INFO: task syz.2.261:7418 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.261 state:D stack:29192 pid:7418 tgid:7408 ppid:5806 task_flags:0x400040 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5325 [inline]
__schedule+0x16f3/0x4c20 kernel/sched/core.c:6929
__schedule_loop kernel/sched/core.c:7011 [inline]
rt_mutex_schedule+0x77/0xf0 kernel/sched/core.c:7307
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
__rwbase_read_lock+0xbc/0x180 kernel/locking/rwbase_rt.c:114
rwbase_read_lock kernel/locking/rwbase_rt.c:147 [inline]
__down_read kernel/locking/rwsem.c:1466 [inline]
down_read+0x127/0x1f0 kernel/locking/rwsem.c:1539
inode_lock_shared include/linux/fs.h:994 [inline]
lookup_slow+0x46/0x70 fs/namei.c:1832
walk_component+0x2d2/0x400 fs/namei.c:2151
lookup_last fs/namei.c:2652 [inline]
path_lookupat+0x163/0x430 fs/namei.c:2676
filename_lookup+0x212/0x570 fs/namei.c:2705
user_path_at+0x3a/0x60 fs/namei.c:3215
do_mount fs/namespace.c:4047 [inline]
__do_sys_mount fs/namespace.c:4238 [inline]
__se_sys_mount+0x2d4/0x410 fs/namespace.c:4215
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: 0033:0x7f17e290eec9
RSP: 002b:00007f17e0b4d038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f17e2b66090 RCX: 00007f17e290eec9
RDX: 0000200000000240 RSI: 0000200000000000 RDI: 0000200000000040
RBP: 00007f17e2991f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000208004 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f17e2b66128 R14: 00007f17e2b66090 R15: 00007ffedd1eb388
Showing all locks held in the system:
1 lock held by khungtaskd/38:
#0: ffffffff8d3aa300 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8d3aa300 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
#0: ffffffff8d3aa300 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
3 locks held by kworker/1:1/44:
#0: ffff88813ff19138 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3238 [inline]
#0: ffff88813ff19138 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3346
#1: ffffc90000b57bc0 (deferred_process_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3239 [inline]
#1: ffffc90000b57bc0 (deferred_process_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3346
#2: ffffffff8e65f378 (rtnl_mutex){+.+.}-{4:4}, at: switchdev_deferred_process_work+0xe/0x20 net/switchdev/switchdev.c:104
4 locks held by kworker/u8:8/1317:
#0: ffff8881404cb138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3238 [inline]
#0: ffff8881404cb138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3346
#1: ffffc9000568fbc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3239 [inline]
#1: ffffc9000568fbc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3346
#2: ffff8880296920d0 (&type->s_umount_key#61){++++}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:562
#3: ffff88805e5e9f28 (&jfs_ip->commit_mutex){+.+.}-{4:4}, at: jfs_commit_inode+0x1ca/0x530 fs/jfs/inode.c:102
4 locks held by kworker/u8:12/3590:
3 locks held by kworker/u8:13/4531:
#0: ffff88813ff29938 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3238 [inline]
#0: ffff88813ff29938 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3346
#1: ffffc9000fda7bc0 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3239 [inline]
#1: ffffc9000fda7bc0 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3346
#2: ffffffff8e65f378 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:303
2 locks held by dhcpcd/5473:
#0: ffff88803a2f2918 (nlk_cb_mutex-ROUTE){+.+.}-{4:4}, at: netlink_dump+0xbd/0xe90 net/netlink/af_netlink.c:2269
#1: ffffffff8e65f378 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
#1: ffffffff8e65f378 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_dumpit+0x92/0x200 net/core/rtnetlink.c:6822
2 locks held by getty/5568:
#0: ffff88823bf288a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc90003e8b2e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x444/0x1400 drivers/tty/n_tty.c:2222
1 lock held by syz-executor/5807:
5 locks held by syz.2.261/7409:
1 lock held by syz.2.261/7418:
#0: ffff88805e5ea2f8 (&type->i_mutex_dir_key#13){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:994 [inline]
#0: ffff88805e5ea2f8 (&type->i_mutex_dir_key#13){++++}-{4:4}, at: lookup_slow+0x46/0x70 fs/namei.c:1832
1 lock held by syz-executor/8505:
#0: ffffffff8e65f378 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
#0: ffffffff8e65f378 (rtnl_mutex){+.+.}-{4:4}, at: inet6_rtm_newaddr+0x5b7/0xd20 net/ipv6/addrconf.c:5027
7 locks held by syz-executor/8663:
#0: ffff8880340d0480 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:3105 [inline]
#0: ffff8880340d0480 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x217/0xb40 fs/read_write.c:682
#1: ffff88805f13a878 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1df/0x540 fs/kernfs/file.c:343
#2: ffff8881433b9e18 (kn->active#53){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#2: ffff8881433b9e18 (kn->active#53){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x232/0x540 fs/kernfs/file.c:344
#3: ffffffff8ded85d8 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: new_device_store+0x12c/0x6f0 drivers/net/netdevsim/bus.c:184
#4: ffff888034c4e0d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline]
#4: ffff888034c4e0d8 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x400 drivers/base/dd.c:1006
#5: ffff888026ac2300 (&devlink->lock_key#13){+.+.}-{4:4}, at: nsim_drv_probe+0xc2/0xba0 drivers/net/netdevsim/dev.c:1582
#6: ffffffff8e65f378 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
#6: ffffffff8e65f378 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_dev_lock+0x257/0x2f0 net/core/dev.c:2142
2 locks held by syz-executor/8898:
#0: ffffffff8ddd1b20 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8ddd1b20 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
#0: ffffffff8ddd1b20 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250 net/core/rtnetlink.c:570
#1: ffffffff8e65f378 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
#1: ffffffff8e65f378 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline]
#1: ffffffff8e65f378 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8e9/0x1c80 net/core/rtnetlink.c:4064
1 lock held by syz-executor/8921:
#0: ffffffff8e65f378 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
#0: ffffffff8e65f378 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x3b0/0x18b0 net/ipv4/devinet.c:978
=============================================
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 08/18/2025
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:332 [inline]
watchdog+0xf60/0xfa0 kernel/hung_task.c:495
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x436/0x7d0 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: 3590 Comm: kworker/u8:12 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Workqueue: netns cleanup_net
RIP: 0010:remove_class_from_lock_chain kernel/locking/lockdep.c:6197 [inline]
RIP: 0010:remove_class_from_lock_chains kernel/locking/lockdep.c:6236 [inline]
RIP: 0010:zap_class+0xc2/0x360 kernel/locking/lockdep.c:6281
Code: 49 81 fc 00 00 08 00 0f 84 a5 01 00 00 4e 8b 2c e5 40 f3 41 92 4d 85 ed 0f 94 c0 49 83 c5 f8 0f 94 c1 08 c1 75 d7 45 8b 7d 00 <41> f6 c7 fc 0f 84 e2 00 00 00 41 c1 ef 08 4e 8d 34 7d 10 f3 86 91
RSP: 0018:ffffc9000e4c7658 EFLAGS: 00000046
RAX: 0000000000012100 RBX: 000000000000107f RCX: 0000000000012100
RDX: ffffffff9283f368 RSI: ffffffff9283f368 RDI: ffffffff9233d658
RBP: ffffffff9285f7b0 R08: 0000000000000000 R09: ffffffff81a7ef08
R10: dffffc0000000000 R11: fffffbfff1d6a987 R12: 00000000000046f7
R13: ffffffff92bafc90 R14: ffffffff918935ae R15: 000000000848e10c
FS: 0000000000000000(0000) GS:ffff88812703b000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055556bb69608 CR3: 000000003b652000 CR4: 00000000003526f0
Call Trace:
__lockdep_free_key_range kernel/locking/lockdep.c:6407 [inline]
lockdep_unregister_key+0x1a6/0x310 kernel/locking/lockdep.c:6609
__qdisc_destroy+0x166/0x420 net/sched/sch_generic.c:1083
qdisc_put net/sched/sch_generic.c:1109 [inline]
dev_shutdown+0x34c/0x440 net/sched/sch_generic.c:1497
unregister_netdevice_many_notify+0xe0f/0x1fe0 net/core/dev.c:12242
ops_exit_rtnl_list net/core/net_namespace.c:187 [inline]
ops_undo_list+0x3dc/0x990 net/core/net_namespace.c:248
cleanup_net+0x4de/0x820 net/core/net_namespace.c:695
process_one_work kernel/workqueue.c:3263 [inline]
process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346
worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x436/0x7d0 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245