INFO: task syz-executor2:22425 blocked for more than 140 seconds. Not tainted 4.19.0-rc1+ #218 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor2 D23704 22425 4697 0x00000004 Call Trace: context_switch kernel/sched/core.c:2825 [inline] __schedule+0x87c/0x1df0 kernel/sched/core.c:3473 schedule+0xfb/0x450 kernel/sched/core.c:3517 wb_wait_for_completion+0x201/0x2e0 fs/fs-writeback.c:221 sync_inodes_sb+0x33e/0x480 fs/fs-writeback.c:2424 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: 0033:0x457099 Code: 48 8b 54 24 38 48 8b 7c 24 48 eb 8d 48 8b 6c 24 50 48 83 c4 58 c3 48 89 04 24 48 89 5c 24 08 e8 0d a9 fb ff 48 8b 44 24 40 48 <8b> 4c 24 48 48 8b 54 24 38 4c 8b 54 24 18 e9 ee fe ff ff 48 89 74 RSP: 002b:00007fdf39f53c78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2 RAX: ffffffffffffffda RBX: 00007fdf39f546d4 RCX: 0000000000457099 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00000000009300a0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000004d6b40 R14: 00000000004c84ee R15: 0000000000000000 Showing all locks held in the system: 3 locks held by kworker/u4:1/22: 1 lock held by khungtaskd/792: #0: 00000000f7f22f5b (rcu_read_lock){....}, at: debug_show_all_locks+0xd0/0x428 kernel/locking/lockdep.c:4436 1 lock held by rsyslogd/4556: #0: 00000000d7edca5a (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x1bb/0x200 fs/file.c:766 2 locks held by getty/4647: #0: 00000000ce8f7221 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000b2c7670b (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4648: #0: 00000000a753abb5 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000001a8e2891 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4649: #0: 000000007026534b (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:353 #1: 0000000087fef9a0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4650: #0: 00000000d2b13bab (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000eecf276e (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4651: #0: 000000008f878226 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000c25acff1 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4652: #0: 00000000f9a76ac9 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000009ab16f1a (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4653: #0: 00000000ca6e027e (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000d6571582 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 1 lock held by syz-executor2/22425: #0: 00000000fc0eea95 (&type->s_umount_key#63){++++}, at: iterate_supers+0xe2/0x290 fs/super.c:631 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 792 Comm: khungtaskd Not tainted 4.19.0-rc1+ #218 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.3+0x48/0x88 lib/nmi_backtrace.c:101 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:144 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:204 [inline] watchdog+0xb39/0x1040 kernel/hung_task.c:265 kthread+0x35a/0x420 kernel/kthread.c:246 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:413 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.958 msecs CPU: 1 PID: 22 Comm: kworker/u4:1 Not tainted 4.19.0-rc1+ #218 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: writeback wb_workfn (flush-7:0) RIP: 0010:write_comp_data+0x0/0x70 Code: fd ff ff 48 8b bd d0 fe ff ff e8 8b fe 3e 00 e9 ad fc ff ff 4c 89 ef e8 de fd 3e 00 e9 76 fc ff ff e8 b4 c7 ca ff 90 90 90 90 <55> 65 4c 8b 04 25 40 ee 01 00 65 8b 05 af 2d 85 7e 48 89 e5 a9 00 RSP: 0018:ffff8801d9835dd8 EFLAGS: 00000a02 RAX: 1ffff1003b306bd0 RBX: 0000000000000002 RCX: ffffffff819b0fff RDX: 0000000000000002 RSI: 0000000000000000 RDI: 0000000000000005 RBP: ffff8801d9835de0 R08: ffff8801d98245c0 R09: ffffed003b306bd0 R10: ffffed003b306bd0 R11: 0000000000000003 R12: ffffea0007132cc0 R13: ffff8801d9836100 R14: 0000000000000001 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff8801db100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffff600400 CR3: 00000001c6050000 CR4: 00000000001406e0 Call Trace: page_cache_get_speculative include/linux/pagemap.h:186 [inline] find_get_entry+0x57f/0xc90 mm/filemap.c:1448 pagecache_get_page+0x11e/0xe40 mm/filemap.c:1541 find_or_create_page include/linux/pagemap.h:322 [inline] grow_dev_page fs/buffer.c:948 [inline] grow_buffers fs/buffer.c:1017 [inline] __getblk_slow fs/buffer.c:1044 [inline] __getblk_gfp+0x3bb/0xb10 fs/buffer.c:1321 __bread_gfp+0x2d/0x310 fs/buffer.c:1355 sb_bread include/linux/buffer_head.h:307 [inline] __fat_write_inode+0x347/0xb60 fs/fat/inode.c:859 fat_write_inode+0x97/0x180 fs/fat/inode.c:908 write_inode fs/fs-writeback.c:1183 [inline] __writeback_single_inode+0xd8e/0x1330 fs/fs-writeback.c:1382 writeback_sb_inodes+0x71f/0x1150 fs/fs-writeback.c:1587 __writeback_inodes_wb+0x1b8/0x340 fs/fs-writeback.c:1656 wb_writeback+0x989/0xe80 fs/fs-writeback.c:1765 wb_check_old_data_flush fs/fs-writeback.c:1867 [inline] wb_do_writeback fs/fs-writeback.c:1920 [inline] wb_workfn+0xee6/0x1610 fs/fs-writeback.c:1949 process_one_work+0xc73/0x1aa0 kernel/workqueue.c:2153 worker_thread+0x189/0x13c0 kernel/workqueue.c:2296 kthread+0x35a/0x420 kernel/kthread.c:246 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:413