9pnet: p9_fd_create_tcp (29254): problem connecting socket to 127.0.0.1 input: syz1 as /devices/virtual/input/input20 INFO: task syz-executor4:29191 blocked for more than 140 seconds. Not tainted 4.20.0-rc3+ #123 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor4 D24488 29191 20399 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:00007f043dd2bc78 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: 00007f043dd2c6d4 R13: 00000000004c3216 R14: 00000000004d8c98 R15: 00000000ffffffff INFO: task syz-executor4:29193 blocked for more than 140 seconds. Not tainted 4.20.0-rc3+ #123 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor4 D19208 29193 20399 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:00007f043dd0ac78 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: 00007f043dd0b6d4 R13: 00000000004c3216 R14: 00000000004d8c98 R15: 00000000ffffffff Showing all locks held in the system: 1 lock held by khungtaskd/1018: #0: 00000000d495a709 (rcu_read_lock){....}, at: debug_show_all_locks+0xd0/0x424 kernel/locking/lockdep.c:4379 2 locks held by rs:main Q:Reg/5936: #0: 00000000ab46afe9 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x1bb/0x200 fs/file.c:766 #1: 000000003bfaeac8 (sb_writers#3){.+.+}, at: file_start_write include/linux/fs.h:2810 [inline] #1: 000000003bfaeac8 (sb_writers#3){.+.+}, at: vfs_write+0x42a/0x560 fs/read_write.c:548 1 lock held by rsyslogd/5939: #0: 00000000c97b82fd (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x1bb/0x200 fs/file.c:766 2 locks held by getty/6028: #0: 000000008cdafdc5 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000da737c44 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/6029: #0: 00000000d9b61c78 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000cf0c8d8f (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/6030: #0: 000000002612dbd0 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 0000000073315a79 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/6031: #0: 000000009c81c243 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000bad2d37b (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/6032: #0: 0000000038c7a99a (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000005e76f0c9 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/6033: #0: 000000008cc646d7 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000ab0a2080 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/6034: #0: 000000006b578cbe (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000003e9c9d97 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 4 locks held by kworker/u4:15/19936: 1 lock held by syz-executor4/29191: #0: 00000000c35c9711 (&type->s_umount_key#57){++++}, at: iterate_supers+0xe2/0x290 fs/super.c:631 1 lock held by syz-executor4/29193: #0: 00000000c35c9711 (&type->s_umount_key#57){++++}, at: iterate_supers+0xe2/0x290 fs/super.c:631 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1018 Comm: khungtaskd Not tainted 4.20.0-rc3+ #123 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:146 [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 0 to CPUs 1: INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 2.508 msecs NMI backtrace for cpu 1 CPU: 1 PID: 19936 Comm: kworker/u4:15 Not tainted 4.20.0-rc3+ #123 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: writeback wb_workfn (flush-7:0) RIP: 0010:__sanitizer_cov_trace_const_cmp4+0xd/0x20 kernel/kcov.c:187 Code: d6 0f b7 f7 bf 03 00 00 00 48 89 e5 48 8b 4d 08 e8 88 fe ff ff 5d c3 66 0f 1f 44 00 00 55 89 f2 89 fe bf 05 00 00 00 48 89 e5 <48> 8b 4d 08 e8 6a fe ff ff 5d c3 0f 1f 84 00 00 00 00 00 55 48 89 RSP: 0018:ffff888180da5cb0 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffff888180da5eb0 RCX: ffffffff87d7e66a RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000005 RBP: ffff888180da5cb0 R08: ffff888188df41c0 R09: ffffed103b5e5b67 R10: ffffed103b5e5b67 R11: ffff8881daf2db3b R12: 0000000000000000 R13: ffff8881cc4fe980 R14: ffff8881cc4fec42 R15: ffff888180da5d80 FS: 0000000000000000(0000) GS:ffff8881daf00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffff600400 CR3: 00000001c4807000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: xa_entry include/linux/xarray.h:709 [inline] xas_descend+0x3fb/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_old_data_flush fs/fs-writeback.c:1860 [inline] wb_do_writeback fs/fs-writeback.c:1913 [inline] wb_workfn+0x1008/0x1790 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