INFO: task syz-executor.3:7759 blocked for more than 143 seconds. Not tainted 5.1.0-rc1+ #34 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D24344 7759 1 0x80000004 Call Trace: context_switch kernel/sched/core.c:2877 [inline] __schedule+0x817/0x1cc0 kernel/sched/core.c:3518 schedule+0x92/0x180 kernel/sched/core.c:3562 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3620 __mutex_lock_common kernel/locking/mutex.c:1002 [inline] __mutex_lock+0x726/0x1310 kernel/locking/mutex.c:1072 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1087 acct_get kernel/acct.c:161 [inline] slow_acct_process kernel/acct.c:577 [inline] acct_process+0x2e5/0x61e kernel/acct.c:605 do_exit+0x17bd/0x2fa0 kernel/exit.c:866 do_group_exit+0x135/0x370 kernel/exit.c:980 get_signal+0x399/0x1d50 kernel/signal.c:2577 do_signal+0x87/0x1940 arch/x86/kernel/signal.c:816 exit_to_usermode_loop+0x244/0x2c0 arch/x86/entry/common.c:162 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline] syscall_return_slowpath arch/x86/entry/common.c:268 [inline] do_syscall_64+0x52d/0x610 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x41224a Code: 48 29 d3 48 89 5c 24 08 48 8d 15 69 e0 29 01 48 89 54 24 18 e8 07 36 00 00 48 8b 44 24 20 48 8b 4c 24 38 48 89 81 20 13 00 00 <48> 8b 6c 24 28 48 83 c4 30 c3 e8 f7 7c 04 00 e9 32 ff ff ff cc cc RSP: 002b:00007ffc50eb7f48 EFLAGS: 00000246 ORIG_RAX: 000000000000003d RAX: fffffffffffffe00 RBX: 0000000000bd7940 RCX: 000000000041224a RDX: 0000000040000000 RSI: 00007ffc50eb7f80 RDI: ffffffffffffffff RBP: 00000000000044a6 R08: 0000000000000001 R09: 0000000000000001 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 R13: 00007ffc50eb7f80 R14: 0000000000bd799b R15: 00007ffc50eb7f90 Showing all locks held in the system: 1 lock held by khungtaskd/1042: #0: 000000001874d3da (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x27e kernel/locking/lockdep.c:5061 1 lock held by rsyslogd/7625: #0: 00000000d8d6d6cf (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xee/0x110 fs/file.c:801 2 locks held by getty/7715: #0: 00000000097b3c64 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000d87aee81 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7716: #0: 00000000efa45b51 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 000000003c705e66 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7717: #0: 00000000a6468b28 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000eb3d6170 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7718: #0: 000000001d56d01b (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000f036c7d3 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7719: #0: 00000000acfe0a5f (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000a51cbd7b (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7720: #0: 000000007fea6178 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000dc7e74bd (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7721: #0: 00000000b35f55c5 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 000000005a98bf9e (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 1 lock held by syz-executor.3/7759: #0: 000000008cad234d (&acct->lock#2){+.+.}, at: acct_get kernel/acct.c:161 [inline] #0: 000000008cad234d (&acct->lock#2){+.+.}, at: slow_acct_process kernel/acct.c:577 [inline] #0: 000000008cad234d (&acct->lock#2){+.+.}, at: acct_process+0x2e5/0x61e kernel/acct.c:605 3 locks held by syz-executor.3/16483: #0: 000000008cad234d (&acct->lock#2){+.+.}, at: acct_get kernel/acct.c:161 [inline] #0: 000000008cad234d (&acct->lock#2){+.+.}, at: slow_acct_process kernel/acct.c:577 [inline] #0: 000000008cad234d (&acct->lock#2){+.+.}, at: acct_process+0x2e5/0x61e kernel/acct.c:605 #1: 00000000f07177ac (sb_writers#3){.+.+}, at: file_start_write_trylock include/linux/fs.h:2829 [inline] #1: 00000000f07177ac (sb_writers#3){.+.+}, at: do_acct_process+0xf37/0x1150 kernel/acct.c:517 #2: 0000000025618fbc (&sb->s_type->i_mutex_key#10){++++}, at: inode_trylock include/linux/fs.h:789 [inline] #2: 0000000025618fbc (&sb->s_type->i_mutex_key#10){++++}, at: ext4_file_write_iter+0x257/0x11a0 fs/ext4/file.c:232 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1042 Comm: khungtaskd Not tainted 5.1.0-rc1+ #34 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x172/0x1f0 lib/dump_stack.c:113 nmi_cpu_backtrace.cold+0x63/0xa4 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1be/0x236 lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:204 [inline] watchdog+0x9b7/0xec0 kernel/hung_task.c:288 kthread+0x357/0x430 kernel/kthread.c:253 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 1 to CPUs 0: