generic_make_request: Trying to write to read-only block-device unknown-block(7,0) (partno 0) INFO: task syz-executor2:17700 blocked for more than 120 seconds. Not tainted 4.16.0-rc2+ #236 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor2 D20768 17700 4272 0x20020004 Call Trace: context_switch kernel/sched/core.c:2862 [inline] __schedule+0x905/0x2070 kernel/sched/core.c:3440 schedule+0xf5/0x430 kernel/sched/core.c:3499 io_schedule+0x1c/0x70 kernel/sched/core.c:5115 __blkdev_direct_IO_simple+0x7bd/0xf50 fs/block_dev.c:241 blkdev_direct_IO+0xccb/0x1060 fs/block_dev.c:428 generic_file_read_iter+0x4cc/0x28e0 mm/filemap.c:2343 blkdev_read_iter+0x105/0x170 fs/block_dev.c:1913 call_read_iter include/linux/fs.h:1775 [inline] new_sync_read fs/read_write.c:401 [inline] __vfs_read+0x6a7/0xa00 fs/read_write.c:413 vfs_read+0x11e/0x350 fs/read_write.c:447 SYSC_pread64 fs/read_write.c:611 [inline] SyS_pread64+0x15b/0x190 fs/read_write.c:598 sys32_pread+0x39/0x50 arch/x86/ia32/sys_ia32.c:180 do_syscall_32_irqs_on arch/x86/entry/common.c:330 [inline] do_fast_syscall_32+0x3ec/0xf9f arch/x86/entry/common.c:392 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139 RIP: 0023:0xf7f44c99 RSP: 002b:00000000f774009c EFLAGS: 00000286 ORIG_RAX: 00000000000000b4 RAX: ffffffffffffffda RBX: 0000000000000013 RCX: 0000000020000000 RDX: 00000000fffffda4 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 Showing all locks held in the system: 2 locks held by khungtaskd/798: #0: (rcu_read_lock){....}, at: [<00000000ce56310c>] check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline] #0: (rcu_read_lock){....}, at: [<00000000ce56310c>] watchdog+0x1c5/0xd60 kernel/hung_task.c:249 #1: (tasklist_lock){.+.+}, at: [<000000001d6db1a0>] debug_show_all_locks+0xd3/0x3d0 kernel/locking/lockdep.c:4470 1 lock held by rsyslogd/4076: #0: (&f->f_pos_lock){+.+.}, at: [<00000000d52b29c5>] __fdget_pos+0x12b/0x190 fs/file.c:765 2 locks held by getty/4198: #0: (&tty->ldisc_sem){++++}, at: [<00000000c4de5d4e>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<0000000077f8237c>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/4199: #0: (&tty->ldisc_sem){++++}, at: [<00000000c4de5d4e>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<0000000077f8237c>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/4200: #0: (&tty->ldisc_sem){++++}, at: [<00000000c4de5d4e>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<0000000077f8237c>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/4201: #0: (&tty->ldisc_sem){++++}, at: [<00000000c4de5d4e>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<0000000077f8237c>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/4202: #0: (&tty->ldisc_sem){++++}, at: [<00000000c4de5d4e>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<0000000077f8237c>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/4203: #0: (&tty->ldisc_sem){++++}, at: [<00000000c4de5d4e>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<0000000077f8237c>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/4204: #0: (&tty->ldisc_sem){++++}, at: [<00000000c4de5d4e>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<0000000077f8237c>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 1 lock held by syz-executor2/17709: #0: (&lo->lo_ctl_mutex/1){+.+.}, at: [<00000000b45aaaae>] lo_ioctl+0x8b/0x1b70 drivers/block/loop.c:1355 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 798 Comm: khungtaskd Not tainted 4.16.0-rc2+ #236 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x194/0x24d lib/dump_stack.c:53 nmi_cpu_backtrace+0x1d2/0x210 lib/nmi_backtrace.c:103 nmi_trigger_cpumask_backtrace+0x122/0x180 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+0x90c/0xd60 kernel/hung_task.c:249 kthread+0x33c/0x400 kernel/kthread.c:238 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:407 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.16.0-rc2+ #236 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:llist_empty include/linux/compiler.h:188 [inline] RIP: 0010:idle_cpu kernel/sched/core.c:3982 [inline] RIP: 0010:got_nohz_idle_kick kernel/sched/core.c:615 [inline] RIP: 0010:scheduler_ipi+0x3c7/0x820 kernel/sched/core.c:1778 RSP: 0018:ffff8801db207d70 EFLAGS: 00000806 RAX: 1ffff1003b640fbd RBX: 000000000002c5c0 RCX: dffffc0000000000 RDX: ffffffff86d28b60 RSI: 1ffff1003b640fbd RDI: ffff8801db22d160 RBP: ffff8801db207e90 R08: 1ffff1003b6459f5 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 1ffff1003b640fb1 R14: ffff8801db207e68 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffd0586feec CR3: 0000000006e22004 CR4: 00000000001606f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: smp_reschedule_interrupt+0xe6/0x650 arch/x86/kernel/smp.c:277 reschedule_interrupt+0x8e/0xa0 arch/x86/entry/entry_64.S:820 RIP: 0010:native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:54 RSP: 0018:ffffffff86e07c38 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff02 RAX: dffffc0000000000 RBX: 1ffffffff0dc0f8a RCX: 0000000000000000 RDX: 1ffffffff0dd92d8 RSI: 0000000000000001 RDI: ffffffff86ec96c0 RBP: ffffffff86e07c38 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: ffffffff86e07cf0 R14: ffffffff876df7e0 R15: 0000000000000000 arch_safe_halt arch/x86/include/asm/paravirt.h:93 [inline] default_idle+0xbf/0x430 arch/x86/kernel/process.c:354 arch_cpu_idle+0xa/0x10 arch/x86/kernel/process.c:345 default_idle_call+0x36/0x90 kernel/sched/idle.c:98 cpuidle_idle_call kernel/sched/idle.c:156 [inline] do_idle+0x24a/0x3b0 kernel/sched/idle.c:246 cpu_startup_entry+0x104/0x120 kernel/sched/idle.c:351 rest_init+0xed/0xf0 init/main.c:436 start_kernel+0x7f1/0x819 init/main.c:716 x86_64_start_reservations+0x2a/0x2c arch/x86/kernel/head64.c:378 x86_64_start_kernel+0x77/0x7a arch/x86/kernel/head64.c:359 secondary_startup_64+0xa5/0xb0 arch/x86/kernel/head_64.S:237 Code: 7b 02 00 00 48 89 c6 48 b9 00 00 00 00 00 fc ff df 4d 8b a4 24 a0 0b 00 00 48 c1 ee 03 80 3c 0e 00 0f 85 2f 02 00 00 48 c1 e8 03 <48> b9 00 00 00 00 00 fc ff df 4d 85 e4 4d 89 66 80 c6 04 08 f8