INFO: task syz.4.5618:27393 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.4.5618      state:D stack:27784 pid:27393 tgid:27391 ppid:21754  task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5526 [inline]
 __schedule+0x16d9/0x5700 kernel/sched/core.c:7276
 __schedule_loop kernel/sched/core.c:7353 [inline]
 schedule+0x164/0x2b0 kernel/sched/core.c:7368
 cgroup_lock_and_drain_offline+0x51a/0x650 kernel/cgroup/cgroup.c:3350
 cgroup_kn_lock_live+0x120/0x230 kernel/cgroup/cgroup.c:1717
 cgroup_subtree_control_write+0x4b5/0x1080 kernel/cgroup/cgroup.c:3652
 cgroup_file_write+0x331/0x8f0 kernel/cgroup/cgroup.c:4412
 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+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f716f0ae159
RSP: 002b:00007f716d306028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f716f335fa0 RCX: 00007f716f0ae159
RDX: 0000000000000005 RSI: 0000200000000040 RDI: 0000000000000005
RBP: 00007f716f14503b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f716f336038 R14: 00007f716f335fa0 R15: 00007ffe1a0d0228
 </TASK>

Showing all locks held in the system:
locks held by khungtaskd/39: 1, last CPU#0:
 #0: ffffffff8e1c3c40 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #0: ffffffff8e1c3c40 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffffffff8e1c3c40 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6871
locks held by getty/17842: 2, on CPU#1:
 #0: ffff888028a880a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc900043982e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x460/0x1360 drivers/tty/n_tty.c:2211
locks held by syz.9.4897/25122: 3, on CPU#1:
 #0: ffff888033ef0b28 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259
 #1: ffff88803479c510 (sb_writers#23){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2753 [inline]
 #1: ffff88803479c510 (sb_writers#23){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683
 #2: ffffffff8e4f8398 (nfsd_mutex){+.+.}-{4:4}, at: write_threads+0x3b4/0x610 fs/nfsd/nfsctl.c:436
locks held by syz.4.5618/27393: 3, on CPU#1:
 #0: ffff888037f48528 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259
 #1: ffff888036bbe510 (sb_writers#9){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2753 [inline]
 #1: ffff888036bbe510 (sb_writers#9){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683
 #2: ffff88803ba5d478 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1d9/0x540 fs/kernfs/file.c:336

=============================================

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 07/24/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:123
 nmi_trigger_cpumask_backtrace+0x17d/0x390 lib/nmi_backtrace.c:66
 trigger_all_cpu_backtrace include/linux/nmi.h:164 [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+0x38b/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
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Tainted: G             L      syzkaller #0 PREEMPT_{RT,(full)} 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:64
Code: bc 61 02 e9 93 d8 03 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 33 dc 12 00 fb f4 <c3> cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90
RSP: 0018:ffffc900001d7e40 EFLAGS: 00000246
RAX: 0000000000a9fd55 RBX: ffffffff819a8000 RCX: 8000000000000001
RDX: 0000000000000001 RSI: ffffffff8d8cb770 RDI: ffffffff8bcc2a80
RBP: ffffc900001d7f10 R08: ffff8880b8733e9b R09: 1ffff110170e67d3
R10: dffffc0000000000 R11: ffffed10170e67d4 R12: 0000000000000000
R13: 1ffff110039dc000 R14: 1ffff9200003afd0 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff888125cce000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000564dd1d0e660 CR3: 000000000dfb0000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 arch_safe_halt arch/x86/kernel/process.c:767 [inline]
 default_idle+0x9/0x20 arch/x86/kernel/process.c:768
 default_idle_call+0x72/0xb0 kernel/sched/idle.c:122
 cpuidle_idle_call kernel/sched/idle.c:199 [inline]
 do_idle+0x2e0/0x540 kernel/sched/idle.c:355
 cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:454
 start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:312
 common_startup_64+0x13e/0x157
 </TASK>