INFO: task kworker/u4:3:155 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:3 state:D stack:21080 pid: 155 ppid: 2 flags:0x00004000
Workqueue: writeback wb_workfn (flush-7:0)
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_background_flush fs/fs-writeback.c:2182 [inline]
wb_do_writeback fs/fs-writeback.c:2270 [inline]
wb_workfn+0xbd6/0xf20 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:
4 locks held by kworker/u4:0/9:
#0: ffff888018fb0138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
#1: ffffc90000ce7d00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
#2: ffff88807e3c20e0 (&type->s_umount_key#54){.+.+}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:418
#3: ffff8880293b91b0 (&sbi->gc_lock){+.+.}-{3:3}, at: f2fs_balance_fs+0x47e/0x650 fs/f2fs/segment.c:528
1 lock held by khungtaskd/27:
#0: ffffffff8c31f320 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
4 locks held by kworker/u4:3/155:
#0: ffff888018fb0138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
#1: ffffc90002017d00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
#2: ffff88807dc4e0e0 (&type->s_umount_key#54){.+.+}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:418
#3: ffff88807b2991b0 (&sbi->gc_lock){+.+.}-{3:3}, at: f2fs_balance_fs+0x47e/0x650 fs/f2fs/segment.c:528
4 locks held by kworker/u4:4/1277:
#0: ffff888018fb0138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
#1: ffffc90004fc7d00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
#2: ffff88807e27a0e0 (&type->s_umount_key#54){.+.+}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:418
#3: ffff888077b111b0 (&sbi->gc_lock){+.+.}-{3:3}, at: f2fs_balance_fs+0x47e/0x650 fs/f2fs/segment.c:528
2 locks held by getty/3950:
#0: ffff88802c494098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
#1: ffffc900026562e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x5df/0x1a70 drivers/tty/n_tty.c:2158
4 locks held by kworker/u4:5/4308:
#0: ffff888018fb0138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
#1: ffffc9000313fd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
#2: ffff88807bd7e0e0 (&type->s_umount_key#54){.+.+}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:418
#3: ffff88807c76d1b0 (&sbi->gc_lock){+.+.}-{3:3}, at: f2fs_balance_fs+0x47e/0x650 fs/f2fs/segment.c:528
4 locks held by kworker/u4:6/5051:
#0: ffff888018fb0138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
#1: ffffc9000318fd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
#2: ffff888147a560e0 (&type->s_umount_key#54){.+.+}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:418
#3: ffff88807c6e51b0 (&sbi->gc_lock){+.+.}-{3:3}, at: f2fs_balance_fs+0x47e/0x650 fs/f2fs/segment.c:528
5 locks held by syz.0.16/5057:
5 locks held by syz.1.17/5077:
6 locks held by syz.2.18/5096:
4 locks held by kworker/u4:7/5112:
#0: ffff888018fb0138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
#1: ffffc900033efd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
#2: ffff888078a460e0 (&type->s_umount_key#54){.+.+}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:418
#3: ffff888073c251b0 (&sbi->gc_lock){+.+.}-{3:3}, at: f2fs_balance_fs+0x47e/0x650 fs/f2fs/segment.c:528
6 locks held by syz.3.19/5119:
4 locks held by kworker/u4:8/5136:
#0: ffff888018fb0138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
#1: ffffc900034cfd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
#2: ffff88805e8860e0 (&type->s_umount_key#54){.+.+}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:418
#3: ffff88807dc811b0 (&sbi->gc_lock){+.+.}-{3:3}, at: f2fs_balance_fs+0x47e/0x650 fs/f2fs/segment.c:528
6 locks held by syz.4.20/5152:
6 locks held by syz.5.21/5183:
5 locks held by syz.6.22/5217:
4 locks held by kworker/u4:12/5234:
#0: ffff888018fb0138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
#1: ffffc9000378fd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
#2: ffff88801adc00e0 (&type->s_umount_key#54){.+.+}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:418
#3: ffff88807e68d1b0 (&sbi->gc_lock){+.+.}-{3:3}, at: f2fs_balance_fs+0x47e/0x650 fs/f2fs/segment.c:528
7 locks held by syz.7.23/5246:
=============================================
NMI backtrace for cpu 0
CPU: 0 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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 5166 Comm: kworker/u4:9 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Workqueue: events_unbound cfg80211_wiphy_work
RIP: 0010:get_lock_parent_ip include/linux/ftrace.h:857 [inline]
RIP: 0010:preempt_latency_start kernel/sched/core.c:5490 [inline]
RIP: 0010:preempt_count_add+0x85/0x190 kernel/sched/core.c:5515
Code: 14 00 75 11 65 8b 05 62 fd af 7e 0f b6 c0 3d f5 00 00 00 73 58 65 8b 05 51 fd af 7e 25 ff ff ff 7f 39 f8 75 42 48 8b 5c 24 18 <48> 89 df e8 33 d1 0b 00 85 c0 74 09 31 db 31 ff e8 26 d1 0b 00 65
RSP: 0018:ffffc900035ef268 EFLAGS: 00000246
RAX: 0000000000000001 RBX: ffffffff81351d2c RCX: ffffffff962dcf03
RDX: ffffc900035ef438 RSI: dffffc0000000000 RDI: 0000000000000001
RBP: ffffc900035ef3f0 R08: ffffc900035ef407 R09: ffffc900035ef3f8
R10: dffffc0000000000 R11: fffff520006bde81 R12: ffffffff812cd8ba
R13: ffffc900035ef3a8 R14: dffffc0000000000 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000056165f290a38 CR3: 0000000059633000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
unwind_next_frame+0xac/0x1d90 arch/x86/kernel/unwind_orc.c:433
__unwind_start+0x5bb/0x740 arch/x86/kernel/unwind_orc.c:704
unwind_start arch/x86/include/asm/unwind.h:60 [inline]
arch_stack_walk+0xda/0x140 arch/x86/kernel/stacktrace.c:24
stack_trace_save+0xa6/0xf0 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:38 [inline]
kasan_set_track+0x4b/0x70 mm/kasan/common.c:46
kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:360
____kasan_slab_free+0xd5/0x110 mm/kasan/common.c:366
kasan_slab_free include/linux/kasan.h:230 [inline]
slab_free_hook mm/slub.c:1710 [inline]
slab_free_freelist_hook+0xea/0x170 mm/slub.c:1736
slab_free mm/slub.c:3504 [inline]
kfree+0xef/0x2a0 mm/slub.c:4564
ieee80211_bss_info_update+0x846/0xa70 net/mac80211/scan.c:232
ieee80211_rx_bss_info net/mac80211/ibss.c:1123 [inline]
ieee80211_rx_mgmt_probe_beacon net/mac80211/ibss.c:1614 [inline]
ieee80211_ibss_rx_queued_mgmt+0x1700/0x2ab0 net/mac80211/ibss.c:1643
ieee80211_iface_process_skb net/mac80211/iface.c:1459 [inline]
ieee80211_iface_work+0x70e/0xc60 net/mac80211/iface.c:1513
cfg80211_wiphy_work+0x221/0x260 net/wireless/core.c:433
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