INFO: task kworker/u4:1:144 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:1 state:D stack:23640 pid: 144 ppid: 2 flags:0x00004000
Workqueue: writeback wb_workfn (flush-7:4)
Call Trace:
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11ef/0x43c0 kernel/sched/core.c:6395
schedule+0x11b/0x1e0 kernel/sched/core.c:6478
rwsem_down_write_slowpath+0xc87/0x1260 kernel/locking/rwsem.c:1165
f2fs_balance_fs+0x47e/0x650 fs/f2fs/segment.c:528
f2fs_write_inode+0x531/0x760 fs/f2fs/inode.c:745
write_inode fs/fs-writeback.c:1505 [inline]
__writeback_single_inode+0x6c3/0xda0 fs/fs-writeback.c:1715
writeback_sb_inodes+0xa4e/0x1680 fs/fs-writeback.c:1940
__writeback_inodes_wb+0x12a/0x3f0 fs/fs-writeback.c:2011
wb_writeback+0x46f/0xbe0 fs/fs-writeback.c:2116
wb_check_old_data_flush fs/fs-writeback.c:2216 [inline]
wb_do_writeback fs/fs-writeback.c:2269 [inline]
wb_workfn+0xb15/0xf20 fs/fs-writeback.c:2298
process_one_work+0x85f/0x1010 kernel/workqueue.c:2310
worker_thread+0xaa6/0x1290 kernel/workqueue.c:2457
kthread+0x436/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
Showing all locks held in the system:
1 lock held by khungtaskd/27:
#0: ffffffff8c31f320 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
4 locks held by kworker/u4:1/144:
#0: ffff888142bf9138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
#1: ffffc900010afd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
#2: ffff88801a5ec0e0 (&type->s_umount_key#65){++++}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:418
#3: ffff88807f1c11b0 (&sbi->gc_lock){+.+.}-{3:3}, at: f2fs_balance_fs+0x47e/0x650 fs/f2fs/segment.c:528
8 locks held by kworker/u4:2/154:
#0: ffff888016dcd938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
#1: ffffc900010cfd00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
#2: ffffffff8d431cd0 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x148/0xba0 net/core/net_namespace.c:589
#3: ffffffff8d43dbc8 (rtnl_mutex){+.+.}-{3:3}, at: ieee80211_unregister_hw+0x4d/0x220 net/mac80211/main.c:1392
#4: ffff88802ade0688 (&rdev->wiphy.mtx){+.+.}-{3:3}, at: wiphy_lock include/net/cfg80211.h:5319 [inline]
#4: ffff88802ade0688 (&rdev->wiphy.mtx){+.+.}-{3:3}, at: cfg80211_netdev_notifier_call+0x4a9/0x11b0 net/wireless/core.c:1483
#5: ffff88805fe34d40 (&wdev->mtx){+.+.}-{3:3}, at: wdev_lock net/wireless/core.h:226 [inline]
#5: ffff88805fe34d40 (&wdev->mtx){+.+.}-{3:3}, at: cfg80211_leave net/wireless/core.c:1323 [inline]
#5: ffff88805fe34d40 (&wdev->mtx){+.+.}-{3:3}, at: cfg80211_netdev_notifier_call+0x4bd/0x11b0 net/wireless/core.c:1484
#6: ffff88802ade1810 (&local->sta_mtx){+.+.}-{3:3}, at: __sta_info_flush+0x18b/0x460 net/mac80211/sta_info.c:1224
#7: ffffffff8c323da8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:290 [inline]
#7: ffffffff8c323da8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x2d1/0x750 kernel/rcu/tree_exp.h:845
1 lock held by dhcpcd/3855:
2 locks held by getty/3954:
#0: ffff88807f03a098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
#1: ffffc900025e62e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x5df/0x1a70 drivers/tty/n_tty.c:2158
9 locks held by syz.4.16/4370:
2 locks held by syz-executor/4526:
#0: ffff8880206e3d18 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0xf9/0x7d0 block/bdev.c:915
#1: ffff8880209e3468 (&lo->lo_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0xaa/0xb90 drivers/block/loop.c:1366
2 locks held by kworker/1:16/5858:
#0: ffff888016c72138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
#1: ffffc9000435fd00 ((work_completion)(&rew.rew_work)){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
=============================================
NMI backtrace for cpu 1
CPU: 1 PID: 27 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Call Trace:
dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
nmi_cpu_backtrace+0x3a2/0x3d0 lib/nmi_backtrace.c:111
nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:212 [inline]
watchdog+0xe0f/0xe50 kernel/hung_task.c:369
kthread+0x436/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 7 Comm: kworker/0:0 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Workqueue: events nsim_dev_trap_report_work
RIP: 0010:check_wait_context kernel/locking/lockdep.c:4709 [inline]
RIP: 0010:__lock_acquire+0x892/0x7d10 kernel/locking/lockdep.c:4962
Code: 00 42 0f b6 04 00 84 c0 0f 85 d8 64 00 00 41 83 3f 00 41 0f 94 c5 45 00 ed 41 80 c5 02 48 8b 84 24 88 00 00 00 42 0f b6 04 00 <84> c0 0f 85 35 62 00 00 44 3b 33 0f 8d 86 02 00 00 49 63 de 48 8d
RSP: 0018:ffffc90000cc7660 EFLAGS: 00000002
RAX: 0000000000000000 RBX: ffff888016e9c668 RCX: 0000000000000002
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff901d60c0
RBP: ffffc90000cc78b0 R08: dffffc0000000000 R09: 1ffffffff203ac18
R10: dffffc0000000000 R11: fffffbfff203ac19 R12: 0000000000000000
R13: ffff888016e9c604 R14: 0000000000000000 R15: ffff888016e9c654
FS: 0000000000000000(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f77863e6286 CR3: 000000002b36d000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623
local_lock_acquire+0x1d/0x70 include/linux/local_lock_internal.h:29
___slab_alloc+0x515/0xdd0 mm/slub.c:2988
__slab_alloc mm/slub.c:3100 [inline]
slab_alloc_node mm/slub.c:3191 [inline]
kmem_cache_alloc_node+0x1c3/0x2d0 mm/slub.c:3261
__alloc_skb+0xf4/0x750 net/core/skbuff.c:415
alloc_skb include/linux/skbuff.h:1162 [inline]
nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:664 [inline]
nsim_dev_trap_report drivers/net/netdevsim/dev.c:721 [inline]
nsim_dev_trap_report_work+0x2a1/0xb40 drivers/net/netdevsim/dev.c:762
process_one_work+0x85f/0x1010 kernel/workqueue.c:2310
worker_thread+0xaa6/0x1290 kernel/workqueue.c:2457
kthread+0x436/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287