INFO: task syz.4.99:6685 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.99 state:D stack:26416 pid:6685 tgid:6660 ppid:5836 task_flags:0x400040 flags:0x00004006
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
__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
__super_lock fs/super.c:59 [inline]
super_lock+0x2a9/0x3b0 fs/super.c:121
__iterate_supers+0x126/0x290 fs/super.c:923
ksys_sync+0x94/0x150 fs/sync.c:102
__ia32_sys_sync+0xe/0x20 fs/sync.c:113
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: 0033:0x7f63139eebe9
RSP: 002b:00007f6311c2d038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f6313c26090 RCX: 00007f63139eebe9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f6313c26090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f6313c26128 R14: 00007f6313c26090 R15: 00007ffcb3aad318
Showing all locks held in the system:
4 locks held by pr/legacy/17:
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/u8:4/67:
#0: ffff888019881138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline]
#0: ffff888019881138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319
#1: ffffc9000152fbc0 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline]
#1: ffffc9000152fbc0 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319
#2: ffffffff8ecd2938 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:303
7 locks held by kworker/u8:5/69:
2 locks held by kworker/u8:6/1165:
3 locks held by kworker/u8:7/1298:
#0: ffff88814d2c5138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline]
#0: ffff88814d2c5138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319
#1: ffffc90004ec7bc0 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline]
#1: ffffc90004ec7bc0 ((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 dhcpcd/5498:
#0: ffff88803aef2908 (nlk_cb_mutex-ROUTE){+.+.}-{4:4}, at: netlink_dump+0xbd/0xe90 net/netlink/af_netlink.c:2269
#1: ffffffff8ecd2938 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
#1: ffffffff8ecd2938 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_dumpit+0x92/0x200 net/core/rtnetlink.c:6814
2 locks held by getty/5595:
#0: ffff88823bf700a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc90003e832e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x444/0x1410 drivers/tty/n_tty.c:2222
3 locks held by syz-executor/5834:
1 lock held by syz.4.99/6685:
#0: ffff88805da5c0d0 (&type->s_umount_key#73){++++}-{4:4}, at: __super_lock fs/super.c:59 [inline]
#0: ffff88805da5c0d0 (&type->s_umount_key#73){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:121
1 lock held by syz-executor/7169:
#0: ffffffff8ecd2938 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:634 [inline]
#0: ffffffff8ecd2938 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x41/0x1c0 drivers/net/tun.c:3433
1 lock held by syz-executor/7182:
#0: ffffffff8ecd2938 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:634 [inline]
#0: ffffffff8ecd2938 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x41/0x1c0 drivers/net/tun.c:3433
2 locks held by syz-executor/7420:
#0: ffffffff8f1d7988 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8f1d7988 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
#0: ffffffff8f1d7988 (&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
2 locks held by syz-executor/7444:
#0: ffffffff8ecc5a20 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x304/0x4d0 net/core/net_namespace.c:566
#1: ffffffff8ecd2938 (rtnl_mutex){+.+.}-{4:4}, at: ip_tunnel_init_net+0x2ab/0x800 net/ipv4/ip_tunnel.c:1160
2 locks held by syz-executor/7451:
#0: ffffffff8ecc5a20 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x304/0x4d0 net/core/net_namespace.c:566
#1: ffffffff8ecd2938 (rtnl_mutex){+.+.}-{4:4}, at: ip_tunnel_init_net+0x2ab/0x800 net/ipv4/ip_tunnel.c:1160
2 locks held by syz-executor/7465:
#0: ffffffff8ecc5a20 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x304/0x4d0 net/core/net_namespace.c:566
#1: ffffffff8ecd2938 (rtnl_mutex){+.+.}-{4:4}, at: ip_tunnel_init_net+0x2ab/0x800 net/ipv4/ip_tunnel.c:1160
=============================================
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: 69 Comm: kworker/u8:5 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Workqueue: netns cleanup_net
RIP: 0010:kasan_check_range+0x5/0x2c0 mm/kasan/generic.c:188
Code: 21 8d e8 2e 2c 0a ff 90 0f 0b cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 66 0f 1f 00 55 <41> 57 41 56 41 55 41 54 53 b0 01 48 85 f6 0f 84 ba 01 00 00 4c 8d
RSP: 0018:ffffc9000154f250 EFLAGS: 00000246
RAX: 72bd546deb0bec00 RBX: 0000000000000010 RCX: ffffffff84bfd07b
RDX: 0000000000000001 RSI: 0000000000000010 RDI: ffffc9000154f290
RBP: 0000000000000000 R08: ffffffff8f1d5137 R09: 1ffffffff1e3aa26
R10: dffffc0000000000 R11: fffffbfff1e3aa27 R12: ffff88802df84510
R13: ffff88802df84400 R14: ffffc9000154f290 R15: ffff88802df84400
FS: 0000000000000000(0000) GS:ffff8881268c1000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f483da3c039 CR3: 0000000026b6e000 CR4: 00000000003526f0
Call Trace:
__asan_memset+0x22/0x50 mm/kasan/shadow.c:84
debug_object_active_state+0x3b/0x260 lib/debugobjects.c:1036
debug_rcu_head_queue kernel/rcu/rcu.h:237 [inline]
kvfree_call_rcu+0x67/0x410 mm/slab_common.c:1953
__ipv6_dev_mc_dec+0x2f5/0x330 net/ipv6/mcast.c:1012
ipv6_mc_destroy_dev+0x375/0x5c0 net/ipv6/mcast.c:2849
addrconf_ifdown+0x13e2/0x18c0 net/ipv6/addrconf.c:3996
addrconf_notify+0x1bc/0x1010 net/ipv6/addrconf.c:-1
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]
unregister_netdevice_many_notify+0x14d7/0x1fe0 net/core/dev.c:12166
unregister_netdevice_many net/core/dev.c:12229 [inline]
default_device_exit_batch+0x819/0x890 net/core/dev.c:12733
ops_exit_list net/core/net_namespace.c:204 [inline]
ops_undo_list+0x525/0x990 net/core/net_namespace.c:251
cleanup_net+0x4cb/0x800 net/core/net_namespace.c:682
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