syzbot


INFO: task hung in do_task_dead (6)

Status: auto-obsoleted due to no activity on 2025/07/24 12:34
Subsystems: kernel
[Documentation on labels]
First crash: 116d, last: 116d
Similar bugs (7)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in do_task_dead (4) kernel 1 1 881d 881d 0/29 auto-obsoleted due to no activity on 2023/06/20 16:27
android-6-12 INFO: task hung in do_task_dead 1 1 17d 17d 0/1 premoderation: reported on 2025/08/01 20:46
upstream INFO: task hung in do_task_dead kernel 1 1 2339d 2339d 0/29 auto-closed as invalid on 2019/09/21 14:08
upstream INFO: task hung in do_task_dead (3) mtd 1 2 1968d 1969d 0/29 auto-closed as invalid on 2020/06/28 13:10
upstream INFO: task hung in do_task_dead (2) kernel 1 1 2086d 2086d 0/29 auto-closed as invalid on 2020/03/01 19:02
linux-4.14 INFO: task hung in do_task_dead 1 1 1834d 1834d 0/1 auto-closed as invalid on 2020/12/09 18:36
upstream INFO: task hung in do_task_dead (5) kernel 1 2 330d 371d 0/29 auto-obsoleted due to no activity on 2024/12/21 21:23

Sample crash report:
INFO: task syz.7.1707:12681 blocked for more than 143 seconds.
      Not tainted 6.15.0-rc3-syzkaller-00094-g02ddfb981de8 #0
      Blocked by coredump.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.7.1707      state:D stack:25192 pid:12681 tgid:12681 ppid:9448   task_flags:0x40044c flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x16e2/0x4cd0 kernel/sched/core.c:6767
 do_task_dead+0xc7/0xe0 kernel/sched/core.c:6784
 do_exit+0x1cac/0x2550 kernel/exit.c:1004
 do_group_exit+0x21c/0x2d0 kernel/exit.c:1102
 get_signal+0x125e/0x1310 kernel/signal.c:3034
 arch_do_signal_or_restart+0x95/0x780 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:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x8b/0x120 kernel/entry/common.c:218
 do_syscall_64+0x103/0x210 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 00fb:0x294e66b3c7c44cb4
RSP: 002b:0000000000000000 EFLAGS: 00000202 ORIG_RAX: ce3d5c200518e753
RAX: 6d02b596a6d6b2c6 RBX: 46b00e13ac8c17fa RCX: 1d6d567492f1521e
RDX: eb30e365dd53f3a0 RSI: c553273f825e1cf7 RDI: b331ef28487276fd
RBP: 9c8c83e20081ee00 R08: cf9d780a350b4549 R09: c7e58b697db8ef3d
R10: d68d02d45a22dc24 R11: 19b4d49ef33da9ed R12: 000002b6fa6cb3d1
R13: a8d7b5dbf29d588f R14: 9b8908dcbb4f02b4 R15: 107b9d1451766018
 </TASK>

Showing all locks held in the system:
3 locks held by kworker/u8:0/12:
1 lock held by khungtaskd/31:
 #0: ffffffff8e13b860 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8e13b860 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
 #0: ffffffff8e13b860 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6764
6 locks held by kworker/u8:2/36:
 #0: ffff88801b2f6148 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline]
 #0: ffff88801b2f6148 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x9b1/0x17a0 kernel/workqueue.c:3319
 #1: ffffc90000ad7c60 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline]
 #1: ffffc90000ad7c60 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ec/0x17a0 kernel/workqueue.c:3319

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/04/25 12:28 upstream 02ddfb981de8 e3715315 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: task hung in do_task_dead
* Struck through repros no longer work on HEAD.