INFO: task kworker/u8:15:6570 blocked for more than 144 seconds.
Tainted: G L syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:15 state:D stack:22272 pid:6570 tgid:6570 ppid:2 task_flags:0x4208060 flags:0x00080000
Workqueue: writeback wb_workfn (flush-7:4)
Call Trace:
context_switch kernel/sched/core.c:5295 [inline]
__schedule+0x1585/0x5340 kernel/sched/core.c:6907
__schedule_loop kernel/sched/core.c:6989 [inline]
schedule+0x164/0x360 kernel/sched/core.c:7004
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7061
rwsem_down_write_slowpath+0x899/0x1040 kernel/locking/rwsem.c:1185
__down_write_common kernel/locking/rwsem.c:1317 [inline]
__down_write kernel/locking/rwsem.c:1326 [inline]
down_write+0x1bc/0x200 kernel/locking/rwsem.c:1591
f2fs_down_write fs/f2fs/f2fs.h:2407 [inline]
f2fs_down_write_trace fs/f2fs/checkpoint.c:180 [inline]
f2fs_issue_checkpoint+0x437/0x790 fs/f2fs/checkpoint.c:2104
f2fs_balance_fs_bg+0x576/0x990 fs/f2fs/segment.c:545
f2fs_write_node_pages+0x158/0x700 fs/f2fs/node.c:2251
do_writepages+0x32e/0x550 mm/page-writeback.c:2554
__writeback_single_inode+0x133/0x11a0 fs/fs-writeback.c:1750
writeback_sb_inodes+0x944/0x19a0 fs/fs-writeback.c:2041
__writeback_inodes_wb+0x111/0x240 fs/fs-writeback.c:2118
wb_writeback+0x46a/0xb70 fs/fs-writeback.c:2229
wb_check_old_data_flush fs/fs-writeback.c:2333 [inline]
wb_do_writeback fs/fs-writeback.c:2386 [inline]
wb_workfn+0xb4c/0xf50 fs/fs-writeback.c:2414
process_one_work kernel/workqueue.c:3275 [inline]
process_scheduled_works+0xb02/0x1830 kernel/workqueue.c:3358
worker_thread+0xa50/0xfc0 kernel/workqueue.c:3439
kthread+0x388/0x470 kernel/kthread.c:467
ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Showing all locks held in the system:
1 lock held by khungtaskd/31:
#0: ffffffff8e7602e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
#0: ffffffff8e7602e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
#0: ffffffff8e7602e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
3 locks held by kworker/u8:4/58:
#0: ffff88813fe44148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3250 [inline]
#0: ffff88813fe44148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x9ea/0x1830 kernel/workqueue.c:3358
#1: ffffc900015f7c40 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline]
#1: ffffc900015f7c40 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0xa25/0x1830 kernel/workqueue.c:3358
#2: ffffffff8fbcb808 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:313
2 locks held by getty/5574:
#0: ffff88803613a0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc9000332e2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13c0 drivers/tty/n_tty.c:2211
3 locks held by kworker/u8:9/5995:
#0: ffff8880312bf148 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3250 [inline]
#0: ffff8880312bf148 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0x9ea/0x1830 kernel/workqueue.c:3358
#1: ffffc90002f77c40 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline]
#1: ffffc90002f77c40 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa25/0x1830 kernel/workqueue.c:3358
#2: ffffffff8fbcb808 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
#2: ffffffff8fbcb808 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_dad_work+0x11e/0x14c0 net/ipv6/addrconf.c:4199
3 locks held by kworker/u8:11/6054:
#0: ffff88801bb63948 ((wq_completion)cfg80211){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3250 [inline]
#0: ffff88801bb63948 ((wq_completion)cfg80211){+.+.}-{0:0}, at: process_scheduled_works+0x9ea/0x1830 kernel/workqueue.c:3358
#1: ffffc900026d7c40 ((work_completion)(&(&rdev->dfs_update_channels_wk)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline]
#1: ffffc900026d7c40 ((work_completion)(&(&rdev->dfs_update_channels_wk)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa25/0x1830 kernel/workqueue.c:3358
#2: ffffffff8fbcb808 (rtnl_mutex){+.+.}-{4:4}, at: cfg80211_dfs_channels_update_work+0xd6/0x660 net/wireless/mlme.c:1040
4 locks held by kworker/u8:15/6570:
#0: ffff88801faac948 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3250 [inline]
#0: ffff88801faac948 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9ea/0x1830 kernel/workqueue.c:3358
#1: ffffc900049bfc40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline]
#1: ffffc900049bfc40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa25/0x1830 kernel/workqueue.c:3358
#2: ffff88804ee860e0 (&type->s_umount_key#72){++++}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:565
#3: ffff88804fc09518 (&sbi->gc_lock){+.+.}-{4:4}, at: f2fs_down_write fs/f2fs/f2fs.h:2407 [inline]
#3: ffff88804fc09518 (&sbi->gc_lock){+.+.}-{4:4}, at: f2fs_down_write_trace fs/f2fs/checkpoint.c:180 [inline]
#3: ffff88804fc09518 (&sbi->gc_lock){+.+.}-{4:4}, at: f2fs_issue_checkpoint+0x437/0x790 fs/f2fs/checkpoint.c:2104
1 lock held by syz-executor/7383:
5 locks held by syz.4.2099/19828:
2 locks held by syz.2.2420/22114:
#0: ffff88804ee860e0 (&type->s_umount_key#72){++++}-{4:4}, at: __super_lock fs/super.c:60 [inline]
#0: ffff88804ee860e0 (&type->s_umount_key#72){++++}-{4:4}, at: super_lock+0x2d6/0x3d0 fs/super.c:122
#1: ffff888025c40820 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:397 [inline]
#1: ffff888025c40820 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: sync_inodes_sb+0x1c2/0xbd0 fs/fs-writeback.c:2922
5 locks held by syz-executor/22162:
#0: ffff88805f098ec0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_do_close net/bluetooth/hci_core.c:500 [inline]
#0: ffff88805f098ec0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_unregister_dev+0x212/0x5a0 net/bluetooth/hci_core.c:2716
#1: ffff88805f0980c0 (&hdev->lock){+.+.}-{4:4}, at: hci_dev_close_sync+0x640/0x10e0 net/bluetooth/hci_sync.c:5346
#2: ffffffff8fd57ea8 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:2151 [inline]
#2: ffffffff8fd57ea8 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_conn_hash_flush+0xa1/0x260 net/bluetooth/hci_conn.c:2644
#3: ffff888054fcd2f8 (&conn->lock#2){+.+.}-{4:4}, at: l2cap_conn_del+0x7b/0x5c0 net/bluetooth/l2cap_core.c:1755
#4: ffffffff8e766578 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:343 [inline]
#4: ffffffff8e766578 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x38d/0x770 kernel/rcu/tree_exp.h:961
1 lock held by syz-executor/24177:
#0: ffffffff8fbcb808 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
#0: ffffffff8fbcb808 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x404/0x1ad0 net/ipv4/devinet.c:978
3 locks held by syz.8.2628/24855:
3 locks held by syz.3.2646/25013:
#0: ffffffff8fbcb808 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
#0: ffffffff8fbcb808 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline]
#0: ffffffff8fbcb808 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8a1/0x1be0 net/core/rtnetlink.c:4071
#1: ffff8880664b8788 (&rdev->wiphy.mtx){+.+.}-{4:4}, at: class_wiphy_constructor include/net/cfg80211.h:6441 [inline]
#1: ffff8880664b8788 (&rdev->wiphy.mtx){+.+.}-{4:4}, at: ieee80211_stop+0x126/0x240 net/mac80211/iface.c:822
#2: ffffffff8e766578 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:311 [inline]
#2: ffffffff8e766578 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2d0/0x770 kernel/rcu/tree_exp.h:961
3 locks held by syz.9.2640/25020:
1 lock held by dhcpcd-run-hook/25025:
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:161 [inline]
__sys_info lib/sys_info.c:157 [inline]
sys_info+0x135/0x170 lib/sys_info.c:165
check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline]
watchdog+0xfd9/0x1030 kernel/hung_task.c:515
kthread+0x388/0x470 kernel/kthread.c:467
ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 6569 Comm: kworker/u8:14 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Workqueue: events_unbound cfg80211_wiphy_work
RIP: 0010:__debug_check_no_obj_freed lib/debugobjects.c:1089 [inline]
RIP: 0010:debug_check_no_obj_freed+0x1d9/0x550 lib/debugobjects.c:1129
Code: 00 00 48 ba 00 00 00 00 00 fc ff df ff c3 48 8b 04 24 48 89 c5 48 85 c0 0f 84 44 03 00 00 49 89 ee 49 c1 ee 03 41 80 3c 16 00 <74> 12 48 89 ef e8 1d 8c 77 fd 48 ba 00 00 00 00 00 fc ff df 48 8b
RSP: 0018:ffffc900049cf888 EFLAGS: 00000046
RAX: ffff888055013a80 RBX: 0000000000000001 RCX: 0000000000000001
RDX: dffffc0000000000 RSI: 0000000000000004 RDI: ffffc900049cf7e0
RBP: ffff888055013a80 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff52000939efc R12: ffff8880543f7380
R13: ffff8880543f70c0 R14: 1ffff1100aa02750 R15: ffff888056eb9340
FS: 0000000000000000(0000) GS:ffff888125566000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb81640e420 CR3: 0000000028446000 CR4: 0000000000350ef0
Call Trace:
slab_free_hook mm/slub.c:2618 [inline]
slab_free mm/slub.c:6124 [inline]
kmem_cache_free+0x100/0x630 mm/slub.c:6254
skb_kfree_head net/core/skbuff.c:1087 [inline]
skb_free_head net/core/skbuff.c:1101 [inline]
skb_release_data+0x6c3/0x940 net/core/skbuff.c:1128
skb_release_all net/core/skbuff.c:1203 [inline]
__kfree_skb+0x5d/0x210 net/core/skbuff.c:1217
ieee80211_iface_work+0xb8e/0x1340 net/mac80211/iface.c:1804
cfg80211_wiphy_work+0x2ab/0x4a0 net/wireless/core.c:440
process_one_work kernel/workqueue.c:3275 [inline]
process_scheduled_works+0xb02/0x1830 kernel/workqueue.c:3358
worker_thread+0xa50/0xfc0 kernel/workqueue.c:3439
kthread+0x388/0x470 kernel/kthread.c:467
ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245