RDX: 0000000000000001 RSI: 0000000020000540 RDI: 0000000000000013 RBP: 000000000072bea0 R08: 0000000020000180 R09: 0000000000000010 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000014 R13: 00000000004c1158 R14: 00000000004d1848 R15: 0000000000000001 dccp_invalid_packet: P.type (REQUEST) not Data || [Data]Ack, while P.X == 0 INFO: task syz-executor4:12081 blocked for more than 140 seconds. Not tainted 4.18.0-rc4+ #146 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor4 D25408 12081 4548 0x00000004 Call Trace: context_switch kernel/sched/core.c:2853 [inline] __schedule+0x87c/0x1ed0 kernel/sched/core.c:3501 schedule+0xfb/0x450 kernel/sched/core.c:3545 __rwsem_down_write_failed_common+0x95d/0x1630 kernel/locking/rwsem-xadd.c:566 rwsem_down_write_failed+0xe/0x10 kernel/locking/rwsem-xadd.c:595 call_rwsem_down_write_failed+0x17/0x30 arch/x86/lib/rwsem.S:117 __down_write arch/x86/include/asm/rwsem.h:142 [inline] down_write+0xaa/0x130 kernel/locking/rwsem.c:72 inode_lock include/linux/fs.h:715 [inline] chmod_common+0x1b1/0x590 fs/open.c:546 do_fchmodat+0xc3/0x160 fs/open.c:590 __do_sys_chmod fs/open.c:608 [inline] __se_sys_chmod fs/open.c:606 [inline] __x64_sys_chmod+0x5c/0x80 fs/open.c:606 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x455ab9 Code: e0 1f 48 89 04 24 e8 b6 6f fd ff e8 81 6a fd ff e8 5c 68 fd ff 48 8d 05 92 9a 48 00 48 89 04 24 48 c7 44 24 08 1d 00 00 00 e8 <13> 5e fd ff 0f 0b e8 8c 44 00 00 e9 07 f0 ff ff cc cc cc cc cc cc RSP: 002b:00007f0fd4c06c68 EFLAGS: 00000246 ORIG_RAX: 000000000000005a RAX: ffffffffffffffda RBX: 00007f0fd4c076d4 RCX: 0000000000455ab9 RDX: 0000000000000000 RSI: 0000000000000600 RDI: 00000000200004c0 RBP: 000000000072bff0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000004bb0de R14: 00000000004c8c68 R15: 0000000000000002 Showing all locks held in the system: 1 lock held by khungtaskd/901: #0: 00000000f92932f8 (rcu_read_lock){....}, at: debug_show_all_locks+0xd0/0x428 kernel/locking/lockdep.c:4461 1 lock held by rsyslogd/4408: 2 locks held by getty/4498: #0: 0000000039245b3a (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000eb0bb0e1 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4499: #0: 000000004e6f6a2c (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 000000003ddba549 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4500: #0: 000000009bc3a30f (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000d5262f02 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4501: #0: 000000004a27386e (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000c1a6312e (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4502: #0: 00000000d5a8c204 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000e0f8717f (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4503: #0: 00000000e6083ec8 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 000000009b815f8e (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4504: #0: 0000000011f360b4 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000a7817cdb (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by syz-executor4/12009: #0: 000000007cb4e708 (sb_writers#15){.+.+}, at: sb_start_write include/linux/fs.h:1554 [inline] #0: 000000007cb4e708 (sb_writers#15){.+.+}, at: mnt_want_write+0x3f/0xc0 fs/namespace.c:386 #1: 000000006f9caa03 (&sb->s_type->i_mutex_key#20){++++}, at: inode_lock include/linux/fs.h:715 [inline] #1: 000000006f9caa03 (&sb->s_type->i_mutex_key#20){++++}, at: chmod_common+0x1b1/0x590 fs/open.c:546 2 locks held by syz-executor4/12081: #0: 000000007cb4e708 (sb_writers#15){.+.+}, at: sb_start_write include/linux/fs.h:1554 [inline] #0: 000000007cb4e708 (sb_writers#15){.+.+}, at: mnt_want_write+0x3f/0xc0 fs/namespace.c:386 #1: 000000006f9caa03 (&sb->s_type->i_mutex_key#20){++++}, at: inode_lock include/linux/fs.h:715 [inline] #1: 000000006f9caa03 (&sb->s_type->i_mutex_key#20){++++}, at: chmod_common+0x1b1/0x590 fs/open.c:546 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 901 Comm: khungtaskd Not tainted 4.18.0-rc4+ #146 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