INFO: task hwrng:750 blocked for more than 143 seconds. Not tainted 6.6.0-syzkaller-15365-g305230142ae0 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:hwrng state:D stack:29696 pid:750 tgid:750 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5376 [inline] __schedule+0xee2/0x59a0 kernel/sched/core.c:6688 __schedule_loop kernel/sched/core.c:6763 [inline] schedule+0xe7/0x270 kernel/sched/core.c:6778 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6835 __mutex_lock_common kernel/locking/mutex.c:679 [inline] __mutex_lock+0x969/0x1340 kernel/locking/mutex.c:747 hwrng_fillfn+0x145/0x430 drivers/char/hw_random/core.c:504 kthread+0x33c/0x440 kernel/kthread.c:388 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242 Showing all locks held in the system: 1 lock held by khungtaskd/30: #0: ffffffff8cfacfe0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:301 [inline] #0: ffffffff8cfacfe0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:747 [inline] #0: ffffffff8cfacfe0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x75/0x340 kernel/locking/lockdep.c:6613 1 lock held by hwrng/750: #0: ffffffff8dbb72c8 (reading_mutex){+.+.}-{3:3}, at: hwrng_fillfn+0x145/0x430 drivers/char/hw_random/core.c:504 2 locks held by getty/4819: #0: ffff88814c2400a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc90002f062f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0xfc6/0x1490 drivers/tty/n_tty.c:2201 3 locks held by kworker/1:5/5162: #0: ffff888013070d38 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x787/0x15c0 kernel/workqueue.c:2605 #1: ffffc90004aa7d80 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x7e9/0x15c0 kernel/workqueue.c:2606 #2: ffffffff8eab77e8 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0x51/0xc0 net/core/link_watch.c:277 2 locks held by kworker/u4:15/10301: #0: ffff888013071938 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x787/0x15c0 kernel/workqueue.c:2605 #1: ffffc90014ad7d80 (connector_reaper_work){+.+.}-{0:0}, at: process_one_work+0x7e9/0x15c0 kernel/workqueue.c:2606 3 locks held by kworker/1:1/16223: #0: ffff888013070d38 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x787/0x15c0 kernel/workqueue.c:2605 #1: ffff8880b9928888 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x2d9/0x900 kernel/sched/psi.c:988 #2: ffff88803e492538 (&idev->mc_lock){+.+.}-{3:3}, at: mld_ifc_work+0x42/0xcd0 net/ipv6/mcast.c:2649 2 locks held by kworker/1:0/24005: #0: ffff888013072938 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x787/0x15c0 kernel/workqueue.c:2605 #1: ffffc90004ac7d80 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work+0x7e9/0x15c0 kernel/workqueue.c:2606 3 locks held by kworker/1:4/32208: #0: ffff88814b3cd538 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x787/0x15c0 kernel/workqueue.c:2605 #1: ffffc900053dfd80 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7e9/0x15c0 kernel/workqueue.c:2606 #2: ffffffff8eab77e8 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_dad_work+0xcf/0x14b0 net/ipv6/addrconf.c:4137 2 locks held by kworker/u4:0/9259: #0: ffff888013071938 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x787/0x15c0 kernel/workqueue.c:2605 #1: ffffc900159a7d80 ((reaper_work).work){+.+.}-{0:0}, at: process_one_work+0x7e9/0x15c0 kernel/workqueue.c:2606 3 locks held by syz-executor.3/14438: 1 lock held by syz-executor.3/14441: 2 locks held by syz-executor.1/14484: 1 lock held by syz-executor.3/14650: 1 lock held by syz-executor.1/14659: 1 lock held by syz-executor.3/14725: #0: ffffffff8eab77e8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline] #0: ffffffff8eab77e8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x372/0xe00 net/core/rtnetlink.c:6555 2 locks held by syz-executor.1/14732: #0: ffffffff8eab77e8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline] #0: ffffffff8eab77e8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x372/0xe00 net/core/rtnetlink.c:6555 #1: ffffffff8cfb89f8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:293 [inline] #1: ffffffff8cfb89f8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x69e/0x7e0 kernel/rcu/tree_exp.h:996 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 30 Comm: khungtaskd Not tainted 6.6.0-syzkaller-15365-g305230142ae0 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/09/2023 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106 nmi_cpu_backtrace+0x277/0x380 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x299/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline] watchdog+0xf87/0x1210 kernel/hung_task.c:379 kthread+0x33c/0x440 kernel/kthread.c:388 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242 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:48 [inline] NMI backtrace for cpu 0 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:86 [inline] NMI backtrace for cpu 0 skipped: idling at acpi_safe_halt+0x1b/0x20 drivers/acpi/processor_idle.c:112