syzbot


INFO: task hung in freezer_fork

Status: auto-obsoleted due to no activity on 2025/03/10 18:27
Subsystems: cgroups
[Documentation on labels]
First crash: 236d, last: 236d

Sample crash report:
INFO: task syz-executor:5831 blocked for more than 143 seconds.
      Not tainted 6.13.0-rc2-syzkaller-00018-g7cb1b4663150 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:19968 pid:5831  tgid:5831  ppid:1      flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5369 [inline]
 __schedule+0x1850/0x4c30 kernel/sched/core.c:6756
 __schedule_loop kernel/sched/core.c:6833 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6848
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6905
 __mutex_lock_common kernel/locking/mutex.c:665 [inline]
 __mutex_lock+0x7e7/0xee0 kernel/locking/mutex.c:735
 freezer_fork+0x105/0x470 kernel/cgroup/legacy_freezer.c:228
 cgroup_post_fork+0x425/0x880 kernel/cgroup/cgroup.c:6733
 copy_process+0x39e9/0x3d50 kernel/fork.c:2621
 kernel_clone+0x226/0x8e0 kernel/fork.c:2807
 __do_sys_clone kernel/fork.c:2950 [inline]
 __se_sys_clone kernel/fork.c:2934 [inline]
 __x64_sys_clone+0x258/0x2a0 kernel/fork.c:2934
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f58a4176793
RSP: 002b:00007ffdabec4e28 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f58a4176793
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000
R10: 00005555791be7d0 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000003818a R14: 0000000000037788 R15: 00007ffdabec4fb0
 </TASK>
INFO: task syz.5.413:7712 blocked for more than 144 seconds.
      Not tainted 6.13.0-rc2-syzkaller-00018-g7cb1b4663150 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.5.413       state:D stack:24128 pid:7712  tgid:7712  ppid:5830   flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5369 [inline]
 __schedule+0x1850/0x4c30 kernel/sched/core.c:6756
 __schedule_loop kernel/sched/core.c:6833 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6848
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6905
 __mutex_lock_common kernel/locking/mutex.c:665 [inline]
 __mutex_lock+0x7e7/0xee0 kernel/locking/mutex.c:735
 freezer_fork+0x105/0x470 kernel/cgroup/legacy_freezer.c:228
 cgroup_post_fork+0x425/0x880 kernel/cgroup/cgroup.c:6733
 copy_process+0x39e9/0x3d50 kernel/fork.c:2621
 kernel_clone+0x226/0x8e0 kernel/fork.c:2807
 __do_sys_clone3 kernel/fork.c:3111 [inline]
 __se_sys_clone3+0x2d8/0x360 kernel/fork.c:3090
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f10ec5b4769
RSP: 002b:00007ffc683890d8 EFLAGS: 00000206 ORIG_RAX: 00000000000001b3
RAX: ffffffffffffffda RBX: 00007f10ec536b90 RCX: 00007f10ec5b4769
RDX: 00007f10ec536b90 RSI: 0000000000000058 RDI: 00007ffc68389120
RBP: 00007f10ed42b6c0 R08: 00007f10ed42b6c0 R09: 00007ffc68389207
R10: 0000000000000008 R11: 0000000000000206 R12: ffffffffffffffa8
R13: 000000000000006e R14: 00007ffc68389120 R15: 00007ffc68389208
 </TASK>

Showing all locks held in the system:
1 lock held by kthreadd/2:
 #0: ffffffff8e96ea10 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: copy_process+0x219b/0x3d50 kernel/fork.c:2491
4 locks held by kworker/0:1/9:
3 locks held by kworker/u8:0/11:
 #0: ffff88801ac81148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline]
 #0: ffff88801ac81148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1840 kernel/workqueue.c:3310
 #1: ffffc90000107d00 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline]
 #1: ffffc90000107d00 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1840 kernel/workqueue.c:3310
 #2: ffffffff8e96ea10 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: copy_process+0x219b/0x3d50 kernel/fork.c:2491
3 locks held by kworker/u8:1/12:
 #0: ffff88801ac81148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline]
 #0: ffff88801ac81148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1840 kernel/workqueue.c:3310
 #1: ffffc90000117d00 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline]
 #1: ffffc90000117d00 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1840 kernel/workqueue.c:3310
 #2: ffffffff8e96ea10 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: copy_process+0x219b/0x3d50 kernel/fork.c:2491
1 lock held by khungtaskd/30:
 #0: ffffffff8e937ae0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
 #0: ffffffff8e937ae0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffffffff8e937ae0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6744
1 lock held by kworker/u9:0/54:
 #0: ffffffff8e96ea10 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: do_exit+0x6b4/0x28e0 kernel/exit.c:895
2 locks held by kworker/u8:4/61:
 #0: ffff88801ac81148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline]
 #0: ffff88801ac81148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1840 kernel/workqueue.c:3310
 #1: ffffc9000214fd00 ((work_completion)(&pool->idle_cull_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline]
 #1: ffffc9000214fd00 ((work_completion)(&pool->idle_cull_work)){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1840 kernel/workqueue.c:3310
2 locks held by kworker/0:2/969:
1 lock held by klogd/5187:
1 lock held by udevd/5198:
 #0: ffffffff8e96ea10 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: copy_process+0x219b/0x3d50 kernel/fork.c:2491
1 lock held by dhcpcd/5492:
 #0: ffffffff8e96ea10 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: copy_process+0x219b/0x3d50 kernel/fork.c:2491
2 locks held by getty/5581:
 #0: ffff88803552a0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x6a6/0x1e00 drivers/tty/n_tty.c:2211
2 locks held by syz-executor/5831:
 #0: ffffffff8e96ea10 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: copy_process+0x219b/0x3d50 kernel/fork.c:2491
 #1: ffffffff8e979828 (freezer_mutex){+.+.}-{4:4}, at: freezer_fork+0x105/0x470 kernel/cgroup/legacy_freezer.c:228
2 locks held by syz-executor/5832:
 #0: ffffffff8e96ea10 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: copy_process+0x219b/0x3d50 kernel/fork.c:2491
 #1: ffffffff8e979828 (freezer_mutex){+.+.}-{4:4}, at: freezer_fork+0x105/0x470 kernel/cgroup/legacy_freezer.c:228
2 locks held by syz-executor/5833:
 #0: ffffffff8e96ea10 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: copy_process+0x219b/0x3d50 kernel/fork.c:2491
 #1: ffffffff8e979828 (freezer_mutex){+.+.}-{4:4}, at: freezer_fork+0x105/0x470 kernel/cgroup/legacy_freezer.c:228
2 locks held by syz-executor/5843:
 #0: ffffffff8e96ea10 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: copy_process+0x219b/0x3d50 kernel/fork.c:2491
 #1: ffffffff8e979828 (freezer_mutex){+.+.}-{4:4}, at: freezer_fork+0x105/0x470 kernel/cgroup/legacy_freezer.c:228
3 locks held by kworker/0:7/5902:
3 locks held by kworker/u8:8/5951:
 #0: ffff88801ac81148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline]
 #0: ffff88801ac81148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1840 kernel/workqueue.c:3310
 #1: ffffc90002f07d00 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline]
 #1: ffffc90002f07d00 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1840 kernel/workqueue.c:3310
 #2: ffffffff8e96ea10 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: copy_process+0x219b/0x3d50 kernel/fork.c:2491
2 locks held by syz.5.413/7712:
 #0: ffffffff8e96ea10 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: copy_process+0x219b/0x3d50 kernel/fork.c:2491
 #1: ffffffff8e979828 (freezer_mutex){+.+.}-{4:4}, at: freezer_fork+0x105/0x470 kernel/cgroup/legacy_freezer.c:228
2 locks held by syz.4.417/7730:
1 lock held by syz-executor/7759:
 #0: ffffffff8e96ea10 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: do_exit+0x6b4/0x28e0 kernel/exit.c:895
5 locks held by syz-executor/7760:
 #0: ffff888033d48420 (sb_writers#10){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2964 [inline]
 #0: ffff888033d48420 (sb_writers#10){.+.+}-{0:0}, at: vfs_write+0x225/0xd30 fs/read_write.c:675
 #1: ffff888040086488 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1ea/0x500 fs/kernfs/file.c:325
 #2: ffffffff8e96e828 (cgroup_mutex){+.+.}-{4:4}, at: cgroup_lock include/linux/cgroup.h:368 [inline]
 #2: ffffffff8e96e828 (cgroup_mutex){+.+.}-{4:4}, at: cgroup_kn_lock_live+0xe6/0x290 kernel/cgroup/cgroup.c:1662
 #3: ffffffff8e7d2ed0 (cpu_hotplug_lock){++++}-{0:0}, at: cgroup_attach_lock kernel/cgroup/cgroup.c:2435 [inline]
 #3: ffffffff8e7d2ed0 (cpu_hotplug_lock){++++}-{0:0}, at: cgroup_procs_write_start+0x1a0/0x660 kernel/cgroup/cgroup.c:2939
 #4: ffffffff8e96ea10 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: cgroup_attach_lock kernel/cgroup/cgroup.c:2437 [inline]
 #4: ffffffff8e96ea10 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: cgroup_procs_write_start+0x1b5/0x660 kernel/cgroup/cgroup.c:2939
3 locks held by syz-executor/7773:
 #0: ffff888033d48420 (sb_writers#10){.+.+}-{0:0}, at: mnt_want_write+0x3f/0x90 fs/namespace.c:515
 #1: ffff88807a72e988 (&type->i_mutex_dir_key#6/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:853 [inline]
 #1: ffff88807a72e988 (&type->i_mutex_dir_key#6/1){+.+.}-{4:4}, at: filename_create+0x260/0x540 fs/namei.c:4080
 #2: ffffffff8e96e828 (cgroup_mutex){+.+.}-{4:4}, at: cgroup_lock include/linux/cgroup.h:368 [inline]
 #2: ffffffff8e96e828 (cgroup_mutex){+.+.}-{4:4}, at: cgroup_kn_lock_live+0xe6/0x290 kernel/cgroup/cgroup.c:1662
2 locks held by syz-executor/7776:
 #0: ffff888033d48420 (sb_writers#10){.+.+}-{0:0}, at: mnt_want_write+0x3f/0x90 fs/namespace.c:515
 #1: ffff88807a72e988 (&type->i_mutex_dir_key#6/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:853 [inline]
 #1: ffff88807a72e988 (&type->i_mutex_dir_key#6/1){+.+.}-{4:4}, at: filename_create+0x260/0x540 fs/namei.c:4080

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Not tainted 6.13.0-rc2-syzkaller-00018-g7cb1b4663150 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x49c/0x4d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x198/0x320 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:234 [inline]
 watchdog+0xff6/0x1040 kernel/hung_task.c:397
 kthread+0x2f2/0x390 kernel/kthread.c:389
 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 5902 Comm: kworker/0:7 Not tainted 6.13.0-rc2-syzkaller-00018-g7cb1b4663150 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Workqueue: wg-crypt-wg0 wg_packet_tx_worker
RIP: 0010:unwind_next_frame+0x179b/0x22d0
Code: d0 48 c1 e8 03 0f b6 04 28 84 c0 0f 85 93 0a 00 00 48 0f bf 03 48 8b 34 24 48 01 c6 49 8d 55 40 4c 89 ef e8 37 0e 00 00 84 c0 <0f> 84 66 01 00 00 49 bc 00 00 00 00 00 fc ff df 48 8b 44 24 20 42
RSP: 0018:ffffc90000007130 EFLAGS: 00000002
RAX: 1ffff92000000e01 RBX: ffffffff90af5aae RCX: 0000000000000000
RDX: dffffc0000000000 RSI: ffffc90000000000 RDI: ffffc900000075a8
RBP: dffffc0000000000 R08: ffffc900000075a8 R09: ffffc90000007250
R10: dffffc0000000000 R11: fffff52000000e4c R12: ffffc90000008000
R13: ffffc90000007200 R14: ffffffff82058ac8 R15: ffffc90000007250
FS:  0000000000000000(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffbd9e2ed58 CR3: 00000000274f2000 CR4: 0000000000350ef0
Call Trace:
 <NMI>
 </NMI>
 <IRQ>
 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x118/0x1d0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
 __kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:394
 kasan_kmalloc include/linux/kasan.h:260 [inline]
 __kmalloc_cache_noprof+0x243/0x390 mm/slub.c:4314
 kmalloc_noprof include/linux/slab.h:901 [inline]
 dummy_urb_enqueue+0x7d/0x780 drivers/usb/gadget/udc/dummy_hcd.c:1272
 usb_hcd_submit_urb+0x36e/0x1e80 drivers/usb/core/hcd.c:1533
 ath9k_hif_usb_reg_in_cb+0x4ce/0x6e0 drivers/net/wireless/ath/ath9k/hif_usb.c:790
 __usb_hcd_giveback_urb+0x42e/0x6e0 drivers/usb/core/hcd.c:1650
 dummy_timer+0x856/0x4620 drivers/usb/gadget/udc/dummy_hcd.c:1993
 __run_hrtimer kernel/time/hrtimer.c:1739 [inline]
 __hrtimer_run_queues+0x59d/0xd30 kernel/time/hrtimer.c:1803
 hrtimer_run_softirq+0x19a/0x2c0 kernel/time/hrtimer.c:1820
 handle_softirqs+0x2d6/0x9b0 kernel/softirq.c:561
 __do_softirq kernel/softirq.c:595 [inline]
 invoke_softirq kernel/softirq.c:435 [inline]
 __irq_exit_rcu+0xf7/0x220 kernel/softirq.c:662
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:678
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1049
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:should_resched arch/x86/include/asm/preempt.h:103 [inline]
RIP: 0010:__local_bh_enable_ip+0x170/0x200 kernel/softirq.c:396
Code: 8c e8 94 73 66 0a 65 66 8b 05 34 21 a2 7e 66 85 c0 75 5d bf 01 00 00 00 e8 5d bd 0b 00 e8 18 73 45 00 fb 65 8b 05 f8 20 a2 7e <85> c0 75 05 e8 77 92 a8 ff 48 c7 44 24 20 0e 36 e0 45 49 c7 04 1c
RSP: 0018:ffffc90003567a80 EFLAGS: 00000282
RAX: 0000000080000000 RBX: 1ffff920006acf54 RCX: ffffffff817b11ca
RDX: dffffc0000000000 RSI: ffffffff8c0a9760 RDI: ffffffff8c5f9680
RBP: ffffc90003567b40 R08: ffffffff942a1987 R09: 1ffffffff2854330
R10: dffffc0000000000 R11: fffffbfff2854331 R12: dffffc0000000000
R13: 1ffff920006acf58 R14: ffffc90003567ac0 R15: 0000000000000200
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 rcu_read_unlock_bh include/linux/rcupdate.h:919 [inline]
 keep_key_fresh drivers/net/wireguard/send.c:135 [inline]
 wg_packet_create_data_done drivers/net/wireguard/send.c:259 [inline]
 wg_packet_tx_worker+0x755/0x810 drivers/net/wireguard/send.c:276
 process_one_work kernel/workqueue.c:3229 [inline]
 process_scheduled_works+0xa68/0x1840 kernel/workqueue.c:3310
 worker_thread+0x870/0xd30 kernel/workqueue.c:3391
 kthread+0x2f2/0x390 kernel/kthread.c:389
 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/12/10 18:27 upstream 7cb1b4663150 cfc402b4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: task hung in freezer_fork
* Struck through repros no longer work on HEAD.