INFO: task kworker/u8:1:13 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:1 state:D stack:22504 pid:13 tgid:13 ppid:2 task_flags:0x4208060 flags:0x00004000
Workqueue: writeback wb_workfn (flush-7:3)
Call Trace:
context_switch kernel/sched/core.c:5357 [inline]
__schedule+0x16f3/0x4c20 kernel/sched/core.c:6961
__schedule_loop kernel/sched/core.c:7043 [inline]
rt_mutex_schedule+0x77/0xf0 kernel/sched/core.c:7339
rt_mutex_slowlock_block kernel/locking/rtmutex.c:1647 [inline]
__rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline]
__rt_mutex_slowlock_locked+0x1e04/0x25e0 kernel/locking/rtmutex.c:1760
rt_mutex_slowlock+0xb5/0x160 kernel/locking/rtmutex.c:1800
__rt_mutex_lock kernel/locking/rtmutex.c:1815 [inline]
rwbase_write_lock+0x14f/0x750 kernel/locking/rwbase_rt.c:244
f2fs_down_write fs/f2fs/f2fs.h:2234 [inline]
f2fs_issue_checkpoint+0x39c/0x570 fs/f2fs/checkpoint.c:1846
f2fs_balance_fs_bg+0x54b/0x9c0 fs/f2fs/segment.c:544
f2fs_write_node_pages+0x146/0x6e0 fs/f2fs/node.c:2193
do_writepages+0x32b/0x550 mm/page-writeback.c:2634
__writeback_single_inode+0x145/0x1000 fs/fs-writeback.c:1680
writeback_sb_inodes+0x6b7/0xf60 fs/fs-writeback.c:1976
__writeback_inodes_wb+0x111/0x240 fs/fs-writeback.c:2047
wb_writeback+0x44f/0xaf0 fs/fs-writeback.c:2158
wb_check_old_data_flush fs/fs-writeback.c:2262 [inline]
wb_do_writeback fs/fs-writeback.c:2315 [inline]
wb_workfn+0xaf4/0xf00 fs/fs-writeback.c:2343
process_one_work kernel/workqueue.c:3236 [inline]
process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3319
worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400
kthread+0x70e/0x8a0 kernel/kthread.c:463
ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Showing all locks held in the system:
3 locks held by kworker/0:0/9:
#0: ffff888019898538 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline]
#0: ffff888019898538 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319
#1: ffffc900000e7bc0 ((work_completion)(&sbi->s_error_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline]
#1: ffffc900000e7bc0 ((work_completion)(&sbi->s_error_work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319
#2: ffff888033df4078 (&sbi->sb_lock){++++}-{4:4}, at: f2fs_down_write fs/f2fs/f2fs.h:2234 [inline]
#2: ffff888033df4078 (&sbi->sb_lock){++++}-{4:4}, at: f2fs_record_stop_reason fs/f2fs/super.c:4418 [inline]
#2: ffff888033df4078 (&sbi->sb_lock){++++}-{4:4}, at: f2fs_record_error_work+0x59/0x1c0 fs/f2fs/super.c:4570
4 locks held by kworker/u8:1/13:
#0: ffff888143680938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline]
#0: ffff888143680938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319
#1: ffffc90000127bc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline]
#1: ffffc90000127bc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319
#2: ffff88805fe2c0d0 (&type->s_umount_key#68){++++}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:563
#3: ffff888033df5990 (&sbi->gc_lock){+.+.}-{4:4}, at: f2fs_down_write fs/f2fs/f2fs.h:2234 [inline]
#3: ffff888033df5990 (&sbi->gc_lock){+.+.}-{4:4}, at: f2fs_issue_checkpoint+0x39c/0x570 fs/f2fs/checkpoint.c:1846
1 lock held by khungtaskd/38:
#0: ffffffff8d9a8bc0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8d9a8bc0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
#0: ffffffff8d9a8bc0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
3 locks held by kworker/u8:2/43:
#0: ffff88814cb6c938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline]
#0: ffff88814cb6c938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319
#1: ffffc90000b47bc0 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline]
#1: ffffc90000b47bc0 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319
#2: ffffffff8ecd2938 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
#2: ffffffff8ecd2938 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_dad_work+0x119/0x15a0 net/ipv6/addrconf.c:4194
2 locks held by kworker/u8:11/1923:
4 locks held by kworker/u8:12/2834:
#0: ffff88801a6f4138 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline]
#0: ffff88801a6f4138 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319
#1: ffffc9000ccffbc0 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline]
#1: ffffc9000ccffbc0 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319
#2: ffffffff8ecc5a20 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf7/0x800 net/core/net_namespace.c:658
#3: ffffffff8ecd2938 (rtnl_mutex){+.+.}-{4:4}, at: default_device_exit_batch+0xdc/0x890 net/core/dev.c:12719
3 locks held by dhcpcd/5501:
#0: ffffffff8ed38940 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218
#1: ffff8880355c2908 (nlk_cb_mutex-GENERIC){+.+.}-{4:4}, at: __netlink_dump_start+0xfe/0x7e0 net/netlink/af_netlink.c:2406
#2: ffffffff8ecd2938 (rtnl_mutex){+.+.}-{4:4}, at: nl80211_prepare_wdev_dump+0x3dc/0x6a0 net/wireless/nl80211.c:1050
2 locks held by getty/5595:
#0: ffff88823bf4c8a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc90003e7b2e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x444/0x1410 drivers/tty/n_tty.c:2222
2 locks held by syz.3.27/6152:
8 locks held by syz-executor/6874:
1 lock held by syz-executor/6885:
#0: ffffffff8ecd2938 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
#0: ffffffff8ecd2938 (rtnl_mutex){+.+.}-{4:4}, at: inet6_rtm_newaddr+0x5b7/0xd20 net/ipv6/addrconf.c:5027
7 locks held by syz-executor/6929:
#0: ffff888034954488 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:3107 [inline]
#0: ffff888034954488 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x217/0xb40 fs/read_write.c:682
#1: ffff88802f41c478 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1e1/0x4f0 fs/kernfs/file.c:325
#2: ffff8880270023c8 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x204/0x4f0 fs/kernfs/file.c:326
#3: ffffffff8e542278 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x360 drivers/net/netdevsim/bus.c:234
#4: ffff88805fc690d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:911 [inline]
#4: ffff88805fc690d8 (&dev->mutex){....}-{4:4}, at: __device_driver_lock drivers/base/dd.c:1096 [inline]
#4: ffff88805fc690d8 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0xb6/0x800 drivers/base/dd.c:1294
#5: ffff88805e282300 (&devlink->lock_key#14){+.+.}-{4:4}, at: nsim_drv_remove+0x50/0x160 drivers/net/netdevsim/dev.c:1721
#6: ffffffff8ecd2938 (rtnl_mutex){+.+.}-{4:4}, at: nsim_destroy+0xe5/0x670 drivers/net/netdevsim/netdev.c:1135
4 locks held by syz-executor/6935:
#0: ffff888034954488 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:3107 [inline]
#0: ffff888034954488 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x217/0xb40 fs/read_write.c:682
#1: ffff888032383c78 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1e1/0x4f0 fs/kernfs/file.c:325
#2: ffff8880270023c8 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x204/0x4f0 fs/kernfs/file.c:326
#3: ffffffff8e542278 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x360 drivers/net/netdevsim/bus.c:234
2 locks held by syz-executor/6968:
#0: ffffffff8e43ace0 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8e43ace0 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
#0: ffffffff8e43ace0 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250 net/core/rtnetlink.c:570
#1: ffffffff8ecd2938 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
#1: ffffffff8ecd2938 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline]
#1: ffffffff8ecd2938 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8db/0x1c70 net/core/rtnetlink.c:4056
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 38 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:328 [inline]
watchdog+0xf93/0xfe0 kernel/hung_task.c:491
kthread+0x70e/0x8a0 kernel/kthread.c:463
ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 6874 Comm: syz-executor Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:__bfs kernel/locking/lockdep.c:1815 [inline]
RIP: 0010:__bfs_backwards kernel/locking/lockdep.c:1860 [inline]
RIP: 0010:check_irq_usage kernel/locking/lockdep.c:2796 [inline]
RIP: 0010:check_prev_add kernel/locking/lockdep.c:3169 [inline]
RIP: 0010:check_prevs_add kernel/locking/lockdep.c:3284 [inline]
RIP: 0010:validate_chain+0xfd7/0x2140 kernel/locking/lockdep.c:3908
Code: 25 ff 0f 00 00 39 05 74 5e 61 11 73 06 89 05 6c 5e 61 11 49 8b 04 24 48 89 de 48 39 e8 0f 84 33 fe ff ff 4c 89 68 30 48 8b 00 <48> 39 e8 75 f4 48 89 de e9 1f fe ff ff 48 c7 c7 90 91 87 8d 48 89
RSP: 0018:ffffc900051062f8 EFLAGS: 00000002
RAX: ffffffff95a895d8 RBX: 00000000000003cd RCX: 0000000000000146
RDX: 0000000000000008 RSI: 00000000000003cd RDI: ffff8880377ebb80
RBP: ffffffff929edc28 R08: ffffc900051062c0 R09: 0000000000000020
R10: dffffc0000000000 R11: ffffffff819c6430 R12: ffffffff95814218
R13: ffffffff959ac278 R14: ffff8880377ec808 R15: 0000000000000145
FS: 000055558db36500(0000) GS:ffff8881268c1000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000559cd4ad3948 CR3: 000000005106a000 CR4: 00000000003526f0
Call Trace:
__lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237
lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
_raw_spin_lock_nested+0x32/0x50 kernel/locking/spinlock.c:378
raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:636
raw_spin_rq_lock kernel/sched/sched.h:1519 [inline]
rq_lock kernel/sched/sched.h:1841 [inline]
ttwu_queue kernel/sched/core.c:4002 [inline]
try_to_wake_up+0x635/0x12b0 kernel/sched/core.c:4328
kick_pool+0x47d/0x640 kernel/workqueue.c:1283
__queue_work+0xd70/0x1010 kernel/workqueue.c:2340
mod_delayed_work_on+0xf8/0x200 kernel/workqueue.c:2595
kblockd_mod_delayed_work_on+0x29/0x40 block/blk-core.c:1115
mq_flush_data_end_io+0x35c/0x4e0 block/blk-flush.c:362
__blk_mq_end_request+0x530/0x740 block/blk-mq.c:1141
blk_complete_reqs block/blk-mq.c:1226 [inline]
blk_done_softirq+0x10a/0x160 block/blk-mq.c:1231
handle_softirqs+0x22f/0x710 kernel/softirq.c:579
__do_softirq kernel/softirq.c:613 [inline]
__local_bh_enable_ip+0x179/0x270 kernel/softirq.c:259
local_bh_enable include/linux/bottom_half.h:33 [inline]
spin_unlock_bh include/linux/spinlock_rt.h:111 [inline]
igmpv3_del_delrec+0x22d/0x730 net/ipv4/igmp.c:1240
____ip_mc_inc_group+0x993/0xdf0 net/ipv4/igmp.c:1561
__ip_mc_inc_group net/ipv4/igmp.c:1573 [inline]
ip_mc_inc_group net/ipv4/igmp.c:1579 [inline]
ip_mc_up+0x125/0x300 net/ipv4/igmp.c:1880
inetdev_event+0xfb3/0x15b0 net/ipv4/devinet.c:1631
notifier_call_chain+0x1b3/0x3e0 kernel/notifier.c:85
call_netdevice_notifiers_extack net/core/dev.c:2267 [inline]
call_netdevice_notifiers net/core/dev.c:2281 [inline]
__dev_notify_flags+0x18d/0x2e0 net/core/dev.c:-1
netif_change_flags+0xe8/0x1a0 net/core/dev.c:9617
do_setlink+0xc55/0x41c0 net/core/rtnetlink.c:3143
rtnl_changelink net/core/rtnetlink.c:3761 [inline]
__rtnl_newlink net/core/rtnetlink.c:3920 [inline]
rtnl_newlink+0x160b/0x1c70 net/core/rtnetlink.c:4057
rtnetlink_rcv_msg+0x7cc/0xb70 net/core/rtnetlink.c:6946
netlink_rcv_skb+0x205/0x470 net/netlink/af_netlink.c:2552
netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
netlink_unicast+0x843/0xa10 net/netlink/af_netlink.c:1346
netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1896
sock_sendmsg_nosec net/socket.c:714 [inline]
__sock_sendmsg+0x21c/0x270 net/socket.c:729
__sys_sendto+0x3c7/0x520 net/socket.c:2228
__do_sys_sendto net/socket.c:2235 [inline]
__se_sys_sendto net/socket.c:2231 [inline]
__x64_sys_sendto+0xde/0x100 net/socket.c:2231
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f3568960a7c
Code: 2a 5f 02 00 44 8b 4c 24 2c 4c 8b 44 24 20 89 c5 44 8b 54 24 28 48 8b 54 24 18 b8 2c 00 00 00 48 8b 74 24 10 8b 7c 24 08 0f 05 <48> 3d 00 f0 ff ff 77 34 89 ef 48 89 44 24 08 e8 70 5f 02 00 48 8b
RSP: 002b:00007ffedaaf2aa0 EFLAGS: 00000293 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f35696c4620 RCX: 00007f3568960a7c
RDX: 000000000000002c RSI: 00007f35696c4670 RDI: 0000000000000003
RBP: 0000000000000000 R08: 00007ffedaaf2af4 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000003
R13: 0000000000000000 R14: 00007f35696c4670 R15: 0000000000000000