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INFO: task hung in iterate_supers

Status: premoderation: reported C repro on 2025/06/21 16:44
Bug presence: origin:upstream
[Documentation on labels]
Reported-by: syzbot+53026d8de9c01a44d38e@syzkaller.appspotmail.com
First crash: 3d04h, last: 1d04h
▶ ▼ Bug presence (2)
Date Name Commit Repro Result
2025/06/24 lts (merge base) e0e2f7824338 C [report] INFO: task hung in iterate_supers
2025/06/24 upstream (ToT) 78f4e737a53e C [report] INFO: task hung in __iterate_supers
▶ ▼ Similar bugs (13)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-414 INFO: task hung in iterate_supers 1 2429d 2267d 0/1 auto-closed as invalid on 2019/04/28 09:45
linux-4.14 INFO: task hung in iterate_supers 16 1637d 2252d 0/1 auto-closed as invalid on 2021/04/29 12:11
linux-4.19 INFO: task hung in iterate_supers (2) 1 1839d 1839d 0/1 auto-closed as invalid on 2020/10/09 12:15
upstream INFO: task hung in iterate_supers 9p C error 5804 28d 2541d 0/29 upstream: reported C repro on 2018/07/10 10:30
linux-5.15 INFO: task hung in iterate_supers origin:lts-only C 308 2d06h 839d 0/3 upstream: reported C repro on 2023/03/08 18:22
linux-6.1 INFO: task hung in iterate_supers origin:upstream C 299 2d03h 836d 0/3 upstream: reported C repro on 2023/03/10 21:24
linux-4.14 INFO: task hung in iterate_supers (2) 1 851d 851d 0/1 upstream: reported on 2023/02/24 15:59
linux-4.19 INFO: task hung in iterate_supers 7 1971d 2159d 0/1 auto-closed as invalid on 2020/05/29 21:42
linux-4.19 INFO: task hung in iterate_supers (3) vfs reiserfs ntfs syz 378 841d 1647d 0/1 upstream: reported syz repro on 2020/12/20 03:38
android-49 INFO: task hung in iterate_supers 19 2491d 2591d 0/3 auto-closed as invalid on 2019/02/25 14:49
linux-6.6 INFO: task hung in iterate_supers 1 4d20h 4d20h 0/2 upstream: reported on 2025/06/20 00:37
android-414 INFO: task hung in iterate_supers (2) 1 2248d 2248d 0/1 auto-closed as invalid on 2019/10/25 08:49
upstream INFO: task can't die in iterate_supers (2) ceph fs 1 1471d 1467d 0/29 auto-closed as invalid on 2021/08/13 03:51

Sample crash report:
INFO: task syz-executor196:300 blocked for more than 122 seconds.
      Not tainted 6.12.23-syzkaller-gd9fd901baa98 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor196 state:D stack:0     pid:300   tgid:297   ppid:296    flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5924 [inline]
 __schedule+0x145b/0x1f10 kernel/sched/core.c:7750
 __schedule_loop kernel/sched/core.c:7831 [inline]
 schedule+0xc6/0x240 kernel/sched/core.c:7846
 super_lock+0x150/0x300 fs/super.c:115
 super_lock_shared fs/super.c:140 [inline]
 iterate_supers+0x8a/0x560 fs/super.c:934
 ksys_sync+0x95/0x160 fs/sync.c:103
 __ia32_sys_sync+0x12/0x20 fs/sync.c:114
 x64_sys_call+0x2a58/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:163
 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: 0033:0x7f34db49a7e9
RSP: 002b:00007f34db426218 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f34db5243f8 RCX: 00007f34db49a7e9
RDX: 00007f34db476e86 RSI: 0000000000000000 RDI: 00007f34db426fb0
RBP: 00007f34db5243f0 R08: 00007ffe7fb51527 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f34db4f107c
R13: 000000000000006e R14: 0030656c69662f2e R15: 00002000000002c0
 </TASK>
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 37 Comm: khungtaskd Not tainted 6.12.23-syzkaller-gd9fd901baa98 #0 f1acc3ef52b3e732a05c4f7a2560722db90bb473
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
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:229 [inline]
 watchdog+0xd8f/0xed0 kernel/hung_task.c:385
 kthread+0x2c7/0x370 kernel/kthread.c:389
 ret_from_fork+0x64/0xa0 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:48 [inline]
NMI backtrace for cpu 0 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:106 [inline]
NMI backtrace for cpu 0 skipped: idling at default_idle+0x17/0x20 arch/x86/kernel/process.c:748

Crashes (12):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/06/23 03:07 android16-6.12 d9fd901baa98 d6cdfb8a .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/06/22 21:39 android16-6.12 d9fd901baa98 d6cdfb8a .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/06/22 17:48 android16-6.12 d9fd901baa98 d6cdfb8a .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/06/22 08:10 android16-6.12 d9fd901baa98 d6cdfb8a .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/06/23 16:46 android16-6.12 5bf4b91e3333 d6cdfb8a .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/06/23 15:09 android16-6.12 5bf4b91e3333 d6cdfb8a .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/06/23 09:49 android16-6.12 5bf4b91e3333 d6cdfb8a .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/06/23 09:44 android16-6.12 5bf4b91e3333 d6cdfb8a .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/06/22 23:54 android16-6.12 d9fd901baa98 d6cdfb8a .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/06/22 21:17 android16-6.12 d9fd901baa98 d6cdfb8a .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/06/21 18:21 android16-6.12 d9fd901baa98 d6cdfb8a .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/06/21 16:43 android16-6.12 d9fd901baa98 d6cdfb8a .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
* Struck through repros no longer work on HEAD.