syzbot


INFO: task hung in sys_acct

Status: upstream: reported syz repro on 2026/06/05 08:15
Reported-by: syzbot+cff878472cf6cfd3875a@syzkaller.appspotmail.com
First crash: 4d04h, last: 4d04h
Similar bugs (4)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in acct kernel 1 C 1 265d 265d 0/29 auto-obsoleted due to no activity on 2025/12/25 18:56
upstream INFO: task hung in sys_acct kernel 1 C error inconclusive 2 1724d 1759d 0/29 auto-obsoleted due to no activity on 2023/04/16 06:03
upstream INFO: task hung in sys_acct (3) kernel 1 1 670d 670d 0/29 auto-obsoleted due to no activity on 2024/11/06 02:40
upstream INFO: task hung in sys_acct (2) kernel 1 1 791d 791d 0/29 auto-obsoleted due to no activity on 2024/07/07 13:32

Sample crash report:
INFO: task syz.8.25:5469 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.8.25        state:D stack:0     pid:5469  ppid:5446   flags:0x00000001
Call trace:
 __switch_to+0x2f4/0x550 arch/arm64/kernel/process.c:555
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0xdd0/0x1b0c kernel/sched/core.c:6562
 schedule+0xc4/0x170 kernel/sched/core.c:6638
 schedule_preempt_disabled+0x18/0x2c kernel/sched/core.c:6697
 __mutex_lock_common+0xafc/0x1f60 kernel/locking/mutex.c:679
 __mutex_lock kernel/locking/mutex.c:747 [inline]
 mutex_lock_nested+0x38/0x44 kernel/locking/mutex.c:799
 __do_sys_acct kernel/acct.c:327 [inline]
 __se_sys_acct kernel/acct.c:315 [inline]
 __arm64_sys_acct+0xcc/0x714 kernel/acct.c:315
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
 #0: ffff800015417df0 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x40/0xbb4 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
 #0: ffff800015418610 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x40/0xbb4 kernel/rcu/tasks.h:517
3 locks held by kworker/0:1/14:
 #0: ffff0000c0020938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x6b8/0x13a4 kernel/workqueue.c:2265
 #1: ffff80001ca47c20 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_one_work+0x6fc/0x13a4 kernel/workqueue.c:2267
 #2: ffff0000dc785240 (&data->fib_lock){+.+.}-{3:3}, at: nsim_fib_event_work+0x1d0/0x27cc drivers/net/netdevsim/fib.c:1491
1 lock held by khungtaskd/28:
 #0: ffff800015417480 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0xc/0x44 include/linux/rcupdate.h:349
2 locks held by getty/4083:
 #0: ffff0000d8c28098 (&tty->ldisc_sem){++++}-{0:0}, at: ldsem_down_read+0x3c/0x4c drivers/tty/tty_ldsem.c:340
 #1: ffff8000208fe2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x2ec/0xfa0 drivers/tty/n_tty.c:2198
2 locks held by syz.7.24/5310:
1 lock held by syz.8.25/5469:
 #0: ffff80001543ba08 (acct_on_mutex){+.+.}-{3:3}, at: __do_sys_acct kernel/acct.c:327 [inline]
 #0: ffff80001543ba08 (acct_on_mutex){+.+.}-{3:3}, at: __se_sys_acct kernel/acct.c:315 [inline]
 #0: ffff80001543ba08 (acct_on_mutex){+.+.}-{3:3}, at: __arm64_sys_acct+0xcc/0x714 kernel/acct.c:315
1 lock held by syz.9.26/5628:
 #0: ffff80001543ba08 (acct_on_mutex){+.+.}-{3:3}, at: __do_sys_acct kernel/acct.c:327 [inline]
 #0: ffff80001543ba08 (acct_on_mutex){+.+.}-{3:3}, at: __se_sys_acct kernel/acct.c:315 [inline]
 #0: ffff80001543ba08 (acct_on_mutex){+.+.}-{3:3}, at: __arm64_sys_acct+0xcc/0x714 kernel/acct.c:315
1 lock held by syz.0.27/5895:
 #0: ffff80001543ba08 (acct_on_mutex){+.+.}-{3:3}, at: __do_sys_acct kernel/acct.c:327 [inline]
 #0: ffff80001543ba08 (acct_on_mutex){+.+.}-{3:3}, at: __se_sys_acct kernel/acct.c:315 [inline]
 #0: ffff80001543ba08 (acct_on_mutex){+.+.}-{3:3}, at: __arm64_sys_acct+0xcc/0x714 kernel/acct.c:315
1 lock held by syz.1.28/6355:
 #0: ffff80001543ba08 (acct_on_mutex){+.+.}-{3:3}, at: __do_sys_acct kernel/acct.c:327 [inline]
 #0: ffff80001543ba08 (acct_on_mutex){+.+.}-{3:3}, at: __se_sys_acct kernel/acct.c:315 [inline]
 #0: ffff80001543ba08 (acct_on_mutex){+.+.}-{3:3}, at: __arm64_sys_acct+0xcc/0x714 kernel/acct.c:315
1 lock held by syz.2.29/6846:
 #0: ffff80001543ba08 (acct_on_mutex){+.+.}-{3:3}, at: __do_sys_acct kernel/acct.c:327 [inline]
 #0: ffff80001543ba08 (acct_on_mutex){+.+.}-{3:3}, at: __se_sys_acct kernel/acct.c:315 [inline]
 #0: ffff80001543ba08 (acct_on_mutex){+.+.}-{3:3}, at: __arm64_sys_acct+0xcc/0x714 kernel/acct.c:315
1 lock held by syz.3.30/7289:
 #0: ffff80001543ba08 (acct_on_mutex){+.+.}-{3:3}, at: __do_sys_acct kernel/acct.c:327 [inline]
 #0: ffff80001543ba08 (acct_on_mutex){+.+.}-{3:3}, at: __se_sys_acct kernel/acct.c:315 [inline]
 #0: ffff80001543ba08 (acct_on_mutex){+.+.}-{3:3}, at: __arm64_sys_acct+0xcc/0x714 kernel/acct.c:315
1 lock held by syz.4.31/7823:
 #0: ffff80001543ba08 (acct_on_mutex){+.+.}-{3:3}, at: __do_sys_acct kernel/acct.c:327 [inline]
 #0: ffff80001543ba08 (acct_on_mutex){+.+.}-{3:3}, at: __se_sys_acct kernel/acct.c:315 [inline]
 #0: ffff80001543ba08 (acct_on_mutex){+.+.}-{3:3}, at: __arm64_sys_acct+0xcc/0x714 kernel/acct.c:315
1 lock held by syz.5.32/8269:
 #0: ffff80001543ba08 (acct_on_mutex){+.+.}-{3:3}, at: __do_sys_acct kernel/acct.c:327 [inline]
 #0: ffff80001543ba08 (acct_on_mutex){+.+.}-{3:3}, at: __se_sys_acct kernel/acct.c:315 [inline]
 #0: ffff80001543ba08 (acct_on_mutex){+.+.}-{3:3}, at: __arm64_sys_acct+0xcc/0x714 kernel/acct.c:315
1 lock held by syz.6.33/8792:
 #0: ffff80001543ba08 (acct_on_mutex){+.+.}-{3:3}, at: __do_sys_acct kernel/acct.c:327 [inline]
 #0: ffff80001543ba08 (acct_on_mutex){+.+.}-{3:3}, at: __se_sys_acct kernel/acct.c:315 [inline]
 #0: ffff80001543ba08 (acct_on_mutex){+.+.}-{3:3}, at: __arm64_sys_acct+0xcc/0x714 kernel/acct.c:315
3 locks held by dhcpcd-run-hook/8984:

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


Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/06/05 08:14 linux-6.1.y 228da13e907e 197909be .config console log report syz / log [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-6-1-kasan-arm64 INFO: task hung in sys_acct
* Struck through repros no longer work on HEAD.