syzbot


linux-next boot error: INFO: task hung in add_early_randomness

Status: closed as invalid on 2022/05/31 06:01
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 181d, last: 181d
similar bugs (1):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream linux-next boot error: INFO: task hung in add_early_randomness (2) 14 173d 179d 23/24 upstream: reported on 2022/06/02 07:39

Sample crash report:
INFO: task swapper/0:1 blocked for more than 143 seconds.
      Not tainted 5.18.0-next-20220531-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:swapper/0       state:D stack:23544 pid:    1 ppid:     0 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5116 [inline]
 __schedule+0xa00/0x4b30 kernel/sched/core.c:6428
 schedule+0xd2/0x1f0 kernel/sched/core.c:6500
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6559
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0xa70/0x1350 kernel/locking/mutex.c:747
 add_early_randomness+0x1a/0x170 drivers/char/hw_random/core.c:69
 hwrng_register+0x399/0x510 drivers/char/hw_random/core.c:599
 virtrng_scan+0x37/0x90 drivers/char/hw_random/virtio-rng.c:205
 virtio_dev_probe+0x639/0x910 drivers/virtio/virtio.c:313
 call_driver_probe drivers/base/dd.c:562 [inline]
 really_probe+0x23e/0xb90 drivers/base/dd.c:641
 __driver_probe_device+0x338/0x4d0 drivers/base/dd.c:774
 driver_probe_device+0x4c/0x1a0 drivers/base/dd.c:804
 __driver_attach+0x22d/0x550 drivers/base/dd.c:1173
 bus_for_each_dev+0x147/0x1d0 drivers/base/bus.c:301
 bus_add_driver+0x422/0x640 drivers/base/bus.c:618
 driver_register+0x220/0x3a0 drivers/base/driver.c:240
 do_one_initcall+0x103/0x650 init/main.c:1298
 do_initcall_level init/main.c:1373 [inline]
 do_initcalls init/main.c:1389 [inline]
 do_basic_setup init/main.c:1408 [inline]
 kernel_init_freeable+0x6b1/0x73a init/main.c:1615
 kernel_init+0x1a/0x1d0 init/main.c:1504
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:302
 </TASK>

Showing all locks held in the system:
2 locks held by swapper/0/1:
 #0: ffff8881468ab170 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:835 [inline]
 #0: ffff8881468ab170 (&dev->mutex){....}-{3:3}, at: __device_driver_lock drivers/base/dd.c:1064 [inline]
 #0: ffff8881468ab170 (&dev->mutex){....}-{3:3}, at: __driver_attach+0x222/0x550 drivers/base/dd.c:1172
 #1: ffffffff8c8342c8 (reading_mutex){+.+.}-{3:3}, at: add_early_randomness+0x1a/0x170 drivers/char/hw_random/core.c:69
2 locks held by kworker/u4:0/8:
 #0: ffff888010c69138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
 #0: ffff888010c69138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline]
 #0: ffff888010c69138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1280 [inline]
 #0: ffff888010c69138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:636 [inline]
 #0: ffff888010c69138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:663 [inline]
 #0: ffff888010c69138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x87a/0x1610 kernel/workqueue.c:2260
 #1: ffffc900000d7da8 ((work_completion)(&(&kfence_timer)->work)){+.+.}-{0:0}, at: process_one_work+0x8ae/0x1610 kernel/workqueue.c:2264
2 locks held by pr/ttyS0/16:
1 lock held by khungtaskd/29:
 #0: ffffffff8bd87020 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6491
1 lock held by hwrng/756:
 #0: ffffffff8c8342c8 (reading_mutex){+.+.}-{3:3}, at: hwrng_fillfn+0x141/0x370 drivers/char/hw_random/core.c:503

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Crashes (1):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci-upstream-linux-next-kasan-gce-root 2022/05/31 05:12 linux-next 3b46e4e44180 af70c3a9 .config log report linux-next boot error: INFO: task hung in add_early_randomness
* Struck through repros no longer work on HEAD.