[v6.1] INFO: task hung in sys_acct

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 228da13e907e Linux 6.1.175
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=169d8f2e580000
kernel config: https://syzkaller.appspot.com/x/.config?x=29caf4bae4b0566f
dashboard link: https://syzkaller.appspot.com/bug?extid=cff878472cf6cfd3875a
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
userspace arch: arm64
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=163edf2e580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/bf27a408696a/disk-228da13e.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/264d4943ab43/vmlinux-228da13e.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a499b0d2a133/Image-228da13e.gz.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/8b51c424e8c2/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+cff878...@syzkaller.appspotmail.com

INFO: task syz.8.25:5469 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.8.25 state:D stack:0 pid:5469 ppid:5446 flags:0x00000001
Call trace:
__switch_to+0x2f4/0x550 arch/arm64/kernel/process.c:555
context_switch kernel/sched/core.c:5245 [inline]
__schedule+0xdd0/0x1b0c kernel/sched/core.c:6562
schedule+0xc4/0x170 kernel/sched/core.c:6638
schedule_preempt_disabled+0x18/0x2c kernel/sched/core.c:6697
__mutex_lock_common+0xafc/0x1f60 kernel/locking/mutex.c:679
__mutex_lock kernel/locking/mutex.c:747 [inline]
mutex_lock_nested+0x38/0x44 kernel/locking/mutex.c:799
__do_sys_acct kernel/acct.c:327 [inline]
__se_sys_acct kernel/acct.c:315 [inline]
__arm64_sys_acct+0xcc/0x714 kernel/acct.c:315
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204
el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
#0: ffff800015417df0 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x40/0xbb4 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
#0: ffff800015418610 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x40/0xbb4 kernel/rcu/tasks.h:517
3 locks held by kworker/0:1/14:
#0: ffff0000c0020938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x6b8/0x13a4 kernel/workqueue.c:2265
#1: ffff80001ca47c20 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_one_work+0x6fc/0x13a4 kernel/workqueue.c:2267
#2: ffff0000dc785240 (&data->fib_lock){+.+.}-{3:3}, at: nsim_fib_event_work+0x1d0/0x27cc drivers/net/netdevsim/fib.c:1491
1 lock held by khungtaskd/28:
#0: ffff800015417480 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0xc/0x44 include/linux/rcupdate.h:349
2 locks held by getty/4083:
#0: ffff0000d8c28098 (&tty->ldisc_sem){++++}-{0:0}, at: ldsem_down_read+0x3c/0x4c drivers/tty/tty_ldsem.c:340
#1: ffff8000208fe2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x2ec/0xfa0 drivers/tty/n_tty.c:2198
2 locks held by syz.7.24/5310:
1 lock held by syz.8.25/5469:
#0: ffff80001543ba08 (acct_on_mutex){+.+.}-{3:3}, at: __do_sys_acct kernel/acct.c:327 [inline]
#0: ffff80001543ba08 (acct_on_mutex){+.+.}-{3:3}, at: __se_sys_acct kernel/acct.c:315 [inline]
#0: ffff80001543ba08 (acct_on_mutex){+.+.}-{3:3}, at: __arm64_sys_acct+0xcc/0x714 kernel/acct.c:315
1 lock held by syz.9.26/5628:
#0: ffff80001543ba08 (acct_on_mutex){+.+.}-{3:3}, at: __do_sys_acct kernel/acct.c:327 [inline]
#0: ffff80001543ba08 (acct_on_mutex){+.+.}-{3:3}, at: __se_sys_acct kernel/acct.c:315 [inline]
#0: ffff80001543ba08 (acct_on_mutex){+.+.}-{3:3}, at: __arm64_sys_acct+0xcc/0x714 kernel/acct.c:315
1 lock held by syz.0.27/5895:
#0: ffff80001543ba08 (acct_on_mutex){+.+.}-{3:3}, at: __do_sys_acct kernel/acct.c:327 [inline]
#0: ffff80001543ba08 (acct_on_mutex){+.+.}-{3:3}, at: __se_sys_acct kernel/acct.c:315 [inline]
#0: ffff80001543ba08 (acct_on_mutex){+.+.}-{3:3}, at: __arm64_sys_acct+0xcc/0x714 kernel/acct.c:315
1 lock held by syz.1.28/6355:
#0: ffff80001543ba08 (acct_on_mutex){+.+.}-{3:3}, at: __do_sys_acct kernel/acct.c:327 [inline]
#0: ffff80001543ba08 (acct_on_mutex){+.+.}-{3:3}, at: __se_sys_acct kernel/acct.c:315 [inline]
#0: ffff80001543ba08 (acct_on_mutex){+.+.}-{3:3}, at: __arm64_sys_acct+0xcc/0x714 kernel/acct.c:315
1 lock held by syz.2.29/6846:
#0: ffff80001543ba08 (acct_on_mutex){+.+.}-{3:3}, at: __do_sys_acct kernel/acct.c:327 [inline]
#0: ffff80001543ba08 (acct_on_mutex){+.+.}-{3:3}, at: __se_sys_acct kernel/acct.c:315 [inline]
#0: ffff80001543ba08 (acct_on_mutex){+.+.}-{3:3}, at: __arm64_sys_acct+0xcc/0x714 kernel/acct.c:315
1 lock held by syz.3.30/7289:
#0: ffff80001543ba08 (acct_on_mutex){+.+.}-{3:3}, at: __do_sys_acct kernel/acct.c:327 [inline]
#0: ffff80001543ba08 (acct_on_mutex){+.+.}-{3:3}, at: __se_sys_acct kernel/acct.c:315 [inline]
#0: ffff80001543ba08 (acct_on_mutex){+.+.}-{3:3}, at: __arm64_sys_acct+0xcc/0x714 kernel/acct.c:315
1 lock held by syz.4.31/7823:
#0: ffff80001543ba08 (acct_on_mutex){+.+.}-{3:3}, at: __do_sys_acct kernel/acct.c:327 [inline]
#0: ffff80001543ba08 (acct_on_mutex){+.+.}-{3:3}, at: __se_sys_acct kernel/acct.c:315 [inline]
#0: ffff80001543ba08 (acct_on_mutex){+.+.}-{3:3}, at: __arm64_sys_acct+0xcc/0x714 kernel/acct.c:315
1 lock held by syz.5.32/8269:
#0: ffff80001543ba08 (acct_on_mutex){+.+.}-{3:3}, at: __do_sys_acct kernel/acct.c:327 [inline]
#0: ffff80001543ba08 (acct_on_mutex){+.+.}-{3:3}, at: __se_sys_acct kernel/acct.c:315 [inline]
#0: ffff80001543ba08 (acct_on_mutex){+.+.}-{3:3}, at: __arm64_sys_acct+0xcc/0x714 kernel/acct.c:315
1 lock held by syz.6.33/8792:
#0: ffff80001543ba08 (acct_on_mutex){+.+.}-{3:3}, at: __do_sys_acct kernel/acct.c:327 [inline]
#0: ffff80001543ba08 (acct_on_mutex){+.+.}-{3:3}, at: __se_sys_acct kernel/acct.c:315 [inline]
#0: ffff80001543ba08 (acct_on_mutex){+.+.}-{3:3}, at: __arm64_sys_acct+0xcc/0x714 kernel/acct.c:315
3 locks held by dhcpcd-run-hook/8984:

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