INFO: task syz-executor.2:24628 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.2 D28328 24628 17060 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:5829 __io_sqe_files_update.isra.0+0x3a1/0xb00 fs/io_uring.c:5870 io_sqe_files_update fs/io_uring.c:5921 [inline] __io_uring_register+0x377/0x2c00 fs/io_uring.c:7134 __do_sys_io_uring_register fs/io_uring.c:7205 [inline] __se_sys_io_uring_register fs/io_uring.c:7187 [inline] __x64_sys_io_uring_register+0x192/0x560 fs/io_uring.c:7187 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45c4a9 Code: 00 00 48 8b 6d 00 48 c7 44 24 38 00 00 00 00 66 c7 84 24 88 00 00 00 01 00 48 8b 05 a1 07 c5 01 48 89 44 24 78 48 8d 44 24 2c <48> 89 84 24 80 00 00 00 66 c7 84 24 b0 00 00 00 01 00 48 8b 05 76 RSP: 002b:00007ff334041c78 EFLAGS: 00000246 ORIG_RAX: 00000000000001ab RAX: ffffffffffffffda RBX: 00007ff3340426d4 RCX: 000000000045c4a9 RDX: 0000000020000100 RSI: 0000000000000006 RDI: 0000000000000006 RBP: 000000000076bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000008 R13: 00000000000001fe R14: 00000000004d2970 R15: 0000000000000000 Showing all locks held in the system: 1 lock held by khungtaskd/1134: #0: ffffffff897accc0 (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:5331 1 lock held by rsyslogd/10276: #0: ffff8880a7e53ae0 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xe3/0x100 fs/file.c:821 2 locks held by getty/10400: #0: ffff888093882090 (&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/10401: #0: ffff88809d3f6090 (&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/10402: #0: ffff88809efc1090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc900017cb2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 2 locks held by getty/10403: #0: ffff8880a1e7a090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc9000186b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 2 locks held by getty/10404: #0: ffff8880828c7090 (&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/10405: #0: ffff8880a7fbe090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc900017eb2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 2 locks held by getty/10406: #0: ffff88809185b090 (&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 8 locks held by syz-fuzzer/10426: #0: ffff8880ae637518 (&rq->lock){-.-.}, at: rq_lock kernel/sched/sched.h:1215 [inline] #0: ffff8880ae637518 (&rq->lock){-.-.}, at: __schedule+0x232/0x1f90 kernel/sched/core.c:4028 #1: ffffffff897accc0 (rcu_read_lock){....}, at: trace_sched_stat_runtime include/trace/events/sched.h:435 [inline] #1: ffffffff897accc0 (rcu_read_lock){....}, at: update_curr+0x2e1/0x8a0 kernel/sched/fair.c:859 #2: ffffffff897accc0 (rcu_read_lock){....}, at: trace_sched_stat_runtime include/trace/events/sched.h:435 [inline] #2: ffffffff897accc0 (rcu_read_lock){....}, at: update_curr+0x2e1/0x8a0 kernel/sched/fair.c:859 #3: ffff8880989b7538 (&ep->lock){...-}, at: ep_poll_callback+0xc4/0xe30 fs/eventpoll.c:1189 #4: ffff8880a4689250 (&dev->qdisc_tx_busylock_key){+...}, at: spin_trylock include/linux/spinlock.h:348 [inline] #4: ffff8880a4689250 (&dev->qdisc_tx_busylock_key){+...}, at: qdisc_run_begin include/net/sch_generic.h:159 [inline] #4: ffff8880a4689250 (&dev->qdisc_tx_busylock_key){+...}, at: qdisc_run include/net/pkt_sched.h:120 [inline] #4: ffff8880a4689250 (&dev->qdisc_tx_busylock_key){+...}, at: __dev_xmit_skb net/core/dev.c:3668 [inline] #4: ffff8880a4689250 (&dev->qdisc_tx_busylock_key){+...}, at: __dev_queue_xmit+0x27d6/0x30a0 net/core/dev.c:4021 #5: ffff8880a4689138 (&dev->qdisc_running_key){+...}, at: neigh_hh_output include/net/neighbour.h:499 [inline] #5: ffff8880a4689138 (&dev->qdisc_running_key){+...}, at: neigh_output include/net/neighbour.h:508 [inline] #5: ffff8880a4689138 (&dev->qdisc_running_key){+...}, at: ip_finish_output2+0x17b7/0x2610 net/ipv4/ip_output.c:228 #6: ffff88809f465098 (&dev->qdisc_xmit_lock_key){+.-.}, at: spin_lock include/linux/spinlock.h:338 [inline] #6: ffff88809f465098 (&dev->qdisc_xmit_lock_key){+.-.}, at: __netif_tx_lock include/linux/netdevice.h:4004 [inline] #6: ffff88809f465098 (&dev->qdisc_xmit_lock_key){+.-.}, at: sch_direct_xmit+0x2be/0xc20 net/sched/sch_generic.c:311 #7: ffffffff897accc0 (rcu_read_lock){....}, at: is_bpf_image_address+0x0/0x280 kernel/bpf/trampoline.c:85 1 lock held by syz-executor.2/24628: #0: ffff888048d9b320 (&ctx->uring_lock){+.+.}, at: __do_sys_io_uring_register fs/io_uring.c:7204 [inline] #0: ffff888048d9b320 (&ctx->uring_lock){+.+.}, at: __se_sys_io_uring_register fs/io_uring.c:7187 [inline] #0: ffff888048d9b320 (&ctx->uring_lock){+.+.}, at: __x64_sys_io_uring_register+0x181/0x560 fs/io_uring.c:7187 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1134 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+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