INFO: task syz-executor6:7855 blocked for more than 120 seconds. Not tainted 4.17.0-rc4+ #46 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor6 D19384 7855 4549 0x00000004 Call Trace: context_switch kernel/sched/core.c:2859 [inline] __schedule+0x801/0x1e30 kernel/sched/core.c:3501 schedule+0xef/0x430 kernel/sched/core.c:3545 __rwsem_down_read_failed_common kernel/locking/rwsem-xadd.c:269 [inline] rwsem_down_read_failed+0x350/0x5e0 kernel/locking/rwsem-xadd.c:286 call_rwsem_down_read_failed+0x18/0x30 arch/x86/lib/rwsem.S:94 __down_read arch/x86/include/asm/rwsem.h:83 [inline] down_read+0xbd/0x1b0 kernel/locking/rwsem.c:26 inode_lock_shared include/linux/fs.h:723 [inline] ext4_direct_IO_read fs/ext4/inode.c:3828 [inline] ext4_direct_IO+0x653/0x2110 fs/ext4/inode.c:3865 generic_file_read_iter+0x510/0x2f00 mm/filemap.c:2341 ext4_file_read_iter+0x18b/0x3c0 fs/ext4/file.c:77 call_read_iter include/linux/fs.h:1778 [inline] generic_file_splice_read+0x552/0x910 fs/splice.c:307 do_splice_to+0x12e/0x190 fs/splice.c:880 splice_direct_to_actor+0x268/0x8d0 fs/splice.c:952 do_splice_direct+0x2cc/0x400 fs/splice.c:1061 do_sendfile+0x60f/0xe00 fs/read_write.c:1440 __do_sys_sendfile64 fs/read_write.c:1495 [inline] __se_sys_sendfile64 fs/read_write.c:1487 [inline] __x64_sys_sendfile64+0x155/0x240 fs/read_write.c:1487 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x455979 RSP: 002b:00007f433652fc68 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00007f43365306d4 RCX: 0000000000455979 RDX: 0000000020000180 RSI: 0000000000000015 RDI: 000000000000001a RBP: 000000000072c0b0 R08: 0000000000000000 R09: 0000000000000000 R10: 0020000000011ffe R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000579 R14: 00000000006fc3f8 R15: 0000000000000003 Showing all locks held in the system: 2 locks held by khungtaskd/892: #0: 00000000068c5076 (rcu_read_lock){....}, at: check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline] #0: 00000000068c5076 (rcu_read_lock){....}, at: watchdog+0x1ff/0xf60 kernel/hung_task.c:249 #1: 000000001ff4f1ee (tasklist_lock){.+.+}, at: debug_show_all_locks+0xde/0x34a kernel/locking/lockdep.c:4470 1 lock held by rsyslogd/4378: #0: 000000002f91cc37 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x1a9/0x1e0 fs/file.c:766 2 locks held by getty/4468: #0: 000000002dc15303 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000d6d05a90 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4469: #0: 0000000056014cd7 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 000000002e24c7bd (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4470: #0: 0000000064592345 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000b1fec5aa (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4471: #0: 000000004ec951f3 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000448836e6 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4472: #0: 00000000016ad281 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 000000003741a7c3 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4473: #0: 00000000716ec5e4 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000290eabf3 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4474: #0: 0000000028994fb2 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 000000009d0fb4da (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by syz-executor6/7855: #0: 0000000035229bc9 (sb_writers#4){.+.+}, at: file_start_write include/linux/fs.h:2718 [inline] #0: 0000000035229bc9 (sb_writers#4){.+.+}, at: do_sendfile+0xb05/0xe00 fs/read_write.c:1439 #1: 00000000aa98361f (&sb->s_type->i_mutex_key#10){++++}, at: inode_lock_shared include/linux/fs.h:723 [inline] #1: 00000000aa98361f (&sb->s_type->i_mutex_key#10){++++}, at: ext4_direct_IO_read fs/ext4/inode.c:3828 [inline] #1: 00000000aa98361f (&sb->s_type->i_mutex_key#10){++++}, at: ext4_direct_IO+0x653/0x2110 fs/ext4/inode.c:3865 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 892 Comm: khungtaskd Not tainted 4.17.0-rc4+ #46 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+0x1b9/0x294 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_task kernel/hung_task.c:132 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:190 [inline] watchdog+0xc10/0xf60 kernel/hung_task.c:249 kthread+0x345/0x410 kernel/kthread.c:240 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