syzbot

INFO: task syz-executor:15307 blocked for more than 144 seconds.
      Not tainted 6.14.0-syzkaller-01103-g2df0c02dab82 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:21032 pid:15307 tgid:15307 ppid:1      task_flags:0x400140 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5367 [inline]
 __schedule+0x1b18/0x50e0 kernel/sched/core.c:6748
 __schedule_loop kernel/sched/core.c:6825 [inline]
 schedule+0x163/0x360 kernel/sched/core.c:6840
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6897
 rwsem_down_write_slowpath+0xeeb/0x13b0 kernel/locking/rwsem.c:1176
 __down_write_common kernel/locking/rwsem.c:1304 [inline]
 __down_write kernel/locking/rwsem.c:1313 [inline]
 down_write+0x1da/0x220 kernel/locking/rwsem.c:1578
 __super_lock fs/super.c:56 [inline]
 __super_lock_excl fs/super.c:71 [inline]
 deactivate_super+0xb5/0xf0 fs/super.c:505
 cleanup_mnt+0x422/0x4c0 fs/namespace.c:1435
 task_work_run+0x253/0x310 kernel/task_work.c:227
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x13f/0x340 kernel/entry/common.c:218
 do_syscall_64+0x100/0x230 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb7fb98e497
RSP: 002b:00007ffcafc79eb8 EFLAGS: 00000246
 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007fb7fba0e08c RCX: 00007fb7fb98e497
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffcafc79f70
RBP: 00007ffcafc79f70 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffcafc7b000
R13: 00007fb7fba0e08c R14: 00000000001074b5 R15: 00007ffcafc7b040
 </TASK>
INFO: task syz.6.2880:16527 blocked for more than 144 seconds.
      Not tainted 6.14.0-syzkaller-01103-g2df0c02dab82 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.6.2880      state:D stack:26528 pid:16527 tgid:16523 ppid:13719  task_flags:0x400140 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5367 [inline]
 __schedule+0x1b18/0x50e0 kernel/sched/core.c:6748
 __schedule_loop kernel/sched/core.c:6825 [inline]
 schedule+0x163/0x360 kernel/sched/core.c:6840
 jfs_flush_journal+0x737/0xed0 fs/jfs/jfs_logmgr.c:1564
 jfs_sync_fs+0x80/0xa0 fs/jfs/super.c:649
 iterate_supers+0xc8/0x190 fs/super.c:934
 ksys_sync+0xe0/0x1d0 fs/sync.c:104
 __do_sys_sync+0xe/0x20 fs/sync.c:113
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f09dff8d169
RSP: 002b:00007f09e0d40038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f09e01a6080 RCX: 00007f09dff8d169
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f09e01a6080 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f09e01a6080 R15: 00007fffa1199958
 </TASK>

Showing all locks held in the system:
2 locks held by rcu_tasks_trace/29:
 #0: ffffffff8eb3ad30 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{4:4}, at: rcu_tasks_one_gp+0xaf6/0xe20 kernel/rcu/tasks.h:613
 #1: ffffffff8eb3fc78 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:336 [inline]
 #1: ffffffff8eb3fc78 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x454/0x830 kernel/rcu/tree_exp.h:998
1 lock held by khungtaskd/31:
 #0: ffffffff8eb3a760 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8eb3a760 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
 #0: ffffffff8eb3a760 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x30/0x180 kernel/locking/lockdep.c:6761
5 locks held by kworker/u8:3/54:
2 locks held by getty/5578:
 #0: ffff888034c620a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc90002fde2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x53d/0x16b0 drivers/tty/n_tty.c:2211
4 locks held by kworker/u8:6/12705:
 #0: ffff88801ac81148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline]
 #0: ffff88801ac81148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x990/0x18e0 kernel/workqueue.c:3319
 #1: ffffc90002f17c60 ((work_completion)(&(&kfence_timer)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline]
 #1: ffffc90002f17c60 ((work_completion)(&(&kfence_timer)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9cb/0x18e0 kernel/workqueue.c:3319
 #2: ffff8880b8639ad8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:595
 #3: ffffffff8eb3a760 (rcu_read_lock){....}-{1:3}, at: __debug_check_no_obj_freed lib/debugobjects.c:1088 [inline]
 #3: ffffffff8eb3a760 (rcu_read_lock){....}-{1:3}, at: debug_check_no_obj_freed+0x245/0x590 lib/debugobjects.c:1129
1 lock held by syz-executor/15307:
 #0: ffff888049eec0e0 (&type->s_umount_key#113){++++}-{4:4}, at: __super_lock fs/super.c:56 [inline]
 #0: ffff888049eec0e0 (&type->s_umount_key#113){++++}-{4:4}, at: __super_lock_excl fs/super.c:71 [inline]
 #0: ffff888049eec0e0 (&type->s_umount_key#113){++++}-{4:4}, at: deactivate_super+0xb5/0xf0 fs/super.c:505
3 locks held by kworker/u8:18/15987:
 #0: ffff8880b8639ad8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:595
 #1: ffff8880b8623b08 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x41f/0x7a0 kernel/sched/psi.c:987
 #2: ffff8880b8625558 (&base->lock){-.-.}-{2:2}, at: __mod_timer+0x977/0x10f0 kernel/time/timer.c:1159
1 lock held by syz.6.2880/16527:
 #0: ffff888049eec0e0 (&type->s_umount_key#113){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline]
 #0: ffff888049eec0e0 (&type->s_umount_key#113){++++}-{4:4}, at: super_lock+0x27c/0x400 fs/super.c:120
1 lock held by syz.2.3112/17454:
 #0: ffff888049eec0e0 (&type->s_umount_key#113){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline]
 #0: ffff888049eec0e0 (&type->s_umount_key#113){++++}-{4:4}, at: super_lock+0x27c/0x400 fs/super.c:120

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.14.0-syzkaller-01103-g2df0c02dab82 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x4ab/0x4e0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x198/0x320 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:158 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:236 [inline]
 watchdog+0x1058/0x10a0 kernel/hung_task.c:399
 kthread+0x7ab/0x920 kernel/kthread.c:464
 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 14635 Comm: kworker/0:2 Not tainted 6.14.0-syzkaller-01103-g2df0c02dab82 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Workqueue: events free_obj_work
RIP: 0010:preempt_latency_start kernel/sched/core.c:5825 [inline]
RIP: 0010:preempt_count_add+0xaa/0x190 kernel/sched/core.c:5848
Code: ff 7f 39 d8 75 44 4c 8b 74 24 18 4c 89 f7 e8 8d 02 0f 00 85 c0 74 0a 45 31 f6 31 ff e8 7f 02 0f 00 65 48 8b 1c 25 08 c0 3f 93 <48> 81 c3 e0 14 00 00 48 89 d8 48 c1 e8 03 42 80 3c 38 00 74 08 48
RSP: 0018:ffffc90002fe7510 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffff88802b578000 RCX: ffffffff8c1da600
RDX: dffffc0000000000 RSI: ffffffff85036ba5 RDI: ffffffff816ddb90
RBP: ffffc90002fe7638 R08: 0000000000000004 R09: ffffc90002fe76f0
R10: dffffc0000000000 R11: ffffffff81aed460 R12: dffffc0000000000
R13: ffffc90002fe7600 R14: ffffffff816ddb90 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff888125224000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f005c378ab8 CR3: 0000000012246000 CR4: 0000000000350ef0
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 unwind_next_frame+0xb0/0x22f0 arch/x86/kernel/unwind_orc.c:479
 arch_stack_walk+0x11e/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x11a/0x1d0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:576
 poison_slab_object mm/kasan/common.c:247 [inline]
 __kasan_slab_free+0x59/0x70 mm/kasan/common.c:264
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2376 [inline]
 slab_free mm/slub.c:4633 [inline]
 kmem_cache_free+0x197/0x410 mm/slub.c:4735
 free_object_list lib/debugobjects.c:326 [inline]
 free_obj_work+0x395/0x4e0 lib/debugobjects.c:513
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xac5/0x18e0 kernel/workqueue.c:3319
 worker_thread+0x870/0xd30 kernel/workqueue.c:3400
 kthread+0x7ab/0x920 kernel/kthread.c:464
 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>