syzbot

INFO: task syz-executor798:4248 blocked for more than 143 seconds.
      Not tainted 6.1.141-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor798 state:D stack:24352 pid:4248  ppid:4247   flags:0x00004002
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
 io_schedule+0x7c/0xd0 kernel/sched/core.c:8797
 folio_wait_bit_common+0x6e1/0xf60 mm/filemap.c:1324
 truncate_inode_pages_range+0x9a2/0xff0 mm/truncate.c:422
 evict+0x498/0x870 fs/inode.c:707
 dispose_list fs/inode.c:738 [inline]
 evict_inodes+0x604/0x690 fs/inode.c:792
 generic_shutdown_super+0x93/0x340 fs/super.c:480
 kill_block_super+0x7c/0xe0 fs/super.c:1470
 deactivate_locked_super+0x93/0xf0 fs/super.c:332
 cleanup_mnt+0x463/0x4f0 fs/namespace.c:1182
 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: 0033:0x7f0e5fa11447
RSP: 002b:00007ffdc1212e98 EFLAGS: 00000202 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 0000000000000063 RCX: 00007f0e5fa11447
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffdc1212f50
RBP: 00007ffdc1212f50 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000202 R12: 00007ffdc1213fc0
R13: 000055558faa36c0 R14: 0000000000000001 R15: 431bde82d7b634db
 </TASK>

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
 #0: ffffffff8c92b430 (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: ffffffff8c92bc50 (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: ffffffff8c92aaa0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 #0: ffffffff8c92aaa0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
 #0: ffffffff8c92aaa0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6513
2 locks held by getty/4012:
 #0: ffff88814d646098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
 #1: ffffc9000326b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x41b/0x1380 drivers/tty/n_tty.c:2198
1 lock held by syz-executor798/4248:
 #0: ffff888024cf00e0 (&type->s_umount_key#42){+.+.}-{3:3}, at: deactivate_super+0xa0/0xd0 fs/super.c:362

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

NMI backtrace for cpu 0
CPU: 0 PID: 28 Comm: khungtaskd Not tainted 6.1.141-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 9 Comm: kworker/u4:0 Not tainted 6.1.141-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:insn_get_modrm+0x90/0x7a0 arch/x86/lib/insn.c:348
Code: 18 84 c0 0f 85 c0 04 00 00 41 0f b6 2f 31 ff 89 ee e8 44 28 7d f7 85 ed 0f 84 9d 01 00 00 e8 d7 25 7d f7 49 8d 56 4c 48 89 d0 <48> c1 e8 03 48 89 44 24 10 0f b6 04 18 84 c0 48 89 14 24 0f 85 a1
RSP: 0018:ffffc900000e77a0 EFLAGS: 00000293
RAX: ffffc900000e79ac RBX: dffffc0000000000 RCX: ffff88813fe80000
RDX: ffffc900000e79ac RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: dffffc0000000000 R09: ffffc900000e7960
R10: fffff5200001cf37 R11: 1ffff9200001cf2c R12: 1ffff9200001cf30
R13: ffffc900000e7984 R14: ffffc900000e7960 R15: ffffc900000e797c
FS:  0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005591d9ddd168 CR3: 000000000c68e000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 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>
INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.038 msecs