syzbot


INFO: task hung in do_task_dead (5)

Status: auto-obsoleted due to no activity on 2024/12/21 21:23
Subsystems: kernel
[Documentation on labels]
First crash: 160d, last: 120d
Similar bugs (5)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in do_task_dead (4) kernel 1 670d 670d 0/28 auto-obsoleted due to no activity on 2023/06/20 16:27
upstream INFO: task hung in do_task_dead kernel 1 2128d 2128d 0/28 auto-closed as invalid on 2019/09/21 14:08
upstream INFO: task hung in do_task_dead (3) mtd 2 1757d 1759d 0/28 auto-closed as invalid on 2020/06/28 13:10
upstream INFO: task hung in do_task_dead (2) kernel 1 1876d 1876d 0/28 auto-closed as invalid on 2020/03/01 19:02
linux-4.14 INFO: task hung in do_task_dead 1 1623d 1623d 0/1 auto-closed as invalid on 2020/12/09 18:36

Sample crash report:
INFO: task syz.0.867:11931 blocked for more than 159 seconds.
      Not tainted 6.11.0-syzkaller-08829-gaf9c191ac2a0 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.867       state:D stack:24560 pid:11931 tgid:11921 ppid:11701  flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5315 [inline]
 __schedule+0x1895/0x4b30 kernel/sched/core.c:6674
 do_task_dead+0xc4/0xd0 kernel/sched/core.c:6690
 do_exit+0x1f7f/0x28e0 kernel/exit.c:990
 do_group_exit+0x207/0x2c0 kernel/exit.c:1088
 get_signal+0x176f/0x1810 kernel/signal.c:2936
 arch_do_signal_or_restart+0x96/0x860 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0xc9/0x370 kernel/entry/common.c:218
 do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f6b0c17dafb
RSP: 002b:00007f6b0bbbaf10 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: fffffffffffffffc RBX: 0000000000000008 RCX: 00007f6b0c17dafb
RDX: 00007f6b0bbbbfe0 RSI: 0000000080085502 RDI: 0000000000000008
RBP: 00007f6b0bbbbfe0 R08: 0000000000000080 R09: 00007f6b0bbbafd8
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000080085502
R13: 0000000800000000 R14: 0000000000000024 R15: 00007f6b0c1fab50
 </TASK>

Showing all locks held in the system:
8 locks held by kworker/0:0/8:
1 lock held by kworker/R-mm_pe/13:
1 lock held by khungtaskd/30:
 #0: ffffffff8e937ee0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
 #0: ffffffff8e937ee0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffffffff8e937ee0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6701
4 locks held by kworker/u8:2/35:
6 locks held by kworker/u8:5/206:
 #0: ffff88801baed948 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline]
 #0: ffff88801baed948 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1850 kernel/workqueue.c:3310
 #1: ffffc90002f67d00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline]
 #1: ffffc90002f67d00 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1850 kernel/workqueue.c:3310
 #2: ffffffff8fcbf1d0 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x16a/0xcc0 net/core/net_namespace.c:580
 #3: ffffffff8fccbcc8 (rtnl_mutex){+.+.}-{3:3}, at: wiphy_unregister+0x236/0xb00 net/wireless/core.c:1100
 #4: ffff888068b48768 (&rdev->wiphy.mtx){+.+.}-{3:3}, at: wiphy_lock include/net/cfg80211.h:6014 [inline]
 #4: ffff888068b48768 (&rdev->wiphy.mtx){+.+.}-{3:3}, at: wiphy_unregister+0x240/0xb00 net/wireless/core.c:1101
 #5: ffffffff8e93d478 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:329 [inline]
 #5: ffffffff8e93d478 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x451/0x830 kernel/rcu/tree_exp.h:976
3 locks held by kworker/u8:8/2544:
 #0: ffff88802e421948 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline]
 #0: ffff88802e421948 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1850 kernel/workqueue.c:3310
 #1: ffffc9000955fd00 ((work_completion)(&(&net->ipv6.addr_chk_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline]
 #1: ffffc9000955fd00 ((work_completion)(&(&net->ipv6.addr_chk_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1850 kernel/workqueue.c:3310
 #2: ffffffff8fccbcc8 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_verify_work+0x19/0x30 net/ipv6/addrconf.c:4736
5 locks held by kworker/u9:1/4621:
 #0: ffff888030a48148 ((wq_completion)hci4){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline]
 #0: ffff888030a48148 ((wq_completion)hci4){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1850 kernel/workqueue.c:3310
 #1: ffffc9000e267d00 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline]
 #1: ffffc9000e267d00 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1850 kernel/workqueue.c:3310
 #2: ffff888063b74d80 (&hdev->req_lock){+.+.}-{3:3}, at: hci_cmd_sync_work+0x1ec/0x400 net/bluetooth/hci_sync.c:327
 #3: ffff888063b74078 (&hdev->lock){+.+.}-{3:3}, at: hci_abort_conn_sync+0x1ea/0xde0 net/bluetooth/hci_sync.c:5567
 #4: ffffffff8fe384a8 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_connect_cfm include/net/bluetooth/hci_core.h:1957 [inline]
 #4: ffffffff8fe384a8 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_conn_failed+0x15d/0x300 net/bluetooth/hci_conn.c:1262
1 lock held by klogd/4672:
4 locks held by udevd/4683:
2 locks held by getty/4987:
 #0: ffff88814bb260a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc90002efe2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6a6/0x1e00 drivers/tty/n_tty.c:2211
2 locks held by syz-executor/5215:
6 locks held by kworker/u9:4/5234:
 #0: ffff888025d4c148 ((wq_completion)hci0){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline]
 #0: ffff888025d4c148 ((wq_completion)hci0){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1850 kernel/workqueue.c:3310
 #1: ffffc90002e77d00 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline]
 #1: ffffc90002e77d00 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1850 kernel/workqueue.c:3310

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/09/22 21:13 upstream af9c191ac2a0 6f888b75 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: task hung in do_task_dead
2024/08/13 05:10 upstream d74da846046a 7b0f4b46 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: task hung in do_task_dead
* Struck through repros no longer work on HEAD.