syzbot


INFO: task hung in iterate_supers

Status: upstream: reported C repro on 2023/03/08 18:22
Bug presence: origin:lts-only
[Documentation on labels]
Reported-by: syzbot+b2fb36aa868ed8376328@syzkaller.appspotmail.com
First crash: 814d, last: 14h47m
Bug presence (2)
Date Name Commit Repro Result
2023/05/03 linux-5.15.y (ToT) 8a7f2a5c5aa1 C [report] INFO: task hung in iterate_supers
2023/05/03 upstream (ToT) 348551ddaf31 C Didn't crash
Similar bugs (11)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-414 INFO: task hung in iterate_supers 1 2405d 2242d 0/1 auto-closed as invalid on 2019/04/28 09:45
linux-4.14 INFO: task hung in iterate_supers 16 1612d 2227d 0/1 auto-closed as invalid on 2021/04/29 12:11
linux-4.19 INFO: task hung in iterate_supers (2) 1 1814d 1814d 0/1 auto-closed as invalid on 2020/10/09 12:15
upstream INFO: task hung in iterate_supers 9p C error 5804 4d04h 2517d 0/28 upstream: reported C repro on 2018/07/10 10:30
linux-6.1 INFO: task hung in iterate_supers origin:upstream C 284 5d22h 812d 0/3 upstream: reported C repro on 2023/03/10 21:24
linux-4.14 INFO: task hung in iterate_supers (2) 1 826d 826d 0/1 upstream: reported on 2023/02/24 15:59
linux-4.19 INFO: task hung in iterate_supers 7 1947d 2134d 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 816d 1623d 0/1 upstream: reported syz repro on 2020/12/20 03:38
android-49 INFO: task hung in iterate_supers 19 2466d 2567d 0/3 auto-closed as invalid on 2019/02/25 14:49
android-414 INFO: task hung in iterate_supers (2) 1 2223d 2223d 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 1447d 1443d 0/28 auto-closed as invalid on 2021/08/13 03:51
Fix bisection attempts (1)
Created Duration User Patch Repo Result
2023/10/19 02:40 2h25m fix candidate upstream OK (0) job log log

Sample crash report:
INFO: task syz-executor268:4194 blocked for more than 143 seconds.
      Not tainted 5.15.184-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor268 state:D stack:27824 pid: 4194 ppid:  4190 flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5030 [inline]
 __schedule+0x11b8/0x43b0 kernel/sched/core.c:6376
 schedule+0x11b/0x1e0 kernel/sched/core.c:6459
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6518
 rwsem_down_read_slowpath+0x528/0x990 kernel/locking/rwsem.c:1055
 __down_read_common kernel/locking/rwsem.c:1239 [inline]
 __down_read kernel/locking/rwsem.c:1252 [inline]
 down_read+0x96/0x2e0 kernel/locking/rwsem.c:1500
 iterate_supers+0xa4/0x1d0 fs/super.c:716
 ksys_sync+0x91/0x150 fs/sync.c:102
 __ia32_sys_sync+0xa/0x10 fs/sync.c:113
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fbb60d4b7a9
RSP: 002b:00007fbb60ceb218 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007fbb60dd53f8 RCX: 00007fbb60d4b7a9
RDX: 00007fbb60d27e46 RSI: 0000000000000000 RDI: 00007fbb60cebfb0
RBP: 00007fbb60dd53f0 R08: 00007ffc0a754aa7 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fbb60da207c
R13: 0030656c69662f2e R14: 0000200000000040 R15: 00007ffc0a754aa8
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/27:
 #0: ffffffff8c11c060 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
2 locks held by getty/3937:
 #0: ffff88802b9dd098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
 #1: ffffc900026362e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x5ba/0x1a30 drivers/tty/n_tty.c:2158
1 lock held by syz-executor268/4192:
 #0: ffff88801a1d00e0 (&type->s_umount_key#42/1){+.+.}-{3:3}, at: alloc_super+0x201/0x950 fs/super.c:229
1 lock held by syz-executor268/4194:
 #0: ffff88801a1d00e0 (&type->s_umount_key#65){.+.+}-{3:3}, at: iterate_supers+0xa4/0x1d0 fs/super.c:716

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

NMI backtrace for cpu 1
CPU: 1 PID: 27 Comm: khungtaskd Not tainted 5.15.184-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x397/0x3d0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:212 [inline]
 watchdog+0xe0f/0xe50 kernel/hung_task.c:369
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </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:51 [inline]
NMI backtrace for cpu 0 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
NMI backtrace for cpu 0 skipped: idling at default_idle+0xb/0x10 arch/x86/kernel/process.c:722

Crashes (298):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/05/28 02:46 linux-5.15.y 98f47d0e9b8c 874a1386 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in iterate_supers
2025/03/03 10:07 linux-5.15.y c16c81c81336 c3901742 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in iterate_supers
2025/02/26 05:34 linux-5.15.y c16c81c81336 d34966d1 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in iterate_supers
2024/05/12 10:44 linux-5.15.y 284087d4f7d5 9026e142 .config console log report syz C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in iterate_supers
2023/03/19 08:17 linux-5.15.y 8020ae3c051d 7939252e .config console log report syz C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in iterate_supers
2024/05/02 12:09 linux-5.15.y b925f60c6ee7 3ba885bc .config console log report syz C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 INFO: task hung in iterate_supers
2025/05/30 21:08 linux-5.15.y 98f47d0e9b8c 3d2f584d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in iterate_supers
2025/05/25 03:53 linux-5.15.y 98f47d0e9b8c ed351ea7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in iterate_supers
2025/05/19 10:19 linux-5.15.y a68c15152131 f41472b0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in iterate_supers
2025/05/19 03:26 linux-5.15.y a68c15152131 f41472b0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in iterate_supers
2025/05/11 10:59 linux-5.15.y 3b8db0e4f263 77908e5f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in iterate_supers
2025/05/09 22:24 linux-5.15.y 3b8db0e4f263 77908e5f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in iterate_supers
2025/05/01 07:35 linux-5.15.y f7347f400572 ce7952f4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in iterate_supers
2025/04/24 12:27 linux-5.15.y f7347f400572 9882047a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in iterate_supers
2025/04/22 03:13 linux-5.15.y f7347f400572 2a20f901 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in iterate_supers
2025/04/22 02:04 linux-5.15.y f7347f400572 2a20f901 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in iterate_supers
2025/04/20 19:54 linux-5.15.y f7347f400572 2a20f901 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in iterate_supers
2025/04/20 12:44 linux-5.15.y f7347f400572 2a20f901 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in iterate_supers
2025/04/19 23:57 linux-5.15.y f7347f400572 2a20f901 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in iterate_supers
2025/04/16 02:45 linux-5.15.y f7347f400572 a95239b1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in iterate_supers
2025/04/15 16:57 linux-5.15.y f7347f400572 23b969b7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in iterate_supers
2025/04/12 00:31 linux-5.15.y f7347f400572 0bd6db41 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in iterate_supers
2025/04/09 14:04 linux-5.15.y 0c935c049b5c 47d015b1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in iterate_supers
2025/04/09 09:28 linux-5.15.y 0c935c049b5c a775275d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in iterate_supers
2025/04/09 08:25 linux-5.15.y 0c935c049b5c a775275d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in iterate_supers
2025/04/08 21:01 linux-5.15.y 0c935c049b5c a775275d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in iterate_supers
2025/04/08 14:45 linux-5.15.y 0c935c049b5c a775275d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in iterate_supers
2025/04/08 07:17 linux-5.15.y 0c935c049b5c a2ada0e7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in iterate_supers
2025/04/02 00:51 linux-5.15.y 0c935c049b5c b8645499 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in iterate_supers
2025/03/30 21:31 linux-5.15.y 0c935c049b5c d3999433 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in iterate_supers
2025/03/25 13:40 linux-5.15.y 0c935c049b5c 875573af .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in iterate_supers
2025/03/22 00:43 linux-5.15.y 0c935c049b5c c6512ef7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in iterate_supers
2025/03/19 15:03 linux-5.15.y 0c935c049b5c 8d0a2921 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in iterate_supers
2025/03/14 04:06 linux-5.15.y 0c935c049b5c e2826670 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in iterate_supers
2025/03/13 01:55 linux-5.15.y c16c81c81336 1a5d9317 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in iterate_supers
2025/03/07 20:19 linux-5.15.y c16c81c81336 7e3bd60d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in iterate_supers
2025/03/04 04:50 linux-5.15.y c16c81c81336 c3901742 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in iterate_supers
2025/02/27 23:29 linux-5.15.y c16c81c81336 6a8fcbc4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in iterate_supers
2025/02/24 03:30 linux-5.15.y c16c81c81336 d34966d1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in iterate_supers
2025/02/20 07:21 linux-5.15.y c16c81c81336 50668798 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in iterate_supers
2025/02/19 19:19 linux-5.15.y c16c81c81336 b257a9b7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in iterate_supers
2025/02/14 07:10 linux-5.15.y c16c81c81336 d9a046cf .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in iterate_supers
2025/02/10 00:13 linux-5.15.y c16c81c81336 ef44b750 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in iterate_supers
2025/02/09 03:13 linux-5.15.y c16c81c81336 ef44b750 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in iterate_supers
2025/01/30 19:27 linux-5.15.y 003148680b79 4c6ac32f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in iterate_supers
2025/01/30 09:18 linux-5.15.y 003148680b79 afe4eff5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in iterate_supers
2025/01/26 01:53 linux-5.15.y 003148680b79 9fbd772e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in iterate_supers
2025/05/13 20:42 linux-5.15.y 3b8db0e4f263 7344edeb .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 INFO: task hung in iterate_supers
2025/05/08 21:31 linux-5.15.y 16fdf2c7111b dbf35fa1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 INFO: task hung in iterate_supers
2025/05/08 09:25 linux-5.15.y 16fdf2c7111b dbf35fa1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 INFO: task hung in iterate_supers
2025/04/23 01:43 linux-5.15.y f7347f400572 53a8b9bd .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 INFO: task hung in iterate_supers
2025/04/04 23:03 linux-5.15.y 0c935c049b5c 1c4febdb .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 INFO: task hung in iterate_supers
2025/03/09 05:30 linux-5.15.y c16c81c81336 163f510d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 INFO: task hung in iterate_supers
2025/03/03 01:45 linux-5.15.y c16c81c81336 c3901742 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 INFO: task hung in iterate_supers
2025/01/28 02:51 linux-5.15.y 003148680b79 18070896 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 INFO: task hung in iterate_supers
2023/03/08 18:22 linux-5.15.y d9b4a0c83a2d 4fc6d98d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in iterate_supers
* Struck through repros no longer work on HEAD.