INFO: task syz-executor:5873 blocked for more than 143 seconds. Tainted: G U syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor state:D stack:23432 pid:5873 tgid:5873 ppid:1 task_flags:0x400140 flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x1190/0x5de0 kernel/sched/core.c:6961 __schedule_loop kernel/sched/core.c:7043 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:7058 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7115 __mutex_lock_common kernel/locking/mutex.c:676 [inline] __mutex_lock+0x81b/0x1060 kernel/locking/mutex.c:760 nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:596 nfsd_umount+0x48/0xe0 fs/nfsd/nfsctl.c:1386 deactivate_locked_super+0xbe/0x1a0 fs/super.c:474 deactivate_super fs/super.c:507 [inline] deactivate_super+0xde/0x100 fs/super.c:503 cleanup_mnt+0x225/0x450 fs/namespace.c:1375 task_work_run+0x150/0x240 kernel/task_work.c:227 get_signal+0x1d1/0x26d0 kernel/signal.c:2807 arch_do_signal_or_restart+0x8f/0x790 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop+0x84/0x110 kernel/entry/common.c:40 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [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+0x41c/0x4c0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f995dd901f7 RSP: 002b:00007ffd6714ecf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 00007f995de11d7d RCX: 00007f995dd901f7 RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffd6714edb0 RBP: 00007ffd6714edb0 R08: 0000000000000000 R09: 0000000000000000 R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffd6714fe40 R13: 00007f995de11d7d R14: 0000000000046d20 R15: 00007ffd6714fe80 Showing all locks held in the system: 1 lock held by khungtaskd/31: #0: ffffffff8e5c1520 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8e5c1520 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8e5c1520 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6775 3 locks held by udevd/5237: 2 locks held by kworker/u9:3/5871: #0: ffff8880268e3148 ((wq_completion)nbd1-recv){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3211 #1: ffffc90003e4fd10 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3212 2 locks held by syz-executor/5873: #0: ffff88805bb8c0e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: __super_lock fs/super.c:57 [inline] #0: ffff88805bb8c0e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline] #0: ffff88805bb8c0e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: deactivate_super fs/super.c:506 [inline] #0: ffff88805bb8c0e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: deactivate_super+0xd6/0x100 fs/super.c:503 #1: ffffffff8e9da048 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:596 2 locks held by syz.1.522/8626: #0: ffffffff9042c210 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218 #1: ffffffff8e9da048 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_set_doit+0x687/0xbc0 fs/nfsd/nfsctl.c:1629 2 locks held by syz-executor/8811: #0: ffff888078bfa0e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: __super_lock fs/super.c:57 [inline] #0: ffff888078bfa0e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline] #0: ffff888078bfa0e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: deactivate_super fs/super.c:506 [inline] #0: ffff888078bfa0e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: deactivate_super+0xd6/0x100 fs/super.c:503 #1: ffffffff8e9da048 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:596 3 locks held by kworker/u8:35/9739: #0: ffff8880b843a458 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested kernel/sched/core.c:644 [inline] #0: ffff8880b843a458 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x7e/0x130 kernel/sched/core.c:629 #1: ffff8880b8524088 (psi_seq){-.-.}-{0:0}, at: psi_sched_switch kernel/sched/stats.h:220 [inline] #1: ffff8880b8524088 (psi_seq){-.-.}-{0:0}, at: __schedule+0x1861/0x5de0 kernel/sched/core.c:6955 #2: ffff8880b8525b18 (&base->lock){-.-.}-{2:2}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #2: ffff8880b8525b18 (&base->lock){-.-.}-{2:2}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #2: ffff8880b8525b18 (&base->lock){-.-.}-{2:2}, at: batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:408 [inline] #2: ffff8880b8525b18 (&base->lock){-.-.}-{2:2}, at: batadv_nc_worker+0x159/0x1030 net/batman-adv/network-coding.c:719 2 locks held by syz.0.793/10013: #0: ffff8880510f00e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: __super_lock fs/super.c:57 [inline] #0: ffff8880510f00e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline] #0: ffff8880510f00e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: deactivate_super fs/super.c:506 [inline] #0: ffff8880510f00e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: deactivate_super+0xd6/0x100 fs/super.c:503 #1: ffffffff8e9da048 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:596 2 locks held by getty/10567: #0: ffff8880349be0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc90003bab2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x41b/0x14f0 drivers/tty/n_tty.c:2222 2 locks held by syz.2.974/10888: 2 locks held by syz.6.999/11007: #0: ffffffff90388d48 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:634 [inline] #0: ffffffff90388d48 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x38/0x230 drivers/net/tun.c:3436 #1: ffffffff8e5ccab8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x284/0x3c0 kernel/rcu/tree_exp.h:311 1 lock held by syz.2.1000/11003: #0: ffff88807ac537a0 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:415 [inline] #0: ffff88807ac537a0 (&mm->mmap_lock){++++}-{4:4}, at: vm_mmap_pgoff+0x1f5/0x470 mm/util.c:578 1 lock held by syz.2.1000/11005: 3 locks held by syz.7.1003/11014: #0: ffff88807e1eb208 (&sb->s_type->i_mutex_key#11){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:870 [inline] #0: ffff88807e1eb208 (&sb->s_type->i_mutex_key#11){+.+.}-{4:4}, at: __sock_release+0x86/0x270 net/socket.c:648 #1: ffff888058518e58 (sk_lock-AF_QIPCRTR){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1669 [inline] #1: ffff888058518e58 (sk_lock-AF_QIPCRTR){+.+.}-{0:0}, at: qrtr_release+0x51/0x380 net/qrtr/af_qrtr.c:1213 #2: ffffffff8e5ccab8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x1a3/0x3c0 kernel/rcu/tree_exp.h:343 ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Tainted: G U syzkaller #0 PREEMPT(full) Tainted: [U]=USER Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x29c/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+0xf0e/0x1260 kernel/hung_task.c:491 kthread+0x3c2/0x780 kernel/kthread.c:463 ret_from_fork+0x56d/0x730 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 11005 Comm: syz.2.1000 Tainted: G U syzkaller #0 PREEMPT(full) Tainted: [U]=USER Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:27 [inline] RIP: 0010:check_kcov_mode kernel/kcov.c:183 [inline] RIP: 0010:write_comp_data+0x11/0x90 kernel/kcov.c:246 Code: d9 09 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 49 89 d2 49 89 f8 49 89 f1 65 48 8b 15 17 6f 1b 12 <65> 8b 05 28 6f 1b 12 a9 00 01 ff 00 74 1d f6 c4 01 74 67 a9 00 00 RSP: 0018:ffffc9001926f158 EFLAGS: 00000246 RAX: 0000000000000001 RBX: 0000000000000001 RCX: ffffffff81cb3096 RDX: ffff888021f35a00 RSI: 0000000000000000 RDI: 0000000000000005 RBP: 00007f1da6f8eec9 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: ffffffff81a67410 R13: ffffc9001926f280 R14: 0000000000000000 R15: ffff888021f35a00 FS: 00007f1da7eaa6c0(0000) GS:ffff8881247b9000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffdc1272fd8 CR3: 0000000085250000 CR4: 00000000003526f0 Call Trace: rcu_read_lock include/linux/rcupdate.h:842 [inline] is_bpf_text_address+0x46/0x1a0 kernel/bpf/core.c:776 kernel_text_address kernel/extable.c:125 [inline] kernel_text_address+0x8d/0x100 kernel/extable.c:94 __kernel_text_address+0xd/0x40 kernel/extable.c:79 unwind_get_return_address+0x59/0xa0 arch/x86/kernel/unwind_orc.c:369 arch_stack_walk+0xa6/0x100 arch/x86/kernel/stacktrace.c:26 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 save_stack+0x160/0x1f0 mm/page_owner.c:156 __set_page_owner+0x91/0x550 mm/page_owner.c:329 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1c0/0x230 mm/page_alloc.c:1851 prep_new_page mm/page_alloc.c:1859 [inline] get_page_from_freelist+0x132b/0x38e0 mm/page_alloc.c:3858 __alloc_frozen_pages_noprof+0x261/0x23f0 mm/page_alloc.c:5148 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2416 folio_alloc_mpol_noprof+0x36/0x2f0 mm/mempolicy.c:2435 vma_alloc_folio_noprof+0xed/0x1e0 mm/mempolicy.c:2470 folio_prealloc mm/memory.c:1061 [inline] alloc_anon_folio mm/memory.c:4997 [inline] do_anonymous_page mm/memory.c:5054 [inline] do_pte_missing+0x2230/0x3ba0 mm/memory.c:4232 handle_pte_fault mm/memory.c:6052 [inline] __handle_mm_fault+0x152a/0x2a50 mm/memory.c:6195 handle_mm_fault+0x589/0xd10 mm/memory.c:6364 faultin_page mm/gup.c:1144 [inline] __get_user_pages+0x551/0x34a0 mm/gup.c:1446 populate_vma_page_range+0x267/0x3f0 mm/gup.c:1880 __mm_populate+0x1d8/0x380 mm/gup.c:1983 mm_populate include/linux/mm.h:3367 [inline] __do_sys_mlockall+0x516/0x5d0 mm/mlock.c:769 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f1da6f8eec9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f1da7eaa038 EFLAGS: 00000246 ORIG_RAX: 0000000000000097 RAX: ffffffffffffffda RBX: 00007f1da71e5fa0 RCX: 00007f1da6f8eec9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000001 RBP: 00007f1da7011f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f1da71e6038 R14: 00007f1da71e5fa0 R15: 00007ffcdf7e5f98