syzbot


INFO: task hung in deactivate_super (3)

Status: upstream: reported C repro on 2024/05/27 12:00
Bug presence: origin:lts-only
[Documentation on labels]
Reported-by: syzbot+4ae63a93dbe1440d6ba3@syzkaller.appspotmail.com
First crash: 258d, last: 16m
Fix commit to backport (bisect log) :
tree: upstream
commit fb6f20ecb121cef4d7946f834a6ee867c4e21b4a
Author: Jan Kara <jack@suse.cz>
Date: Thu Oct 17 10:28:23 2024 +0000

  reiserfs: The last commit

  
Bug presence (2)
Date Name Commit Repro Result
2025/01/05 linux-6.1.y (ToT) 7dc732d24ff7 C [report] INFO: task hung in deactivate_super
2025/01/05 upstream (ToT) ab75170520d4 C Didn't crash
Similar bugs (10)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-49 INFO: task hung in deactivate_super 3 2403d 2420d 0/3 auto-closed as invalid on 2019/02/22 12:34
linux-6.1 INFO: task hung in deactivate_super 4 541d 590d 0/3 auto-obsoleted due to no activity on 2023/11/26 12:17
linux-4.14 INFO: task hung in deactivate_super 1 2113d 2113d 0/1 auto-closed as invalid on 2019/10/25 08:42
upstream INFO: task hung in deactivate_super exfat 36 2224d 2327d 0/28 closed as dup on 2018/10/27 13:17
upstream INFO: task hung in deactivate_super (2) reiserfs C inconclusive done 121 343d 682d 25/28 fixed on 2024/04/08 19:23
upstream INFO: task hung in deactivate_super (3) jfs bcachefs 69 28d 213d 0/28 upstream: reported on 2024/07/11 01:05
linux-5.15 INFO: task hung in deactivate_super 4 538d 626d 0/3 auto-obsoleted due to no activity on 2023/11/29 20:11
linux-6.1 INFO: task hung in deactivate_super (2) 1 361d 361d 0/3 auto-obsoleted due to no activity on 2024/05/24 05:27
linux-5.15 INFO: task hung in deactivate_super (2) origin:upstream missing-backport C done 3 4d10h 105d 0/3 upstream: reported C repro on 2024/10/27 03:45
linux-4.19 INFO: task hung in deactivate_super 4 715d 816d 0/1 upstream: reported on 2022/11/16 10:48
Fix bisection attempts (1)
Created Duration User Patch Repo Result
2025/01/11 04:26 8h25m fix candidate upstream OK (1) job log

Sample crash report:
INFO: task syz-executor329:4248 blocked for more than 143 seconds.
      Not tainted 6.1.128-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor329 state:D stack:23880 pid:4248  ppid:4245   flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5241 [inline]
 __schedule+0x143f/0x4570 kernel/sched/core.c:6558
 schedule+0xbf/0x180 kernel/sched/core.c:6634
 rwsem_down_write_slowpath+0xea1/0x14b0 kernel/locking/rwsem.c:1189
 deactivate_super+0xa9/0xe0 fs/super.c:362
 cleanup_mnt+0x490/0x520 fs/namespace.c:1186
 task_work_run+0x246/0x300 kernel/task_work.c:203
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0xde/0x100 kernel/entry/common.c:177
 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
 syscall_exit_to_user_mode+0x60/0x270 kernel/entry/common.c:303
 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:87
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fcb54d8a467
RSP: 002b:00007ffd26d97e68 EFLAGS: 00000202 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007fcb54d8a467
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffd26d97f20
RBP: 00007ffd26d97f20 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000202 R12: 00007ffd26d98fd0
R13: 000055556228c700 R14: 431bde82d7b634db R15: 00007ffd26d98f74
 </TASK>

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
 #0: ffffffff8d32b290 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x29/0xe30 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
 #0: ffffffff8d32ba90 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x29/0xe30 kernel/rcu/tasks.h:517
1 lock held by khungtaskd/28:
 #0: ffffffff8d32b0c0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 #0: ffffffff8d32b0c0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
 #0: ffffffff8d32b0c0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6510
2 locks held by getty/4007:
 #0: ffff88803125a098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
 #1: ffffc9000325e2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6a7/0x1db0 drivers/tty/n_tty.c:2198
1 lock held by syz-executor329/4248:
 #0: ffff88807dd380e0 (&type->s_umount_key#31){++++}-{3:3}, at: deactivate_super+0xa9/0xe0 fs/super.c:362
2 locks held by ext4lazyinit/4615:

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

NMI backtrace for cpu 0
CPU: 0 PID: 28 Comm: khungtaskd Not tainted 6.1.128-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
 nmi_cpu_backtrace+0x4e1/0x560 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x1ae/0x3f0 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline]
 watchdog+0xf88/0xfd0 kernel/hung_task.c:377
 kthread+0x28d/0x320 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 4615 Comm: ext4lazyinit Not tainted 6.1.128-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
RIP: 0010:preempt_count_add+0x0/0x180 kernel/sched/core.c:5697
Code: 48 8b 0c 24 80 e1 07 80 c1 03 38 c1 7c 97 48 8b 3c 24 e8 73 a1 83 00 eb 8c e9 f2 fe ff ff 66 2e 0f 1f 84 00 00 00 00 00 66 90 <41> 57 41 56 53 89 fb 48 c7 c0 60 71 35 97 48 c1 e8 03 49 bf 00 00
RSP: 0018:ffffc90004be7a28 EFLAGS: 00000282
RAX: ffffea0001d363c0 RBX: ffff888148c8cbc8 RCX: ffff88802b46bb80
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000001
RBP: ffffc90004be7b78 R08: ffffffff81bb4446 R09: fffff940003a6c79
R10: 0000000000000000 R11: dffffc0000000001 R12: ffff888148c8cbc8
R13: ffffea0001d363c0 R14: 1ffff11029191913 R15: ffff888148c8c89a
FS:  0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055636b4e4600 CR3: 000000007eaa4000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 __raw_spin_lock include/linux/spinlock_api_smp.h:132 [inline]
 _raw_spin_lock+0xe/0x40 kernel/locking/spinlock.c:154
 spin_lock include/linux/spinlock.h:351 [inline]
 __find_get_block_slow fs/buffer.c:206 [inline]
 __find_get_block+0x3f8/0x1120 fs/buffer.c:1307
 __getblk_slow fs/buffer.c:1034 [inline]
 __getblk_gfp+0x146/0xa20 fs/buffer.c:1333
 sb_getblk include/linux/buffer_head.h:356 [inline]
 ext4_read_block_bitmap_nowait+0x1ff/0x980 fs/ext4/balloc.c:482
 ext4_mb_prefetch+0x46d/0x640 fs/ext4/mballoc.c:2587
 ext4_run_li_request fs/ext4/super.c:3644 [inline]
 ext4_lazyinit_thread+0x54d/0x1ad0 fs/ext4/super.c:3770
 kthread+0x28d/0x320 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>

Crashes (16):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/02/09 23:23 linux-6.1.y 0cbb5f65e52f ef44b750 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro #1 (clean fs)] [mounted in repro #2 (corrupt fs)] ci2-linux-6-1-kasan INFO: task hung in deactivate_super
2025/01/04 15:55 linux-6.1.y 7dc732d24ff7 f3558dbf .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-6-1-kasan INFO: task hung in deactivate_super
2025/02/05 05:53 linux-6.1.y 0cbb5f65e52f 5896748e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in deactivate_super
2025/02/05 05:51 linux-6.1.y 0cbb5f65e52f 5896748e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in deactivate_super
2025/01/21 02:02 linux-6.1.y f4f677285b38 6e87cfa2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in deactivate_super
2024/12/28 04:16 linux-6.1.y 563edd786f0a d3ccff63 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in deactivate_super
2024/12/13 16:52 linux-6.1.y e4d90d63d385 3547e30f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in deactivate_super
2024/11/28 05:29 linux-6.1.y e4d90d63d385 5df23865 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in deactivate_super
2024/11/23 03:13 linux-6.1.y e4d90d63d385 68da6d95 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in deactivate_super
2024/10/08 23:22 linux-6.1.y aa4cd140bba5 402f1df0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in deactivate_super
2024/09/26 13:00 linux-6.1.y e526b12bf916 0d19f247 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in deactivate_super
2024/09/12 07:27 linux-6.1.y 5ca5b389fddf d94c83d8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in deactivate_super
2024/08/14 16:45 linux-6.1.y 117ac406ba90 e6b88e20 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in deactivate_super
2024/07/30 11:12 linux-6.1.y c1cec4dad96b 5187fc86 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in deactivate_super
2024/12/08 03:31 linux-6.1.y e4d90d63d385 9ac0fdc6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 INFO: task hung in deactivate_super
2024/05/27 12:00 linux-6.1.y 88690811da69 761766e6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 INFO: task hung in deactivate_super
* Struck through repros no longer work on HEAD.