INFO: task hung in acct

Kernel	Title	Rank 🛈	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	INFO: task hung in acct_collect trace	1				1	2507d	2507d	0/29	auto-closed as invalid on 2019/11/08 17:03
INFO: task syz.0.2357:13173 blocked for more than 143 seconds.
      Tainted: G             L      syzkaller #0
      Blocked by coredump.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.2357      state:D
 stack:24512 pid:13173 tgid:13173 ppid:5844   task_flags:0x40004c flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5352 [inline]
 __schedule+0x1665/0x5590 kernel/sched/core.c:6964
 __schedule_loop kernel/sched/core.c:7047 [inline]
 schedule+0x164/0x360 kernel/sched/core.c:7062
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7119
 rwsem_down_read_slowpath+0x6d9/0x940 kernel/locking/rwsem.c:1114
 __down_read_common kernel/locking/rwsem.c:1291 [inline]
 __down_read kernel/locking/rwsem.c:1304 [inline]
 down_read+0x99/0x2e0 kernel/locking/rwsem.c:1570
 mmap_read_lock include/linux/mmap_lock.h:592 [inline]
 acct_collect+0x19f/0x7c0 kernel/acct.c:568
 do_exit+0x82c/0x2490 kernel/exit.c:938
 do_group_exit+0x21b/0x2d0 kernel/exit.c:1116
 __do_sys_exit_group kernel/exit.c:1127 [inline]
 __se_sys_exit_group kernel/exit.c:1125 [inline]
 __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1125
 x64_sys_call+0x221a/0x2240 arch/x86/include/generated/asm/syscalls_64.h:232
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f22a219c799
RSP: 002b:00007fffff9c8f18 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f22a219c799
RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007fffff9c8f7c R08: 0000000000000000 R09: 00000000000927c0
R10: 0000000000000006 R11: 0000000000000246 R12: 000000000000024d
R13: 00000000000927c0 R14: 00000000000a731c R15: 00007fffff9c8fd0
 </TASK>
INFO: task syz.0.2357:13175 blocked for more than 144 seconds.
      Tainted: G             L      syzkaller #0
      Blocked by coredump.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.2357      state:D stack:27216 pid:13175 tgid:13173 ppid:5844   task_flags:0x40054c flags:0x00080001
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5352 [inline]
 __schedule+0x1665/0x5590 kernel/sched/core.c:6964
 __schedule_loop kernel/sched/core.c:7047 [inline]
 schedule+0x164/0x360 kernel/sched/core.c:7062
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7119
 rwsem_down_read_slowpath+0x6d9/0x940 kernel/locking/rwsem.c:1114
 __down_read_common kernel/locking/rwsem.c:1291 [inline]
 __down_read kernel/locking/rwsem.c:1304 [inline]
 down_read+0x99/0x2e0 kernel/locking/rwsem.c:1570
 mmap_read_lock include/linux/mmap_lock.h:592 [inline]
 exit_mm+0x73/0x250 kernel/exit.c:557
 do_exit+0x8b9/0x2490 kernel/exit.c:962
 do_group_exit+0x21b/0x2d0 kernel/exit.c:1116
 get_signal+0x1284/0x1330 kernel/signal.c:3035
 arch_do_signal_or_restart+0xbc/0x830 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
 exit_to_user_mode_loop+0x86/0x480 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:269 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline]
 do_syscall_64+0x32d/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f22a219c799
RSP: 002b:00007f22a300b028 EFLAGS: 00000246
 ORIG_RAX: 0000000000000133
RAX: 000000000000000b RBX: 00007f22a2415fa0 RCX: 00007f22a219c799
RDX: 0000000000000318 RSI: 00002000000bd000 RDI: 0000000000000005
RBP: 00007f22a2232c99 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f22a2416038 R14: 00007f22a2415fa0 R15: 00007fffff9c8bd8
 </TASK>
INFO: task syz.0.2357:13177 blocked for more than 145 seconds.
      Tainted: G             L      syzkaller #0
      Blocked by coredump.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.2357      state:D stack:25584 pid:13177 tgid:13173 ppid:5844   task_flags:0x40044c flags:0x00080001
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5352 [inline]
 __schedule+0x1665/0x5590 kernel/sched/core.c:6964
 __schedule_loop kernel/sched/core.c:7047 [inline]
 schedule+0x164/0x360 kernel/sched/core.c:7062
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7119
 rwsem_down_read_slowpath+0x6d9/0x940 kernel/locking/rwsem.c:1114
 __down_read_common kernel/locking/rwsem.c:1291 [inline]
 __down_read kernel/locking/rwsem.c:1304 [inline]
 down_read+0x99/0x2e0 kernel/locking/rwsem.c:1570
 mmap_read_lock include/linux/mmap_lock.h:592 [inline]
 exit_mm+0x73/0x250 kernel/exit.c:557
 do_exit+0x8b9/0x2490 kernel/exit.c:962
 do_group_exit+0x21b/0x2d0 kernel/exit.c:1116
 get_signal+0x1284/0x1330 kernel/signal.c:3035
 arch_do_signal_or_restart+0xbc/0x830 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
 exit_to_user_mode_loop+0x86/0x480 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:269 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline]
 do_syscall_64+0x32d/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f22a219c799
RSP: 002b:00007f22a2fea028 EFLAGS: 00000246 ORIG_RAX: 000000000000012b
RAX: 0000000000001cfd RBX: 00007f22a2416090 RCX: 00007f22a219c799
RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000004
RBP: 00007f22a2232c99 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f22a2416128 R14: 00007f22a2416090 R15: 00007fffff9c8bd8
 </TASK>
INFO: task syz.0.2357:13178 blocked for more than 146 seconds.
      Tainted: G             L      syzkaller #0
      Blocked by coredump.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.2357      state:D stack:27176 pid:13178 tgid:13173 ppid:5844   task_flags:0x40054c flags:0x00080001
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5352 [inline]
 __schedule+0x1665/0x5590 kernel/sched/core.c:6964
 __schedule_loop kernel/sched/core.c:7047 [inline]
 schedule+0x164/0x360 kernel/sched/core.c:7062
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7119
 rwsem_down_read_slowpath+0x6d9/0x940 kernel/locking/rwsem.c:1114
 __down_read_common kernel/locking/rwsem.c:1291 [inline]
 __down_read kernel/locking/rwsem.c:1304 [inline]
 down_read+0x99/0x2e0 kernel/locking/rwsem.c:1570
 mmap_read_lock include/linux/mmap_lock.h:592 [inline]
 exit_mm+0x73/0x250 kernel/exit.c:557
 do_exit+0x8b9/0x2490 kernel/exit.c:962
 do_group_exit+0x21b/0x2d0 kernel/exit.c:1116
 get_signal+0x1284/0x1330 kernel/signal.c:3035
 arch_do_signal_or_restart+0xbc/0x830 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
 exit_to_user_mode_loop+0x86/0x480 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:269 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline]
 do_syscall_64+0x32d/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f22a219c799
RSP: 002b:00007f22a2fc9028 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: fffffffffffffffc RBX: 00007f22a2416180 RCX: 00007f22a219c799
RDX: 0000000003000007 RSI: 0000000000b36000 RDI: 0000200000000000
RBP: 00007f22a2232c99 R08: 0000000000000007 R09: 0000000000000000
R10: 0000000000038011 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f22a2416218 R14: 00007f22a2416180 R15: 00007fffff9c8bd8
 </TASK>
INFO: task syz.0.2357:13179 blocked for more than 147 seconds.
      Tainted: G             L      syzkaller #0
      Blocked by coredump.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.2357      state:D stack:25360 pid:13179 tgid:13173 ppid:5844   task_flags:0x40054c flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5352 [inline]
 __schedule+0x1665/0x5590 kernel/sched/core.c:6964
 __schedule_loop kernel/sched/core.c:7047 [inline]
 schedule+0x164/0x360 kernel/sched/core.c:7062
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7119
 rwsem_down_read_slowpath+0x6d9/0x940 kernel/locking/rwsem.c:1114
 __down_read_common kernel/locking/rwsem.c:1291 [inline]
 __down_read kernel/locking/rwsem.c:1304 [inline]
 down_read+0x99/0x2e0 kernel/locking/rwsem.c:1570
 mmap_read_lock include/linux/mmap_lock.h:592 [inline]
 exit_mm+0x73/0x250 kernel/exit.c:557
 do_exit+0x8b9/0x2490 kernel/exit.c:962
 do_group_exit+0x21b/0x2d0 kernel/exit.c:1116
 get_signal+0x1284/0x1330 kernel/signal.c:3035
 arch_do_signal_or_restart+0xbc/0x830 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
 exit_to_user_mode_loop+0x86/0x480 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:269 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline]
 do_syscall_64+0x32d/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f22a219c799
RSP: 002b:00007f22a2fa80e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007f22a2416278 RCX: 00007f22a219c799
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f22a2416278
RBP: 00007f22a2416270 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f22a2416308 R14: 00007fffff9c8af0 R15: 00007fffff9c8bd8
 </TASK>

Showing all locks held in the system:
2 locks held by kworker/1:0/24:
 #0: 
ffff8880b863ade0
 (
&rq->__lock
){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0xb6/0x150 kernel/sched/core.c:655
 #1: ffff8880b8724588 (psi_seq){-.-.}-{0:0}, at: psi_task_switch+0x53/0x880 kernel/sched/psi.c:933
1 lock held by khungtaskd/31:
 #0: ffffffff8e75d6a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
 #0: ffffffff8e75d6a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
 #0: ffffffff8e75d6a0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
2 locks held by getty/5587:
 #0: ffff888036aa20a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000332b2e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13c0 drivers/tty/n_tty.c:2211
1 lock held by syz.0.2357/13173:
 #0: ffff88807bca8fb8 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_lock include/linux/mmap_lock.h:592 [inline]
 #0: ffff88807bca8fb8 (&mm->mmap_lock){++++}-{4:4}, at: acct_collect+0x19f/0x7c0 kernel/acct.c:568
1 lock held by syz.0.2357/13175:
 #0: ffff88807bca8fb8 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_lock include/linux/mmap_lock.h:592 [inline]
 #0: ffff88807bca8fb8 (&mm->mmap_lock){++++}-{4:4}, at: exit_mm+0x73/0x250 kernel/exit.c:557
1 lock held by syz.0.2357/13177:
 #0: ffff88807bca8fb8 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_lock include/linux/mmap_lock.h:592 [inline]
 #0: ffff88807bca8fb8 (&mm->mmap_lock){++++}-{4:4}, at: exit_mm+0x73/0x250 kernel/exit.c:557
1 lock held by syz.0.2357/13178:
 #0: ffff88807bca8fb8 (
&mm->mmap_lock){++++}-{4:4}, at: mmap_read_lock include/linux/mmap_lock.h:592 [inline]
&mm->mmap_lock){++++}-{4:4}, at: exit_mm+0x73/0x250 kernel/exit.c:557
1 lock held by syz.0.2357/13179:
 #0: 
ffff88807bca8fb8 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_lock include/linux/mmap_lock.h:592 [inline]
ffff88807bca8fb8 (&mm->mmap_lock){++++}-{4:4}, at: exit_mm+0x73/0x250 kernel/exit.c:557

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline]
 __sys_info lib/sys_info.c:157 [inline]
 sys_info+0x135/0x170 lib/sys_info.c:165
 check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline]
 watchdog+0x1002/0x1060 kernel/hung_task.c:561
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x51e/0xb90 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: 12365 Comm: kworker/1:9 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Workqueue: events legacy_dvb_usb_read_remote_control
RIP: 0010:io_serial_out+0x7c/0xc0 drivers/tty/serial/8250/8250_port.c:408
Code: 0c 83 fc 44 89 f9 d3 e5 49 83 c6 40 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 8c 71 ec fc 41 03 2e 89 d8 89 ea ee <5b> 41 5c 41 5e 41 5f 5d c3 cc cc cc cc cc 44 89 f9 80 e1 07 38 c1
RSP: 0018:ffffc9001d1274d0 EFLAGS: 00000002
RAX: 000000000000005b RBX: 000000000000005b RCX: 0000000000000000
RDX: 00000000000003f8 RSI: 0000000000000000 RDI: 0000000000000020
RBP: 00000000000003f8 R08: ffff8881436a822f R09: 1ffff110286d5045
R10: dffffc0000000000 R11: ffffffff85439630 R12: dffffc0000000000
R13: ffffffff9a2e0961 R14: ffffffff9a5f8ca0 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff888125536000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000400030 CR3: 000000007806e000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 serial_port_out include/linux/serial_core.h:811 [inline]
 serial8250_console_putchar drivers/tty/serial/8250/8250_port.c:3217 [inline]
 serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:-1 [inline]
 serial8250_console_write+0x140c/0x1ba0 drivers/tty/serial/8250/8250_port.c:3357
 console_emit_next_record kernel/printk/printk.c:3183 [inline]
 console_flush_one_record kernel/printk/printk.c:3269 [inline]
 console_flush_all+0x718/0xb20 kernel/printk/printk.c:3343
 __console_flush_and_unlock kernel/printk/printk.c:3373 [inline]
 console_unlock+0xd1/0x1c0 kernel/printk/printk.c:3413
 vprintk_emit+0x485/0x560 kernel/printk/printk.c:2479
 _printk+0xdd/0x130 kernel/printk/printk.c:2504
 m920x_read drivers/media/usb/dvb-usb/m920x.c:40 [inline]
 m920x_rc_query+0x2f6/0x830 drivers/media/usb/dvb-usb/m920x.c:-1
 legacy_dvb_usb_read_remote_control+0x107/0x450 drivers/media/usb/dvb-usb/dvb-usb-remote.c:123
 process_one_work+0x9ab/0x1780 kernel/workqueue.c:3289
 process_scheduled_works kernel/workqueue.c:3380 [inline]
 worker_thread+0xb49/0x1140 kernel/workqueue.c:3461
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>