INFO: task syz-executor0:8207 blocked for more than 140 seconds. Not tainted 4.20.0-rc1+ #323 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor0 D22776 8207 5671 0x00000004 Call Trace: context_switch kernel/sched/core.c:2831 [inline] __schedule+0x8cf/0x21d0 kernel/sched/core.c:3472 schedule+0xfe/0x460 kernel/sched/core.c:3516 wb_wait_for_completion+0x1f9/0x2d0 fs/fs-writeback.c:221 sync_inodes_sb+0x33e/0x480 fs/fs-writeback.c:2417 sync_inodes_one_sb+0x59/0x70 fs/sync.c:74 iterate_supers+0x149/0x290 fs/super.c:633 ksys_sync+0xec/0x1e0 fs/sync.c:113 __ia32_sys_sync+0xe/0x20 fs/sync.c:124 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457569 Code: Bad RIP value. RSP: 002b:00007fb119bb9c78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2 RAX: ffffffffffffffda RBX: 000000000072bf08 RCX: 0000000000457569 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fb119bba6d4 R13: 00000000004c311f R14: 00000000004d7fd8 R15: 00000000ffffffff INFO: task syz-executor0:8209 blocked for more than 140 seconds. Not tainted 4.20.0-rc1+ #323 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor0 D21992 8209 5671 0x00000004 Call Trace: context_switch kernel/sched/core.c:2831 [inline] __schedule+0x8cf/0x21d0 kernel/sched/core.c:3472 schedule+0xfe/0x460 kernel/sched/core.c:3516 wb_wait_for_completion+0x1f9/0x2d0 fs/fs-writeback.c:221 sync_inodes_sb+0x33e/0x480 fs/fs-writeback.c:2417 sync_inodes_one_sb+0x59/0x70 fs/sync.c:74 iterate_supers+0x149/0x290 fs/super.c:633 ksys_sync+0xec/0x1e0 fs/sync.c:113 __ia32_sys_sync+0xe/0x20 fs/sync.c:124 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457569 Code: Bad RIP value. RSP: 002b:00007fb119b98c78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2 RAX: ffffffffffffffda RBX: 000000000072bfa8 RCX: 0000000000457569 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 000000000072bfa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fb119b996d4 R13: 00000000004c311f R14: 00000000004d7fd8 R15: 00000000ffffffff Showing all locks held in the system: 4 locks held by kworker/u4:0/7: 1 lock held by khungtaskd/1009: #0: 000000002765d38b (rcu_read_lock){....}, at: debug_show_all_locks+0xd0/0x424 kernel/locking/lockdep.c:4379 1 lock held by rsyslogd/5540: #0: 00000000306ca473 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x1bb/0x200 fs/file.c:766 2 locks held by getty/5630: #0: 00000000048e7585 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 0000000094daf4a2 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/5631: #0: 000000000022b207 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000003b0a107e (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/5632: #0: 000000005aad7c3f (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000389f21be (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/5633: #0: 000000006e2a38dc (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000c4538316 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/5634: #0: 00000000b5e32419 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000002ef299df (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/5635: #0: 000000009ef35472 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000db4fd79a (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/5636: #0: 00000000586bdb4d (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000da877295 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 1 lock held by syz-executor0/8207: #0: 00000000271ff04f (&type->s_umount_key#54){++++}, at: iterate_supers+0xe2/0x290 fs/super.c:631 1 lock held by syz-executor0/8209: #0: 00000000271ff04f (&type->s_umount_key#54){++++}, at: iterate_supers+0xe2/0x290 fs/super.c:631 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1009 Comm: khungtaskd Not tainted 4.20.0-rc1+ #323 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+0x244/0x39d lib/dump_stack.c:113 nmi_cpu_backtrace.cold.2+0x5c/0xa1 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1e8/0x22a 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:144 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:205 [inline] watchdog+0xb51/0x1060 kernel/hung_task.c:289 kthread+0x35a/0x440 kernel/kthread.c:246 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.970 msecs CPU: 0 PID: 7 Comm: kworker/u4:0 Not tainted 4.20.0-rc1+ #323 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: writeback wb_workfn (flush-7:0) RIP: 0010:debug_smp_processor_id+0x0/0x20 include/linux/bitmap.h:317 Code: ff ff e8 33 9f 2f fe eb a6 48 89 c7 e8 49 9f 2f fe e9 b3 fe ff ff 48 89 45 d0 e8 3b 9f 2f fe 48 8b 45 d0 e9 7f fe ff ff 66 90 <55> 48 89 e5 e8 e7 51 ec fd 48 c7 c6 a0 bf 60 88 48 c7 c7 e0 bf 60 RSP: 0018:ffff8801d9ae5c08 EFLAGS: 00000246 RAX: dffffc0000000000 RBX: 1ffff1003b35cb83 RCX: 0000000000000000 RDX: 1ffff1003b35b66e RSI: 0000000000000000 RDI: ffff8801d9adb370 RBP: ffff8801d9ae5ca0 R08: ffffed003b5c5b68 R09: ffffed003b5c5b67 R10: ffffed003b5c5b67 R11: ffff8801dae2db3b R12: 0000000000000001 R13: dffffc0000000000 R14: ffff8801d9ae5c78 R15: ffff8801d9ae5d80 FS: 0000000000000000(0000) GS:ffff8801dae00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffff600400 CR3: 00000001d7163000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: rcu_read_lock_held+0x90/0xc0 kernel/rcu/update.c:279 xa_entry include/linux/xarray.h:709 [inline] xas_descend+0x413/0x510 lib/xarray.c:198 xas_load+0x145/0x1e0 lib/xarray.c:234 find_get_entry+0x3ca/0x1120 mm/filemap.c:1415 pagecache_get_page+0x12f/0xf00 mm/filemap.c:1518 find_or_create_page include/linux/pagemap.h:322 [inline] grow_dev_page fs/buffer.c:947 [inline] grow_buffers fs/buffer.c:1016 [inline] __getblk_slow fs/buffer.c:1043 [inline] __getblk_gfp+0x3aa/0xd50 fs/buffer.c:1320 __bread_gfp+0x2d/0x310 fs/buffer.c:1354 sb_bread include/linux/buffer_head.h:307 [inline] fat_clusters_flush+0x127/0x3c0 fs/fat/misc.c:70 fat_write_inode+0x110/0x180 fs/fat/inode.c:905 write_inode fs/fs-writeback.c:1176 [inline] __writeback_single_inode+0xf56/0x1660 fs/fs-writeback.c:1375 writeback_sb_inodes+0x71f/0x1210 fs/fs-writeback.c:1580 __writeback_inodes_wb+0x1b9/0x340 fs/fs-writeback.c:1649 wb_writeback+0xa73/0xfc0 fs/fs-writeback.c:1758 wb_check_start_all fs/fs-writeback.c:1882 [inline] wb_do_writeback fs/fs-writeback.c:1908 [inline] wb_workfn+0xee9/0x1790 fs/fs-writeback.c:1942 process_one_work+0xc90/0x1c40 kernel/workqueue.c:2153 worker_thread+0x17f/0x1390 kernel/workqueue.c:2296 kthread+0x35a/0x440 kernel/kthread.c:246 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352