syzbot


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: 144d, last: 12h23m
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 Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-414 INFO: task hung in iterate_supers 1 1 2570d 2408d 0/1 auto-closed as invalid on 2019/04/28 09:45
linux-4.14 INFO: task hung in iterate_supers 1 16 1778d 2393d 0/1 auto-closed as invalid on 2021/04/29 12:11
linux-4.19 INFO: task hung in iterate_supers (2) 1 1 1980d 1980d 0/1 auto-closed as invalid on 2020/10/09 12:15
upstream INFO: task hung in iterate_supers 9p 1 C error error 5804 61d 2682d 0/29 upstream: reported C repro on 2018/07/10 10:30
linux-5.15 INFO: task hung in iterate_supers origin:lts-only 1 C 346 6d15h 980d 0/3 upstream: reported C repro on 2023/03/08 18:22
linux-6.1 INFO: task hung in iterate_supers origin:upstream 1 C 319 2d03h 978d 0/3 upstream: reported C repro on 2023/03/10 21:24
linux-4.14 INFO: task hung in iterate_supers (2) 1 1 992d 992d 0/1 upstream: reported on 2023/02/24 15:59
linux-4.19 INFO: task hung in iterate_supers 1 7 2113d 2300d 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 1 syz 378 982d 1789d 0/1 upstream: reported syz repro on 2020/12/20 03:38
android-49 INFO: task hung in iterate_supers 1 19 2632d 2732d 0/3 auto-closed as invalid on 2019/02/25 14:49
linux-6.6 INFO: task hung in iterate_supers origin:upstream missing-backport 1 C 26 8h11m 146d 0/2 upstream: reported C repro on 2025/06/20 00:37
android-414 INFO: task hung in iterate_supers (2) 1 1 2389d 2389d 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 1 1613d 1609d 0/29 auto-closed as invalid on 2021/08/13 03:51

Sample crash report:
INFO: task syz.2.17:383 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:383   tgid:380   ppid:370    flags:0x00004004
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
 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: 0033:0x7f5e6998f6c9
RSP: 002b:00007f5e6a89f038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f5e69be6090 RCX: 00007f5e6998f6c9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f5e69be6090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5e69be6128 R14: 00007f5e69be6090 R15: 00007ffe1080a3b8
 </TASK>
INFO: task syz.3.18:401 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:401   tgid:397   ppid:387    flags:0x00004004
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
 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: 0033:0x7f56af18f6c9
RSP: 002b:00007f56aefff038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f56af3e6090 RCX: 00007f56af18f6c9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f56af3e6090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f56af3e6128 R14: 00007f56af3e6090 R15: 00007ffd45d99588
 </TASK>
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 37 Comm: khungtaskd Not tainted syzkaller #0 0b5ffdee5fcd2f7749818d1ff954e9c21353764e
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
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 0b5ffdee5fcd2f7749818d1ff954e9c21353764e
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:pv_native_safe_halt+0x17/0x20 arch/x86/kernel/paravirt.c:106
Code: cc cc cc b8 69 d8 84 08 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d c3 e2 39 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: ffff88810366cc00 RCX: ffffffff858d70be
RDX: 0000000000000001 RSI: 0000000000000004 RDI: 0000000000044a4c
RBP: ffffc900001a7e00 R08: ffff8881f6f39733 R09: 1ffff1103ede72e6
R10: dffffc0000000000 R11: ffffed103ede72e7 R12: 1ffff110206cd980
R13: 0000000000000001 R14: 0000000000000000 R15: ffffffff87cb2128
FS:  0000000000000000(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555591ede4a8 CR3: 00000001056f0000 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 (1359):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/11/06 11:01 android16-6.12 0d6730ee6542 a6c9c731 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/11/01 10:21 android16-6.12 0d6730ee6542 2c50b6a9 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/11/01 00:05 android16-6.12 0d6730ee6542 2c50b6a9 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/10/29 14:37 android16-6.12 0d6730ee6542 fd2207e7 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/10/06 09:49 android16-6.12 5af7694050d7 49379ee0 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/09/21 11:34 android16-6.12 8419b8c58fd1 67c37560 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/09/17 21:41 android16-6.12 c882e6efcea1 e2beed91 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/09/11 22:36 android16-6.12 6d5091a761f0 e2beed91 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/09/06 03:56 android16-6.12 6904c5603852 d291dd2d .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/09/01 12:32 android16-6.12 2e5a4bace74a 807a3b61 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/08/11 06:25 android16-6.12 c46482c03ae9 32a0e5ed .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 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
2025/11/12 16:38 android16-6.12 0d6730ee6542 07e030de .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/11/12 15:09 android16-6.12 0d6730ee6542 07e030de .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/11/12 13:53 android16-6.12 0d6730ee6542 07e030de .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/11/12 05:17 android16-6.12 0d6730ee6542 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/11/11 21:21 android16-6.12 0d6730ee6542 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/11/11 18:43 android16-6.12 0d6730ee6542 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/11/11 17:41 android16-6.12 0d6730ee6542 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/11/11 10:20 android16-6.12 0d6730ee6542 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/11/11 09:02 android16-6.12 0d6730ee6542 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/11/11 03:52 android16-6.12 0d6730ee6542 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/11/10 22:20 android16-6.12 0d6730ee6542 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/11/10 19:23 android16-6.12 0d6730ee6542 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/11/10 15:03 android16-6.12 0d6730ee6542 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/11/10 11:21 android16-6.12 0d6730ee6542 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/11/10 05:12 android16-6.12 0d6730ee6542 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/11/09 22:33 android16-6.12 0d6730ee6542 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/11/09 19:30 android16-6.12 0d6730ee6542 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/11/09 13:57 android16-6.12 0d6730ee6542 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/11/09 08:18 android16-6.12 0d6730ee6542 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/11/09 03:56 android16-6.12 0d6730ee6542 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/11/08 21:48 android16-6.12 0d6730ee6542 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/11/08 16:25 android16-6.12 0d6730ee6542 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/11/08 11:27 android16-6.12 0d6730ee6542 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/11/08 08:31 android16-6.12 0d6730ee6542 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/11/08 03:20 android16-6.12 0d6730ee6542 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/11/07 12:50 android16-6.12 0d6730ee6542 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/11/07 07:31 android16-6.12 0d6730ee6542 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/11/07 01:48 android16-6.12 0d6730ee6542 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/11/06 23:37 android16-6.12 0d6730ee6542 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/11/06 20:48 android16-6.12 0d6730ee6542 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/11/06 16:01 android16-6.12 0d6730ee6542 a6c9c731 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/11/06 13:13 android16-6.12 0d6730ee6542 a6c9c731 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/11/06 10:45 android16-6.12 0d6730ee6542 a6c9c731 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/11/06 09:26 android16-6.12 0d6730ee6542 a6c9c731 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/11/06 08:08 android16-6.12 0d6730ee6542 a6c9c731 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/11/06 06:35 android16-6.12 0d6730ee6542 a6c9c731 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/11/06 05:22 android16-6.12 0d6730ee6542 a6c9c731 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/11/06 01:39 android16-6.12 0d6730ee6542 a6c9c731 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/11/06 00:02 android16-6.12 0d6730ee6542 a6c9c731 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/11/05 20:53 android16-6.12 0d6730ee6542 a6c9c731 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/11/05 19:53 android16-6.12 0d6730ee6542 a6c9c731 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/11/05 17:31 android16-6.12 0d6730ee6542 a6c9c731 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/11/05 13:00 android16-6.12 0d6730ee6542 a6c9c731 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/11/05 11:56 android16-6.12 0d6730ee6542 a6c9c731 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/11/05 07:51 android16-6.12 0d6730ee6542 a6c9c731 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/11/04 22:49 android16-6.12 0d6730ee6542 686bf657 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in iterate_supers
2025/11/04 09:41 android16-6.12 0d6730ee6542 686bf657 .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.