[syzbot] usb-testing boot error: INFO: task hung in add_early_randomness

* [syzbot] usb-testing boot error: INFO: task hung in add_early_randomness
@ 2022-06-07  6:33 syzbot
  2022-06-10  8:32 ` Dmitry Vyukov
  0 siblings, 1 reply; 2+ messages in thread
From: syzbot @ 2022-06-07  6:33 UTC (permalink / raw)
  To: herbert, linux-crypto, linux-kernel, linux-usb, linux, mpm,
	syzkaller-bugs

Hello,

syzbot found the following issue on:

HEAD commit:    f2906aa86338 Linux 5.19-rc1
git tree:       https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing
console output: https://syzkaller.appspot.com/x/log.txt?x=1042a03bf00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=3bafeb86189666d4
dashboard link: https://syzkaller.appspot.com/bug?extid=695f4009c37860232f35
compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+695f4009c37860232f35@syzkaller.appspotmail.com

INFO: task swapper/0:1 blocked for more than 143 seconds.
      Not tainted 5.19.0-rc1-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:swapper/0       state:D stack:23984 pid:    1 ppid:     0 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5116 [inline]
 __schedule+0x93c/0x25e0 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:555 [inline]
 really_probe+0x23e/0xb90 drivers/base/dd.c:634
 __driver_probe_device+0x338/0x4d0 drivers/base/dd.c:764
 driver_probe_device+0x4c/0x1a0 drivers/base/dd.c:794
 __driver_attach+0x22d/0x550 drivers/base/dd.c:1163
 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:1295
 do_initcall_level init/main.c:1368 [inline]
 do_initcalls init/main.c:1384 [inline]
 do_basic_setup init/main.c:1403 [inline]
 kernel_init_freeable+0x6ac/0x735 init/main.c:1610
 kernel_init+0x1a/0x1d0 init/main.c:1499
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:302
 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: ffff88810cb9e170 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:835 [inline]
 #0: ffff88810cb9e170 (&dev->mutex){....}-{3:3}, at: __device_driver_lock drivers/base/dd.c:1054 [inline]
 #0: ffff88810cb9e170 (&dev->mutex){....}-{3:3}, at: __driver_attach+0x222/0x550 drivers/base/dd.c:1162
 #1: ffffffff87edbbe8 (reading_mutex){+.+.}-{3:3}, at: add_early_randomness+0x1a/0x170 drivers/char/hw_random/core.c:69
2 locks held by pr/ttyS0/14:
1 lock held by khungtaskd/27:
 #0: ffffffff87a94840 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6491
1 lock held by hwrng/150:
 #0: ffffffff87edbbe8 (reading_mutex){+.+.}-{3:3}, at: hwrng_fillfn+0x141/0x370 drivers/char/hw_random/core.c:503

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

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