INFO: task syz.3.808:8599 blocked for more than 143 seconds.
Not tainted 6.6.101-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.808 state:D stack:22640 pid:8599 ppid:5796 flags:0x00004006
Call Trace:
context_switch kernel/sched/core.c:5381 [inline]
__schedule+0x14d2/0x44d0 kernel/sched/core.c:6700
schedule+0xbd/0x170 kernel/sched/core.c:6774
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6833
__mutex_lock_common kernel/locking/mutex.c:679 [inline]
__mutex_lock+0x6b7/0xcc0 kernel/locking/mutex.c:747
sync_bdevs+0x1af/0x330 block/bdev.c:1059
ksys_sync+0xba/0x150 fs/sync.c:105
__ia32_sys_sync+0xe/0x20 fs/sync.c:113
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f6740f8ebe9
RSP: 002b:00007f6741da2038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f67411b5fa0 RCX: 00007f6740f8ebe9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f67411b5fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f67411b6038 R14: 00007f67411b5fa0 R15: 00007ffcef57d5b8
Showing all locks held in the system:
1 lock held by khungtaskd/29:
#0: ffffffff8cd2fba0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
#0: ffffffff8cd2fba0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline]
#0: ffffffff8cd2fba0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x290 kernel/locking/lockdep.c:6633
5 locks held by kworker/u4:8/2117:
#0: ffff888017873938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
#0: ffff888017873938 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
#1: ffffc90005317d00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
#1: ffffc90005317d00 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
#2: ffffffff8dfaea90 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x136/0xb90 net/core/net_namespace.c:606
#3: ffff8880311dd3e8 (&wg->device_update_lock){+.+.}-{3:3}, at: wg_destruct+0x116/0x310 drivers/net/wireguard/device.c:250
#4: ffffffff8cd35a40 (rcu_state.barrier_mutex){+.+.}-{3:3}, at: rcu_barrier+0x4c/0x580 kernel/rcu/tree.c:4089
2 locks held by getty/5547:
#0: ffff8880327480a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc9000326e2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x425/0x1380 drivers/tty/n_tty.c:2217
1 lock held by udevd/5792:
#0: ffff888021ea34c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x121/0x600 block/bdev.c:788
2 locks held by kworker/0:4/5850:
#0: ffff888017872538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
#0: ffff888017872538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
#1: ffffc9000491fd00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
#1: ffffc9000491fd00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
2 locks held by udevd/7441:
1 lock held by syz.3.808/8599:
#0: ffff888021ea34c8 (&disk->open_mutex){+.+.}-{3:3}, at: sync_bdevs+0x1af/0x330 block/bdev.c:1059
2 locks held by syz-executor/11124:
#0: ffffffff8dfbb888 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:78 [inline]
#0: ffffffff8dfbb888 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x76f/0xf10 net/core/rtnetlink.c:6472
#1: ffffffff8cd35b78 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:292 [inline]
#1: ffffffff8cd35b78 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x448/0x830 kernel/rcu/tree_exp.h:1004
1 lock held by syz.0.1751/11220:
=============================================
NMI backtrace for cpu 1
CPU: 1 PID: 29 Comm: khungtaskd Not tainted 6.6.101-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106
nmi_cpu_backtrace+0x39b/0x3d0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x17a/0x2f0 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline]
watchdog+0xf41/0xf80 kernel/hung_task.c:379
kthread+0x2fa/0x390 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 48 Comm: kworker/u4:3 Not tainted 6.6.101-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Workqueue: loop0 loop_rootcg_workfn
RIP: 0010:shmem_get_folio_gfp+0x0/0x2ac0 mm/shmem.c:1953
Code: 41 5f 5d c3 44 89 e9 80 e1 07 80 c1 03 38 c1 7c c7 4c 89 ef e8 f1 20 1e 00 eb bd 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 <55> 41 57 41 56 41 55 41 54 53 48 81 ec f8 00 00 00 4d 89 ce 44 89
RSP: 0018:ffffc90000b8f708 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffff88802d1cba80 RCX: 0000000000000000
RDX: ffffc90000b8f798 RSI: 000000000000002c RDI: ffff88802d1cb768
RBP: ffff88802d1cb7a8 R08: 0000000000100c0a R09: 0000000000000000
R10: ffffc90000b8f890 R11: fffff52000171f14 R12: 0000000000000400
R13: 000000000000002c R14: 0000000000001000 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff457b92000 CR3: 000000007718e000 CR4: 00000000003506f0
Call Trace:
shmem_get_folio mm/shmem.c:2165 [inline]
shmem_file_read_iter+0x1f3/0x9c0 mm/shmem.c:2779
do_iter_readv_writev fs/read_write.c:-1 [inline]
do_iter_read+0x798/0xc80 fs/read_write.c:795
lo_read_simple drivers/block/loop.c:285 [inline]
do_req_filebacked drivers/block/loop.c:495 [inline]
loop_handle_cmd drivers/block/loop.c:1911 [inline]
loop_process_work+0x969/0x1ed0 drivers/block/loop.c:1946
process_one_work kernel/workqueue.c:2634 [inline]
process_scheduled_works+0xa45/0x15b0 kernel/workqueue.c:2711
worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792
kthread+0x2fa/0x390 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293