INFO: task syz-executor7:23953 blocked for more than 140 seconds. Not tainted 4.18.0-rc3+ #6 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor7 D24696 23953 4572 0x00000004 Call Trace: context_switch kernel/sched/core.c:2862 [inline] __schedule+0x87c/0x1ed0 kernel/sched/core.c:3504 schedule+0xfb/0x450 kernel/sched/core.c:3548 __rwsem_down_read_failed_common kernel/locking/rwsem-xadd.c:269 [inline] rwsem_down_read_failed+0x362/0x600 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] __percpu_down_read+0x16e/0x210 kernel/locking/percpu-rwsem.c:85 percpu_down_read_preempt_disable include/linux/percpu-rwsem.h:49 [inline] percpu_down_read include/linux/percpu-rwsem.h:59 [inline] __sb_start_write+0x2d7/0x300 fs/super.c:1403 sb_start_pagefault include/linux/fs.h:1583 [inline] ext4_page_mkwrite+0x1d0/0x1430 fs/ext4/inode.c:6125 do_page_mkwrite+0x14e/0x520 mm/memory.c:2380 wp_page_shared mm/memory.c:2676 [inline] do_wp_page+0xf78/0x19b0 mm/memory.c:2776 handle_pte_fault mm/memory.c:3988 [inline] __handle_mm_fault+0x2a84/0x4460 mm/memory.c:4096 handle_mm_fault+0x53e/0xc80 mm/memory.c:4133 __do_page_fault+0x620/0xe50 arch/x86/mm/fault.c:1396 do_page_fault+0xf6/0x8c0 arch/x86/mm/fault.c:1471 page_fault+0x1e/0x30 arch/x86/entry/entry_64.S:1160 RIP: 0033:0x4084b0 Code: 24 1f e9 d2 00 00 00 48 ff c2 48 83 fa 08 0f 83 ad 00 00 00 84 01 0f b6 1c 11 38 d8 75 e9 48 89 54 24 20 48 8b 5c 24 48 0f b6 <73> 50 48 0f af f2 0f b6 5b 51 48 89 cf 48 8d 74 3e 08 84 db 74 7c RSP: 002b:00007ffd14eea280 EFLAGS: 00010287 RAX: 0000001b3102093c RBX: 0000000000000000 RCX: 0000001b32020000 RDX: 0000001b31020940 RSI: 0000000000730b20 RDI: 0000000000000002 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 00007ffd14eea2c0 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000002 R14: 000000000072bea0 R15: 000000000072bea0 Showing all locks held in the system: 1 lock held by khungtaskd/903: #0: 00000000ccfe852a (rcu_read_lock){....}, at: debug_show_all_locks+0xd0/0x428 kernel/locking/lockdep.c:4461 2 locks held by rs:main Q:Reg/4427: #0: 00000000a26b0e34 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x1bb/0x200 fs/file.c:766 #1: 000000001f12f5fa (sb_writers#6){++++}, at: file_start_write include/linux/fs.h:2737 [inline] #1: 000000001f12f5fa (sb_writers#6){++++}, at: vfs_write+0x452/0x560 fs/read_write.c:548 1 lock held by rsyslogd/4429: #0: 00000000e66b00fd (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x1bb/0x200 fs/file.c:766 2 locks held by getty/4519: #0: 00000000c6250a65 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000eaa63ff3 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4520: #0: 0000000006398708 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000b883260d (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4521: #0: 0000000049ffdcc3 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000af2b1903 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4522: #0: 0000000091952b11 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 000000000116991f (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4523: #0: 00000000c0b91d16 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 0000000035103b24 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4524: #0: 0000000088b78ef7 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 000000001619dedd (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4525: #0: 000000007d5ac174 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 0000000041c378cc (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by syz-executor7/23953: #0: 000000000142f9bf (&mm->mmap_sem){++++}, at: __do_page_fault+0x389/0xe50 arch/x86/mm/fault.c:1325 #1: 000000001e404eb0 (sb_pagefaults){++++}, at: sb_start_pagefault include/linux/fs.h:1583 [inline] #1: 000000001e404eb0 (sb_pagefaults){++++}, at: ext4_page_mkwrite+0x1d0/0x1430 fs/ext4/inode.c:6125 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 903 Comm: khungtaskd Not tainted 4.18.0-rc3+ #6 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: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