syzbot

INFO: task syz-executor400:4977 blocked for more than 143 seconds.
      Not tainted 6.1.136-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor400 state:D stack:27368 pid:4977  ppid:4263   flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x10e9/0x40d0 kernel/sched/core.c:6561
 schedule+0xb9/0x180 kernel/sched/core.c:6637
 perf_pending_task_sync kernel/events/core.c:5033 [inline]
 _free_event+0x171/0x10a0 kernel/events/core.c:5039
 put_event kernel/events/core.c:5164 [inline]
 perf_event_release_kernel+0x832/0x8c0 kernel/events/core.c:5289
 perf_release+0x37/0x40 kernel/events/core.c:5299
 __fput+0x22c/0x920 fs/file_table.c:320
 task_work_run+0x1ca/0x250 kernel/task_work.c:203
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177
 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:87
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f970c8d9ab9
RSP: 002b:00007ffca0cd6858 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007f970c8d9ab9
RDX: 00007f970c8d9ab9 RSI: ffffffffffffffff RDI: 0000000000000003
RBP: 000000000001f296 R08: 0000000000000006 R09: 0000000000000006
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffca0cd686c
R13: 431bde82d7b634db R14: 0000000000000001 R15: 0000000000000001
 </TASK>

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
 #0: ffffffff8c92b2f0 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
 #0: ffffffff8c92bb10 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517
1 lock held by khungtaskd/28:
 #0: ffffffff8c92a960 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 #0: ffffffff8c92a960 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
 #0: ffffffff8c92a960 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6513
2 locks held by getty/4010:
 #0: ffff88814d101098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
 #1: ffffc9000325e2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x41b/0x1380 drivers/tty/n_tty.c:2198

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

NMI backtrace for cpu 1
CPU: 1 PID: 28 Comm: khungtaskd Not tainted 6.1.136-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3f4/0x470 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x1d4/0x450 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline]
 watchdog+0xeee/0xf30 kernel/hung_task.c:377
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 11 Comm: kworker/u4:1 Not tainted 6.1.136-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:__insn_get_emulate_prefix arch/x86/lib/insn.c:91 [inline]
RIP: 0010:insn_get_emulate_prefix arch/x86/lib/insn.c:106 [inline]
RIP: 0010:insn_get_prefixes+0xe5/0x16d0 arch/x86/lib/insn.c:134
Code: 8b 3b 4d 39 fc 4c 89 74 24 18 48 89 5c 24 28 0f 87 67 0e 00 00 4c 89 eb 48 c1 eb 03 48 b8 00 00 00 00 00 fc ff df 0f b6 04 03 <84> c0 0f 85 61 11 00 00 41 0f b6 75 00 83 fe 0f 41 0f 94 c6 bf 0f
RSP: 0018:ffffc90000107630 EFLAGS: 00000a06
RAX: 0000000000000000 RBX: 1ffffffff03a2bf0 RCX: 1ffff92000020f38
RDX: ffff88813fe83b80 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: dffffc0000000000 R09: ffffc90000107960
R10: fffff52000020f37 R11: 1ffff92000020f2c R12: ffffffff81d15f83
R13: ffffffff81d15f82 R14: ffffc900001079c8 R15: ffffffff81d15f91
FS:  0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000562f38d7d600 CR3: 000000000c68e000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 insn_get_opcode+0x1bc/0xa30 arch/x86/lib/insn.c:272
 insn_get_modrm+0x229/0x7a0 arch/x86/lib/insn.c:343
 insn_get_sib arch/x86/lib/insn.c:421 [inline]
 insn_get_displacement+0x156/0xa20 arch/x86/lib/insn.c:464
 insn_get_immediate+0x325/0x1290 arch/x86/lib/insn.c:632
 insn_get_length arch/x86/lib/insn.c:707 [inline]
 insn_decode+0x386/0x520 arch/x86/lib/insn.c:747
 arch_jump_entry_size arch/x86/kernel/jump_label.c:24 [inline]
 __jump_label_patch+0xd8/0x430 arch/x86/kernel/jump_label.c:45
 arch_jump_label_transform_queue+0x48/0xd0 arch/x86/kernel/jump_label.c:137
 __jump_label_update+0x17d/0x390 kernel/jump_label.c:510
 static_key_disable_cpuslocked+0xc1/0x1a0 kernel/jump_label.c:237
 static_key_disable+0x16/0x20 kernel/jump_label.c:245
 toggle_allocation_gate+0x38f/0x430 mm/kfence/core.c:819
 process_one_work+0x898/0x1160 kernel/workqueue.c:2292
 worker_thread+0xaa2/0x1250 kernel/workqueue.c:2439
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>