INFO: task syz-executor.0:5827 blocked for more than 143 seconds. Not tainted 5.6.0-rc4-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D28328 5827 9509 0x80004004 Call Trace: schedule+0xd0/0x2a0 kernel/sched/core.c:4154 schedule_timeout+0x6db/0xba0 kernel/time/timer.c:1871 do_wait_for_common kernel/sched/completion.c:83 [inline] __wait_for_common kernel/sched/completion.c:104 [inline] wait_for_common kernel/sched/completion.c:115 [inline] wait_for_completion+0x26a/0x3c0 kernel/sched/completion.c:136 io_queue_file_removal+0x1af/0x1e0 fs/io_uring.c:5808 __io_sqe_files_update.isra.0+0x3a1/0xb00 fs/io_uring.c:5849 io_sqe_files_update fs/io_uring.c:5900 [inline] __io_uring_register+0x377/0x2c00 fs/io_uring.c:7113 __do_sys_io_uring_register fs/io_uring.c:7184 [inline] __se_sys_io_uring_register fs/io_uring.c:7166 [inline] __x64_sys_io_uring_register+0x192/0x560 fs/io_uring.c:7166 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45c4a9 Code: Bad RIP value. RSP: 002b:00007fd36fa8ac78 EFLAGS: 00000246 ORIG_RAX: 00000000000001ab RAX: ffffffffffffffda RBX: 00007fd36fa8b6d4 RCX: 000000000045c4a9 RDX: 0000000020000300 RSI: 0000000000000006 RDI: 0000000000000004 RBP: 000000000076bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000006 R13: 00000000000001fe R14: 00000000004d2970 R15: 0000000000000000 Showing all locks held in the system: 1 lock held by khungtaskd/1135: #0: ffffffff897accc0 (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:5331 1 lock held by rsyslogd/9377: #0: ffff8880936e2920 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xe3/0x100 fs/file.c:821 2 locks held by getty/9469: #0: ffff88809a721090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc9000181b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 2 locks held by getty/9470: #0: ffff88808d93c090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc9000182b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 2 locks held by getty/9471: #0: ffff88809f33c090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc9000183b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 2 locks held by getty/9472: #0: ffff8880a3bf3090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc900017fb2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 2 locks held by getty/9473: #0: ffff8880921d7090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc9000185b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 2 locks held by getty/9474: #0: ffff88809fb27090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc9000184b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 2 locks held by getty/9475: #0: ffff88809efeb090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc900017ab2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 1 lock held by syz-executor.0/5827: #0: ffff888095cc2320 (&ctx->uring_lock){+.+.}, at: __do_sys_io_uring_register fs/io_uring.c:7183 [inline] #0: ffff888095cc2320 (&ctx->uring_lock){+.+.}, at: __se_sys_io_uring_register fs/io_uring.c:7166 [inline] #0: ffff888095cc2320 (&ctx->uring_lock){+.+.}, at: __x64_sys_io_uring_register+0x181/0x560 fs/io_uring.c:7166 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1135 Comm: khungtaskd Not tainted 5.6.0-rc4-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+0x188/0x20d lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x70/0xb1 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x231/0x27e 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+0xa8c/0x1010 kernel/hung_task.c:289 kthread+0x357/0x430 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+0xe/0x10 arch/x86/include/asm/irqflags.h:60