[v6.1] INFO: task hung in journal_read

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: fb28aa725e05 Linux 6.1.180
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=142f9db9580000
kernel config: https://syzkaller.appspot.com/x/.config?x=31dfefc4a14efea3
dashboard link: https://syzkaller.appspot.com/bug?extid=dfdda9cbc3b8fab332b0
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/9a6fe2a54d0f/disk-fb28aa72.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/742b23a1d931/vmlinux-fb28aa72.xz
kernel image: https://storage.googleapis.com/syzbot-assets/b3f257c16d2e/bzImage-fb28aa72.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+dfdda9...@syzkaller.appspotmail.com

INFO: task syz.3.633:6096 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.633 state:D stack:21648 pid:6096 ppid:4278 flags:0x00104004
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5246 [inline]
__schedule+0x107f/0x4030 kernel/sched/core.c:6563
schedule+0xb9/0x180 kernel/sched/core.c:6639
io_schedule+0x7c/0xd0 kernel/sched/core.c:8799
bit_wait_io+0xd/0xc0 kernel/sched/wait_bit.c:209
__wait_on_bit+0x9b/0x2c0 kernel/sched/wait_bit.c:49
out_of_line_wait_on_bit+0x138/0x190 kernel/sched/wait_bit.c:64
wait_on_buffer include/linux/buffer_head.h:385 [inline]
reiserfs_breada fs/reiserfs/journal.c:2352 [inline]
journal_read+0xae5/0x3af0 fs/reiserfs/journal.c:2451
journal_init+0x1a2d/0x2470 fs/reiserfs/journal.c:2899
reiserfs_fill_super+0xdf0/0x20e0 fs/reiserfs/super.c:2022
mount_bdev+0x28a/0x3c0 fs/super.c:1443
legacy_get_tree+0xe6/0x180 fs/fs_context.c:632
vfs_get_tree+0x88/0x270 fs/super.c:1573
do_new_mount+0x247/0xa40 fs/namespace.c:3078
do_mount fs/namespace.c:3421 [inline]
__do_sys_mount fs/namespace.c:3629 [inline]
__se_sys_mount+0x2e3/0x3d0 fs/namespace.c:3606
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fea7079f28a
RSP: 002b:00007fea7165ae58 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fea7165aee0 RCX: 00007fea7079f28a
RDX: 0000200000000180 RSI: 0000200000000280 RDI: 00007fea7165aea0
RBP: 0000200000000180 R08: 00007fea7165aee0 R09: 0000000001000098
R10: 0000000001000098 R11: 0000000000000246 R12: 0000200000000280
R13: 00007fea7165aea0 R14: 00000000000010fd R15: 00002000000002c0
</TASK>

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
#0: ffffffff8cb2e4f0 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xef0 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
#0: ffffffff8cb2ed10 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xef0 kernel/rcu/tasks.h:517
1 lock held by khungtaskd/28:
#0: ffffffff8cb2db60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
#0: ffffffff8cb2db60 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
#0: ffffffff8cb2db60 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6527
4 locks held by kworker/u4:2/31:
2 locks held by getty/4028:
#0: ffff88814d132098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
#1: ffffc9000327b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x41e/0x1360 drivers/tty/n_tty.c:2198
2 locks held by kworker/0:13/5035:
#0: ffff888017472138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#1: ffffc9001be57d00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
3 locks held by kworker/0:15/5039:
#0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#1: ffffc9001be87d00 ((work_completion)(&pwq->unbound_release_work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#2: ffffffff8cb33838 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:323 [inline]
#2: ffffffff8cb33838 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x3c0/0x890 kernel/rcu/tree_exp.h:962
1 lock held by syz.3.633/6096:
#0: ffff888028de40e0 (&type->s_umount_key#25/1){+.+.}-{3:3}, at: alloc_super+0x1fb/0x930 fs/super.c:228
4 locks held by kvm-nx-lpage-re/8706:
#0: ffffffff8cb56648 (cgroup_mutex){+.+.}-{3:3}, at: cgroup_lock include/linux/cgroup.h:442 [inline]
#0: ffffffff8cb56648 (cgroup_mutex){+.+.}-{3:3}, at: cgroup_attach_task_all+0x22/0xe0 kernel/cgroup/cgroup-v1.c:61
#1: ffffffff8c9ca530 (cpu_hotplug_lock){++++}-{0:0}, at: cgroup_attach_lock+0xd/0x30 kernel/cgroup/cgroup.c:2476
#2: ffffffff8cb56830 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: cgroup_attach_task_all+0x2c/0xe0 kernel/cgroup/cgroup-v1.c:62
#3: ffffffff8cb33838 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:291 [inline]
#3: ffffffff8cb33838 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x2ec/0x890 kernel/rcu/tree_exp.h:962
1 lock held by dhcpcd/8717:
#0: ffff888028db8130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1805 [inline]
#0: ffff888028db8130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x33/0xd40 net/packet/af_packet.c:3255
1 lock held by dhcpcd/8718:
#0: ffff8880277a4130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1805 [inline]
#0: ffff8880277a4130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x33/0xd40 net/packet/af_packet.c:3255
1 lock held by dhcpcd/8719:
#0: ffff88807db34130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1805 [inline]
#0: ffff88807db34130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x33/0xd40 net/packet/af_packet.c:3255

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

NMI backtrace for cpu 0
CPU: 0 PID: 28 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
<TASK>
dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106
nmi_cpu_backtrace+0x3e6/0x460 lib/nmi_backtrace.c:111
nmi_trigger_cpumask_backtrace+0x1d4/0x450 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline]
watchdog+0xf0e/0xf50 kernel/hung_task.c:377
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
</TASK>


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