syzbot


INFO: task hung in lmLogOpen (2)

Status: auto-obsoleted due to no activity on 2026/02/06 01:14
Subsystems: jfs
[Documentation on labels]
First crash: 487d, last: 118d
Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.6 INFO: task hung in lmLogOpen 1 2 125d 182d 0/2 auto-obsoleted due to no activity on 2026/02/09 19:50
upstream INFO: task hung in lmLogOpen jfs 1 2 632d 643d 0/29 auto-obsoleted due to no activity on 2024/09/10 01:34

Sample crash report:
INFO: task syz.6.85:6738 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.6.85        state:D stack:25768 pid:6738  tgid:6737  ppid:6442   task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5325 [inline]
 __schedule+0x16f3/0x4c20 kernel/sched/core.c:6929
 __schedule_loop kernel/sched/core.c:7011 [inline]
 rt_mutex_schedule+0x77/0xf0 kernel/sched/core.c:7307
 rt_mutex_slowlock_block+0x5ba/0x6d0 kernel/locking/rtmutex.c:1647
 __rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline]
 __rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1760 [inline]
 rt_mutex_slowlock+0x2b1/0x6e0 kernel/locking/rtmutex.c:1800
 __rt_mutex_lock kernel/locking/rtmutex.c:1815 [inline]
 __mutex_lock_common kernel/locking/rtmutex_api.c:536 [inline]
 mutex_lock_nested+0x16a/0x1d0 kernel/locking/rtmutex_api.c:547
 open_dummy_log fs/jfs/jfs_logmgr.c:1191 [inline]
 lmLogOpen+0x1a1/0xfa0 fs/jfs/jfs_logmgr.c:1066
 jfs_mount_rw+0xe9/0x670 fs/jfs/jfs_mount.c:257
 jfs_fill_super+0x754/0xd80 fs/jfs/super.c:532
 get_tree_bdev_flags+0x40e/0x4d0 fs/super.c:1691
 vfs_get_tree+0x92/0x2b0 fs/super.c:1751
 fc_mount fs/namespace.c:1208 [inline]
 do_new_mount_fc fs/namespace.c:3651 [inline]
 do_new_mount+0x302/0xa10 fs/namespace.c:3727
 do_mount fs/namespace.c:4050 [inline]
 __do_sys_mount fs/namespace.c:4238 [inline]
 __se_sys_mount+0x313/0x410 fs/namespace.c:4215
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f19ae2c0e6a
RSP: 002b:00007f19ac51de68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f19ac51def0 RCX: 00007f19ae2c0e6a
RDX: 00002000000001c0 RSI: 0000200000000140 RDI: 00007f19ac51deb0
RBP: 00002000000001c0 R08: 00007f19ac51def0 R09: 0000000000000002
R10: 0000000000000002 R11: 0000000000000246 R12: 0000200000000140
R13: 00007f19ac51deb0 R14: 0000000000006188 R15: 0000200000000300
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/38:
 #0: ffffffff8d5aa840 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8d5aa840 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
 #0: ffffffff8d5aa840 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
6 locks held by kworker/u8:4/69:
 #0: ffff888019ad4938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3238 [inline]
 #0: ffff888019ad4938 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3346
 #1: ffffc9000154fba0 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3239 [inline]
 #1: ffffc9000154fba0 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3346
 #2: ffffffff8e8563e0 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf7/0x820 net/core/net_namespace.c:669
 #3: ffff88803bf4b0d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline]
 #3: ffff88803bf4b0d8 (&dev->mutex){....}-{4:4}, at: devl_dev_lock net/devlink/devl_internal.h:108 [inline]
 #3: ffff88803bf4b0d8 (&dev->mutex){....}-{4:4}, at: devlink_pernet_pre_exit+0x10a/0x3d0 net/devlink/core.c:506
 #4: ffff888026274300 (&devlink->lock_key#16){+.+.}-{4:4}, at: devl_lock net/devlink/core.c:276 [inline]
 #4: ffff888026274300 (&devlink->lock_key#16){+.+.}-{4:4}, at: devl_dev_lock net/devlink/devl_internal.h:109 [inline]
 #4: ffff888026274300 (&devlink->lock_key#16){+.+.}-{4:4}, at: devlink_pernet_pre_exit+0x11c/0x3d0 net/devlink/core.c:506
 #5: ffffffff8e8632f8 (rtnl_mutex){+.+.}-{4:4}, at: nsim_destroy+0xed/0x680 drivers/net/netdevsim/netdev.c:1173
1 lock held by klogd/5157:
2 locks held by getty/5561:
 #0: ffff88823bf840a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc90003e762e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x444/0x1400 drivers/tty/n_tty.c:2222
2 locks held by syz-executor/5804:
 #0: ffff88803e9d00d0 (&type->s_umount_key#83){++++}-{4:4}, at: __super_lock fs/super.c:57 [inline]
 #0: ffff88803e9d00d0 (&type->s_umount_key#83){++++}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline]
 #0: ffff88803e9d00d0 (&type->s_umount_key#83){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:505
 #1: ffffffff8d9dfa78 (jfs_log_mutex){+.+.}-{4:4}, at: lmLogClose+0xb4/0x520 fs/jfs/jfs_logmgr.c:1443
2 locks held by syz-executor/6624:
 #0: ffff8880286620d0 (&type->s_umount_key#83){++++}-{4:4}, at: __super_lock fs/super.c:57 [inline]
 #0: ffff8880286620d0 (&type->s_umount_key#83){++++}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline]
 #0: ffff8880286620d0 (&type->s_umount_key#83){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:505
 #1: ffffffff8d9dfa78 (jfs_log_mutex){+.+.}-{4:4}, at: lmLogClose+0xb4/0x520 fs/jfs/jfs_logmgr.c:1443
2 locks held by syz.6.85/6738:
 #0: ffff88802f1940d0 (&type->s_umount_key#79/1){+.+.}-{4:4}, at: alloc_super+0x1ba/0x9a0 fs/super.c:344
 #1: ffffffff8d9dfa78 (jfs_log_mutex){+.+.}-{4:4}, at: open_dummy_log fs/jfs/jfs_logmgr.c:1191 [inline]
 #1: ffffffff8d9dfa78 (jfs_log_mutex){+.+.}-{4:4}, at: lmLogOpen+0x1a1/0xfa0 fs/jfs/jfs_logmgr.c:1066
2 locks held by syz-executor/6792:
 #0: ffff88803a6160d0 (&type->s_umount_key#83){++++}-{4:4}, at: __super_lock fs/super.c:57 [inline]
 #0: ffff88803a6160d0 (&type->s_umount_key#83){++++}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline]
 #0: ffff88803a6160d0 (&type->s_umount_key#83){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:505
 #1: ffffffff8d9dfa78 (jfs_log_mutex){+.+.}-{4:4}, at: lmLogClose+0xb4/0x520 fs/jfs/jfs_logmgr.c:1443
2 locks held by syz-executor/7592:
2 locks held by syz-executor/7962:
 #0: ffffffff8ed65da8 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8ed65da8 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
 #0: ffffffff8ed65da8 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250 net/core/rtnetlink.c:570
 #1: ffffffff8e8632f8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
 #1: ffffffff8e8632f8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline]
 #1: ffffffff8e8632f8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8e9/0x1c80 net/core/rtnetlink.c:4064
2 locks held by syz.7.215/8088:
2 locks held by syz.8.214/8091:
1 lock held by rm/8097:

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 38 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:332 [inline]
 watchdog+0xf60/0xfa0 kernel/hung_task.c:495
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 5157 Comm: klogd Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:26 [inline]
RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:109 [inline]
RIP: 0010:arch_local_irq_save arch/x86/include/asm/irqflags.h:127 [inline]
RIP: 0010:lock_acquire+0xcd/0x360 kernel/locking/lockdep.c:5864
Code: 0f 85 eb 00 00 00 65 48 8b 04 25 08 70 a2 91 83 b8 5c 0b 00 00 00 0f 85 d5 00 00 00 48 c7 44 24 30 00 00 00 00 9c 8f 44 24 30 <4c> 89 74 24 10 4d 89 fe 4c 8b 7c 24 30 fa 48 c7 c7 11 18 da 8c e8
RSP: 0018:ffffc90003e4f238 EFLAGS: 00000246
RAX: ffff888035a6da00 RBX: 0000000000000000 RCX: b0c0a0df6edd9900
RDX: 0000000000000000 RSI: ffffffff81737d12 RDI: 1ffffffff1ab5508
RBP: ffffffff81737cf5 R08: 0000000000000000 R09: 0000000000000000
R10: ffffc90003e4f408 R11: fffff520007c9e8d R12: 0000000000000002
R13: ffffffff8d5aa840 R14: 0000000000000000 R15: 0000000000000000
FS:  00007f72add30c80(0000) GS:ffff888126ef9000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000561a8d9cc950 CR3: 0000000035bec000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 rcu_read_lock include/linux/rcupdate.h:867 [inline]
 class_rcu_constructor include/linux/rcupdate.h:1195 [inline]
 unwind_next_frame+0xc2/0x2390 arch/x86/kernel/unwind_orc.c:479
 __unwind_start+0x5b9/0x760 arch/x86/kernel/unwind_orc.c:758
 unwind_start arch/x86/include/asm/unwind.h:64 [inline]
 arch_stack_walk+0xe4/0x150 arch/x86/kernel/stacktrace.c:24
 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:56 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:77
 unpoison_slab_object mm/kasan/common.c:342 [inline]
 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:368
 kasan_slab_alloc include/linux/kasan.h:252 [inline]
 slab_post_alloc_hook mm/slub.c:4974 [inline]
 slab_alloc_node mm/slub.c:5284 [inline]
 kmem_cache_alloc_node_noprof+0x23b/0x6e0 mm/slub.c:5336
 __alloc_skb+0x112/0x2d0 net/core/skbuff.c:660
 alloc_skb include/linux/skbuff.h:1383 [inline]
 alloc_skb_with_frags+0xca/0x890 net/core/skbuff.c:6671
 sock_alloc_send_pskb+0x859/0x990 net/core/sock.c:2965
 unix_dgram_sendmsg+0x461/0x1850 net/unix/af_unix.c:2153
 sock_sendmsg_nosec net/socket.c:727 [inline]
 __sock_sendmsg+0x21c/0x270 net/socket.c:742
 __sys_sendto+0x3c7/0x520 net/socket.c:2244
 __do_sys_sendto net/socket.c:2251 [inline]
 __se_sys_sendto net/socket.c:2247 [inline]
 __x64_sys_sendto+0xde/0x100 net/socket.c:2247
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f72ade80407
Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff
RSP: 002b:00007fffb5403f00 EFLAGS: 00000202 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f72add30c80 RCX: 00007f72ade80407
RDX: 0000000000000054 RSI: 00007fffb5404040 RDI: 0000000000000003
RBP: 00007fffb5404470 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000004000 R11: 0000000000000202 R12: 00007fffb5404488
R13: 00007fffb5404040 R14: 0000000000000039 R15: 00007fffb5404040
 </TASK>

Crashes (14):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/11/08 01:10 upstream da32d155f4a8 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in lmLogOpen
2025/10/10 08:20 upstream 5472d60c129f ff1712fe .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in lmLogOpen
2025/08/22 20:50 upstream cf6fc5eefc5b bf27483f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in lmLogOpen
2025/06/15 03:34 upstream 4774cfe3543a 5f4b362d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in lmLogOpen
2025/05/02 04:27 upstream ebd297a2affa 51b137cd .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in lmLogOpen
2025/03/26 04:41 upstream 2df0c02dab82 89d30d73 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in lmLogOpen
2025/02/18 16:12 upstream 2408a807bfc3 c37c7249 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in lmLogOpen
2025/02/03 09:38 upstream 69b8923f5003 568559e4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in lmLogOpen
2025/01/22 19:13 upstream c4b9570cfb63 a44b0418 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in lmLogOpen
2024/12/06 19:19 upstream b8f52214c61a 9ac0fdc6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in lmLogOpen
2024/12/02 21:31 upstream e70140ba0d2b b499ea68 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in lmLogOpen
2024/11/07 21:44 upstream ff7afaeca1a1 867e44df .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in lmLogOpen
2024/11/06 17:01 upstream 2e1b3cc9d7f7 df3dc63b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in lmLogOpen
2024/11/04 22:06 upstream 557329bcecc2 509da429 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in lmLogOpen
* Struck through repros no longer work on HEAD.