INFO: task hung in do_truncate

Status: auto-obsoleted due to no activity on 2026/03/07 06:20
Bug presence: origin:lts
[Documentation on labels]
Reported-by: syzbot+37f4f261ff8716a0b58f@syzkaller.appspotmail.com
First crash: 300d, last: 285d
▶ ▼ Bug presence (2)
Date Name Commit Repro Result
2025/10/06 lts (merge base) b0c51e95f54e C [report] INFO: task hung in do_truncate
2025/10/06 upstream (ToT) 7a405dbb0f03 C Didn't crash
▶ ▼ Similar bugs (7)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 INFO: task hung in do_truncate (3) 1 12 580d 753d 0/3 auto-obsoleted due to no activity on 2025/04/05 19:26
upstream INFO: task hung in do_truncate (3) f2fs 1 syz error 80 432d 602d 0/29 auto-obsoleted due to no activity on 2025/08/02 00:14
linux-5.15 INFO: task hung in do_truncate 1 1 1228d 1228d 0/3 auto-obsoleted due to no activity on 2023/07/17 23:13
linux-5.15 INFO: task hung in do_truncate (2) 1 1 1076d 1076d 0/3 auto-obsoleted due to no activity on 2023/11/27 08:00
linux-6.6 INFO: task hung in do_truncate 1 1 224d 224d 0/2 auto-obsoleted due to no activity on 2026/03/27 19:10
upstream INFO: task hung in do_truncate (2) fs 1 syz, C done done 14 919d 2240d 0/29 auto-obsoleted due to no activity on 2024/05/02 07:43
upstream INFO: task hung in do_truncate ext4 1 syz, C 7 2813d 2977d 0/29 closed as dup on 2018/09/08 15:38
▶ ▼ Last patch testing requests (3)
Created Duration User Patch Repo Result
2026/03/07 05:53 15m retest repro android16-6.12 OK log
2025/12/27 05:35 3m retest repro android16-6.12 error
2025/10/17 23:27 15m retest repro android16-6.12 report log

Sample crash report:
INFO: task syz.2.17:385 blocked for more than 122 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.17        state:D stack:0     pid:385   tgid:383   ppid:370    flags:0x00000004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5945 [inline]
 __schedule+0x1322/0x1df0 kernel/sched/core.c:7791
 __schedule_loop kernel/sched/core.c:7872 [inline]
 schedule+0xc6/0x240 kernel/sched/core.c:7887
 schedule_preempt_disabled+0x14/0x30 kernel/sched/core.c:7944
 rwsem_down_write_slowpath+0x9e8/0x1b90 kernel/locking/rwsem.c:1239
 __down_write_common kernel/locking/rwsem.c:1383 [inline]
 __down_write kernel/locking/rwsem.c:1392 [inline]
 down_write+0x152/0x2a0 kernel/locking/rwsem.c:1659
 inode_lock include/linux/fs.h:817 [inline]
 do_truncate+0x187/0x220 fs/open.c:64
 vfs_truncate+0x26e/0x320 fs/open.c:112
 do_sys_truncate+0xdd/0x1a0 fs/open.c:135
 __do_sys_truncate fs/open.c:147 [inline]
 __se_sys_truncate fs/open.c:145 [inline]
 __x64_sys_truncate+0x5f/0x70 fs/open.c:145
 x64_sys_call+0x2698/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:77
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x58/0xf0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7fdb8d38eec9
RSP: 002b:00007fdb8e282038 EFLAGS: 00000246 ORIG_RAX: 000000000000004c
RAX: ffffffffffffffda RBX: 00007fdb8d5e6090 RCX: 00007fdb8d38eec9
RDX: 0000000000000000 RSI: 0000000000000008 RDI: 0000200000000340
RBP: 00007fdb8d411f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fdb8d5e6128 R14: 00007fdb8d5e6090 R15: 00007fffbe1be428
 </TASK>
INFO: task syz.3.18:402 blocked for more than 123 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.18        state:D stack:0     pid:402   tgid:398   ppid:388    flags:0x00000004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5945 [inline]
 __schedule+0x1322/0x1df0 kernel/sched/core.c:7791
 __schedule_loop kernel/sched/core.c:7872 [inline]
 schedule+0xc6/0x240 kernel/sched/core.c:7887
 schedule_preempt_disabled+0x14/0x30 kernel/sched/core.c:7944
 rwsem_down_write_slowpath+0x9e8/0x1b90 kernel/locking/rwsem.c:1239
 __down_write_common kernel/locking/rwsem.c:1383 [inline]
 __down_write kernel/locking/rwsem.c:1392 [inline]
 down_write+0x152/0x2a0 kernel/locking/rwsem.c:1659
 inode_lock include/linux/fs.h:817 [inline]
 do_truncate+0x187/0x220 fs/open.c:64
 vfs_truncate+0x26e/0x320 fs/open.c:112
 do_sys_truncate+0xdd/0x1a0 fs/open.c:135
 __do_sys_truncate fs/open.c:147 [inline]
 __se_sys_truncate fs/open.c:145 [inline]
 __x64_sys_truncate+0x5f/0x70 fs/open.c:145
 x64_sys_call+0x2698/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:77
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x58/0xf0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f74fd18eec9
RSP: 002b:00007f74fdfe7038 EFLAGS: 00000246 ORIG_RAX: 000000000000004c
RAX: ffffffffffffffda RBX: 00007f74fd3e6090 RCX: 00007f74fd18eec9
RDX: 0000000000000000 RSI: 0000000000000008 RDI: 0000200000000340
RBP: 00007f74fd211f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f74fd3e6128 R14: 00007f74fd3e6090 R15: 00007ffc197322a8
 </TASK>
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 37 Comm: khungtaskd Not tainted syzkaller #0 68071847e78a8b5e73ab1b858b320f4e6b4f981b
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
 <TASK>
 __dump_stack+0x21/0x30 lib/dump_stack.c:94
 dump_stack_lvl+0x10c/0x190 lib/dump_stack.c:120
 dump_stack+0x19/0x20 lib/dump_stack.c:129
 nmi_cpu_backtrace+0x2bf/0x2d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x142/0x2c0 lib/nmi_backtrace.c:62
 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:41
 trigger_all_cpu_backtrace include/linux/nmi.h:158 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:267 [inline]
 watchdog+0xd8f/0xed0 kernel/hung_task.c:423
 kthread+0x2ca/0x370 kernel/kthread.c:389
 ret_from_fork+0x67/0xa0 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted syzkaller #0 68071847e78a8b5e73ab1b858b320f4e6b4f981b
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:pv_native_safe_halt+0x17/0x20 arch/x86/kernel/paravirt.c:106
Code: cc cc cc b8 83 13 3d 28 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d c3 32 3a 00 f3 0f 1e fa 55 48 89 e5 fb f4 <5d> e9 d3 54 02 00 cc cc cc b8 00 00 00 00 90 90 90 90 90 90 90 90
RSP: 0018:ffffc900001a7e00 EFLAGS: 000002c2
RAX: ffff8881f6f00000 RBX: ffff88810366b900 RCX: ffffffff858d20be
RDX: 0000000000000001 RSI: 0000000000000004 RDI: 000000000004364c
RBP: ffffc900001a7e00 R08: ffff8881f6f39733 R09: 1ffff1103ede72e6
R10: dffffc0000000000 R11: ffffed103ede72e7 R12: 1ffff110206cd720
R13: 0000000000000001 R14: 0000000000000000 R15: ffffffff87cb1da8
FS:  0000000000000000(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff9b2562d58 CR3: 0000000126a4a000 CR4: 00000000003526b0
Call Trace:
 <TASK>
 arch_safe_halt arch/x86/include/asm/paravirt.h:112 [inline]
 default_idle+0x17/0x30 arch/x86/kernel/process.c:754
 arch_cpu_idle+0xd/0x20 arch/x86/kernel/process.c:791
 default_idle_call+0x3f/0x80 kernel/sched/idle.c:117
 cpuidle_idle_call kernel/sched/idle.c:185 [inline]
 do_idle+0x1a0/0x470 kernel/sched/idle.c:326
 cpu_startup_entry+0x48/0x70 kernel/sched/idle.c:424
 start_secondary+0x12e/0x140 arch/x86/kernel/smpboot.c:314
 common_startup_64+0x13b/0x157
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/10/03 14:28 android16-6.12 6a4218cc2885 49379ee0 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in do_truncate
* Struck through repros no longer work on HEAD.