INFO: task syz.5.2204:13793 blocked for more than 143 seconds. Tainted: G L syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.5.2204 state:D stack:28424 pid:13793 tgid:13791 ppid:5621 task_flags:0x400040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x17d9/0x56c0 kernel/sched/core.c:7234 __schedule_loop kernel/sched/core.c:7311 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7326 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7383 __mutex_lock_common kernel/locking/mutex.c:726 [inline] __mutex_lock+0x7bf/0x1550 kernel/locking/mutex.c:821 write_threads+0x39d/0x5a0 fs/nfsd/nfsctl.c:432 nfsctl_transaction_write+0x10f/0x160 fs/nfsd/nfsctl.c:112 vfs_write+0x296/0xba0 fs/read_write.c:685 ksys_write+0x150/0x270 fs/read_write.c:739 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f9292d9de99 RSP: 002b:00007f9293b81028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f9293026090 RCX: 00007f9292d9de99 RDX: 0000000000000002 RSI: 0000200000000140 RDI: 0000000000000004 RBP: 00007f9292e33eaf R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f9293026128 R14: 00007f9293026090 R15: 00007ffce74dd3a8 INFO: task syz.4.2218:13900 blocked for more than 145 seconds. Tainted: G L syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.4.2218 state:D stack:27440 pid:13900 tgid:13889 ppid:5618 task_flags:0x400140 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x17d9/0x56c0 kernel/sched/core.c:7234 __schedule_loop kernel/sched/core.c:7311 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7326 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7383 __mutex_lock_common kernel/locking/mutex.c:726 [inline] __mutex_lock+0x7bf/0x1550 kernel/locking/mutex.c:821 write_ports+0xb5/0xd10 fs/nfsd/nfsctl.c:860 nfsctl_transaction_write+0x10f/0x160 fs/nfsd/nfsctl.c:112 vfs_write+0x296/0xba0 fs/read_write.c:685 ksys_write+0x150/0x270 fs/read_write.c:739 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fbe5eb9de99 RSP: 002b:00007fbe5fa41028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007fbe5ee25fa0 RCX: 00007fbe5eb9de99 RDX: 0000000000000005 RSI: 00002000000000c0 RDI: 0000000000000003 RBP: 00007fbe5ec33eaf R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fbe5ee26038 R14: 00007fbe5ee25fa0 R15: 00007ffecd0e8d48 INFO: task syz.4.2218:13906 blocked for more than 145 seconds. Tainted: G L syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.4.2218 state:D stack:28424 pid:13906 tgid:13889 ppid:5618 task_flags:0x400040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x17d9/0x56c0 kernel/sched/core.c:7234 __schedule_loop kernel/sched/core.c:7311 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7326 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7383 __mutex_lock_common kernel/locking/mutex.c:726 [inline] __mutex_lock+0x7bf/0x1550 kernel/locking/mutex.c:821 write_threads+0x39d/0x5a0 fs/nfsd/nfsctl.c:432 nfsctl_transaction_write+0x10f/0x160 fs/nfsd/nfsctl.c:112 vfs_write+0x296/0xba0 fs/read_write.c:685 ksys_write+0x150/0x270 fs/read_write.c:739 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fbe5eb9de99 RSP: 002b:00007fbe5fa20028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007fbe5ee26090 RCX: 00007fbe5eb9de99 RDX: 0000000000000002 RSI: 0000200000000140 RDI: 0000000000000004 RBP: 00007fbe5ec33eaf R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fbe5ee26128 R14: 00007fbe5ee26090 R15: 00007ffecd0e8d48 Showing all locks held in the system: 1 lock held by khungtaskd/32: #0: ffffffff8eb59c60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #0: ffffffff8eb59c60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline] #0: ffffffff8eb59c60 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 2 locks held by getty/5375: #0: ffff88803286a0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc900032332e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45a/0x1360 drivers/tty/n_tty.c:2211 3 locks held by syz.5.2204/13792: #0: ffff88802623d0b0 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x246/0x320 fs/file.c:1259 #1: ffff88802564c450 (sb_writers#14){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #1: ffff88802564c450 (sb_writers#14){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683 #2: ffffffff8ee8e620 (nfsd_mutex){+.+.}-{4:4}, at: write_ports+0xb5/0xd10 fs/nfsd/nfsctl.c:860 3 locks held by syz.5.2204/13793: #0: ffff888033f53eb0 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x246/0x320 fs/file.c:1259 #1: ffff88802564c450 (sb_writers#14){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #1: ffff88802564c450 (sb_writers#14){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683 #2: ffffffff8ee8e620 (nfsd_mutex){+.+.}-{4:4}, at: write_threads+0x39d/0x5a0 fs/nfsd/nfsctl.c:432 3 locks held by syz.4.2218/13900: #0: ffff888022f1ad30 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x246/0x320 fs/file.c:1259 #1: ffff88807a7f6450 (sb_writers#14){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #1: ffff88807a7f6450 (sb_writers#14){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683 #2: ffffffff8ee8e620 (nfsd_mutex){+.+.}-{4:4}, at: write_ports+0xb5/0xd10 fs/nfsd/nfsctl.c:860 3 locks held by syz.4.2218/13906: #0: ffff888054c84470 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x246/0x320 fs/file.c:1259 #1: ffff88807a7f6450 (sb_writers#14){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #1: ffff88807a7f6450 (sb_writers#14){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683 #2: ffffffff8ee8e620 (nfsd_mutex){+.+.}-{4:4}, at: write_threads+0x39d/0x5a0 fs/nfsd/nfsctl.c:432 3 locks held by syz.3.2245/14836: #0: ffff888079915eb0 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x246/0x320 fs/file.c:1259 #1: ffff88804f75c450 (sb_writers#14){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #1: ffff88804f75c450 (sb_writers#14){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683 #2: ffffffff8ee8e620 (nfsd_mutex){+.+.}-{4:4}, at: write_ports+0xb5/0xd10 fs/nfsd/nfsctl.c:860 1 lock held by sed/16848: ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 32 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:122 nmi_trigger_cpumask_backtrace+0x17a/0x380 lib/nmi_backtrace.c:65 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline] __sys_info lib/sys_info.c:157 [inline] sys_info+0x135/0x170 lib/sys_info.c:165 check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline] watchdog+0xfd7/0x1030 kernel/hung_task.c:561 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 16851 Comm: sed Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026 RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:26 [inline] RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:109 [inline] RIP: 0010:arch_irqs_disabled arch/x86/include/asm/irqflags.h:151 [inline] RIP: 0010:lock_is_held_type+0xf2/0x150 kernel/locking/lockdep.c:5942 Code: c5 0f 94 c3 eb 05 bb 01 00 00 00 48 c7 c7 e4 28 4b 8e e8 f1 1a 00 00 b8 ff ff ff ff 65 0f c1 05 b4 7c 9c 07 83 f8 01 75 25 9c <58> a9 00 02 00 00 75 39 41 f7 c4 00 02 00 00 74 01 fb 89 d8 5b 41 RSP: 0018:ffffc9000704f260 EFLAGS: 00000046 RAX: 0000000000000001 RBX: 0000000000000001 RCX: 0000000000000046 RDX: 0000000000000000 RSI: ffffffff8e4b28e4 RDI: ffffffff8c4bdc80 RBP: 00000000ffffffff R08: ffff88802856dd00 R09: 0000000000000004 R10: 0000000000000004 R11: 0000000000000000 R12: 0000000000000246 R13: ffff88802856dd00 R14: ffff88802cc0e9b8 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888124f4e000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fec8e7a0eb8 CR3: 0000000077427000 CR4: 0000000000350ef0 Call Trace: lock_is_held include/linux/lockdep.h:249 [inline] mt_locked lib/maple_tree.c:-1 [inline] mt_slot lib/maple_tree.c:715 [inline] mas_slot lib/maple_tree.c:748 [inline] mt_validate_nulls lib/maple_tree.c:6901 [inline] mt_validate+0x3c7c/0x4260 lib/maple_tree.c:6956 validate_mm+0xd4/0x4f0 mm/vma.c:652 mmap_region+0x168a/0x2310 mm/vma.c:2866 do_mmap+0xc3b/0x10c0 mm/mmap.c:560 vm_mmap_pgoff+0x272/0x4e0 mm/util.c:581 ksys_mmap_pgoff+0x4dc/0x760 mm/mmap.c:606 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fec8ea8b242 Code: 08 00 04 00 00 eb e2 90 41 f7 c1 ff 0f 00 00 75 27 55 89 cd 53 48 89 fb 48 85 ff 74 33 41 89 ea 48 89 df b8 09 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 5e 5b 5d c3 0f 1f 00 c7 05 46 40 01 00 16 00 RSP: 002b:00007ffc0fd76e48 EFLAGS: 00000246 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fec8ea8b242 RDX: 0000000000000001 RSI: 000000000002f6d0 RDI: 0000000000000000 RBP: 0000000000000802 R08: 0000000000000003 R09: 0000000000000000 R10: 0000000000000802 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fec8ea60ab0 R14: 00007ffc0fd772c0 R15: 00000fff81faedcc