====================================================== WARNING: possible circular locking dependency detected 4.15.0-rc2-mm1+ #39 Not tainted ------------------------------------------------------ keyring/vboxnet/15264 is trying to acquire lock: (&pipe->mutex/1){+.+.}, at: [<00000000f1bf85eb>] pipe_lock_nested fs/pipe.c:67 [inline] (&pipe->mutex/1){+.+.}, at: [<00000000f1bf85eb>] pipe_lock+0x56/0x70 fs/pipe.c:75 but task is already holding lock: (sb_writers){.+.+}, at: [<000000000d04f3bd>] file_start_write include/linux/fs.h:2719 [inline] (sb_writers){.+.+}, at: [<000000000d04f3bd>] do_splice fs/splice.c:1146 [inline] (sb_writers){.+.+}, at: [<000000000d04f3bd>] SYSC_splice fs/splice.c:1402 [inline] (sb_writers){.+.+}, at: [<000000000d04f3bd>] SyS_splice+0x1117/0x1630 fs/splice.c:1382 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #6 (sb_writers){.+.+}: spin_lock include/linux/spinlock.h:315 [inline] lockref_get_not_dead+0x19/0x80 lib/lockref.c:180 legitimize_path.isra.31+0x7d/0x1a0 fs/namei.c:640 unlazy_walk+0xf2/0x4b0 fs/namei.c:692 complete_walk+0xb2/0x1f0 fs/namei.c:805 path_parentat+0x75/0x140 fs/namei.c:2356 -> #5 ((completion)&req.done){+.+.}: lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:4004 complete_acquire include/linux/completion.h:40 [inline] __wait_for_common kernel/sched/completion.c:109 [inline] wait_for_common kernel/sched/completion.c:123 [inline] wait_for_completion+0xcb/0x7b0 kernel/sched/completion.c:144 devtmpfs_create_node+0x32b/0x4a0 drivers/base/devtmpfs.c:115 device_add+0x120f/0x1640 drivers/base/core.c:1824 device_register+0x1d/0x20 drivers/base/core.c:1905 tty_register_device_attr+0x422/0x740 drivers/tty/tty_io.c:2956 tty_port_register_device_attr_serdev+0x100/0x140 drivers/tty/tty_port.c:166 uart_add_one_port+0xa7a/0x15a0 drivers/tty/serial/serial_core.c:2783 serial8250_register_8250_port+0xfac/0x1990 drivers/tty/serial/8250/8250_core.c:1045 serial_pnp_probe+0x5e7/0xac0 drivers/tty/serial/8250/8250_pnp.c:480 pnp_device_probe+0x15f/0x250 drivers/pnp/driver.c:109 really_probe drivers/base/dd.c:424 [inline] driver_probe_device+0x71b/0xae0 drivers/base/dd.c:566 __driver_attach+0x181/0x1c0 drivers/base/dd.c:800 bus_for_each_dev+0x154/0x1e0 drivers/base/bus.c:313 driver_attach+0x3d/0x50 drivers/base/dd.c:819 bus_add_driver+0x466/0x620 drivers/base/bus.c:669 driver_register+0x1bf/0x3c0 drivers/base/driver.c:168 pnp_register_driver+0x75/0xa0 drivers/pnp/driver.c:272 serial8250_pnp_init+0x15/0x20 drivers/tty/serial/8250/8250_pnp.c:537 serial8250_init+0x8f/0x270 drivers/tty/serial/8250/8250_core.c:1122 do_one_initcall+0x9e/0x330 init/main.c:833 do_initcall_level init/main.c:899 [inline] do_initcalls init/main.c:907 [inline] do_basic_setup init/main.c:925 [inline] kernel_init_freeable+0x469/0x521 init/main.c:1073 kernel_init+0x13/0x172 init/main.c:1000 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:524 -> #4 (&port->mutex){+.+.}: lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:4004 __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0x16f/0x1a80 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 uart_set_termios+0x8f/0x5b0 drivers/tty/serial/serial_core.c:1416 tty_set_termios+0x6d4/0xa40 drivers/tty/tty_ioctl.c:334 set_termios+0x377/0x6b0 drivers/tty/tty_ioctl.c:414 tty_mode_ioctl+0x9fb/0xb10 drivers/tty/tty_ioctl.c:749 n_tty_ioctl_helper+0x40/0x360 drivers/tty/tty_ioctl.c:940 n_tty_ioctl+0x148/0x2d0 drivers/tty/n_tty.c:2435 tty_ioctl+0x32e/0x1600 drivers/tty/tty_io.c:2638 vfs_ioctl fs/ioctl.c:46 [inline] do_vfs_ioctl+0x1b1/0x1530 fs/ioctl.c:686 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692 entry_SYSCALL_64_fastpath+0x1f/0x96 -> #3 (&tty->termios_rwsem){++++}: lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:4004 down_write+0x87/0x120 kernel/locking/rwsem.c:70 n_tty_flush_buffer+0x21/0x320 drivers/tty/n_tty.c:357 tty_buffer_flush+0x29a/0x390 drivers/tty/tty_buffer.c:233 tty_ldisc_flush+0x25/0x70 drivers/tty/tty_ldisc.c:418 tty_port_close_start.part.4+0x1cd/0x4e0 drivers/tty/tty_port.c:603 tty_port_close_start drivers/tty/tty_port.c:646 [inline] tty_port_close+0x3f/0x80 drivers/tty/tty_port.c:640 uart_close+0x77/0x1d0 drivers/tty/serial/serial_core.c:1487 tty_release+0x446/0x14c0 drivers/tty/tty_io.c:1639 __fput+0x333/0x7f0 fs/file_table.c:210 ____fput+0x15/0x20 fs/file_table.c:244 task_work_run+0x199/0x270 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:191 [inline] exit_to_usermode_loop+0x275/0x2f0 arch/x86/entry/common.c:165 prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline] syscall_return_slowpath+0x490/0x550 arch/x86/entry/common.c:264 entry_SYSCALL_64_fastpath+0x94/0x96 -> #2 (&buf->lock){+.+.}: lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:4004 __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0x16f/0x1a80 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 tty_buffer_flush+0xbd/0x390 drivers/tty/tty_buffer.c:222 tty_ldisc_flush+0x25/0x70 drivers/tty/tty_ldisc.c:418 tty_port_close_start.part.4+0x1cd/0x4e0 drivers/tty/tty_port.c:603 tty_port_close_start drivers/tty/tty_port.c:646 [inline] tty_port_close+0x3f/0x80 drivers/tty/tty_port.c:640 uart_close+0x77/0x1d0 drivers/tty/serial/serial_core.c:1487 tty_release+0x446/0x14c0 drivers/tty/tty_io.c:1639 __fput+0x333/0x7f0 fs/file_table.c:210 ____fput+0x15/0x20 fs/file_table.c:244 task_work_run+0x199/0x270 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:191 [inline] exit_to_usermode_loop+0x275/0x2f0 arch/x86/entry/common.c:165 prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline] syscall_return_slowpath+0x490/0x550 arch/x86/entry/common.c:264 entry_SYSCALL_64_fastpath+0x94/0x96 -> #1 (&tty->ldisc_sem){++++}: lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:4004 __ldsem_down_read_nested+0xd1/0xa90 drivers/tty/tty_ldsem.c:325 ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 tty_ldisc_ref_wait+0x25/0x80 drivers/tty/tty_ldisc.c:277 tty_read+0xf8/0x250 drivers/tty/tty_io.c:852 do_loop_readv_writev fs/read_write.c:673 [inline] do_iter_read+0x3db/0x5b0 fs/read_write.c:897 vfs_readv+0x121/0x1c0 fs/read_write.c:959 kernel_readv fs/splice.c:361 [inline] default_file_splice_read+0x508/0xae0 fs/splice.c:416 do_splice_to+0x110/0x170 fs/splice.c:880 do_splice fs/splice.c:1173 [inline] SYSC_splice fs/splice.c:1402 [inline] SyS_splice+0x11a8/0x1630 fs/splice.c:1382 entry_SYSCALL_64_fastpath+0x1f/0x96 -> #0 (&pipe->mutex/1){+.+.}: check_prevs_add kernel/locking/lockdep.c:2031 [inline] validate_chain kernel/locking/lockdep.c:2473 [inline] __lock_acquire+0x3498/0x47f0 kernel/locking/lockdep.c:3500 lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:4004 __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0x16f/0x1a80 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 pipe_lock_nested fs/pipe.c:67 [inline] pipe_lock+0x56/0x70 fs/pipe.c:75 iter_file_splice_write+0x264/0xf30 fs/splice.c:699 do_splice_from fs/splice.c:851 [inline] do_splice fs/splice.c:1147 [inline] SYSC_splice fs/splice.c:1402 [inline] SyS_splice+0x7d5/0x1630 fs/splice.c:1382 entry_SYSCALL_64_fastpath+0x1f/0x96 other info that might help us debug this: Chain exists of: &pipe->mutex/1 --> (completion)&req.done --> sb_writers Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(sb_writers); lock((completion)&req.done); lock(sb_writers); lock(&pipe->mutex/1); *** DEADLOCK *** 1 lock held by keyring/vboxnet/15264: #0: (sb_writers){.+.+}, at: [<000000000d04f3bd>] file_start_write include/linux/fs.h:2719 [inline] #0: (sb_writers){.+.+}, at: [<000000000d04f3bd>] do_splice fs/splice.c:1146 [inline] #0: (sb_writers){.+.+}, at: [<000000000d04f3bd>] SYSC_splice fs/splice.c:1402 [inline] #0: (sb_writers){.+.+}, at: [<000000000d04f3bd>] SyS_splice+0x1117/0x1630 fs/splice.c:1382 stack backtrace: CPU: 1 PID: 15264 Comm: keyring/vboxnet Not tainted 4.15.0-rc2-mm1+ #39 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x194/0x257 lib/dump_stack.c:53 print_circular_bug+0x42d/0x610 kernel/locking/lockdep.c:1271 check_prev_add+0x666/0x15f0 kernel/locking/lockdep.c:1914 check_prevs_add kernel/locking/lockdep.c:2031 [inline] validate_chain kernel/locking/lockdep.c:2473 [inline] __lock_acquire+0x3498/0x47f0 kernel/locking/lockdep.c:3500 lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:4004 __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0x16f/0x1a80 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 pipe_lock_nested fs/pipe.c:67 [inline] pipe_lock+0x56/0x70 fs/pipe.c:75 iter_file_splice_write+0x264/0xf30 fs/splice.c:699 do_splice_from fs/splice.c:851 [inline] do_splice fs/splice.c:1147 [inline] SYSC_splice fs/splice.c:1402 [inline] SyS_splice+0x7d5/0x1630 fs/splice.c:1382 entry_SYSCALL_64_fastpath+0x1f/0x96 RIP: 0033:0x452a09 RSP: 002b:00007f917c7f5c58 EFLAGS: 00000212 ORIG_RAX: 0000000000000113 RAX: ffffffffffffffda RBX: 000000000071bea0 RCX: 0000000000452a09 RDX: 0000000000000017 RSI: 0000000000000000 RDI: 0000000000000015 RBP: 0000000000000589 R08: 00000010fffffdf8 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006f5578 R13: 00000000ffffffff R14: 00007f917c7f66d4 R15: 0000000000000000 kauditd_printk_skb: 35 callbacks suppressed audit: type=1326 audit(1513525905.366:995): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 pid=15395 comm="syz-executor7" exe="/root/syz-executor7" sig=9 arch=c000003e syscall=202 compat=0 ip=0x452a09 code=0x0 audit: type=1326 audit(1513525905.422:996): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 pid=15395 comm="syz-executor7" exe="/root/syz-executor7" sig=9 arch=c000003e syscall=202 compat=0 ip=0x452a09 code=0x0 QAT: Invalid ioctl QAT: Invalid ioctl encrypted_key: insufficient parameters specified encrypted_key: insufficient parameters specified sctp: [Deprecated]: syz-executor6 (pid 16811) Use of int in max_burst socket option deprecated. Use struct sctp_assoc_value instead sctp: [Deprecated]: syz-executor6 (pid 16827) Use of int in max_burst socket option deprecated. Use struct sctp_assoc_value instead QAT: Invalid ioctl QAT: Invalid ioctl nla_parse: 5 callbacks suppressed netlink: 14 bytes leftover after parsing attributes in process `syz-executor5'. netlink: 14 bytes leftover after parsing attributes in process `syz-executor5'. netlink: 14 bytes leftover after parsing attributes in process `syz-executor5'. netlink: 14 bytes leftover after parsing attributes in process `syz-executor5'. netlink: 14 bytes leftover after parsing attributes in process `syz-executor5'. netlink: 14 bytes leftover after parsing attributes in process `syz-executor5'. SELinux: unrecognized netlink message: protocol=0 nlmsg_type=27 sclass=netlink_route_socket pig=17260 comm=syz-executor5 netlink: 14 bytes leftover after parsing attributes in process `syz-executor5'. FAULT_FLAG_ALLOW_RETRY missing 30 CPU: 0 PID: 17850 Comm: syz-executor2 Not tainted 4.15.0-rc2-mm1+ #39 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x194/0x257 lib/dump_stack.c:53 handle_userfault+0xbd9/0x2500 fs/userfaultfd.c:430 do_anonymous_page mm/memory.c:3116 [inline] handle_pte_fault mm/memory.c:3930 [inline] __handle_mm_fault+0x3402/0x3dd0 mm/memory.c:4056 handle_mm_fault+0x38f/0x930 mm/memory.c:4093 __do_page_fault+0x5c9/0xc90 arch/x86/mm/fault.c:1429 do_page_fault+0xee/0x720 arch/x86/mm/fault.c:1504 page_fault+0x2c/0x60 arch/x86/entry/entry_64.S:1243 RIP: 0010:fault_in_pages_readable include/linux/pagemap.h:601 [inline] RIP: 0010:iov_iter_fault_in_readable+0x1a7/0x410 lib/iov_iter.c:421 RSP: 0018:ffff8801c4fb7928 EFLAGS: 00010246 RAX: 0000000000010000 RBX: 0000000020011fd2 RCX: ffffffff8250e6b1 RDX: 0000000000000177 RSI: ffffc90002784000 RDI: ffff8801c4fb7d28 RBP: ffff8801c4fb7a08 R08: ffff8801db324d80 R09: 1ffff100389f6edf R10: ffff8801c6604540 R11: 1ffff1003b6649b4 R12: 1ffff100389f6f28 R13: ffff8801c4fb79e0 R14: 0000000000000000 R15: ffff8801c4fb7d20 generic_perform_write+0x200/0x600 mm/filemap.c:3128 __generic_file_write_iter+0x366/0x5b0 mm/filemap.c:3263 generic_file_write_iter+0x399/0x7a0 mm/filemap.c:3291 call_write_iter include/linux/fs.h:1776 [inline] new_sync_write fs/read_write.c:469 [inline] __vfs_write+0x68a/0x970 fs/read_write.c:482 vfs_write+0x18f/0x510 fs/read_write.c:544 SYSC_write fs/read_write.c:589 [inline] SyS_write+0xef/0x220 fs/read_write.c:581 entry_SYSCALL_64_fastpath+0x1f/0x96 RIP: 0033:0x452a09 RSP: 002b:00007f917c7f5c58 EFLAGS: 00000212 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f917c7f6700 RCX: 0000000000452a09 RDX: 0000000000000030 RSI: 0000000020011fd2 RDI: 0000000000000016 RBP: 0000000000a2f880 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000212 R12: 0000000000000000 R13: 0000000000a2f7ff R14: 00007f917c7f69c0 R15: 0000000000000000 FAULT_FLAG_ALLOW_RETRY missing 30 CPU: 1 PID: 17938 Comm: syz-executor2 Not tainted 4.15.0-rc2-mm1+ #39 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x194/0x257 lib/dump_stack.c:53 handle_userfault+0xbd9/0x2500 fs/userfaultfd.c:430 do_anonymous_page mm/memory.c:3116 [inline] handle_pte_fault mm/memory.c:3930 [inline] __handle_mm_fault+0x3402/0x3dd0 mm/memory.c:4056 handle_mm_fault+0x38f/0x930 mm/memory.c:4093 __do_page_fault+0x5c9/0xc90 arch/x86/mm/fault.c:1429 do_page_fault+0xee/0x720 arch/x86/mm/fault.c:1504 page_fault+0x2c/0x60 arch/x86/entry/entry_64.S:1243 RIP: 0010:fault_in_pages_readable include/linux/pagemap.h:601 [inline] RIP: 0010:iov_iter_fault_in_readable+0x1a7/0x410 lib/iov_iter.c:421 RSP: 0018:ffff8801bf767928 EFLAGS: 00010246 RAX: 0000000000010000 RBX: 0000000020011fd2 RCX: ffffffff8250e6b1 RDX: 0000000000000177 RSI: ffffc90002784000 RDI: ffff8801bf767d28 RBP: ffff8801bf767a08 R08: ffff8801db224d80 R09: 1ffff10037eecedf R10: ffff8801d60f6280 R11: 1ffff1003b6449b4 R12: 1ffff10037eecf28 R13: ffff8801bf7679e0 R14: 0000000000000000 R15: ffff8801bf767d20 generic_perform_write+0x200/0x600 mm/filemap.c:3128 __generic_file_write_iter+0x366/0x5b0 mm/filemap.c:3263 generic_file_write_iter+0x399/0x7a0 mm/filemap.c:3291 call_write_iter include/linux/fs.h:1776 [inline] new_sync_write fs/read_write.c:469 [inline] __vfs_write+0x68a/0x970 fs/read_write.c:482 vfs_write+0x18f/0x510 fs/read_write.c:544 SYSC_write fs/read_write.c:589 [inline] SyS_write+0xef/0x220 fs/read_write.c:581 entry_SYSCALL_64_fastpath+0x1f/0x96 RIP: 0033:0x452a09 RSP: 002b:00007f917c7f5c58 EFLAGS: 00000212 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 000000000071bea0 RCX: 0000000000452a09 RDX: 0000000000000030 RSI: 0000000020011fd2 RDI: 0000000000000016 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000212 R12: 0000000000000000 R13: 0000000000a2f7ff R14: 00007f917c7f69c0 R15: 0000000000000000