INFO: task kworker/u8:5:126 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:5 state:D stack:20576 pid:126 tgid:126 ppid:2 task_flags:0x4208060 flags:0x00080000
Workqueue: writeback wb_workfn (flush-7:6)
Call Trace:
context_switch kernel/sched/core.c:5387 [inline]
__schedule+0x1681/0x54c0 kernel/sched/core.c:7188
__schedule_loop kernel/sched/core.c:7267 [inline]
rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7563
rt_mutex_slowlock_block kernel/locking/rtmutex.c:1662 [inline]
__rt_mutex_slowlock kernel/locking/rtmutex.c:1739 [inline]
__rt_mutex_slowlock_locked+0x1f28/0x2550 kernel/locking/rtmutex.c:1779
rt_mutex_slowlock+0xbd/0x170 kernel/locking/rtmutex.c:1819
__rt_mutex_lock kernel/locking/rtmutex.c:1834 [inline]
rwbase_write_lock+0x14d/0x730 kernel/locking/rwbase_rt.c:245
f2fs_down_write fs/f2fs/f2fs.h:2411 [inline]
f2fs_down_write_trace fs/f2fs/checkpoint.c:180 [inline]
f2fs_issue_checkpoint+0x437/0x790 fs/f2fs/checkpoint.c:2095
f2fs_balance_fs_bg+0x574/0x9d0 fs/f2fs/segment.c:545
f2fs_write_node_pages+0x158/0x700 fs/f2fs/node.c:2257
do_writepages+0x32e/0x550 mm/page-writeback.c:2571
__writeback_single_inode+0x133/0x10e0 fs/fs-writeback.c:1764
writeback_sb_inodes+0x97f/0x1980 fs/fs-writeback.c:2056
__writeback_inodes_wb+0x111/0x240 fs/fs-writeback.c:2132
wb_writeback+0x459/0xb00 fs/fs-writeback.c:2243
wb_check_old_data_flush fs/fs-writeback.c:2347 [inline]
wb_do_writeback fs/fs-writeback.c:2400 [inline]
wb_workfn+0xb17/0xf20 fs/fs-writeback.c:2428
process_one_work kernel/workqueue.c:3302 [inline]
process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3385
worker_thread+0xa53/0xfc0 kernel/workqueue.c:3466
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 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/38:
#0: ffffffff8dfc8140 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffffffff8dfc8140 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#0: ffffffff8dfc8140 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
4 locks held by kworker/u8:5/126:
#0: ffff88801f6ff938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3277 [inline]
#0: ffff88801f6ff938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3385
#1: ffffc900037efc40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3278 [inline]
#1: ffffc900037efc40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3385
#2: ffff888036a420d0 (&type->s_umount_key#107){++++}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:565
#3: ffff88805c3f1a98 (&sbi->gc_lock){+.+.}-{4:4}, at: f2fs_down_write fs/f2fs/f2fs.h:2411 [inline]
#3: ffff88805c3f1a98 (&sbi->gc_lock){+.+.}-{4:4}, at: f2fs_down_write_trace fs/f2fs/checkpoint.c:180 [inline]
#3: ffff88805c3f1a98 (&sbi->gc_lock){+.+.}-{4:4}, at: f2fs_issue_checkpoint+0x437/0x790 fs/f2fs/checkpoint.c:2095
4 locks held by kworker/u8:6/144:
7 locks held by kworker/u8:14/1358:
4 locks held by kworker/u8:17/3332:
#0: ffff88801b290938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3277 [inline]
#0: ffff88801b290938 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3385
#1: ffffc9000e407c40 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3278 [inline]
#1: ffffc9000e407c40 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3385
#2: ffffffff8f347da0 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf4/0x800 net/core/net_namespace.c:673
#3: ffffffff8f356af8 (rtnl_mutex){+.+.}-{4:4}, at: default_device_exit_batch+0xe5/0xa00 net/core/dev.c:13059
3 locks held by kworker/u8:18/3366:
#0: ffff888031cef938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3277 [inline]
#0: ffff888031cef938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3385
#1: ffffc9000e147c40 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3278 [inline]
#1: ffffc9000e147c40 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3385
#2: ffffffff8f356af8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
#2: ffffffff8f356af8 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_dad_work+0x124/0x1680 net/ipv6/addrconf.c:4206
2 locks held by dhcpcd/5262:
#0: ffff888060b60928 (nlk_cb_mutex-ROUTE){+.+.}-{4:4}, at: netlink_dump+0xe2/0xe10 net/netlink/af_netlink.c:2267
#1: ffffffff8f356af8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
#1: ffffffff8f356af8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_dumpit+0x92/0x200 net/core/rtnetlink.c:6863
2 locks held by getty/5356:
#0: ffff888031f390a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc90003cb62e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x462/0x13a0 drivers/tty/n_tty.c:2211
6 locks held by syz.6.267/8034:
1 lock held by syz-executor/9197:
#0: ffffffff8f356af8 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:634 [inline]
#0: ffffffff8f356af8 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x41/0x1c0 drivers/net/tun.c:3438
7 locks held by syz-executor/9333:
#0: ffff888037668480 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2724 [inline]
#0: ffff888037668480 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x22d/0xba0 fs/read_write.c:684
#1: ffff888061dda078 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1df/0x540 fs/kernfs/file.c:343
#2: ffff8880299f34b8 (kn->active#53){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#2: ffff8880299f34b8 (kn->active#53){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x232/0x540 fs/kernfs/file.c:344
#3: ffffffff8ebcf0b8 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: new_device_store+0x13c/0x710 drivers/net/netdevsim/bus.c:184
#4: ffff88803f6e3160 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1040 [inline]
#4: ffff88803f6e3160 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x450 drivers/base/dd.c:1076
#5: ffff888034bf6310 (&devlink->lock_key#33){+.+.}-{4:4}, at: nsim_drv_probe+0xc9/0xc30 drivers/net/netdevsim/dev.c:1658
#6: ffffffff8f356af8 (rtnl_mutex){+.+.}-{4:4}, at: nsim_init_netdevsim drivers/net/netdevsim/netdev.c:1057 [inline]
#6: ffffffff8f356af8 (rtnl_mutex){+.+.}-{4:4}, at: nsim_create+0x894/0x1170 drivers/net/netdevsim/netdev.c:1151
4 locks held by syz-executor/9379:
#0: ffff888037668480 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2724 [inline]
#0: ffff888037668480 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x22d/0xba0 fs/read_write.c:684
#1: ffff88803cf59878 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1df/0x540 fs/kernfs/file.c:343
#2: ffff8880299f34b8 (kn->active#53){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#2: ffff8880299f34b8 (kn->active#53){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x232/0x540 fs/kernfs/file.c:344
#3: ffffffff8ebcf0b8 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: new_device_store+0x13c/0x710 drivers/net/netdevsim/bus.c:184
4 locks held by syz-executor/9462:
#0: ffff888037668480 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2724 [inline]
#0: ffff888037668480 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x22d/0xba0 fs/read_write.c:684
#1: ffff88803952c878 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1df/0x540 fs/kernfs/file.c:343
#2: ffff8880299f33c8 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#2: ffff8880299f33c8 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x232/0x540 fs/kernfs/file.c:344
#3: ffffffff8ebcf0b8 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd7/0x370 drivers/net/netdevsim/bus.c:234
2 locks held by syz-executor/9554:
#0: ffffffff8f347da0 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x4f7/0x730 net/core/net_namespace.c:575
#1: ffffffff8f356af8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock_killable include/linux/rtnetlink.h:145 [inline]
#1: ffffffff8f356af8 (rtnl_mutex){+.+.}-{4:4}, at: register_netdev+0x18/0x60 net/core/dev.c:11533
2 locks held by udevd/9556:
1 lock held by syz-executor/9567:
#0: ffffffff8f356af8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
#0: ffffffff8f356af8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline]
#0: ffffffff8f356af8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x883/0x1bb0 net/core/rtnetlink.c:4108
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 38 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
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:162 [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:353 [inline]
watchdog+0xfd3/0x1030 kernel/hung_task.c:561
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 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: 1358 Comm: kworker/u8:14 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Workqueue: events_unbound nsim_dev_trap_report_work
RIP: 0010:match_held_lock+0x7b/0xb0 kernel/locking/lockdep.c:5337
Code: c7 c2 30 23 13 93 48 29 d0 48 c1 f8 03 48 ba 29 5c 8f c2 f5 28 5c 8f 48 0f af d0 bb 01 00 00 00 48 39 ca 74 02 31 db 89 d8 5b <41> 5e e9 fe be 03 00 cc 90 e8 47 85 81 f9 85 c0 74 1c 83 3d a0 8a
RSP: 0018:ffffc90006917440 EFLAGS: 00000046
RAX: 0000000000000001 RBX: 0000000000000019 RCX: 0000000000000046
RDX: ffffc90006917501 RSI: ffffffff8dfc8140 RDI: ffff88802a1b6900
RBP: ffff88802a1b6900 R08: ffffc90006917f38 R09: 0000000000000000
R10: ffffc900069175d8 R11: fffff52000d22ebd R12: 0000000000000005
R13: 0000000000000005 R14: ffffffff8dfc8140 R15: ffff88802a1b5c40
FS: 0000000000000000(0000) GS:ffff888126279000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffc7b271fe8 CR3: 000000006baf2000 CR4: 00000000003526f0
Call Trace:
find_held_lock kernel/locking/lockdep.c:5350 [inline]
__lock_release kernel/locking/lockdep.c:5535 [inline]
lock_release+0x10c/0x3c0 kernel/locking/lockdep.c:5889
rcu_lock_release include/linux/rcupdate.h:310 [inline]
rcu_read_unlock include/linux/rcupdate.h:869 [inline]
class_rcu_destructor include/linux/rcupdate.h:1181 [inline]
unwind_next_frame+0x1bba/0x2550 arch/x86/kernel/unwind_orc.c:709
arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:57 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
__kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415
kasan_kmalloc include/linux/kasan.h:263 [inline]
__do_kmalloc_node mm/slub.c:5295 [inline]
__kmalloc_node_track_caller_noprof+0x372/0x7e0 mm/slub.c:5403
kmalloc_reserve net/core/skbuff.c:635 [inline]
__alloc_skb+0x2c1/0x7d0 net/core/skbuff.c:713
alloc_skb include/linux/skbuff.h:1383 [inline]
nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:819 [inline]
nsim_dev_trap_report drivers/net/netdevsim/dev.c:876 [inline]
nsim_dev_trap_report_work+0x29f/0xbd0 drivers/net/netdevsim/dev.c:922
process_one_work kernel/workqueue.c:3302 [inline]
process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3385
worker_thread+0xa53/0xfc0 kernel/workqueue.c:3466
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245