INFO: task syz.0.2676:12787 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.0.2676 state:D stack:26400 pid:12787 ppid:4266 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5244 [inline] __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561 schedule+0xb9/0x180 kernel/sched/core.c:6637 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6696 rwsem_down_read_slowpath+0x4f4/0x840 kernel/locking/rwsem.c:1094 __down_read_common kernel/locking/rwsem.c:1261 [inline] __down_read kernel/locking/rwsem.c:1274 [inline] down_read+0x94/0x2d0 kernel/locking/rwsem.c:1522 iterate_supers+0xa4/0x1d0 fs/super.c:755 ksys_sync+0x91/0x150 fs/sync.c:102 __ia32_sys_sync+0xa/0x10 fs/sync.c:113 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f9c79d8eba9 RSP: 002b:00007f9c7ab4b038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2 RAX: ffffffffffffffda RBX: 00007f9c79fd6270 RCX: 00007f9c79d8eba9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007f9c79fd6270 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f9c79fd6308 R14: 00007f9c79fd6270 R15: 00007fff201d7898 INFO: task syz.3.2685:12827 blocked for more than 144 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.3.2685 state:D stack:26400 pid:12827 ppid:4275 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5244 [inline] __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561 schedule+0xb9/0x180 kernel/sched/core.c:6637 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6696 rwsem_down_read_slowpath+0x4f4/0x840 kernel/locking/rwsem.c:1094 __down_read_common kernel/locking/rwsem.c:1261 [inline] __down_read kernel/locking/rwsem.c:1274 [inline] down_read+0x94/0x2d0 kernel/locking/rwsem.c:1522 iterate_supers+0xa4/0x1d0 fs/super.c:755 ksys_sync+0x91/0x150 fs/sync.c:102 __ia32_sys_sync+0xa/0x10 fs/sync.c:113 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f011778eba9 RSP: 002b:00007f01185ef038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2 RAX: ffffffffffffffda RBX: 00007f01179d6270 RCX: 00007f011778eba9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007f01179d6270 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f01179d6308 R14: 00007f01179d6270 R15: 00007fff747c20d8 Showing all locks held in the system: 1 lock held by rcu_tasks_kthre/12: #0: ffffffff8cb2b570 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517 1 lock held by rcu_tasks_trace/13: #0: ffffffff8cb2bd90 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517 1 lock held by khungtaskd/28: #0: ffffffff8cb2abe0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #0: ffffffff8cb2abe0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #0: ffffffff8cb2abe0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6513 2 locks held by kworker/0:2/126: #0: ffff888017472138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267 #1: ffffc90002d97d00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267 2 locks held by getty/4030: #0: ffff88802f5b3098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244 #1: ffffc9000327b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x41b/0x1380 drivers/tty/n_tty.c:2198 1 lock held by syz.4.1779/9739: #0: ffff88802ecce0e0 (&type->s_umount_key#57/1){+.+.}-{3:3}, at: alloc_super+0x1fa/0x930 fs/super.c:228 1 lock held by syz.0.2676/12787: #0: ffff88802ecce0e0 (&type->s_umount_key#58){++++}-{3:3}, at: iterate_supers+0xa4/0x1d0 fs/super.c:755 1 lock held by syz.3.2685/12827: #0: ffff88802ecce0e0 (&type->s_umount_key#58){++++}-{3:3}, at: iterate_supers+0xa4/0x1d0 fs/super.c:755 1 lock held by syz.2.2712/12940: #0: ffff88802ecce0e0 (&type->s_umount_key#58){++++}-{3:3}, at: iterate_supers+0xa4/0x1d0 fs/super.c:755 1 lock held by syz.5.2729/13069: #0: ffff88802ecce0e0 (&type->s_umount_key#58){++++}-{3:3}, at: iterate_supers+0xa4/0x1d0 fs/super.c:755 1 lock held by syz.7.2768/13339: #0: ffff88802ecce0e0 (&type->s_umount_key#58){++++}-{3:3}, at: iterate_supers+0xa4/0x1d0 fs/super.c:755 1 lock held by syz.8.2778/13416: #0: ffff88802ecce0e0 (&type->s_umount_key#58){++++}-{3:3}, at: iterate_supers+0xa4/0x1d0 fs/super.c:755 1 lock held by syz.6.2792/13467: #0: ffff88802ecce0e0 (&type->s_umount_key#58){++++}-{3:3}, at: iterate_supers+0xa4/0x1d0 fs/super.c:755 1 lock held by syz.9.2794/13484: #0: ffff88802ecce0e0 (&type->s_umount_key#58){++++}-{3:3}, at: iterate_supers+0xa4/0x1d0 fs/super.c:755 1 lock held by syz.2.2835/13749: #0: ffff88802ecce0e0 (&type->s_umount_key#58){++++}-{3:3}, at: iterate_supers+0xa4/0x1d0 fs/super.c:755 1 lock held by syz.4.2863/13900: #0: ffff88802ecce0e0 (&type->s_umount_key#58){++++}-{3:3}, at: iterate_supers+0xa4/0x1d0 fs/super.c:755 1 lock held by syz.3.2874/13984: #0: ffff88802ecce0e0 (&type->s_umount_key#58){++++}-{3:3}, at: iterate_supers+0xa4/0x1d0 fs/super.c:755 8 locks held by syz-executor/14026: #0: ffff88807dec2460 (sb_writers#8){.+.+}-{0:0}, at: vfs_write+0x256/0x960 fs/read_write.c:580 #1: ffff888080c4ac88 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1e5/0x4c0 fs/kernfs/file.c:325 #2: ffff888144bcb660 (kn->active#53){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x208/0x4c0 fs/kernfs/file.c:326 #3: ffffffff8d64d7c8 (nsim_bus_dev_list_lock){+.+.}-{3:3}, at: del_device_store+0xce/0x360 drivers/net/netdevsim/bus.c:209 #4: ffff8880733400e8 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:837 [inline] #4: ffff8880733400e8 (&dev->mutex){....}-{3:3}, at: __device_driver_lock drivers/base/dd.c:1080 [inline] #4: ffff8880733400e8 (&dev->mutex){....}-{3:3}, at: device_release_driver_internal+0xb2/0x850 drivers/base/dd.c:1283 #5: ffff8880569ec2f8 (&devlink->lock_key#8){+.+.}-{3:3}, at: nsim_drv_remove+0x54/0x160 drivers/net/netdevsim/dev.c:1677 #6: ffffffff8dd422e8 (rtnl_mutex){+.+.}-{3:3}, at: nsim_destroy+0x3b/0x150 drivers/net/netdevsim/netdev.c:381 #7: ffffffff8cb308b8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:291 [inline] #7: ffffffff8cb308b8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x455/0x830 kernel/rcu/tree_exp.h:962 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 28 Comm: khungtaskd Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Call Trace: dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106 nmi_cpu_backtrace+0x3f4/0x470 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x1d4/0x450 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline] watchdog+0xeee/0xf30 kernel/hung_task.c:377 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 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:51 [inline] NMI backtrace for cpu 0 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline] NMI backtrace for cpu 0 skipped: idling at default_idle+0xb/0x10 arch/x86/kernel/process.c:741