INFO: task syz-executor2:25402 blocked for more than 140 seconds. Not tainted 4.20.0+ #170 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor2 D14616 25402 1 0x80000004 Call Trace: context_switch kernel/sched/core.c:2831 [inline] __schedule+0x86c/0x1ed0 kernel/sched/core.c:3472 schedule+0xfe/0x460 kernel/sched/core.c:3516 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3574 __mutex_lock_common kernel/locking/mutex.c:1002 [inline] __mutex_lock+0xbe7/0x1700 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+0x48b/0x875 kernel/acct.c:605 do_exit+0x1b89/0x26d0 kernel/exit.c:857 do_group_exit+0x177/0x440 kernel/exit.c:970 get_signal+0x8b0/0x1980 kernel/signal.c:2517 do_signal+0x9c/0x21c0 arch/x86/kernel/signal.c:816 exit_to_usermode_loop+0x2e5/0x380 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+0x6be/0x820 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x41169a Code: 00 00 44 89 f7 e8 56 ee 00 00 44 89 f6 48 89 c2 bf f5 31 44 00 31 c0 e8 a4 f9 00 00 49 8b 47 38 8d 53 01 48 89 eb 39 10 7e 32 <48> 8d 6b 01 45 8b 4c 24 10 4d 8b 44 24 18 48 8b 34 24 31 c9 4c 89 RSP: 002b:00007ffd50d7c958 EFLAGS: 00000246 ORIG_RAX: 000000000000003d RAX: fffffffffffffe00 RBX: 0000000000000000 RCX: 000000000041169a RDX: 0000000040000000 RSI: 00007ffd50d7c990 RDI: ffffffffffffffff RBP: 0000000000000723 R08: 0000000000000001 R09: 00000000020a4940 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000148ef5 R14: 00000000000001e1 R15: 0000000000000002 Showing all locks held in the system: 1 lock held by khungtaskd/1026: #0: 00000000f6e9a7fb (rcu_read_lock){....}, at: debug_show_all_locks+0xd0/0x424 kernel/locking/lockdep.c:4389 1 lock held by rsyslogd/7538: #0: 00000000fb6a95be (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x1bb/0x200 fs/file.c:766 2 locks held by getty/7628: #0: 000000005b10b888 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000a782fde8 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/7629: #0: 00000000968e9093 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000e3af3403 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/7630: #0: 000000004d639287 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000f77051f1 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/7631: #0: 00000000fb450343 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000008e7e0784 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/7632: #0: 00000000113defe1 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 0000000020e43da5 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/7633: #0: 0000000060e96855 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 0000000050b1d924 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/7634: #0: 00000000c9bc5ed4 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000577a9d32 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 3 locks held by kworker/u4:5/10119: #0: 000000005260bbed (&rq->lock){-.-.}, at: rq_lock kernel/sched/sched.h:1149 [inline] #0: 000000005260bbed (&rq->lock){-.-.}, at: __schedule+0x236/0x1ed0 kernel/sched/core.c:3410 #1: 00000000cb2f42c4 ((work_completion)(&(&bat_priv->nc.work)->work)){+.+.}, at: process_one_work+0xb9a/0x1c40 kernel/workqueue.c:2128 #2: 00000000a21e7bf3 (&base->lock){-.-.}, at: lock_timer_base+0xbb/0x2b0 kernel/time/timer.c:937 1 lock held by syz-executor2/25402: #0: 0000000057bf7dfb (&acct->lock#2){+.+.}, at: acct_get kernel/acct.c:161 [inline] #0: 0000000057bf7dfb (&acct->lock#2){+.+.}, at: slow_acct_process kernel/acct.c:577 [inline] #0: 0000000057bf7dfb (&acct->lock#2){+.+.}, at: acct_process+0x48b/0x875 kernel/acct.c:605 3 locks held by syz-executor2/7955: #0: 0000000057bf7dfb (&acct->lock#2){+.+.}, at: acct_get kernel/acct.c:161 [inline] #0: 0000000057bf7dfb (&acct->lock#2){+.+.}, at: slow_acct_process kernel/acct.c:577 [inline] #0: 0000000057bf7dfb (&acct->lock#2){+.+.}, at: acct_process+0x48b/0x875 kernel/acct.c:605 #1: 00000000b1925e8b (sb_writers#3){.+.+}, at: file_start_write_trylock include/linux/fs.h:2817 [inline] #1: 00000000b1925e8b (sb_writers#3){.+.+}, at: do_acct_process+0x1338/0x1660 kernel/acct.c:517 #2: 00000000637c6e23 (&sb->s_type->i_mutex_key#9){++++}, at: inode_trylock include/linux/fs.h:777 [inline] #2: 00000000637c6e23 (&sb->s_type->i_mutex_key#9){++++}, at: ext4_file_write_iter+0x2a1/0x1420 fs/ext4/file.c:232 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1026 Comm: khungtaskd Not tainted 4.20.0+ #170 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+0x1d3/0x2c6 lib/dump_stack.c:113 nmi_cpu_backtrace.cold.4+0x63/0xa2 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1c2/0x22c 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:205 [inline] watchdog+0xb51/0x1060 kernel/hung_task.c:289 kthread+0x35a/0x440 kernel/kthread.c:246 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 10119 Comm: kworker/u4:5 Not tainted 4.20.0+ #170 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: bat_events batadv_nc_worker RIP: 0010:find_held_lock+0x16b/0x1c0 kernel/locking/lockdep.c:3466 Code: 74 89 49 89 dc 48 b8 00 00 00 00 00 fc ff df 48 8b 55 d0 48 c1 ea 03 0f b6 04 02 84 c0 74 04 3c 03 7e 28 48 8b 45 d0 44 89 38 <48> 83 c4 10 4c 89 e0 5b 41 5c 41 5d 41 5e 41 5f 5d c3 45 31 e4 eb RSP: 0018:ffff88805e6cf430 EFLAGS: 00000002 RAX: ffff88805e6cf4c0 RBX: 1ffff1100bcd9e94 RCX: ffff88805e6cf4c0 RDX: 1ffff1100bcd9e98 RSI: 0000000000000000 RDI: ffff888098bbc9a0 RBP: ffff88805e6cf468 R08: ffff888098bbc0c0 R09: ffffed1015ce5b8f R10: 0000000000000003 R11: ffff8880ae72dc7b R12: ffff888098bbc990 R13: ffff88805e6cf580 R14: ffffffff8979c040 R15: 0000000000000002 FS: 0000000000000000(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000025f5000 CR3: 0000000092d2c000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __lock_release kernel/locking/lockdep.c:3599 [inline] lock_release+0x2a7/0xa00 kernel/locking/lockdep.c:3860 rcu_lock_release include/linux/rcupdate.h:228 [inline] rcu_read_unlock include/linux/rcupdate.h:661 [inline] batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:423 [inline] batadv_nc_worker+0x32e/0x920 net/batman-adv/network-coding.c:730 process_one_work+0xc90/0x1c40 kernel/workqueue.c:2153 worker_thread+0x17f/0x1390 kernel/workqueue.c:2296 kthread+0x35a/0x440 kernel/kthread.c:246 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352