syzbot

INFO: task syz-executor319:5851 blocked for more than 143 seconds.
      Not tainted 6.15.0-syzkaller-12058-g64980441d269 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor319 state:D stack:25160 pid:5851  tgid:5851  ppid:5848   task_flags:0x400100 flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5396 [inline]
 __schedule+0x16a2/0x4cb0 kernel/sched/core.c:6785
 __schedule_loop kernel/sched/core.c:6863 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6878
 netfs_wait_for_outstanding_io include/linux/netfs.h:553 [inline]
 v9fs_evict_inode+0x170/0x320 fs/9p/vfs_inode.c:348
 evict+0x501/0x9c0 fs/inode.c:810
 __dentry_kill+0x209/0x660 fs/dcache.c:669
 dput+0x19f/0x2b0 fs/dcache.c:911
 shrink_dcache_for_umount+0xa0/0x170 fs/dcache.c:1621
 generic_shutdown_super+0x67/0x2c0 fs/super.c:621
 kill_anon_super+0x3b/0x70 fs/super.c:1280
 v9fs_kill_super+0x4c/0x90 fs/9p/vfs_super.c:193
 deactivate_locked_super+0xbc/0x130 fs/super.c:474
 cleanup_mnt+0x425/0x4c0 fs/namespace.c:1417
 task_work_run+0x1d1/0x260 kernel/task_work.c:227
 ptrace_notify+0x281/0x2c0 kernel/signal.c:2520
 ptrace_report_syscall include/linux/ptrace.h:415 [inline]
 ptrace_report_syscall_exit include/linux/ptrace.h:477 [inline]
 syscall_exit_work+0xc6/0x1d0 kernel/entry/common.c:173
 syscall_exit_to_user_mode_work include/linux/entry-common.h:412 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:449 [inline]
 do_syscall_64+0x2ad/0x3b0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7feaaacf2747
RSP: 002b:00007ffc3beca448 EFLAGS: 00000206 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 000000000001fa00 RCX: 00007feaaacf2747
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffc3beca500
RBP: 00007ffc3beca500 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000206 R12: 00007ffc3becb570
R13: 0000555557a506c0 R14: 00007ffc3becb570 R15: 0000000000000001
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/31:
 #0: ffffffff8e13f060 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8e13f060 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
 #0: ffffffff8e13f060 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6770
2 locks held by getty/5590:
 #0: ffff8880352da0a0 (&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
1 lock held by syz-executor319/5851:
 #0: ffff88802a1740e0 (&type->s_umount_key#43){+.+.}-{4:4}, at: __super_lock fs/super.c:57 [inline]
 #0: ffff88802a1740e0 (&type->s_umount_key#43){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline]
 #0: ffff88802a1740e0 (&type->s_umount_key#43){+.+.}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:506

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.15.0-syzkaller-12058-g64980441d269 #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:158 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:307 [inline]
 watchdog+0xfee/0x1030 kernel/hung_task.c:470
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 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: 49 Comm: kworker/u8:3 Not tainted 6.15.0-syzkaller-12058-g64980441d269 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:___pte_offset_map+0xe/0x2c0 mm/pgtable-generic.c:283
Code: e8 17 6c f7 ff 90 0f 0b 0f 1f 40 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 66 0f 1f 00 55 41 57 41 56 41 55 41 54 53 <50> 49 89 d7 48 89 f3 49 89 fe e8 93 dc b1 ff e8 5e 5c 99 ff 48 8d
RSP: 0018:ffffc90000ba7630 EFLAGS: 00000293
RAX: ffffffff820e74ad RBX: ffff88801a47aaa8 RCX: ffff8881416e5a00
RDX: ffffc90000ba7698 RSI: 00002aaaaaaab000 RDI: ffff88801a47aaa8
RBP: ffffc90000ba7830 R08: ffffea0000085a87 R09: 1ffffd4000010b50
R10: dffffc0000000000 R11: fffff94000010b51 R12: ffffffff8216afbd
R13: fffffffffffffeff R14: ffffc90000ba77c0 R15: 00002aaaaaaab000
FS:  0000000000000000(0000) GS:ffff888125d89000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000557a0c0ae660 CR3: 000000000df38000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __pte_offset_map include/linux/mm.h:2995 [inline]
 __pte_offset_map_lock+0x46/0x210 mm/pgtable-generic.c:398
 get_locked_pte include/linux/mm.h:2703 [inline]
 __text_poke+0x2e6/0xa10 arch/x86/kernel/alternative.c:2474
 text_poke arch/x86/kernel/alternative.c:2559 [inline]
 smp_text_poke_batch_finish+0xd0a/0x1100 arch/x86/kernel/alternative.c:2948
 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146
 static_key_enable_cpuslocked+0x128/0x250 kernel/jump_label.c:210
 static_key_enable+0x1a/0x20 kernel/jump_label.c:223
 toggle_allocation_gate+0xad/0x240 mm/kfence/core.c:850
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3321
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 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>