet.c:978
 #1: ffff88801ded5958 (&n->list_lock){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
 #1: ffff88801ded5958 (&n->list_lock){+.+.}-{3:3}, at: get_partial_node_bulk mm/slub.c:3750 [inline]
 #1: ffff88801ded5958 (&n->list_lock){+.+.}-{3:3}, at: __refill_objects_node+0x87/0x560 mm/slub.c:7027
5 locks held by sed/11848:
3 locks held by syz.9.1740/11850:
5 locks held by syz.9.1740/11851:

=============================================

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 38 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:161 [inline]
 __sys_info lib/sys_info.c:157 [inline]
 sys_info+0x135/0x170 lib/sys_info.c:165
 check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline]
 watchdog+0xfd9/0x1030 kernel/hung_task.c:515
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 1860 Comm: kworker/u8:13 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Workqueue: bat_events batadv_tt_purge
RIP: 0010:__migrate_enable include/linux/sched.h:2409 [inline]
RIP: 0010:migrate_enable include/linux/sched.h:2473 [inline]
RIP: 0010:rt_spin_unlock+0x31/0x200 kernel/locking/spinlock_rt.c:81
Code: 41 56 41 55 41 54 53 48 89 fb 49 bf 00 00 00 00 00 fc ff df 48 83 c7 58 48 8b 74 24 30 e8 17 fc 79 f6 65 4c 8b 2d c7 43 28 07 <4d> 8d b5 c0 04 00 00 4d 89 f4 49 c1 ec 03 43 0f b6 04 3c 84 c0 0f
RSP: 0018:ffffc90006f1f980 EFLAGS: 00000286
RAX: e34c37f6a8c35200 RBX: ffff88805b87af00 RCX: 0000000000000046
RDX: 000000007a71099d RSI: ffffffff8d7c13fe RDI: ffffffff8ba67680
RBP: 0000000000000100 R08: ffffffff8b2661d0 R09: ffffffff8ddcb9c0
R10: 0000000000000000 R11: fffffbfff1ed4dd7 R12: ffff88805b87af00
R13: ffff88802aa51e80 R14: dffffc0000000000 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff888126435000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000040 CR3: 000000002b128000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 spin_unlock_bh include/linux/spinlock_rt.h:115 [inline]
 batadv_tt_local_purge+0x2ed/0x380 net/batman-adv/translation-table.c:1315
 batadv_tt_purge+0x35/0xa10 net/batman-adv/translation-table.c:3509
 process_one_work kernel/workqueue.c:3276 [inline]
 process_scheduled_works+0xb6e/0x18c0 kernel/workqueue.c:3359
 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3440
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>