INFO: task syz-executor.3:5042 blocked for more than 143 seconds. Not tainted 5.6.0-rc5-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D28720 5042 1821 0x80004006 Call Trace: schedule+0xcd/0x2b0 kernel/sched/core.c:4154 wdm_flush+0x2ea/0x3c0 drivers/usb/class/cdc-wdm.c:590 filp_close+0xb4/0x160 fs/open.c:1252 close_files fs/file.c:388 [inline] put_files_struct fs/file.c:416 [inline] put_files_struct+0x1d8/0x2e0 fs/file.c:413 exit_files+0x7e/0xa0 fs/file.c:445 do_exit+0xb36/0x2c80 kernel/exit.c:796 do_group_exit+0x125/0x340 kernel/exit.c:899 get_signal+0x480/0x2470 kernel/signal.c:2739 do_signal+0x88/0x1490 arch/x86/kernel/signal.c:813 exit_to_usermode_loop+0x1a2/0x200 arch/x86/entry/common.c:160 prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline] syscall_return_slowpath arch/x86/entry/common.c:278 [inline] do_syscall_64+0x4e0/0x5a0 arch/x86/entry/common.c:304 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45c849 Code: 0f 85 19 01 00 00 48 8b 84 24 d8 00 00 00 48 89 48 18 48 8d 7c 24 68 0f 57 c0 48 8d 7f e0 48 89 6c 24 f0 48 8d 6c 24 f0 e8 95 <84> ff ff 48 8b 6d 00 48 8d 05 29 46 18 00 48 89 04 24 48 8b 4c 24 RSP: 002b:00007fcfa678dcf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 000000000076c048 RCX: 000000000045c849 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000076c048 RBP: 000000000076c040 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000076c04c R13: 00007ffe78d9329f R14: 00007fcfa678e9c0 R15: 000000000076c04c INFO: task syz-executor.0:5044 blocked for more than 143 seconds. Not tainted 5.6.0-rc5-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D29128 5044 1826 0x80004006 Call Trace: schedule+0xcd/0x2b0 kernel/sched/core.c:4154 wdm_flush+0x2ea/0x3c0 drivers/usb/class/cdc-wdm.c:590 filp_close+0xb4/0x160 fs/open.c:1252 close_files fs/file.c:388 [inline] put_files_struct fs/file.c:416 [inline] put_files_struct+0x1d8/0x2e0 fs/file.c:413 exit_files+0x7e/0xa0 fs/file.c:445 do_exit+0xb36/0x2c80 kernel/exit.c:796 do_group_exit+0x125/0x340 kernel/exit.c:899 get_signal+0x480/0x2470 kernel/signal.c:2739 do_signal+0x88/0x1490 arch/x86/kernel/signal.c:813 exit_to_usermode_loop+0x1a2/0x200 arch/x86/entry/common.c:160 prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline] syscall_return_slowpath arch/x86/entry/common.c:278 [inline] do_syscall_64+0x4e0/0x5a0 arch/x86/entry/common.c:304 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45c849 Code: 0f 85 19 01 00 00 48 8b 84 24 d8 00 00 00 48 89 48 18 48 8d 7c 24 68 0f 57 c0 48 8d 7f e0 48 89 6c 24 f0 48 8d 6c 24 f0 e8 95 <84> ff ff 48 8b 6d 00 48 8d 05 29 46 18 00 48 89 04 24 48 8b 4c 24 RSP: 002b:00007f86c6a1acf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 000000000076c0e8 RCX: 000000000045c849 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000076c0e8 RBP: 000000000076c0e0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000076c0ec R13: 00007fff59d4276f R14: 00007f86c6a1b9c0 R15: 000000000076c0ec Showing all locks held in the system: 1 lock held by khungtaskd/23: #0: ffffffff87109060 (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x264 kernel/locking/lockdep.c:5331 1 lock held by rsyslogd/1677: #0: ffff8881d09f6fe0 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xe3/0x100 fs/file.c:821 2 locks held by getty/1767: #0: ffff8881cee28090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc9000083f2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 2 locks held by getty/1768: #0: ffff8881cee2e090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc900008472e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 2 locks held by getty/1769: #0: ffff8881ce524090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc900008632e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 2 locks held by getty/1770: #0: ffff8881ce020090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc9000086f2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 2 locks held by getty/1771: #0: ffff8881ce525090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc9000086b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 2 locks held by getty/1772: #0: ffff8881ce523090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc9000085f2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 2 locks held by getty/1773: #0: ffff8881ce92e090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc900008372e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 23 Comm: khungtaskd Not tainted 5.6.0-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:77 [inline] dump_stack+0xef/0x16e lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x70/0xb1 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1db/0x207 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:205 [inline] watchdog+0xa99/0xfd0 kernel/hung_task.c:289 kthread+0x318/0x420 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:60 [inline] NMI backtrace for cpu 0 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:103 [inline] NMI backtrace for cpu 0 skipped: idling at default_idle+0x28/0x300 arch/x86/kernel/process.c:695