netlink: 'syz-executor2': attribute type 4 has an invalid length. syz_tun: Invalid MTU 67 requested, hw min 68 netlink: 'syz-executor2': attribute type 4 has an invalid length. syz_tun: Invalid MTU 67 requested, hw min 68 INFO: task syz-executor1:21376 blocked for more than 140 seconds. Not tainted 4.18.0-rc7+ #178 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor1 D25408 21376 4460 0x00000004 Call Trace: context_switch kernel/sched/core.c:2853 [inline] __schedule+0x87c/0x1ec0 kernel/sched/core.c:3501 schedule+0xfb/0x450 kernel/sched/core.c:3545 schedule_preempt_disabled+0x10/0x20 kernel/sched/core.c:3603 __mutex_lock_common kernel/locking/mutex.c:834 [inline] __mutex_lock+0xede/0x1820 kernel/locking/mutex.c:894 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:909 __fdget_pos+0x1bb/0x200 fs/file.c:766 fdget_pos include/linux/file.h:67 [inline] ksys_write+0x7f/0x260 fs/read_write.c:593 __do_sys_write fs/read_write.c:610 [inline] __se_sys_write fs/read_write.c:607 [inline] __x64_sys_write+0x73/0xb0 fs/read_write.c:607 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x456cb9 Code: 18 85 c0 75 12 48 8b 44 24 20 48 89 08 48 8b 6c 24 28 48 83 c4 30 c3 48 8b 44 24 20 48 89 04 24 48 89 4c 24 08 e8 e7 ac fb ff e1 e8 f0 31 00 00 e9 7b ff ff ff cc cc cc cc cc cc cc cc cc cc RSP: 002b:00007f867c067c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f867c0686d4 RCX: 0000000000456cb9 RDX: 0000000000000008 RSI: 00000000200000c0 RDI: 000000000000001a RBP: 00000000009301e0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000004d6810 R14: 00000000004c9daa R15: 0000000000000002 Showing all locks held in the system: 1 lock held by khungtaskd/774: #0: 000000008fbdf501 (rcu_read_lock){....}, at: debug_show_all_locks+0xd0/0x428 kernel/locking/lockdep.c:4461 1 lock held by rsyslogd/4322: 2 locks held by getty/4413: #0: 00000000280d51a0 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 000000001608ac75 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4414: #0: 00000000525e3eca (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 0000000066ddc063 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4415: #0: 00000000f6ce6e78 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000e382d280 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4416: #0: 000000004b851031 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 000000004bfdc312 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4417: #0: 0000000072ae180c (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 000000008f07091d (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4418: #0: 000000000881a619 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 000000002f718186 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4419: #0: 000000007646737f (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000d1efda6e (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by syz-executor1/21309: #0: 00000000f783601a (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x1bb/0x200 fs/file.c:766 #1: 00000000fe8d8f51 (sb_writers#15){.+.+}, at: file_start_write include/linux/fs.h:2738 [inline] #1: 00000000fe8d8f51 (sb_writers#15){.+.+}, at: vfs_write+0x452/0x560 fs/read_write.c:548 1 lock held by syz-executor1/21372: #0: 00000000fe8d8f51 (sb_writers#15){.+.+}, at: sb_start_write include/linux/fs.h:1554 [inline] #0: 00000000fe8d8f51 (sb_writers#15){.+.+}, at: mnt_want_write+0x3f/0xc0 fs/namespace.c:386 1 lock held by syz-executor1/21376: #0: 00000000f783601a (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x1bb/0x200 fs/file.c:766 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 774 Comm: khungtaskd Not tainted 4.18.0-rc7+ #178 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+0x1c9/0x2b4 lib/dump_stack.c:113 nmi_cpu_backtrace.cold.4+0x19/0xce lib/nmi_backtrace.c:103 nmi_trigger_cpumask_backtrace+0x151/0x192 lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_all_cpu_backtrace include/linux/nmi.h:138 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:196 [inline] watchdog+0x9c4/0xf80 kernel/hung_task.c:252 kthread+0x345/0x410 kernel/kthread.c:246 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 skipped: idling at native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:54