INFO: task syz.2.309:7265 blocked for more than 143 seconds.
      Not tainted 6.16.0-rc6-next-20250718-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.309       state:D stack:23528 pid:7265  tgid:7265  ppid:5846   task_flags:0x400040 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5351 [inline]
 __schedule+0x1737/0x4d30 kernel/sched/core.c:6954
 __schedule_loop kernel/sched/core.c:7036 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:7051
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7108
 rwsem_down_write_slowpath+0xbec/0x1030 kernel/locking/rwsem.c:1187
 __down_write_common kernel/locking/rwsem.c:1319 [inline]
 __down_write kernel/locking/rwsem.c:1328 [inline]
 down_write+0x1ab/0x1f0 kernel/locking/rwsem.c:1593
 mmap_write_lock include/linux/mmap_lock.h:356 [inline]
 userfaultfd_release_all+0x15a/0x5e0 mm/userfaultfd.c:2055
 userfaultfd_release+0xe7/0x1b0 fs/userfaultfd.c:868
 __fput+0x449/0xa70 fs/file_table.c:468
 task_work_run+0x1d4/0x260 kernel/task_work.c:227
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop+0xec/0x110 kernel/entry/common.c:43
 exit_to_user_mode_prepare include/linux/irq-entry-common.h:208 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
 do_syscall_64+0x2bd/0x3b0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f3a7898e9a9
RSP: 002b:00007ffc0f8b8d48 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007f3a78bb7ba0 RCX: 00007f3a7898e9a9
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007f3a78bb7ba0 R08: 0000000000000060 R09: 000000060f8b903f
R10: 00007f3a78bb7ac0 R11: 0000000000000246 R12: 00000000000227d8
R13: 00007ffc0f8b8e40 R14: ffffffffffffffff R15: 00007ffc0f8b8e60
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/31:
 #0: ffffffff8e53d8a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8e53d8a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
 #0: ffffffff8e53d8a0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6770
1 lock held by udevd/5216:
2 locks held by getty/5611:
 #0: ffff888033ad60a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222
3 locks held by kworker/0:3/5928:
 #0: ffff888021ea2548 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline]
 #0: ffff888021ea2548 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319
 #1: ffffc90004a27bc0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline]
 #1: ffffc90004a27bc0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319
 #2: ffff8880282de198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:911 [inline]
 #2: ffff8880282de198 (&dev->mutex){....}-{4:4}, at: hub_event+0x184/0x4a20 drivers/usb/core/hub.c:5898
1 lock held by syz.2.309/7265:
 #0: ffff88805c3d4260 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock include/linux/mmap_lock.h:356 [inline]
 #0: ffff88805c3d4260 (&mm->mmap_lock){++++}-{4:4}, at: userfaultfd_release_all+0x15a/0x5e0 mm/userfaultfd.c:2055
2 locks held by syz.2.309/7267:
1 lock held by syz.6.1013/9986:
 #0: ffffffff8e543200 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x570 kernel/rcu/tree.c:3815
1 lock held by sed/9996:

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.16.0-rc6-next-20250718-syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:328 [inline]
 watchdog+0xf93/0xfe0 kernel/hung_task.c:491
 kthread+0x70e/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148
 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: 9999 Comm: dhcpcd-run-hook Not tainted 6.16.0-rc6-next-20250718-syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:rcu_is_watching_curr_cpu include/linux/context_tracking.h:128 [inline]
RIP: 0010:rcu_is_watching+0x10/0xb0 kernel/rcu/tree.c:751
Code: 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 41 57 41 56 53 65 ff 05 20 99 40 11 <e8> 4b d7 d8 09 89 c3 83 f8 08 73 65 49 bf 00 00 00 00 00 fc ff df
RSP: 0018:ffffc9000e457038 EFLAGS: 00000282
RAX: 0000000000000001 RBX: ffffffff90818601 RCX: ffff88802eb5da00
RDX: ffffc9000e457101 RSI: dffffc0000000000 RDI: ffffc9000e457130
RBP: dffffc0000000000 R08: ffffc9000e457490 R09: 0000000000000000
R10: ffffc9000e457178 R11: fffff52001c8ae31 R12: ffffc9000e4574a0
R13: ffffc9000e450000 R14: ffffc9000e457128 R15: ffffffff81730195
FS:  0000000000000000(0000) GS:ffff8881258ab000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1a69c63286 CR3: 000000004add6000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 3a810b1eb6134bdc DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 rcu_read_unlock include/linux/rcupdate.h:869 [inline]
 class_rcu_destructor include/linux/rcupdate.h:1155 [inline]
 unwind_next_frame+0x1965/0x2390 arch/x86/kernel/unwind_orc.c:680
 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576
 poison_slab_object mm/kasan/common.c:247 [inline]
 __kasan_slab_free+0x62/0x70 mm/kasan/common.c:264
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2417 [inline]
 slab_free mm/slub.c:4680 [inline]
 kmem_cache_free+0x18f/0x400 mm/slub.c:4782
 anon_vma_chain_free mm/rmap.c:147 [inline]
 unlink_anon_vmas+0x2cc/0x670 mm/rmap.c:421
 free_pgtables+0x7bf/0xaf0 mm/memory.c:419
 exit_mmap+0x444/0xb50 mm/mmap.c:1291
 __mmput+0x118/0x430 kernel/fork.c:1124
 exec_mmap+0x6ac/0x7d0 fs/exec.c:901
 begin_new_exec+0x129c/0x2120 fs/exec.c:1156
 load_elf_binary+0x998/0x2740 fs/binfmt_elf.c:995
 search_binary_handler fs/exec.c:1670 [inline]
 exec_binprm fs/exec.c:1702 [inline]
 bprm_execve+0x99c/0x1450 fs/exec.c:1754
 do_execveat_common+0x510/0x6a0 fs/exec.c:1860
 do_execve fs/exec.c:1934 [inline]
 __do_sys_execve fs/exec.c:2010 [inline]
 __se_sys_execve fs/exec.c:2005 [inline]
 __x64_sys_execve+0x94/0xb0 fs/exec.c:2005
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1a69ba9107
Code: Unable to access opcode bytes at 0x7f1a69ba90dd.
RSP: 002b:00007ffc4ee84348 EFLAGS: 00000246 ORIG_RAX: 000000000000003b
RAX: ffffffffffffffda RBX: 0000559f5cd56080 RCX: 00007f1a69ba9107
RDX: 0000559f5cd560a8 RSI: 0000559f5cd56080 RDI: 0000559f5cd56138
RBP: 0000559f5cd56138 R08: 00007ffc4ee88dcb R09: 0000000000000000
R10: 0000000000000008 R11: 0000000000000246 R12: 0000559f5cd560a8
R13: 00007f1a69d6ee8b R14: 0000559f5cd560a8 R15: 0000000000000000
 </TASK>