[v5.15] INFO: task hung in __bread_gfp

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Apr 5, 2024, 12:55:30 AMApr 5
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Hello,

syzbot found the following issue on:

HEAD commit: 9465fef4ae35 Linux 5.15.153
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=14292ead180000
kernel config: https://syzkaller.appspot.com/x/.config?x=176c746ee3348b33
dashboard link: https://syzkaller.appspot.com/bug?extid=1cdb43ecf3dc21bae9ce
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/2962c02652ce/disk-9465fef4.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/d0f5a1ce082d/vmlinux-9465fef4.xz
kernel image: https://storage.googleapis.com/syzbot-assets/86b5b1eea636/bzImage-9465fef4.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+1cdb43...@syzkaller.appspotmail.com

INFO: task syz-executor.4:6049 blocked for more than 143 seconds.
Not tainted 5.15.153-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.4 state:D stack:26336 pid: 6049 ppid: 3521 flags:0x00004006
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5030 [inline]
__schedule+0x12c4/0x45b0 kernel/sched/core.c:6376
schedule+0x11b/0x1f0 kernel/sched/core.c:6459
io_schedule+0x88/0x100 kernel/sched/core.c:8484
bit_wait_io+0xe/0xc0 kernel/sched/wait_bit.c:209
__wait_on_bit+0xb9/0x180 kernel/sched/wait_bit.c:49
out_of_line_wait_on_bit+0x1d0/0x250 kernel/sched/wait_bit.c:64
wait_on_bit_io include/linux/wait_bit.h:101 [inline]
__wait_on_buffer fs/buffer.c:122 [inline]
wait_on_buffer include/linux/buffer_head.h:390 [inline]
__bread_slow fs/buffer.c:1181 [inline]
__bread_gfp+0x2d6/0x390 fs/buffer.c:1384
sb_bread include/linux/buffer_head.h:337 [inline]
v7_fill_super+0x19f/0x3d0 fs/sysv/super.c:496
mount_bdev+0x2c9/0x3f0 fs/super.c:1387
legacy_get_tree+0xeb/0x180 fs/fs_context.c:611
vfs_get_tree+0x88/0x270 fs/super.c:1517
do_new_mount+0x2ba/0xb40 fs/namespace.c:3005
do_mount fs/namespace.c:3348 [inline]
__do_sys_mount fs/namespace.c:3556 [inline]
__se_sys_mount+0x2d5/0x3c0 fs/namespace.c:3533
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7f98640dee69
RSP: 002b:00007f98626510c8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f986420cf80 RCX: 00007f98640dee69
RDX: 0000000020001240 RSI: 0000000020001200 RDI: 0000000020000140
RBP: 00007f986412b47a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f986420cf80 R15: 00007ffc30a1f9e8
</TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/27:
#0: ffffffff8c91f720 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
2 locks held by getty/3256:
#0: ffff888024abe098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
#1: ffffc90002bab2e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6af/0x1db0 drivers/tty/n_tty.c:2158
2 locks held by kworker/0:8/3591:
#0: ffff888011c72138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x78a/0x10c0 kernel/workqueue.c:2283
#1: ffffc90004537d20 ((work_completion)(&rew.rew_work)){+.+.}-{0:0}, at: process_one_work+0x7d0/0x10c0 kernel/workqueue.c:2285
3 locks held by kworker/u4:5/3600:
1 lock held by syz-executor.4/6049:
#0: ffff88801eca40e0 (&type->s_umount_key#93/1){+.+.}-{3:3}, at: alloc_super+0x210/0x940 fs/super.c:229
2 locks held by syz-executor.2/6388:
#0: ffff888018562988 (&bdev->bd_fsfreeze_mutex){+.+.}-{3:3}, at: mount_bdev+0x8b/0x3f0 fs/super.c:1354
#1: ffff88801eca40e0 (&type->s_umount_key#95){+.+.}-{3:3}, at: grab_super+0x59/0x1a0 fs/super.c:389
1 lock held by syz-executor.4/6891:
#0: ffff888018562988 (&bdev->bd_fsfreeze_mutex){+.+.}-{3:3}, at: mount_bdev+0x8b/0x3f0 fs/super.c:1354
1 lock held by syz-executor.0/6912:
#0: ffff88801b9aea08 (&nbd->config_lock){+.+.}-{3:3}, at: nbd_ioctl+0x146/0xe10 drivers/block/nbd.c:1460
1 lock held by syz-executor.3/6941:
#0: ffff888018562988 (&bdev->bd_fsfreeze_mutex){+.+.}-{3:3}, at: mount_bdev+0x8b/0x3f0 fs/super.c:1354
2 locks held by syz-executor.0/7052:
#0: ffff88801b732118 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0xfb/0x790 block/bdev.c:912
#1: ffff88801b6df468 (&lo->lo_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0xa9/0xbe0 drivers/block/loop.c:1365
2 locks held by syz-executor.3/7092:
#0: ffff88801b73f918 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0xfb/0x790 block/bdev.c:912
#1: ffff88801b748468 (&lo->lo_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0xa9/0xbe0 drivers/block/loop.c:1365
3 locks held by kworker/0:18/8154:
#0: ffff888011c70938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x78a/0x10c0 kernel/workqueue.c:2283
#1: ffffc90002fafd20 ((work_completion)(&pwq->unbound_release_work)){+.+.}-{0:0}, at: process_one_work+0x7d0/0x10c0 kernel/workqueue.c:2285
#2: ffffffff8c923ce8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:290 [inline]
#2: ffffffff8c923ce8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x280/0x740 kernel/rcu/tree_exp.h:845
6 locks held by kworker/0:20/8156:
#0: ffff888012da3138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x78a/0x10c0 kernel/workqueue.c:2283
#1: ffffc90002fcfd20 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x7d0/0x10c0 kernel/workqueue.c:2285
#2: ffff88801ed5f220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:760 [inline]
#2: ffff88801ed5f220 (&dev->mutex){....}-{3:3}, at: hub_event+0x208/0x54c0 drivers/usb/core/hub.c:5759
#3: ffff88801edb25c0 (&port_dev->status_lock){+.+.}-{3:3}, at: usb_lock_port drivers/usb/core/hub.c:3116 [inline]
#3: ffff88801edb25c0 (&port_dev->status_lock){+.+.}-{3:3}, at: hub_port_connect drivers/usb/core/hub.c:5341 [inline]
#3: ffff88801edb25c0 (&port_dev->status_lock){+.+.}-{3:3}, at: hub_port_connect_change drivers/usb/core/hub.c:5585 [inline]
#3: ffff88801edb25c0 (&port_dev->status_lock){+.+.}-{3:3}, at: port_event drivers/usb/core/hub.c:5731 [inline]
#3: ffff88801edb25c0 (&port_dev->status_lock){+.+.}-{3:3}, at: hub_event+0x2fc1/0x54c0 drivers/usb/core/hub.c:5813
#4: ffff88801df18b68 (hcd->address0_mutex){+.+.}-{3:3}, at: hub_port_connect drivers/usb/core/hub.c:5342 [inline]
#4: ffff88801df18b68 (hcd->address0_mutex){+.+.}-{3:3}, at: hub_port_connect_change drivers/usb/core/hub.c:5585 [inline]
#4: ffff88801df18b68 (hcd->address0_mutex){+.+.}-{3:3}, at: port_event drivers/usb/core/hub.c:5731 [inline]
#4: ffff88801df18b68 (hcd->address0_mutex){+.+.}-{3:3}, at: hub_event+0x2fec/0x54c0 drivers/usb/core/hub.c:5813
#5: ffff8880b9a3a318 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:475
3 locks held by syz-executor.2/8205:
#0: ffff8880756c9a10 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:789 [inline]
#0: ffff8880756c9a10 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: __sock_release net/socket.c:648 [inline]
#0: ffff8880756c9a10 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: sock_close+0x98/0x230 net/socket.c:1336
#1: ffff88807e293120 (sk_lock-AF_CAN){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1668 [inline]
#1: ffff88807e293120 (sk_lock-AF_CAN){+.+.}-{0:0}, at: bcm_release+0x1e0/0x860 net/can/bcm.c:1522
#2: ffffffff8c923ce8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:322 [inline]
#2: ffffffff8c923ce8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x350/0x740 kernel/rcu/tree_exp.h:845

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

NMI backtrace for cpu 1
CPU: 1 PID: 27 Comm: khungtaskd Not tainted 5.15.153-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
nmi_cpu_backtrace+0x46a/0x4a0 lib/nmi_backtrace.c:111
nmi_trigger_cpumask_backtrace+0x181/0x2a0 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:210 [inline]
watchdog+0xe72/0xeb0 kernel/hung_task.c:295
kthread+0x3f6/0x4f0 kernel/kthread.c:319
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298
</TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 3591 Comm: kworker/0:8 Not tainted 5.15.153-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Workqueue: events pwq_unbound_release_workfn
RIP: 0010:remove_class_from_lock_chain kernel/locking/lockdep.c:5913 [inline]
RIP: 0010:remove_class_from_lock_chains kernel/locking/lockdep.c:5952 [inline]
RIP: 0010:zap_class+0x1a1/0x870 kernel/locking/lockdep.c:5994
Code: 7b 48 63 c3 48 8d ac 00 c0 5f 60 8f 48 89 e8 48 c1 e8 03 42 0f b6 04 30 84 c0 75 34 0f b7 45 00 25 ff 1f 00 00 49 39 c4 74 66 <43> 0f b6 44 35 00 84 c0 75 31 41 8b 07 89 c1 c1 e9 08 c1 e8 02 83
RSP: 0018:ffffc90004537ae8 EFLAGS: 00000012
RAX: 00000000000009f7 RBX: 0000000000020eb4 RCX: 0000000000020eb0
RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffffffff913bdce8
RBP: ffffffff8f647d28 R08: dffffc0000000000 R09: fffffbfff2277b9e
R10: 0000000000000000 R11: dffffc0000000001 R12: 00000000000010a4
R13: 1ffffffff1f97fb4 R14: dffffc0000000000 R15: ffffffff8fcbfda0
FS: 0000000000000000(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555555816788 CR3: 0000000060ef0000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<NMI>
</NMI>
<TASK>
__lockdep_free_key_range kernel/locking/lockdep.c:6116 [inline]
lockdep_unregister_key+0x369/0x5b0 kernel/locking/lockdep.c:6312
wq_unregister_lockdep kernel/workqueue.c:3518 [inline]
pwq_unbound_release_workfn+0x23d/0x290 kernel/workqueue.c:3756
process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2310
worker_thread+0xaca/0x1280 kernel/workqueue.c:2457
kthread+0x3f6/0x4f0 kernel/kthread.c:319
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298
</TASK>


---
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