INFO: task syz.0.810:9664[ 756.532185][ T38] INFO: task syz.0.810:9664 blocked for more than 144 seconds.
Tainted: G L syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.810 state:D stack:28008 pid:9664 tgid:9661 ppid:5615 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5402 [inline]
__schedule+0x16f9/0x5500 kernel/sched/core.c:7204
__schedule_loop kernel/sched/core.c:7283 [inline]
rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7579
rt_mutex_slowlock_block kernel/locking/rtmutex.c:1666 [inline]
__rt_mutex_slowlock kernel/locking/rtmutex.c:1743 [inline]
__rt_mutex_slowlock_locked+0x1f28/0x2550 kernel/locking/rtmutex.c:1783
__rwbase_read_lock+0xc3/0x180 kernel/locking/rwbase_rt.c:114
rwbase_read_lock kernel/locking/rwbase_rt.c:147 [inline]
__down_read kernel/locking/rwsem.c:1496 [inline]
down_read+0x132/0x200 kernel/locking/rwsem.c:1570
__super_lock fs/super.c:60 [inline]
super_lock+0x2d6/0x3d0 fs/super.c:122
__iterate_supers+0x126/0x250 fs/super.c:925
ksys_sync fs/sync.c:102 [inline]
__ia32_sys_sync+0xa0/0x120 fs/sync.c:111
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x15f/0x560 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc53d16ce59
RSP: 002b:00007fc53b3a5028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007fc53d3e6090 RCX: 00007fc53d16ce59
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007fc53d3e6090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc53d3e6128 R14: 00007fc53d3e6090 R15: 00007ffc3f476a98
Showing all locks held in the system:
1 lock held by khungtaskd/38:
#0: ffffffff8dfcaa00 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffffffff8dfcaa00 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#0: ffffffff8dfcaa00 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6777
3 locks held by kworker/u8:13/4304:
#0: ffff88813fe84138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x897/0x1630 kernel/workqueue.c:3293
#1: ffffc9000f2b7c40 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x8be/0x1630 kernel/workqueue.c:3294
#2: ffffffff8f37bd38 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:313
2 locks held by dhcpcd/5274:
#0: ffff88802b668928 (nlk_cb_mutex-ROUTE){+.+.}-{4:4}, at: netlink_dump+0xe2/0xe10 net/netlink/af_netlink.c:2268
#1: ffffffff8f37bd38 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
#1: ffffffff8f37bd38 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_dumpit+0x92/0x200 net/core/rtnetlink.c:6877
2 locks held by getty/5369:
#0: ffff888035e160a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc90003cbe2e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x462/0x13a0 drivers/tty/n_tty.c:2211
2 locks held by syz-executor/5616:
#0: ffff8880406b40d0 (&type->s_umount_key#93){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline]
#0: ffff8880406b40d0 (&type->s_umount_key#93){++++}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
#0: ffff8880406b40d0 (&type->s_umount_key#93){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:508
#1: ffff88806043c348 (&sbi->cp_global_sem_key){+.+.}-{4:4}, at: f2fs_down_write fs/f2fs/f2fs.h:2428 [inline]
#1: ffff88806043c348 (&sbi->cp_global_sem_key){+.+.}-{4:4}, at: f2fs_down_write_trace fs/f2fs/checkpoint.c:180 [inline]
#1: ffff88806043c348 (&sbi->cp_global_sem_key){+.+.}-{4:4}, at: f2fs_write_checkpoint+0x2ed/0x26a0 fs/f2fs/checkpoint.c:1861
5 locks held by kworker/u8:16/6979:
#0: ffff88801b68e138 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x897/0x1630 kernel/workqueue.c:3293
#1: ffffc900084dfc40 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x8be/0x1630 kernel/workqueue.c:3294
#2: ffffffff8f36c800 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf4/0x800 net/core/net_namespace.c:673
#3: ffffffff8f37bd38 (rtnl_mutex){+.+.}-{4:4}, at: default_device_exit_batch+0xe5/0x9e0 net/core/dev.c:13101
#4: ffffffff8dfcaa00 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#4: ffffffff8dfcaa00 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#4: ffffffff8dfcaa00 (rcu_read_lock){....}-{1:3}, at: class_rcu_constructor include/linux/rcupdate.h:1181 [inline]
#4: ffffffff8dfcaa00 (rcu_read_lock){....}-{1:3}, at: unwind_next_frame+0xa6/0x2550 arch/x86/kernel/unwind_orc.c:495
1 lock held by syz.0.810/9664:
#0: ffff8880406b40d0 (&type->s_umount_key#93){++++}-{4:4}, at: __super_lock fs/super.c:60 [inline]
#0: ffff8880406b40d0 (&type->s_umount_key#93){++++}-{4:4}, at: super_lock+0x2d6/0x3d0 fs/super.c:122
1 lock held by syz-executor/10336:
#0: ffffffff8f37bd38 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
#0: ffffffff8f37bd38 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline]
#0: ffffffff8f37bd38 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x883/0x1bb0 net/core/rtnetlink.c:4122
2 locks held by syz-executor/10348:
#0: ffffffff8eab6b28 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffffffff8eab6b28 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#0: ffffffff8eab6b28 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250 net/core/rtnetlink.c:570
#1: ffffffff8f37bd38 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
#1: ffffffff8f37bd38 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline]
#1: ffffffff8f37bd38 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x883/0x1bb0 net/core/rtnetlink.c:4122
1 lock held by syz-executor/10453:
#0: ffffffff8f37bd38 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
#0: ffffffff8f37bd38 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline]
#0: ffffffff8f37bd38 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x883/0x1bb0 net/core/rtnetlink.c:4122
2 locks held by syz-executor/10493:
#0: ffffffff8f8bc638 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffffffff8f8bc638 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#0: ffffffff8f8bc638 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250 net/core/rtnetlink.c:570
#1: ffffffff8f37bd38 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
#1: ffffffff8f37bd38 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline]
#1: ffffffff8f37bd38 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x883/0x1bb0 net/core/rtnetlink.c:4122
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 38 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT_{RT,(full)}
Tainted: [L]=SOFTLOCKUP
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+0x389/0x470 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: 17 Comm: pr/legacy Tainted: G L syzkaller #0 PREEMPT_{RT,(full)}
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:io_serial_in+0x77/0xc0 drivers/tty/serial/8250/8250_port.c:401
Code: e8 ce 73 85 fc 44 89 f9 d3 e3 49 83 ee 80 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 2f c2 ef fc 41 03 1e 89 da ec <0f> b6 c0 5b 41 5c 41 5e 41 5f e9 0a e3 ef 05 cc 44 89 f9 80 e1 07
RSP: 0018:ffffc900001679d0 EFLAGS: 00000202
RAX: 1ffffffff3373400 RBX: 00000000000003fd RCX: 0000000000000000
RDX: 00000000000003fd RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffffff99b9a370 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffffff853fe910 R12: dffffc0000000000
R13: 0000000000000000 R14: ffffffff99b9a0e0 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff888125ff4000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f39f67203d5 CR3: 0000000035e6a000 CR4: 00000000003526f0
Call Trace:
serial_in drivers/tty/serial/8250/8250.h:128 [inline]
serial_lsr_in drivers/tty/serial/8250/8250.h:150 [inline]
wait_for_lsr+0x1aa/0x2f0 drivers/tty/serial/8250/8250_port.c:1972
serial8250_fifo_wait_for_lsr_thre drivers/tty/serial/8250/8250_port.c:3209 [inline]
serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3274 [inline]
serial8250_console_write+0x11c9/0x1b90 drivers/tty/serial/8250/8250_port.c:3359
console_emit_next_record kernel/printk/printk.c:3163 [inline]
console_flush_one_record+0x68b/0xb90 kernel/printk/printk.c:3269
legacy_kthread_func+0x1b6/0x250 kernel/printk/printk.c:3712
kthread+0x389/0x470 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