syzbot


INFO: task hung in del_device_store (2)

Status: upstream: reported syz repro on 2026/01/05 21:06
Bug presence: origin:upstream
[Documentation on labels]
Reported-by: syzbot+b0c7b338a85df4f4823b@syzkaller.appspotmail.com
First crash: 7d11h, last: 2d05h
Bug presence (1)
Date Name Commit Repro Result
2026/01/11 upstream (ToT) 755bc1335e3b syz [report] INFO: task hung in corrupted
Similar bugs (5)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 INFO: task hung in del_device_store 1 42 178d 550d 0/3 auto-obsoleted due to no activity on 2025/10/26 20:35
linux-6.6 INFO: task hung in del_device_store origin:upstream 1 C 2 18d 53d 0/2 upstream: reported C repro on 2025/11/21 00:14
linux-5.15 INFO: task hung in del_device_store (2) 1 4 10d 53d 0/3 upstream: reported on 2025/11/20 15:49
linux-6.1 INFO: task hung in del_device_store 1 31 146d 557d 0/3 auto-obsoleted due to no activity on 2025/11/28 01:25
upstream INFO: task hung in del_device_store net 1 C error 1946 1h29m 1044d 0/29 upstream: reported C repro on 2023/03/05 17:44

Sample crash report:
INFO: task syz-executor:4795 blocked for more than 148 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:0     pid:4795  ppid:1      flags:0x00000001
Call trace:
 __switch_to+0x2f4/0x568 arch/arm64/kernel/process.c:555
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0xddc/0x1b18 kernel/sched/core.c:6561
 schedule+0xc4/0x170 kernel/sched/core.c:6637
 schedule_preempt_disabled+0x18/0x2c kernel/sched/core.c:6696
 __mutex_lock_common+0xad4/0x1f38 kernel/locking/mutex.c:679
 __mutex_lock kernel/locking/mutex.c:747 [inline]
 mutex_lock_nested+0x38/0x44 kernel/locking/mutex.c:799
 del_device_store+0xd4/0x31c drivers/net/netdevsim/bus.c:209
 bus_attr_store+0x80/0xa4 drivers/base/bus.c:124
 sysfs_kf_write+0x1f8/0x278 fs/sysfs/file.c:136
 kernfs_fop_write_iter+0x348/0x4c0 fs/kernfs/file.c:352
 call_write_iter include/linux/fs.h:2265 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x5ac/0x7c4 fs/read_write.c:584
 ksys_write+0x120/0x210 fs/read_write.c:637
 __do_sys_write fs/read_write.c:649 [inline]
 __se_sys_write fs/read_write.c:646 [inline]
 __arm64_sys_write+0x7c/0x90 fs/read_write.c:646
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2bc arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x138 arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
 #0: ffff800015227d70 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x40/0xbb4 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
 #0: ffff800015228590 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x40/0xbb4 kernel/rcu/tasks.h:517
1 lock held by khungtaskd/28:
 #0: ffff800015227400 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0xc/0x44 include/linux/rcupdate.h:349
2 locks held by kworker/u4:3/252:
 #0: ffff0000c0029138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x6b4/0x13a8 kernel/workqueue.c:2265
 #1: ffff800020ca7c20 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_one_work+0x6f8/0x13a8 kernel/workqueue.c:2267
4 locks held by kworker/u4:4/1611:
 #0: ffff0000c0845138 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x6b4/0x13a8 kernel/workqueue.c:2265
 #1: ffff800025457c20 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x6f8/0x13a8 kernel/workqueue.c:2267
 #2: ffff8000176af090 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x12c/0xa74 net/core/net_namespace.c:594
 #3: ffff80001522cf80 (rcu_state.barrier_mutex){+.+.}-{3:3}, at: rcu_barrier+0x58/0x5d4 kernel/rcu/tree.c:4023
1 lock held by dhcpcd/3990:
 #0: ffff8000176bb748 (rtnl_mutex){+.+.}-{3:3}, at: __netlink_dump_start+0x104/0x6a4 net/netlink/af_netlink.c:2305
2 locks held by getty/4081:
 #0: ffff0000d6c91098 (&tty->ldisc_sem){++++}-{0:0}, at: ldsem_down_read+0x3c/0x4c drivers/tty/tty_ldsem.c:340
 #1: ffff80001ce432f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x2ec/0xf9c drivers/tty/n_tty.c:2198
3 locks held by kworker/0:4/4468:
 #0: ffff0000c0020938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x6b4/0x13a8 kernel/workqueue.c:2265
 #1: ffff800020ae7c20 (deferred_process_work){+.+.}-{0:0}, at: process_one_work+0x6f8/0x13a8 kernel/workqueue.c:2267
 #2: ffff8000176bb748 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock+0x20/0x2c net/core/rtnetlink.c:74
3 locks held by kworker/0:6/4470:
 #0: ffff0000c0020938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x6b4/0x13a8 kernel/workqueue.c:2265
 #1: ffff800020cc7c20 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_one_work+0x6f8/0x13a8 kernel/workqueue.c:2267
 #2: ffff0000f08a3240 (&data->fib_lock){+.+.}-{3:3}, at: nsim_fib_event_work+0x1c8/0x263c drivers/net/netdevsim/fib.c:1491
3 locks held by kworker/0:10/4549:
 #0: ffff0000c0020938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x6b4/0x13a8 kernel/workqueue.c:2265
 #1: ffff800020fd7c20 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_one_work+0x6f8/0x13a8 kernel/workqueue.c:2267
 #2: ffff0000d0704240 (&data->fib_lock){+.+.}-{3:3}, at: nsim_fib_event_work+0x1c8/0x263c drivers/net/netdevsim/fib.c:1491
2 locks held by kworker/0:13/4552:
 #0: ffff0000c0021938 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x6b4/0x13a8 kernel/workqueue.c:2265
 #1: ffff800021007c20 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work+0x6f8/0x13a8 kernel/workqueue.c:2267
3 locks held by kworker/u4:7/4559:
 #0: ffff0000c0029138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x6b4/0x13a8 kernel/workqueue.c:2265
 #1: ffff8000204a7c20 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x6f8/0x13a8 kernel/workqueue.c:2267
 #2: ffff8000176bb748 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock+0x20/0x2c net/core/rtnetlink.c:74
2 locks held by syz-executor/4699:
 #0: ffff8000176bb748 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock+0x20/0x2c net/core/rtnetlink.c:74
 #1: ffff80001522d0b8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:291 [inline]
 #1: ffff80001522d0b8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x3a8/0x6f0 kernel/rcu/tree_exp.h:962
4 locks held by syz-executor/4702:
 #0: ffff0000d8948460 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x23c/0x7c4 fs/read_write.c:580
 #1: ffff0000c9a21088 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1c0/0x4c0 fs/kernfs/file.c:343
 #2: ffff0000cdf9f490 (kn->active#57){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
 #2: ffff0000cdf9f490 (kn->active#57){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x200/0x4c0 fs/kernfs/file.c:344
 #3: ffff800016a683c8 (nsim_bus_dev_list_lock){+.+.}-{3:3}, at: new_device_store+0x128/0x4f4 drivers/net/netdevsim/bus.c:160
7 locks held by syz-executor/4790:
 #0: ffff0000d8948460 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x23c/0x7c4 fs/read_write.c:580
 #1: ffff0000f6800088 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1c0/0x4c0 fs/kernfs/file.c:343
 #2: ffff0000cdf9f578 (kn->active#56){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
 #2: ffff0000cdf9f578 (kn->active#56){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x200/0x4c0 fs/kernfs/file.c:344
 #3: ffff800016a683c8 (nsim_bus_dev_list_lock){+.+.}-{3:3}, at: del_device_store+0xd4/0x31c drivers/net/netdevsim/bus.c:209
 #4: ffff0000f31730e8 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:840 [inline]
 #4: ffff0000f31730e8 (&dev->mutex){....}-{3:3}, at: __device_driver_lock drivers/base/dd.c:1080 [inline]
 #4: ffff0000f31730e8 (&dev->mutex){....}-{3:3}, at: device_release_driver_internal+0x9c/0x6d0 drivers/base/dd.c:1283
 #5: ffff0000f31712f8 (&devlink->lock_key#5){+.+.}-{3:3}, at: devl_lock+0x24/0x34 net/devlink/leftover.c:275
 #6: ffff8000176bb748 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock+0x20/0x2c net/core/rtnetlink.c:74
4 locks held by syz-executor/4795:
 #0: ffff0000d8948460 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x23c/0x7c4 fs/read_write.c:580
 #1: ffff0000f7766488 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1c0/0x4c0 fs/kernfs/file.c:343
 #2: ffff0000cdf9f578 (kn->active#56){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
 #2: ffff0000cdf9f578 (kn->active#56){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x200/0x4c0 fs/kernfs/file.c:344
 #3: ffff800016a683c8 (nsim_bus_dev_list_lock){+.+.}-{3:3}, at: del_device_store+0xd4/0x31c drivers/net/netdevsim/bus.c:209
1 lock held by syz.3.20/5240:
 #0: ffff80001522cf80 (rcu_state.barrier_mutex){+.+.}-{3:3}, at: rcu_barrier+0x58/0x5d4 kernel/rcu/tree.c:4023
2 locks held by syz-executor/5258:
 #0: ffff8000176af090 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x298/0x588 net/core/net_namespace.c:504
 #1: ffff8000176bb748 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock+0x20/0x2c net/core/rtnetlink.c:74
2 locks held by syz-executor/5264:
 #0: ffff0000db0110b8 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_close net/bluetooth/hci_core.c:508 [inline]
 #0: ffff0000db0110b8 (&hdev->req_lock){+.+.}-{3:3}, at: hci_unregister_dev+0x1f0/0x4b4 net/bluetooth/hci_core.c:2705
 #1: ffff0000db010078 (&hdev->lock){+.+.}-{3:3}, at: hci_dev_close_sync+0x398/0xf18 net/bluetooth/hci_sync.c:5233
1 lock held by syz-executor/5268:
 #0: ffff8000176bb748 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline]
 #0: ffff8000176bb748 (rtnl_mutex){+.+.}-{3:3}, at: __rtnl_newlink net/core/rtnetlink.c:3632 [inline]
 #0: ffff8000176bb748 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_newlink+0x880/0x1a1c net/core/rtnetlink.c:3655
2 locks held by syz-executor/5273:
 #0: ffff8000176af090 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x298/0x588 net/core/net_namespace.c:504
 #1: ffff8000176bb748 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock+0x20/0x2c net/core/rtnetlink.c:74
2 locks held by syz-executor/5277:
 #0: ffff8000176af090 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x298/0x588 net/core/net_namespace.c:504
 #1: ffff8000176bb748 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock+0x20/0x2c net/core/rtnetlink.c:74
1 lock held by syz-executor/5308:
 #0: ffff8000176bb748 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline]
 #0: ffff8000176bb748 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x6ec/0xce4 net/core/rtnetlink.c:6147
2 locks held by syz-executor/5343:
 #0: ffff8000176af090 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x298/0x588 net/core/net_namespace.c:504
 #1: ffff8000176bb748 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock+0x20/0x2c net/core/rtnetlink.c:74
1 lock held by syz-executor/5347:
 #0: ffff8000176bb748 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline]
 #0: ffff8000176bb748 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x6ec/0xce4 net/core/rtnetlink.c:6147

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Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/01/11 02:42 linux-6.1.y 50cbba13faa2 d6526ea3 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 INFO: task hung in del_device_store
2026/01/05 21:06 linux-6.1.y 50cbba13faa2 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in del_device_store
* Struck through repros no longer work on HEAD.