INFO: task hung in ntfs_fallocate

Status: auto-obsoleted due to no activity on 2026/09/26 13:54
Subsystems: ntfs3
Labels: prio:high
[Documentation on labels]
Reported-by: syzbot+3829f3f96d42c57315fe@syzkaller.appspotmail.com
First crash: 309d, last: 188d
Cause bisection: the cause commit could be any of (bisect log):
  1997cdc3e727 fs/ntfs3: Use variable length array instead of fixed size
  c935c6687886 fs/ntfs3: Redesign ntfs_create_inode to return error code instead of inode
   
Fix bisection: failed (error log, bisect log)
  
▶ ▼ ✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision
20e04123 assessment-security DenialOfService: ✅ Exploitable: ❌ FilesystemTrigger: ✅ NetworkTrigger: ❌ PeripheralTrigger: ✅ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ ❓ INFO: task hung in ntfs_fallocate 2026/05/17 13:40 2026/05/17 13:40 2026/05/17 14:40 de5aae85
▶ ▼ Discussions (2)
Title Replies (including bot) Last reply
[syzbot] Monthly ntfs3 report (Apr 2026) 0 (1) 2026/04/01 07:42
[syzbot] [ntfs3?] INFO: task hung in ntfs_fallocate 0 (1) 2025/12/05 05:04
▶ ▼ Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 INFO: task hung in ntfs_fallocate 1 1 1159d 1159d 0/3 auto-obsoleted due to no activity on 2023/11/11 09:02
linux-5.15 INFO: task hung in ntfs_fallocate origin:lts-only 1 syz, C error 11 235d 265d 0/3 upstream: reported C repro on 2026/01/13 10:08
▶ ▼ Last patch testing requests (6)
Created Duration User Patch Repo Result
2026/09/26 13:28 25m retest repro upstream no crash job log log
2026/08/07 19:20 59m retest repro upstream no crash log
2026/06/24 11:09 17m retest repro upstream log
2026/05/18 08:59 2h57m retest repro upstream log
2026/04/15 02:17 19m retest repro upstream error
2025/12/15 08:50 16m retest repro upstream report log
▶ ▼ Fix bisection attempts (2)
Created Duration User Patch Repo Result
2026/02/24 08:45 0m bisect fix upstream error job log
2026/01/18 05:44 2h19m bisect fix upstream OK (0) job log log

Sample crash report:
INFO: task syz.0.59:6257 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.59        state:D stack:28152 pid:6257  tgid:6242  ppid:5808   task_flags:0x400040 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5298 [inline]
 __schedule+0x1553/0x5240 kernel/sched/core.c:6911
 __schedule_loop kernel/sched/core.c:6993 [inline]
 rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7289
 rt_mutex_slowlock_block kernel/locking/rtmutex.c:1647 [inline]
 __rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline]
 __rt_mutex_slowlock_locked+0x1f8f/0x25c0 kernel/locking/rtmutex.c:1760
 rt_mutex_slowlock+0xbd/0x170 kernel/locking/rtmutex.c:1800
 __rt_mutex_lock kernel/locking/rtmutex.c:1815 [inline]
 rwbase_write_lock+0x14d/0x730 kernel/locking/rwbase_rt.c:244
 inode_lock include/linux/fs.h:1028 [inline][  276.361851][   T38]  ntfs_fallocate+0x2e7/0x1230
 ntfs_fallocate+0x2e7/0x1 fs/ntfs3/file.c:489[  276.361851][   T38]  ntfs_fallocate+0x2e7/0x1230
 vfs_fallocate+0x672/0x7f0 fs/open.c:340
 ioctl_preallocate fs/ioctl.c:289 [inline]
 file_ioctl+0x64b/0x870 fs/ioctl.c:332
 do_vfs_ioctl+0xc29/0x1540 fs/ioctl.c:576
 __do_sys_ioctl fs/ioctl.c:595 [inline]
 __se_sys_ioctl+0x82/0x170 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd5d6d7c819
RSP: 002b:00007fd5d4fb5028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fd5d6ff6090 RCX: 00007fd5d6d7c819
RDX: 0000200000000000 RSI: 0000000040305829 RDI: 0000000000000008
RBP: 00007fd5d6e12c91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd5d6ff6128 R14: 00007fd5d6ff6090 R15: 00007ffda4a114e8
 </TASK>
INFO: task syz.0.59:6258 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.59        state:D stack:29024 pid:6258  tgid:6242  ppid:5808   task_flags:0x400040 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5298 [inline]
 __schedule+0x1553/0x5240 kernel/sched/core.c:6911
 __schedule_loop kernel/sched/core.c:6993 [inline]
 rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7289
 rt_mutex_slowlock_block kernel/locking/rtmutex.c:1647 [inline]
 __rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline]
 __rt_mutex_slowlock_locked+0x1f8f/0x25c0 kernel/locking/rtmutex.c:1760
 rt_mutex_slowlock+0xbd/0x170 kernel/locking/rtmutex.c:1800
 __rt_mutex_lock kernel/locking/rtmutex.c:1815 [inline]
 rwbase_write_lock+0x14d/0x730 kernel/locking/rwbase_rt.c:244
 inode_lock include/linux/fs.h:1028 [inline]
 ntfs_fallocate+0x2e7/0x1230 fs/ntfs3/file.c:489
 vfs_fallocate+0x672/0x7f0 fs/open.c:340
 ksys_fallocate fs/open.c:364 [inline]
 __do_sys_fallocate fs/open.c:369 [inline]
 __se_sys_fallocate fs/open.c:367 [inline]
 __x64_sys_fallocate+0xc0/0x110 fs/open.c:367
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd5d6d7c819
RSP: 002b:00007fd5d4f94028 EFLAGS: 00000246 ORIG_RAX: 000000000000011d
RAX: ffffffffffffffda RBX: 00007fd5d6ff6180 RCX: 00007fd5d6d7c819
RDX: 0000000000000000 RSI: 0000000000000020 RDI: 0000000000000007
RBP: 00007fd5d6e12c91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000008000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd5d6ff6218 R14: 00007fd5d6ff6180 R15: 00007ffda4a114e8
 </TASK>

Showing all locks held in the system:
3 locks held by kworker/u8:0/12:
 #0: ffff888019c44138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline]
 #0: ffff888019c44138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0xa52/0x18c0 kernel/workqueue.c:3359
 #1: ffffc90000117c40 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3252 [inline]
 #1: ffffc90000117c40 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0xa8d/0x18c0 kernel/workqueue.c:3359
 #2: ffffffff8f15cb38 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:313
3 locks held by ksoftirqd/0/15:
4 locks held by pr/legacy/17:
1 lock held by khungtaskd/38:
 #0: ffffffff8ddcb9c0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
 #0: ffffffff8ddcb9c0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
 #0: ffffffff8ddcb9c0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
5 locks held by kworker/u8:2/41:
4 locks held by kworker/u8:11/3484:
 #0: ffff88801aee1138 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline]
 #0: ffff88801aee1138 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0xa52/0x18c0 kernel/workqueue.c:3359
 #1: ffffc9000eb07c40 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3252 [inline]
 #1: ffffc9000eb07c40 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0xa8d/0x18c0 kernel/workqueue.c:3359
 #2: ffffffff8f14e380 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf4/0x800 net/core/net_namespace.c:675
 #3: ffffffff8f15cb38 (rtnl_mutex){+.+.}-{4:4}, at: wg_destruct+0x25/0x310 drivers/net/wireguard/device.c:246
6 locks held by kworker/u8:13/3560:
 #0: ffff888019c44138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline]
 #0: ffff888019c44138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0xa52/0x18c0 kernel/workqueue.c:3359
 #1: ffffc9000ee87c40 ((work_completion)(&(&nsim_dev->trap_data->trap_report_dw)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3252 [inline]
 #1: ffffc9000ee87c40 ((work_completion)(&(&nsim_dev->trap_data->trap_report_dw)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa8d/0x18c0 kernel/workqueue.c:3359
 #2: ffff888033aa8300 (&devlink->lock_key#11){+.+.}-{4:4}, at: nsim_dev_trap_report_work+0x57/0xbc0 drivers/net/netdevsim/dev.c:909
 #3: ffff888061fe8d20 (&nsim_trap_data->trap_lock){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
 #3: ffff888061fe8d20 (&nsim_trap_data->trap_lock){+.+.}-{3:3}, at: nsim_dev_trap_report drivers/net/netdevsim/dev.c:862 [inline]
 #3: ffff888061fe8d20 (&nsim_trap_data->trap_lock){+.+.}-{3:3}, at: nsim_dev_trap_report_work+0x1ad/0xbc0 drivers/net/netdevsim/dev.c:922
 #4: ffffffff8ddcb9c0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
 #4: ffffffff8ddcb9c0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
 #4: ffffffff8ddcb9c0 (rcu_read_lock){....}-{1:3}, at: __rt_spin_lock kernel/locking/spinlock_rt.c:50 [inline]
 #4: ffffffff8ddcb9c0 (rcu_read_lock){....}-{1:3}, at: rt_spin_lock+0x1e0/0x400 kernel/locking/spinlock_rt.c:57
 #5: ffff88801d699958 (&n->list_lock){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
 #5: ffff88801d699958 (&n->list_lock){+.+.}-{3:3}, at: get_partial_node_bulk mm/slub.c:3750 [inline]
 #5: ffff88801d699958 (&n->list_lock){+.+.}-{3:3}, at: __refill_objects_node+0x87/0x560 mm/slub.c:7027
3 locks held by kworker/u8:14/4828:
 #0: ffff8880320fc138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline]
 #0: ffff8880320fc138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0xa52/0x18c0 kernel/workqueue.c:3359
 #1: ffffc90010ff7c40 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3252 [inline]
 #1: ffffc90010ff7c40 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa8d/0x18c0 kernel/workqueue.c:3359
 #2: ffffffff8f15cb38 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
 #2: ffffffff8f15cb38 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_dad_work+0x124/0x1680 net/ipv6/addrconf.c:4198
1 lock held by udevd/5165:
2 locks held by dhcpcd/5459:
 #0: ffffffff8f1cb0a0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217
 #1: ffffffff8f15cb38 (rtnl_mutex){+.+.}-{4:4}, at: nl80211_pre_doit+0x5f/0x930 net/wireless/nl80211.c:18061
2 locks held by getty/5553:
 #0: ffff88803740d0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc90003e832e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x462/0x13c0 drivers/tty/n_tty.c:2211
1 lock held by udevd/5786:
3 locks held by syz.0.59/6243:
2 locks held by syz.0.59/6257:
 #0: ffff888031f4a480 (sb_writers#12){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2710 [inline]
 #0: ffff888031f4a480 (sb_writers#12){.+.+}-{0:0}, at: vfs_fallocate+0x5f9/0x7f0 fs/open.c:339
 #1: ffff888062f783b0 (&sb->s_type->i_mutex_key#24){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1028 [inline]
 #1: ffff888062f783b0 (&sb->s_type->i_mutex_key#24){+.+.}-{4:4}, at: ntfs_fallocate+0x2e7/0x1230 fs/ntfs3/file.c:489
2 locks held by syz.0.59/6258:
 #0: ffff888031f4a480 (sb_writers#12){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2710 [inline]
 #0: ffff888031f4a480 (sb_writers#12){.+.+}-{0:0}, at: vfs_fallocate+0x5f9/0x7f0 fs/open.c:339
 #1: ffff888062f783b0 (&sb->s_type->i_mutex_key#24){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1028 [inline]
 #1: ffff888062f783b0 (&sb->s_type->i_mutex_key#24){+.+.}-{4:4}, at: ntfs_fallocate+0x2e7/0x1230 fs/ntfs3/file.c:489
1 lock held by syz-executor/6354:
1 lock held by syz-executor/6494:
2 locks held by syz-executor/7067:
3 locks held by syz-executor/7475:
 #0: ffffffff8e8b80e8 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
 #0: ffffffff8e8b80e8 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
 #0: ffffffff8e8b80e8 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250 net/core/rtnetlink.c:570
 #1: ffffffff8f15cb38 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
 #1: ffffffff8f15cb38 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline]
 #1: ffffffff8f15cb38 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8a1/0x1be0 net/core/rtnetlink.c:4093
 #2: ffff88801d699958 (&n->list_lock){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
 #2: ffff88801d699958 (&n->list_lock){+.+.}-{3:3}, at: get_partial_node_bulk mm/slub.c:3750 [inline]
 #2: ffff88801d699958 (&n->list_lock){+.+.}-{3:3}, at: __refill_objects_node+0x87/0x560 mm/slub.c:7027
1 lock held by syz.7.238/7629:
 #0: ffff8880400800d0 (&type->s_umount_key#58/1){+.+.}-{4:4}, at: alloc_super+0x28c/0xac0 fs/super.c:345

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 38 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:161 [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:346 [inline]
 watchdog+0xfd9/0x1030 kernel/hung_task.c:515
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 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: 17 Comm: pr/legacy Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
RIP: 0010:io_serial_in+0x77/0xc0 drivers/tty/serial/8250/8250_port.c:401
Code: e8 9e 27 94 fc 44 89 f9 d3 e3 49 83 ee 80 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 9f 49 fa fc 41 03 1e 89 da ec <0f> b6 c0 5b 41 5c 41 5e 41 5f e9 9a 29 f7 05 cc 44 89 f9 80 e1 07
RSP: 0018:ffffc900001679d0 EFLAGS: 00000202
RAX: 1ffffffff332b300 RBX: 00000000000003fd RCX: 0000000000000000
RDX: 00000000000003fd RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffffff99959cd0 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffffff85305880 R12: dffffc0000000000
R13: 0000000000000000 R14: ffffffff99959a40 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff888126436000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb30d5a9000 CR3: 000000003531e000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 serial_in drivers/tty/serial/8250/8250.h:128 [inline]
 serial_lsr_in drivers/tty/serial/8250/8250.h:150 [inline]
 wait_for_lsr+0x1aa/0x2f0 drivers/tty/serial/8250/8250_port.c:1970
 serial8250_fifo_wait_for_lsr_thre drivers/tty/serial/8250/8250_port.c:3207 [inline]
 serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3272 [inline]
 serial8250_console_write+0x120d/0x1b90 drivers/tty/serial/8250/8250_port.c:3357
 console_emit_next_record kernel/printk/printk.c:3163 [inline]
 console_flush_one_record+0x68b/0xb90 kernel/printk/printk.c:3269
 legacy_kthread_func+0x1b6/0x250 kernel/printk/printk.c:3712
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Crashes (6):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/03/31 18:09 upstream d0c3bcd5b897 aeea1c72 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in ntfs_fallocate
2026/03/22 07:13 upstream 113ae7b4decc 5b92003d .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-upstream-fs INFO: task hung in ntfs_fallocate
2026/03/22 03:53 upstream 113ae7b4decc 5b92003d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in ntfs_fallocate
2026/01/25 08:40 upstream 5dbeeb268b63 40acda8a .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in ntfs_fallocate
2025/12/01 04:53 upstream e69c7c175115 d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-upstream-fs INFO: task hung in ntfs_fallocate
2025/12/01 01:51 upstream e69c7c175115 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in ntfs_fallocate
* Struck through repros no longer work on HEAD.