====================================================== WARNING: possible circular locking dependency detected 4.15.0-rc2-mm1+ #39 Not tainted ------------------------------------------------------ syz-executor2/10314 is trying to acquire lock: (&tty->ldisc_sem){++++}, at: [<00000000c01a29d2>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 but task is already holding lock: (&pipe->mutex/1){+.+.}, at: [<00000000b53fcd35>] pipe_lock_nested fs/pipe.c:67 [inline] (&pipe->mutex/1){+.+.}, at: [<00000000b53fcd35>] pipe_lock+0x56/0x70 fs/pipe.c:75 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #6 (&pipe->mutex/1){+.+.}: 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 -> #5 (sb_writers){.+.+}: spin_lock include/linux/spinlock.h:315 [inline] fast_dput fs/dcache.c:688 [inline] dput.part.23+0x492/0x830 fs/dcache.c:795 dput+0x1f/0x30 fs/dcache.c:788 path_put+0x31/0x70 fs/namei.c:500 handle_remove+0x2a4/0xb60 drivers/base/devtmpfs.c:339 handle drivers/base/devtmpfs.c:375 [inline] devtmpfsd+0x262/0x4b0 drivers/base/devtmpfs.c:399 -> #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/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 -> #3 (&port->mutex){+.+.}: netlink: 1 bytes leftover after parsing attributes in process `syz-executor4'. 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 -> #2 (&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 netlink: 1 bytes leftover after parsing attributes in process `syz-executor4'. 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 (&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 -> #0 (&tty->ldisc_sem){++++}: 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 __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 other info that might help us debug this: Chain exists of: &tty->ldisc_sem --> sb_writers --> &pipe->mutex/1 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&pipe->mutex/1); lock(sb_writers); lock(&pipe->mutex/1); lock(&tty->ldisc_sem); *** DEADLOCK *** 1 lock held by syz-executor2/10314: #0: (&pipe->mutex/1){+.+.}, at: [<00000000b53fcd35>] pipe_lock_nested fs/pipe.c:67 [inline] #0: (&pipe->mutex/1){+.+.}, at: [<00000000b53fcd35>] pipe_lock+0x56/0x70 fs/pipe.c:75 stack backtrace: CPU: 0 PID: 10314 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 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 __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 RIP: 0033:0x452a09 RSP: 002b:00007fcef436dc58 EFLAGS: 00000212 ORIG_RAX: 0000000000000113 RAX: ffffffffffffffda RBX: 000000000071bea0 RCX: 0000000000452a09 RDX: 0000000000000015 RSI: 0000000000000000 RDI: 0000000000000013 RBP: 000000000000039b R08: 0000000000000200 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006f2728 R13: 00000000ffffffff R14: 00007fcef436e6d4 R15: 0000000000000000 netlink: 4 bytes leftover after parsing attributes in process `syz-executor3'. netlink: 4 bytes leftover after parsing attributes in process `syz-executor3'. netlink: 25 bytes leftover after parsing attributes in process `syz-executor7'. netlink: 25 bytes leftover after parsing attributes in process `syz-executor7'. binder: 10489:10497 ioctl c0306201 20007000 returned -14 binder: 10532 RLIMIT_NICE not set binder: 10531:10540 got reply transaction with no transaction stack binder: 10531:10540 transaction failed 29201/-71, size 0-16 line 2747 binder: 10531:10540 BC_REQUEST_DEATH_NOTIFICATION invalid ref 0 binder: 10531:10532 BC_CLEAR_DEATH_NOTIFICATION invalid ref 0 binder: 10531:10540 BC_REQUEST_DEATH_NOTIFICATION invalid ref 0 binder: 10531:10532 BC_DEAD_BINDER_DONE 0000000000000000 not found binder: 10531:10532 Release 1 refcount change on invalid ref 0 ret -22 binder: 10531:10532 got reply transaction with no transaction stack binder: 10531:10532 transaction failed 29201/-71, size 0-16 line 2747 binder: undelivered TRANSACTION_ERROR: 29201 binder: undelivered TRANSACTION_ERROR: 29201 binder: undelivered death notification, 0000000000000000 device gre0 entered promiscuous mode QAT: Invalid ioctl QAT: Invalid ioctl binder: 10619:10622 transaction failed 29189/-22, size 88-56 line 2832 kauditd_printk_skb: 351 callbacks suppressed audit: type=1400 audit(1513550120.806:2054): avc: denied { setgid } for pid=10610 comm="syz-executor6" capability=6 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=cap_userns permissive=1 SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket pig=10613 comm=syz-executor6 binder: 10619:10635 ERROR: BC_REGISTER_LOOPER called without request binder: 10635 RLIMIT_NICE not set binder: 10619:10635 Acquire 1 refcount change on invalid ref 0 ret -22 binder: 10619:10635 BC_REQUEST_DEATH_NOTIFICATION invalid ref 0 binder: 10619:10643 BC_CLEAR_DEATH_NOTIFICATION invalid ref 0 binder: 10619:10643 transaction failed 29189/-22, size 88-56 line 2832 binder: 10619:10635 ERROR: BC_REGISTER_LOOPER called without request binder: 10619:10635 IncRefs 0 refcount change on invalid ref 0 ret -22 binder: 10635 RLIMIT_NICE not set binder: undelivered TRANSACTION_ERROR: 29189 binder: undelivered TRANSACTION_ERROR: 29189 binder: undelivered death notification, 0000000000000000 audit: type=1400 audit(1513550121.237:2055): avc: denied { setuid } for pid=10716 comm="syz-executor7" capability=7 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=cap_userns permissive=1 dccp_invalid_packet: P.Data Offset(4) too small dccp_invalid_packet: P.Data Offset(4) too small device lo left promiscuous mode nla_parse: 13 callbacks suppressed netlink: 2 bytes leftover after parsing attributes in process `syz-executor7'. audit: type=1400 audit(1513550122.515:2056): avc: denied { map } for pid=11078 comm="syz-executor7" path="/dev/vcs" dev="devtmpfs" ino=31 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=system_u:object_r:tty_device_t:s0 tclass=chr_file permissive=1 FAULT_INJECTION: forcing a failure. name failslab, interval 1, probability 0, space 0, times 1 CPU: 1 PID: 11301 Comm: syz-executor5 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 fail_dump lib/fault-inject.c:51 [inline] should_fail+0x8c0/0xa40 lib/fault-inject.c:149 should_failslab+0xec/0x120 mm/failslab.c:32 slab_pre_alloc_hook mm/slab.h:425 [inline] slab_alloc mm/slab.c:3372 [inline] kmem_cache_alloc+0x47/0x760 mm/slab.c:3546 ptlock_alloc+0x24/0x70 mm/memory.c:4681 ptlock_init include/linux/mm.h:1790 [inline] pgtable_page_ctor include/linux/mm.h:1824 [inline] pte_alloc_one+0x59/0x100 arch/x86/mm/pgtable.c:32 do_huge_pmd_anonymous_page+0xc23/0x1b00 mm/huge_memory.c:689 create_huge_pmd mm/memory.c:3823 [inline] __handle_mm_fault+0x1b68/0x3dd0 mm/memory.c:4027 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+0x4c/0x60 arch/x86/entry/entry_64.S:1243 RIP: 0033:0x40180b RSP: 002b:00007f010669cb90 EFLAGS: 00010246 RAX: 0000000020000000 RBX: 000000000000006e RCX: 0000000000000000 RDX: 9a05568cc14a5bf2 RSI: 0000000000000000 RDI: 00007f010669d608 RBP: 0000000020a08f92 R08: 0000000000000000 R09: 0000000000000000 R10: 000000000000006e R11: 0000000000000000 R12: 00000000006f56c8 R13: 0000000000000013 R14: 00007f010669d6d4 R15: ffffffffffffffff oom_reaper: reaped process 11301 (syz-executor5), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB