INFO: task syz-executor0:17583 blocked for more than 120 seconds. Not tainted 4.17.0+ #102 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor0 D26008 17583 4545 0x00000004 Call Trace: context_switch kernel/sched/core.c:2858 [inline] __schedule+0x84c/0x1ea0 kernel/sched/core.c:3500 schedule+0xfb/0x450 kernel/sched/core.c:3544 schedule_preempt_disabled+0x10/0x20 kernel/sched/core.c:3602 __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: 0033:0x455b29 Code: Bad RIP value. RSP: 002b:00007fc7bfbe1c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007fc7bfbe26d4 RCX: 0000000000455b29 RDX: 0000000000000008 RSI: 0000000020000000 RDI: 0000000000000013 RBP: 000000000072bf50 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000004c25a3 R14: 00000000004d36d8 R15: 0000000000000001 Showing all locks held in the system: 4 locks held by kworker/u4:3/121: 1 lock held by khungtaskd/898: #0: 00000000d15cba12 (rcu_read_lock){....}, at: debug_show_all_locks+0xd0/0x428 kernel/locking/lockdep.c:4461 1 lock held by rsyslogd/4409: 2 locks held by getty/4499: #0: 000000000312a0ac (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 0000000071e45bda (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2131 2 locks held by getty/4500: #0: 00000000e0fdc3cb (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000a880953f (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2131 2 locks held by getty/4501: #0: 00000000e4cc46b7 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 0000000087299285 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2131 2 locks held by getty/4502: #0: 00000000abaabef6 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 000000001df0068f (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2131 2 locks held by getty/4503: #0: 000000005941bf3d (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000fab05792 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2131 2 locks held by getty/4504: #0: 00000000cd9b609d (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 000000001634290c (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2131 2 locks held by getty/4505: #0: 00000000ec7a778c (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 000000008b7943e2 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2131 5 locks held by syz-executor0/17511: 1 lock held by syz-executor0/17583: #0: 00000000db006022 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x1bb/0x200 fs/file.c:766 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 898 Comm: khungtaskd Not tainted 4.17.0+ #102 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 CPU: 0 PID: 17511 Comm: syz-executor0 Not tainted 4.17.0+ #102 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:compound_head include/linux/page-flags.h:144 [inline] RIP: 0010:mark_page_accessed+0x14e/0xd30 mm/swap.c:379 Code: 48 c1 e9 03 80 3c 11 00 0f 85 3d 0a 00 00 49 c1 ef 03 49 89 85 80 fd ff ff 31 ff 48 ba 00 00 00 00 00 fc ff df 41 c6 04 17 f8 <49> 89 c7 41 83 e7 01 48 89 85 30 fd ff ff 4c 89 fe e8 ac 6a dc ff RSP: 0018:ffff8801cd3ce658 EFLAGS: 00000246 RAX: ffffea0006dbf4c8 RBX: 1ffff10039a79cce RCX: 1ffff10039a79cd2 RDX: dffffc0000000000 RSI: ffffffff819f3e69 RDI: 0000000000000000 RBP: ffff8801cd3ce938 R08: ffff8801c6d0e180 R09: ffffed003b5c46d6 R10: 0000000000000003 R11: 0000000000000004 R12: ffffea000725e140 R13: ffff8801cd3ce910 R14: ffffea000725e148 R15: 1ffff10039a79cd2 FS: 00007fc7bfc03700(0000) GS:ffff8801dae00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000014ad000 CR3: 00000001ae996000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: pagecache_get_page+0x766/0xe40 mm/filemap.c:1567 find_or_create_page include/linux/pagemap.h:322 [inline] grow_dev_page fs/buffer.c:940 [inline] grow_buffers fs/buffer.c:1009 [inline] __getblk_slow fs/buffer.c:1036 [inline] __getblk_gfp+0x3bb/0xb10 fs/buffer.c:1313 __bread_gfp+0x2d/0x310 fs/buffer.c:1347 sb_bread include/linux/buffer_head.h:307 [inline] fat_ent_bread+0x173/0x290 fs/fat/fatent.c:106 fat_ent_read_block fs/fat/fatent.c:441 [inline] fat_alloc_clusters+0x8ce/0x16e0 fs/fat/fatent.c:489 fat_add_cluster+0x7a/0x150 fs/fat/inode.c:101 __fat_get_block fs/fat/inode.c:148 [inline] fat_get_block+0x37b/0xb10 fs/fat/inode.c:177 __block_write_begin_int+0x50d/0x1b00 fs/buffer.c:1958 __block_write_begin fs/buffer.c:2008 [inline] block_write_begin+0xda/0x370 fs/buffer.c:2067 cont_write_begin+0x569/0x860 fs/buffer.c:2417 fat_write_begin+0x8d/0x120 fs/fat/inode.c:223 generic_perform_write+0x3ae/0x6c0 mm/filemap.c:3139 __generic_file_write_iter+0x4b9/0x630 mm/filemap.c:3232 generic_file_write_iter+0x438/0x870 mm/filemap.c:3292 call_write_iter include/linux/fs.h:1793 [inline] new_sync_write fs/read_write.c:474 [inline] __vfs_write+0x6c6/0x9f0 fs/read_write.c:487 vfs_write+0x1f8/0x560 fs/read_write.c:549 ksys_write+0x101/0x260 fs/read_write.c:598 __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: 0033:0x455b29 Code: 1d ba fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 eb b9 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fc7bfc02c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007fc7bfc036d4 RCX: 0000000000455b29 RDX: 00000000ffffff43 RSI: 0000000020000180 RDI: 0000000000000013 RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000004c2585 R14: 00000000004d36a8 R15: 0000000000000000 INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.412 msecs