====================================================== WARNING: possible circular locking dependency detected 4.14.0+ #100 Not tainted ------------------------------------------------------ syz-executor0/20426 is trying to acquire lock: (&pipe->mutex/1){+.+.}, at: [] pipe_lock_nested fs/pipe.c:67 [inline] (&pipe->mutex/1){+.+.}, at: [] pipe_lock+0x56/0x70 fs/pipe.c:75 but task is already holding lock: (sb_writers){.+.+}, at: [] file_start_write include/linux/fs.h:2715 [inline] (sb_writers){.+.+}, at: [] do_splice fs/splice.c:1146 [inline] (sb_writers){.+.+}, at: [] SYSC_splice fs/splice.c:1402 [inline] (sb_writers){.+.+}, at: [] SyS_splice+0x1117/0x1630 fs/splice.c:1382 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #5 (sb_writers){.+.+}: spin_lock include/linux/spinlock.h:315 [inline] cache_grow_end.part.37+0x3a/0x180 mm/slab.c:2726 -> #4 ((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/0x15b0 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:826 do_initcall_level init/main.c:892 [inline] do_initcalls init/main.c:900 [inline] do_basic_setup init/main.c:918 [inline] kernel_init_freeable+0x469/0x521 init/main.c:1066 kernel_init+0x13/0x172 init/main.c:993 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:437 -> #3 (&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/0x15f0 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 -> #2 (&tty->termios_rwsem){++++}: lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:4004 down_read+0x96/0x150 kernel/locking/rwsem.c:24 n_tty_write+0x249/0xed0 drivers/tty/n_tty.c:2285 do_tty_write drivers/tty/tty_io.c:949 [inline] tty_write+0x400/0x850 drivers/tty/tty_io.c:1033 redirected_tty_write+0xa1/0xb0 drivers/tty/tty_io.c:1054 __vfs_write+0xef/0x970 fs/read_write.c:480 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 -> #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 do_syscall_32_irqs_on arch/x86/entry/common.c:327 [inline] do_fast_syscall_32+0x3ee/0xf9d arch/x86/entry/common.c:389 entry_SYSENTER_compat+0x51/0x60 arch/x86/entry/entry_64_compat.S:125 -> #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 do_syscall_32_irqs_on arch/x86/entry/common.c:327 [inline] do_fast_syscall_32+0x3ee/0xf9d arch/x86/entry/common.c:389 entry_SYSENTER_compat+0x51/0x60 arch/x86/entry/entry_64_compat.S:125 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 syz-executor0/20426: #0: (sb_writers){.+.+}, at: [] file_start_write include/linux/fs.h:2715 [inline] #0: (sb_writers){.+.+}, at: [] do_splice fs/splice.c:1146 [inline] #0: (sb_writers){.+.+}, at: [] SYSC_splice fs/splice.c:1402 [inline] #0: (sb_writers){.+.+}, at: [] SyS_splice+0x1117/0x1630 fs/splice.c:1382 stack backtrace: CPU: 1 PID: 20426 Comm: syz-executor0 Not tainted 4.14.0+ #100 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 do_syscall_32_irqs_on arch/x86/entry/common.c:327 [inline] do_fast_syscall_32+0x3ee/0xf9d arch/x86/entry/common.c:389 entry_SYSENTER_compat+0x51/0x60 arch/x86/entry/entry_64_compat.S:125 RIP: 0023:0xf7f10c79 RSP: 002b:00000000f770c01c EFLAGS: 00000296 ORIG_RAX: 0000000000000139 RAX: ffffffffffffffda RBX: 0000000000000017 RCX: 0000000000000000 RDX: 0000000000000019 RSI: 0000000000000000 RDI: 00000000fffffdf8 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 rfkill: input handler enabled rfkill: input handler disabled rfkill: input handler enabled rfkill: input handler disabled QAT: Invalid ioctl QAT: Invalid ioctl QAT: Invalid ioctl QAT: Invalid ioctl QAT: Invalid ioctl QAT: Invalid ioctl QAT: Invalid ioctl QAT: Invalid ioctl rfkill: input handler enabled rfkill: input handler disabled rfkill: input handler enabled rfkill: input handler disabled rfkill: input handler enabled rfkill: input handler disabled rfkill: input handler enabled rfkill: input handler disabled rfkill: input handler enabled rfkill: input handler disabled rfkill: input handler enabled rfkill: input handler disabled rfkill: input handler enabled rfkill: input handler disabled rfkill: input handler enabled rfkill: input handler disabled rfkill: input handler enabled rfkill: input handler disabled rfkill: input handler enabled rfkill: input handler disabled rfkill: 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