INFO: task syz.3.3285:19436 blocked for more than 143 seconds.
Tainted: G L syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.3285 state:D stack:28240 pid:19436 tgid:19434 ppid:15551 task_flags:0x400040 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x1709/0x5530 kernel/sched/core.c:7231
__schedule_loop kernel/sched/core.c:7308 [inline]
schedule+0x164/0x2b0 kernel/sched/core.c:7323
cgroup_lock_and_drain_offline+0x51a/0x650 kernel/cgroup/cgroup.c:3275
cgroup_kn_lock_live+0x120/0x230 kernel/cgroup/cgroup.c:1715
cgroup_subtree_control_write+0x4b5/0x1080 kernel/cgroup/cgroup.c:3577
cgroup_file_write+0x331/0x8f0 kernel/cgroup/cgroup.c:4316
kernfs_fop_write_iter+0x3a5/0x540 fs/kernfs/file.c:345
new_sync_write fs/read_write.c:595 [inline]
vfs_write+0x61e/0xbb0 fs/read_write.c:687
ksys_write+0x156/0x270 fs/read_write.c:739
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x17b/0x530 arch/x86/entry/syscall_64.c:85
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f9e13fcde99
RSP: 002b:00007f9e12205028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f9e14256090 RCX: 00007f9e13fcde99
RDX: 0000000000000005 RSI: 0000200000000040 RDI: 0000000000000006
RBP: 00007f9e14063eaf R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9e14256128 R14: 00007f9e14256090 R15: 00007ffea547a2c8
Showing all locks held in the system:
locks held by khungtaskd/39: 1, last CPU#0:
#0: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#0: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6835
locks held by getty/5345: 2, on CPU#1:
#0: ffff888029cde0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc900044cb2e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x460/0x1360 drivers/tty/n_tty.c:2211
locks held by kworker/u8:13/5904: 2, on CPU#0:
#0: ffff88801aea4138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffff88801aea4138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#0: ffff88801aea4138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x7fd/0x1480 kernel/workqueue.c:3344
#1: ffffc9000606fc60 (connector_reaper_work){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#1: ffffc9000606fc60 (connector_reaper_work){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#1: ffffc9000606fc60 (connector_reaper_work){+.+.}-{0:0}, at: process_one_work+0x7fd/0x1480 kernel/workqueue.c:3344
locks held by kworker/u8:57/9594: 5, last CPU#0:
#0: ffff88801bee0938 ((wq_completion)netns){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffff88801bee0938 ((wq_completion)netns){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#0: ffff88801bee0938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x7fd/0x1480 kernel/workqueue.c:3344
#1: ffffc90010fffc60 (net_cleanup_work){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#1: ffffc90010fffc60 (net_cleanup_work){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#1: ffffc90010fffc60 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x7fd/0x1480 kernel/workqueue.c:3344
#2: ffffffff8f7b5760 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf5/0x810 net/core/net_namespace.c:677
#3: ffffffff8f7c4a78 (rtnl_mutex){+.+.}-{4:4}, at: default_device_exit_batch+0xe5/0x9a0 net/core/dev.c:13225
#4: ffff88805f274e80 (&net->mpls.platform_mutex){+.+.}-{4:4}, at: mpls_dev_notify+0x82/0xd30 net/mpls/af_mpls.c:1644
locks held by kworker/u8:64/11720: 3, on CPU#0:
#0: ffff88803285e138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffff88803285e138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#0: ffff88803285e138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x7fd/0x1480 kernel/workqueue.c:3344
#1: ffffc9001b5afc60 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#1: ffffc9001b5afc60 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#1: ffffc9001b5afc60 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7fd/0x1480 kernel/workqueue.c:3344
#2: ffffffff8f7c4a78 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:134 [inline]
#2: ffffffff8f7c4a78 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_dad_work+0x123/0x16e0 net/ipv6/addrconf.c:4229
locks held by kworker/0:4/13428: 3, on CPU#0:
#0: ffff88813fe63938 ((wq_completion)events){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffff88813fe63938 ((wq_completion)events){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#0: ffff88813fe63938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7fd/0x1480 kernel/workqueue.c:3344
#1: ffffc90005df7c60 (netdev_work){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#1: ffffc90005df7c60 (netdev_work){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#1: ffffc90005df7c60 (netdev_work){+.+.}-{0:0}, at: process_one_work+0x7fd/0x1480 kernel/workqueue.c:3344
#2: ffffffff8f7c4a78 (rtnl_mutex){+.+.}-{4:4}, at: netdev_work_proc+0x72/0x7f0 net/core/netdev_work.c:116
locks held by syz.3.3285/19436: 3, on CPU#0:
#0: ffff88802592c328 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259
#1: ffff88803a288510 (sb_writers#9){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2731 [inline]
#1: ffff88803a288510 (sb_writers#9){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683
#2: ffff88803c867878 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1d9/0x540 fs/kernfs/file.c:336
locks held by udevd/20388: 1, last CPU#0:
#0: ffffffff8eb36f78 (tomoyo_ss){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:187 [inline]
#0: ffffffff8eb36f78 (tomoyo_ss){.+.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:294 [inline]
#0: ffffffff8eb36f78 (tomoyo_ss){.+.+}-{0:0}, at: tomoyo_read_lock security/tomoyo/common.h:1112 [inline]
#0: ffffffff8eb36f78 (tomoyo_ss){.+.+}-{0:0}, at: tomoyo_path_number_perm+0x219/0x5f0 security/tomoyo/file.c:727
locks held by syz-executor/20391: 1, on CPU#0:
#0: ffffffff8f7c4a78 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:134 [inline]
#0: ffffffff8f7c4a78 (rtnl_mutex){+.+.}-{4:4}, at: inet6_rtm_newaddr+0x667/0xe00 net/ipv6/addrconf.c:5062
locks held by syz-executor/20626: 1, on CPU#0:
#0: ffffffff8f7c4a78 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
#0: ffffffff8f7c4a78 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:366 [inline]
#0: ffffffff8f7c4a78 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0xc10/0x1c30 net/core/rtnetlink.c:4194
locks held by syz-executor/20686: 2, on CPU#0:
#0: ffffffff8f7b5760 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x4e2/0x720 net/core/net_namespace.c:579
#1: ffffffff8f7c4a78 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock_killable include/linux/rtnetlink.h:149 [inline]
#1: ffffffff8f7c4a78 (rtnl_mutex){+.+.}-{4:4}, at: register_netdev+0x18/0x60 net/core/dev.c:11565
locks held by dhcpcd-run-hook/20738: 2, last CPU#0:
#0: ffff88802bfa62b0 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock include/linux/mmap_lock.h:544 [inline]
#0: ffff88802bfa62b0 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x2d8/0x9f0 mm/mmap.c:1308
#1: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#1: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#1: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: class_rcu_constructor include/linux/rcupdate.h:1183 [inline]
#1: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: unwind_next_frame+0x8f/0x2550 arch/x86/kernel/unwind_orc.c:495
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 39 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT_{RT,(full)}
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
Call Trace:
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:122
nmi_trigger_cpumask_backtrace+0x17a/0x380 lib/nmi_backtrace.c:65
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+0xfd7/0x1030 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