[v6.1] INFO: task hung in hwrng_fillfn

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: adc4d740ad9e Linux 6.1.58
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=172002a9680000
kernel config: https://syzkaller.appspot.com/x/.config?x=e75c35550cb95b59
dashboard link: https://syzkaller.appspot.com/bug?extid=90d756a49307d63516d8
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
userspace arch: arm64

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/8d0dd0d22f19/disk-adc4d740.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/6aea2ecd3389/vmlinux-adc4d740.xz
kernel image: https://storage.googleapis.com/syzbot-assets/d32e9ad63891/Image-adc4d740.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+90d756...@syzkaller.appspotmail.com

INFO: task hwrng:1184 blocked for more than 143 seconds.
Not tainted 6.1.58-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:hwrng state:D stack:0 pid:1184 ppid:2 flags:0x00000008
Call trace:
__switch_to+0x320/0x754 arch/arm64/kernel/process.c:553
context_switch kernel/sched/core.c:5241 [inline]
__schedule+0xee4/0x1c98 kernel/sched/core.c:6554
schedule+0xc4/0x170 kernel/sched/core.c:6630
schedule_preempt_disabled+0x18/0x2c kernel/sched/core.c:6689
__mutex_lock_common+0xbd8/0x21a0 kernel/locking/mutex.c:679
__mutex_lock kernel/locking/mutex.c:747 [inline]
mutex_lock_nested+0x38/0x44 kernel/locking/mutex.c:799
hwrng_fillfn+0x6c/0x2b0 drivers/char/hw_random/core.c:506
kthread+0x250/0x2d8 kernel/kthread.c:376
ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:864

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
#0: ffff800015a84d70 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x44/0xcf4 kernel/rcu/tasks.h:516
1 lock held by rcu_tasks_trace/13:
#0: ffff800015a85570 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x44/0xcf4 kernel/rcu/tasks.h:516
1 lock held by khungtaskd/28:
#0: ffff800015a84ba0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0xc/0x44 include/linux/rcupdate.h:305
1 lock held by hwrng/1184:
#0: ffff800016ca5368 (reading_mutex){+.+.}-{3:3}, at: hwrng_fillfn+0x6c/0x2b0 drivers/char/hw_random/core.c:506
1 lock held by klogd/3832:
2 locks held by getty/3988:
#0: ffff0000d78d8098 (&tty->ldisc_sem){++++}-{0:0}, at: ldsem_down_read+0x3c/0x4c drivers/tty/tty_ldsem.c:340
#1: ffff80001bd302f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x414/0x1214 drivers/tty/n_tty.c:2188
1 lock held by syz-executor.3/8123:
1 lock held by syz-executor.2/8178:
1 lock held by syz-executor.3/8216:
1 lock held by syz-executor.2/8276:
2 locks held by syz-executor.2/8375:
2 locks held by kworker/u4:0/22723:
2 locks held by syz-executor.4/24438:
1 lock held by syz-executor.4/24442:
1 lock held by syz-executor.4/24516:
1 lock held by syz-executor.5/24604:

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