INFO: task hung in nilfs_transaction_begin (3)

Status: upstream: reported C repro on 2026/07/16 07:51
Subsystems: nilfs
Labels: prio:normal
[Documentation on labels]
Reported-by: syzbot+cae54346a70bbceeff2c@syzkaller.appspotmail.com
Fix commit: ce5a5ad1a833 nilfs2: fix infinite loop in nilfs_clean_segments()
Patched on: [ci-qemu-gce-upstream-auto ci-qemu-upstream ci-qemu-upstream-386 ci-qemu2-arm32 ci-qemu2-arm64 ci-qemu2-arm64-compat ci-qemu2-arm64-mte ci-qemu2-riscv64 ci-snapshot-upstream-root ci-upstream-bpf-kasan-gce ci-upstream-bpf-next-kasan-gce ci-upstream-gce-leak ci-upstream-kasan-badwrites-root ci-upstream-kasan-gce ci-upstream-kasan-gce-386 ci-upstream-kasan-gce-root ci-upstream-kasan-gce-selinux-root ci-upstream-kasan-gce-smack-root ci-upstream-linux-next-kasan-gce-root ci-upstream-net-kasan-gce ci-upstream-net-this-kasan-gce ci-upstream-rust-kasan-gce ci2-upstream-fs ci2-upstream-kcsan-gce], missing on: [ci-qemu-native-arm64-kvm ci-upstream-gce-arm64 ci-upstream-kmsan-gce-386-root ci-upstream-kmsan-gce-root ci2-upstream-usb]
First crash: 37d, last: 9d13h
Cause bisection: failed (error log, bisect log)
  
▶ ▼ ✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision
31b55954 assessment-security DenialOfService: ✅ Exploitable: ❌ FilesystemTrigger: ✅ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ ❓ INFO: task hung in nilfs_transaction_begin (3) 2026/07/16 00:00 2026/07/16 00:00 2026/07/16 00:55 10d97020
▶ ▼ Discussions (3)
Title Replies (including bot) Last reply
[PATCH v2] nilfs2: fix infinite loop in nilfs_clean_segments() 3 (3) 2026/07/28 23:43
[syzbot] [nilfs?] INFO: task hung in nilfs_transaction_begin (3) 0 (4) 2026/07/22 07:40
[PATCH] nilfs2: fix infinite loop in nilfs_clean_segments() 3 (3) 2026/07/17 10:40
▶ ▼ Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in nilfs_transaction_begin nilfs 1 1 941d 941d 0/29 auto-obsoleted due to no activity on 2024/04/23 10:04
upstream INFO: task hung in nilfs_transaction_begin (2) prio:low nilfs 1 syz, C error 14 76d 117d 29/29 fixed on 2026/07/15 08:27
▶ ▼ Last patch testing requests (3)
Created Duration User Patch Repo Result
2026/07/22 07:40 31m joshua.crofts1@gmail.com patch upstream log
2026/07/16 22:05 3h53m joshua.crofts1@gmail.com patch git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 58717b2a1365 log
2026/07/16 11:19 6h01m joshua.crofts1@gmail.com patch upstream log

Sample crash report:
INFO: task syz.3.20:6062 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.20        state:D
 stack:25640 pid:6062  tgid:6052  ppid:5793   task_flags:0x400040 flags:0x00080002
Call Trace:
 <TASK>
 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
 rwsem_down_read_slowpath+0x6ba/0x920 kernel/locking/rwsem.c:1114
 __down_read_common kernel/locking/rwsem.c:1291 [inline]
 __down_read kernel/locking/rwsem.c:1304 [inline]
 down_read+0x9c/0x330 kernel/locking/rwsem.c:1576
 nilfs_transaction_begin+0x364/0x710 fs/nilfs2/segment.c:221
 nilfs_mkdir+0xd6/0x390 fs/nilfs2/namei.c:228
 vfs_mkdir+0x406/0x620 fs/namei.c:5276
 filename_mkdirat+0x285/0x510 fs/namei.c:5309
 __do_sys_mkdirat fs/namei.c:5330 [inline]
 __se_sys_mkdirat+0x35/0x150 fs/namei.c:5327
 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: 0033:0x7f1613b9de59
RSP: 002b:00007f16131fe028 EFLAGS: 00000246
 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007f1613e26090 RCX: 00007f1613b9de59
RDX: 00000000000001c0 RSI: 0000200000000040 RDI: ffffffffffffff9c
RBP: 00007f1613c33e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1613e26128 R14: 00007f1613e26090 R15: 00007ffd7ee97478
 </TASK>
INFO: task syz.2.19:6076 blocked for more than 147 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.19        state:D stack:26920 pid:6076  tgid:6073  ppid:5797   task_flags:0x400040 flags:0x00080002
Call Trace:
 <TASK>
 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
 rwsem_down_read_slowpath+0x6ba/0x920 kernel/locking/rwsem.c:1114
 __down_read_common kernel/locking/rwsem.c:1291 [inline]
 __down_read kernel/locking/rwsem.c:1304 [inline]
 down_read+0x9c/0x330 kernel/locking/rwsem.c:1576
 nilfs_transaction_begin+0x364/0x710 fs/nilfs2/segment.c:221
 nilfs_mkdir+0xd6/0x390 fs/nilfs2/namei.c:228
 vfs_mkdir+0x406/0x620 fs/namei.c:5276
 filename_mkdirat+0x285/0x510 fs/namei.c:5309
 __do_sys_mkdirat fs/namei.c:5330 [inline]
 __se_sys_mkdirat+0x35/0x150 fs/namei.c:5327
 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: 0033:0x7feb9c39de59
RSP: 002b:00007feb9d17e028 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007feb9c626090 RCX: 00007feb9c39de59
RDX: 00000000000001c0 RSI: 0000200000000040 RDI: ffffffffffffff9c
RBP: 00007feb9c433e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007feb9c626128 R14: 00007feb9c626090 R15: 00007fff8cce9fb8
 </TASK>
INFO: task syz.0.17:6080 blocked for more than 149 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.17        state:D
 stack:25640 pid:6080  tgid:6077  ppid:5784   task_flags:0x400040 flags:0x00080002
Call Trace:
 <TASK>
 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
 rwsem_down_read_slowpath+0x6ba/0x920 kernel/locking/rwsem.c:1114
 __down_read_common kernel/locking/rwsem.c:1291 [inline]
 __down_read kernel/locking/rwsem.c:1304 [inline]
 down_read+0x9c/0x330 kernel/locking/rwsem.c:1576
 nilfs_transaction_begin+0x364/0x710 fs/nilfs2/segment.c:221
 nilfs_mkdir+0xd6/0x390 fs/nilfs2/namei.c:228
 vfs_mkdir+0x406/0x620 fs/namei.c:5276
 filename_mkdirat+0x285/0x510 fs/namei.c:5309
 __do_sys_mkdirat fs/namei.c:5330 [inline]
 __se_sys_mkdirat+0x35/0x150 fs/namei.c:5327
 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: 0033:0x7f172919de59
RSP: 002b:00007f172a11e028 EFLAGS: 00000246
 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007f1729426090 RCX: 00007f172919de59
RDX: 00000000000001c0 RSI: 0000200000000040 RDI: ffffffffffffff9c
RBP: 00007f1729233e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1729426128 R14: 00007f1729426090 R15: 00007ffcc8738ab8
 </TASK>
INFO: task syz.5.22:6086 blocked for more than 153 seconds.
      Not tainted syzkaller #0

Crashes (6):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/07/15 21:18 upstream 58717b2a1365 209f0369 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci-upstream-kasan-gce-root INFO: task hung in nilfs_transaction_begin
2026/07/31 21:54 upstream 8ba098e6b6ff 7664cf44 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: task hung in nilfs_transaction_begin
2026/07/29 16:28 upstream fc02acf6ac0c cb1587ea .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: task hung in nilfs_transaction_begin
2026/07/27 19:13 upstream f5098b6bae76 4cb2b096 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: task hung in nilfs_transaction_begin
2026/07/15 17:06 upstream 58717b2a1365 209f0369 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: task hung in nilfs_transaction_begin
2026/08/13 02:11 linux-next 28d012efb432 7ae4acc7 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: task hung in nilfs_transaction_begin
* Struck through repros no longer work on HEAD.