syzbot


INFO: task hung in flush_delayed_work

Status: upstream: reported on 2024/10/23 15:23
Reported-by: syzbot+f92a92d2c25c22004c40@syzkaller.appspotmail.com
First crash: 46d, last: 46d
Similar bugs (2)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in flush_delayed_work ocfs2 C error 166 15m 32d 0/28 upstream: reported C repro on 2024/11/06 08:07
linux-5.15 INFO: task hung in flush_delayed_work 1 102d 102d 0/3 auto-obsoleted due to no activity on 2024/12/07 07:17

Sample crash report:
INFO: task syz-executor:4296 blocked for more than 143 seconds.
      Not tainted 6.1.114-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:0     pid:4296  ppid:1      flags:0x00000009
Call trace:
 __switch_to+0x320/0x754 arch/arm64/kernel/process.c:553
 context_switch kernel/sched/core.c:5241 [inline]
 __schedule+0xef4/0x1d44 kernel/sched/core.c:6558
 schedule+0xc4/0x170 kernel/sched/core.c:6634
 schedule_timeout+0xb8/0x344 kernel/time/timer.c:1941
 do_wait_for_common+0x30c/0x468 kernel/sched/completion.c:85
 __wait_for_common kernel/sched/completion.c:106 [inline]
 wait_for_common kernel/sched/completion.c:117 [inline]
 wait_for_completion+0x48/0x60 kernel/sched/completion.c:138
 __flush_work+0x12c/0x1c0 kernel/workqueue.c:3076
 flush_work kernel/workqueue.c:3097 [inline]
 flush_delayed_work+0xe4/0x110 kernel/workqueue.c:3221
 invalidate_dquots fs/quota/dquot.c:578 [inline]
 dquot_disable+0x63c/0x17c0 fs/quota/dquot.c:2306
 ocfs2_disable_quotas+0xf0/0x1d4 fs/ocfs2/super.c:963
 ocfs2_dismount_volume+0x1c4/0x99c fs/ocfs2/super.c:1872
 ocfs2_put_super+0x110/0x3e8 fs/ocfs2/super.c:1609
 generic_shutdown_super+0x130/0x328 fs/super.c:501
 kill_block_super+0x70/0xdc fs/super.c:1470
 deactivate_locked_super+0xac/0x124 fs/super.c:332
 deactivate_super+0xf0/0x110 fs/super.c:363
 cleanup_mnt+0x394/0x41c fs/namespace.c:1186
 __cleanup_mnt+0x20/0x30 fs/namespace.c:1193
 task_work_run+0x240/0x2f0 kernel/task_work.c:203
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 do_notify_resume+0x2148/0x3474 arch/arm64/kernel/signal.c:1132
 prepare_exit_to_user_mode arch/arm64/kernel/entry-common.c:137 [inline]
 exit_to_user_mode arch/arm64/kernel/entry-common.c:142 [inline]
 el0_svc+0x9c/0x168 arch/arm64/kernel/entry-common.c:638
 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: ffff800015ba5bf0 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x44/0xcf4 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
 #0: ffff800015ba63f0 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x44/0xcf4 kernel/rcu/tasks.h:517
3 locks held by kworker/1:1/24:
 #0: ffff0000d5f8dd38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x664/0x1404 kernel/workqueue.c:2265
 #1: ffff80001d217c20 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x6a8/0x1404 kernel/workqueue.c:2267
 #2: ffff800017ff4448 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock+0x20/0x2c net/core/rtnetlink.c:74
1 lock held by khungtaskd/28:
 #0: ffff800015ba5a20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0xc/0x44 include/linux/rcupdate.h:349
5 locks held by kworker/u4:6/1861:
2 locks held by getty/4068:
 #0: 
ffff0000d65b2098
 (&tty->ldisc_sem){++++}-{0:0}, at: ldsem_down_read+0x3c/0x4c drivers/tty/tty_ldsem.c:340
 #1: ffff80001efe02f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x414/0x1214 drivers/tty/n_tty.c:2198
1 lock held by syz-executor/4296:
 #0: 
ffff0000d4d500e0
 (&type->s_umount_key#48){++++}-{3:3}, at: deactivate_super+0xe8/0x110 fs/super.c:362
1 lock held by syz-executor/4306:
 #0: ffff0000ef3a20e0 (&type->s_umount_key#30){++++}-{3:3}, at: deactivate_super+0xe8/0x110 fs/super.c:362
1 lock held by syz-executor/4309:
 #0: ffff0000d35420e0 (&type->s_umount_key#48){++++}-{3:3}, at: deactivate_super+0xe8/0x110 fs/super.c:362
3 locks held by kworker/1:9/4451:
 #0: ffff0000d5f8dd38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x664/0x1404 kernel/workqueue.c:2265
 #1: ffff800021657c20 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x6a8/0x1404 kernel/workqueue.c:2267
 #2: ffff800017ff4448 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock+0x20/0x2c net/core/rtnetlink.c:74
3 locks held by kworker/0:8/4454:
 #0: ffff0000d5f8dd38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x664/0x1404 kernel/workqueue.c:2265
 #1: ffff8000214d7c20 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x6a8/0x1404 kernel/workqueue.c:2267
 #2: ffff0001b3cf9758 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x108/0x214 kernel/time/timer.c:999
2 locks held by kworker/0:10/4459:
 #0: ffff0000c0021938 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x664/0x1404 kernel/workqueue.c:2265
 #1: ffff8000214e7c20 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work+0x6a8/0x1404 kernel/workqueue.c:2267
2 locks held by kworker/1:16/4463:
 #0: ffff0000c0020938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x664/0x1404 kernel/workqueue.c:2265
 #1: ffff800021557c20 (free_ipc_work){+.+.}-{0:0}, at: process_one_work+0x6a8/0x1404 kernel/workqueue.c:2267
2 locks held by kworker/u4:11/4741:
2 locks held by syz.4.126/4886:
 #0: ffff0000d276e460 (sb_writers#4){.+.+}-{0:0}, at: do_sendfile+0x4a4/0xcb0 fs/read_write.c:1254
 #1: ffff0000d4d500e0 (&type->s_umount_key#48){++++}-{3:3}, at: iterate_supers+0xb0/0x1dc fs/super.c:755
4 locks held by kworker/u4:14/4953:
 #0: ffff0000c03dd138 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x664/0x1404 kernel/workqueue.c:2265
 #1: ffff800022b07c20 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x6a8/0x1404 kernel/workqueue.c:2267
 #2: ffff800017fe8610 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0xf4/0x994 net/core/net_namespace.c:566
 #3: ffff0000dc4953e8 (&wg->device_update_lock){+.+.}-{3:3}, at: wg_destruct+0x11c/0x2dc drivers/net/wireguard/device.c:249
1 lock held by syz-executor/5080:
 #0: ffff0000c932c0e0 (&type->s_umount_key#48){++++}-{3:3}, at: deactivate_super+0xe8/0x110 fs/super.c:362
1 lock held by syz-executor/6083:
 #0: ffff800015baaff8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:323 [inline]
 #0: ffff800015baaff8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x30c/0x77c kernel/rcu/tree_exp.h:962
1 lock held by syz-executor/6095:
 #0: ffff0000d6b960e0 (&type->s_umount_key#48){++++}-{3:3}, at: deactivate_super+0xe8/0x110 fs/super.c:362
1 lock held by syz-executor/6632:
 #0: 
ffff800017fe8610
 (
pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x2d0/0x58c net/core/net_namespace.c:477
3 locks held by syz-executor/6636:
 #0: 
ffff0000d94f10b8
 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_close net/bluetooth/hci_core.c:508 [inline]
 (&hdev->req_lock){+.+.}-{3:3}, at: hci_unregister_dev+0x1f8/0x4c4 net/bluetooth/hci_core.c:2707
 #1: ffff0000d94f0078 (&hdev->lock){+.+.}-{3:3}
, at: hci_dev_close_sync+0x39c/0xf6c net/bluetooth/hci_sync.c:5053
 #2: 
ffff800018141ea8
 (
hci_cb_list_lock
){+.+.}-{3:3}
, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:1800 [inline]
, at: hci_conn_hash_flush+0xb0/0x27c net/bluetooth/hci_conn.c:2444
1 lock held by syz-executor/6640:
 #0: ffff800015baaff8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:323 [inline]
 #0: ffff800015baaff8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x30c/0x77c kernel/rcu/tree_exp.h:962

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


Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/10/23 15:22 linux-6.1.y 7ec6f9fa3d97 15fa2979 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 INFO: task hung in flush_delayed_work
* Struck through repros no longer work on HEAD.