[syzbot] INFO: task hung in sys_acct

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 9a73fa375d58 Merge branch 'for-5.14-fixes' of git://git.ke..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1551216e300000
kernel config: https://syzkaller.appspot.com/x/.config?x=e3a20bae04b96ccd
dashboard link: https://syzkaller.appspot.com/bug?extid=2a9f6d6707c6afef5056
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.1
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16e0d7be300000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=14325779300000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+2a9f6d...@syzkaller.appspotmail.com

INFO: task syz-executor050:8462 blocked for more than 143 seconds.
Not tainted 5.14.0-rc5-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor050 state:D stack:29784 pid: 8462 ppid: 1 flags:0x00000000
Call Trace:
context_switch kernel/sched/core.c:4681 [inline]
__schedule+0x93a/0x26f0 kernel/sched/core.c:5938
schedule+0xd3/0x270 kernel/sched/core.c:6017
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6076
__mutex_lock_common kernel/locking/mutex.c:1036 [inline]
__mutex_lock+0x7b6/0x10a0 kernel/locking/mutex.c:1104
__do_sys_acct kernel/acct.c:285 [inline]
__se_sys_acct kernel/acct.c:273 [inline]
__x64_sys_acct+0xa3/0x1f0 kernel/acct.c:273
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x445779
RSP: 002b:00007f219fbcd308 EFLAGS: 00000246 ORIG_RAX: 00000000000000a3
RAX: ffffffffffffffda RBX: 00000000004ca408 RCX: 0000000000445779
RDX: 0000000000445779 RSI: 0000000000000000 RDI: 00000000200001c0
RBP: 00000000004ca400 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004ca40c
R13: 000000000049a074 R14: 0030656c69662f2e R15: 0000000000022000
INFO: task syz-executor050:8465 blocked for more than 143 seconds.
Not tainted 5.14.0-rc5-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor050 state:D stack:29784 pid: 8465 ppid: 1 flags:0x00000000
Call Trace:
context_switch kernel/sched/core.c:4681 [inline]
__schedule+0x93a/0x26f0 kernel/sched/core.c:5938
schedule+0xd3/0x270 kernel/sched/core.c:6017
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6076
__mutex_lock_common kernel/locking/mutex.c:1036 [inline]
__mutex_lock+0x7b6/0x10a0 kernel/locking/mutex.c:1104
__do_sys_acct kernel/acct.c:285 [inline]
__se_sys_acct kernel/acct.c:273 [inline]
__x64_sys_acct+0xa3/0x1f0 kernel/acct.c:273
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x445779
RSP: 002b:00007f219fbcd308 EFLAGS: 00000246 ORIG_RAX: 00000000000000a3
RAX: ffffffffffffffda RBX: 00000000004ca408 RCX: 0000000000445779
RDX: 0000000000445779 RSI: 0000000000000000 RDI: 00000000200001c0
RBP: 00000000004ca400 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004ca40c
R13: 000000000049a074 R14: 0030656c69662f2e R15: 0000000000022000
INFO: task syz-executor050:8468 blocked for more than 143 seconds.
Not tainted 5.14.0-rc5-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor050 state:D stack:29904 pid: 8468 ppid: 1 flags:0x00000000
Call Trace:
context_switch kernel/sched/core.c:4681 [inline]
__schedule+0x93a/0x26f0 kernel/sched/core.c:5938
schedule+0xd3/0x270 kernel/sched/core.c:6017
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6076
__mutex_lock_common kernel/locking/mutex.c:1036 [inline]
__mutex_lock+0x7b6/0x10a0 kernel/locking/mutex.c:1104
__do_sys_acct kernel/acct.c:285 [inline]
__se_sys_acct kernel/acct.c:273 [inline]
__x64_sys_acct+0xa3/0x1f0 kernel/acct.c:273
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x445779
RSP: 002b:00007f219fbcd308 EFLAGS: 00000246 ORIG_RAX: 00000000000000a3
RAX: ffffffffffffffda RBX: 00000000004ca408 RCX: 0000000000445779
RDX: 0000000000445779 RSI: 00000000000f4240 RDI: 00000000200001c0
RBP: 00000000004ca400 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004ca40c
R13: 000000000049a074 R14: 0030656c69662f2e R15: 0000000000022000
INFO: task syz-executor050:8470 blocked for more than 143 seconds.
Not tainted 5.14.0-rc5-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor050 state:D stack:28280 pid: 8470 ppid: 8441 flags:0x00000004
Call Trace:
context_switch kernel/sched/core.c:4681 [inline]
__schedule+0x93a/0x26f0 kernel/sched/core.c:5938
schedule+0xd3/0x270 kernel/sched/core.c:6017
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6076
__mutex_lock_common kernel/locking/mutex.c:1036 [inline]
__mutex_lock+0x7b6/0x10a0 kernel/locking/mutex.c:1104
__do_sys_acct kernel/acct.c:285 [inline]
__se_sys_acct kernel/acct.c:273 [inline]
__x64_sys_acct+0xa3/0x1f0 kernel/acct.c:273
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x445779
RSP: 002b:00007f219fbcd308 EFLAGS: 00000246 ORIG_RAX: 00000000000000a3
RAX: ffffffffffffffda RBX: 00000000004ca408 RCX: 0000000000445779
RDX: 0000000000445779 RSI: 0000000000000000 RDI: 00000000200001c0
RBP: 00000000004ca400 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004ca40c
R13: 000000000049a074 R14: 0030656c69662f2e R15: 0000000000022000

Showing all locks held in the system:
1 lock held by khungtaskd/1646:
#0: ffffffff8b97c1c0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6446
1 lock held by in:imklog/8353:
#0: ffff888018f6e0f0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:974
1 lock held by syz-executor050/8459:
#0: ffffffff8b9b4088 (acct_on_mutex){+.+.}-{3:3}, at: __do_sys_acct kernel/acct.c:285 [inline]
#0: ffffffff8b9b4088 (acct_on_mutex){+.+.}-{3:3}, at: __se_sys_acct kernel/acct.c:273 [inline]
#0: ffffffff8b9b4088 (acct_on_mutex){+.+.}-{3:3}, at: __x64_sys_acct+0xa3/0x1f0 kernel/acct.c:273
1 lock held by syz-executor050/8462:
#0: ffffffff8b9b4088 (acct_on_mutex){+.+.}-{3:3}, at: __do_sys_acct kernel/acct.c:285 [inline]
#0: ffffffff8b9b4088 (acct_on_mutex){+.+.}-{3:3}, at: __se_sys_acct kernel/acct.c:273 [inline]
#0: ffffffff8b9b4088 (acct_on_mutex){+.+.}-{3:3}, at: __x64_sys_acct+0xa3/0x1f0 kernel/acct.c:273
1 lock held by syz-executor050/8465:
#0: ffffffff8b9b4088 (acct_on_mutex){+.+.}-{3:3}, at: __do_sys_acct kernel/acct.c:285 [inline]
#0: ffffffff8b9b4088 (acct_on_mutex){+.+.}-{3:3}, at: __se_sys_acct kernel/acct.c:273 [inline]
#0: ffffffff8b9b4088 (acct_on_mutex){+.+.}-{3:3}, at: __x64_sys_acct+0xa3/0x1f0 kernel/acct.c:273
1 lock held by syz-executor050/8468:
#0: ffffffff8b9b4088 (acct_on_mutex){+.+.}-{3:3}, at: __do_sys_acct kernel/acct.c:285 [inline]
#0: ffffffff8b9b4088 (acct_on_mutex){+.+.}-{3:3}, at: __se_sys_acct kernel/acct.c:273 [inline]
#0: ffffffff8b9b4088 (acct_on_mutex){+.+.}-{3:3}, at: __x64_sys_acct+0xa3/0x1f0 kernel/acct.c:273
1 lock held by syz-executor050/8470:
#0: ffffffff8b9b4088 (acct_on_mutex){+.+.}-{3:3}, at: __do_sys_acct kernel/acct.c:285 [inline]
#0: ffffffff8b9b4088 (acct_on_mutex){+.+.}-{3:3}, at: __se_sys_acct kernel/acct.c:273 [inline]
#0: ffffffff8b9b4088 (acct_on_mutex){+.+.}-{3:3}, at: __x64_sys_acct+0xa3/0x1f0 kernel/acct.c:273

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

NMI backtrace for cpu 0
CPU: 0 PID: 1646 Comm: khungtaskd Not tainted 5.14.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:105
nmi_cpu_backtrace.cold+0x44/0xd7 lib/nmi_backtrace.c:105
nmi_trigger_cpumask_backtrace+0x1b3/0x230 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:210 [inline]
watchdog+0xd0a/0xfc0 kernel/hung_task.c:295
kthread+0x3e5/0x4d0 kernel/kthread.c:319
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline]
NMI backtrace for cpu 1 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
NMI backtrace for cpu 1 skipped: idling at acpi_safe_halt drivers/acpi/processor_idle.c:109 [inline]
NMI backtrace for cpu 1 skipped: idling at acpi_idle_do_entry+0x1c6/0x250 drivers/acpi/processor_idle.c:553


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[syzbot]

Auto-closing this bug as obsolete.
No recent activity, existing reproducers are no longer triggering the issue.