WARNING: possible circular locking dependency detected
4.15.0-rc1-next-20171128+ #54 Not tainted
------------------------------------------------------
syz-executor6/5063 is trying to acquire lock:
 (console_lock){+.+.}, at: [<ffffffff82894d69>] vcs_read+0x129/0xae0 drivers/tty/vt/vc_screen.c:219

but task is already holding lock:
 (&pipe->mutex/1){+.+.}, at: [<ffffffff81b0aa76>] pipe_lock_nested fs/pipe.c:67 [inline]
 (&pipe->mutex/1){+.+.}, at: [<ffffffff81b0aa76>] pipe_lock+0x56/0x70 fs/pipe.c:75

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #3 (&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

-> #2 (sb_writers){.+.+}:
       try_to_wake_up+0xbc/0x1600 kernel/sched/core.c:1989

-> #1 ((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_create_groups_vargs+0x1f3/0x250 drivers/base/core.c:2430
       device_create_vargs drivers/base/core.c:2470 [inline]
       device_create+0xda/0x110 drivers/base/core.c:2506
       vcs_make_sysfs+0x35/0x60 drivers/tty/vt/vc_screen.c:629
       vc_allocate+0x4b7/0x6b0 drivers/tty/vt/vt.c:797
       con_install+0x52/0x440 drivers/tty/vt/vt.c:2876
       tty_driver_install_tty drivers/tty/tty_io.c:1215 [inline]
       tty_init_dev+0xf6/0x4a0 drivers/tty/tty_io.c:1315
       tty_open_by_driver drivers/tty/tty_io.c:1942 [inline]
       tty_open+0x608/0xab0 drivers/tty/tty_io.c:1990
       chrdev_open+0x257/0x730 fs/char_dev.c:417
       do_dentry_open+0x682/0xd70 fs/open.c:752
       vfs_open+0x107/0x230 fs/open.c:866
       do_last fs/namei.c:3388 [inline]
       path_openat+0x1157/0x3530 fs/namei.c:3528
       do_filp_open+0x25b/0x3b0 fs/namei.c:3563
       do_sys_open+0x502/0x6d0 fs/open.c:1059
       SYSC_open fs/open.c:1077 [inline]
       SyS_open+0x2d/0x40 fs/open.c:1072
       entry_SYSCALL_64_fastpath+0x1f/0x96

-> #0 (console_lock){+.+.}:
       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
       console_lock+0x4b/0x80 kernel/printk/printk.c:2047
       vcs_read+0x129/0xae0 drivers/tty/vt/vc_screen.c:219
       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:
  console_lock --> sb_writers --> &pipe->mutex/1

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&pipe->mutex/1);
                               lock(sb_writers);
                               lock(&pipe->mutex/1);
  lock(console_lock);

 *** DEADLOCK ***

1 lock held by syz-executor6/5063:
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff81b0aa76>] pipe_lock_nested fs/pipe.c:67 [inline]
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff81b0aa76>] pipe_lock+0x56/0x70 fs/pipe.c:75

stack backtrace:
CPU: 0 PID: 5063 Comm: syz-executor6 Not tainted 4.15.0-rc1-next-20171128+ #54
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
 console_lock+0x4b/0x80 kernel/printk/printk.c:2047
 vcs_read+0x129/0xae0 drivers/tty/vt/vc_screen.c:219
 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: 0033:0x4529d9
RSP: 002b:00007fa985f0ec58 EFLAGS: 00000212 ORIG_RAX: 0000000000000113
RAX: ffffffffffffffda RBX: 0000000000758020 RCX: 00000000004529d9
RDX: 0000000000000015 RSI: 0000000000000000 RDI: 0000000000000013
RBP: 000000000000008a R08: 0000000000000fff R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006edd90
R13: 00000000ffffffff R14: 00007fa985f0f6d4 R15: 0000000000000000
SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket pig=5065 comm=syz-executor7
QAT: Invalid ioctl
do_dccp_getsockopt: sockopt(PACKET_SIZE) is deprecated: fix your app
QAT: Invalid ioctl
QAT: Invalid ioctl
QAT: Invalid ioctl
QAT: Invalid ioctl
do_dccp_getsockopt: sockopt(PACKET_SIZE) is deprecated: fix your app
xprt_adjust_timeout: rq_timeout = 0!
QAT: Invalid ioctl
QAT: Invalid ioctl
QAT: Invalid ioctl
xprt_adjust_timeout: rq_timeout = 0!
SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket pig=5148 comm=syz-executor7
QAT: failed to copy from user cfg_data.
QAT: failed to copy from user cfg_data.
nla_parse: 13 callbacks suppressed
netlink: 1 bytes leftover after parsing attributes in process `syz-executor4'.
netlink: 1 bytes leftover after parsing attributes in process `syz-executor4'.
netlink: 2 bytes leftover after parsing attributes in process `syz-executor6'.
netlink: 2 bytes leftover after parsing attributes in process `syz-executor6'.
semctl(GETNCNT/GETZCNT) is since 3.16 Single Unix Specification compliant.
The task syz-executor4 (5413) triggered the difference, watch for misbehavior.
kauditd_printk_skb: 91 callbacks suppressed
audit: type=1326 audit(1511907936.140:100): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=kernel pid=5434 comm="syz-executor4" exe="/root/syz-executor4" sig=31 arch=c000003e syscall=202 compat=0 ip=0x4529d9 code=0xffff0000
audit: type=1326 audit(1511907936.231:101): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=kernel pid=5434 comm="syz-executor4" exe="/root/syz-executor4" sig=31 arch=c000003e syscall=202 compat=0 ip=0x4529d9 code=0xffff0000
encrypted_key: insufficient parameters specified
encrypted_key: insufficient parameters specified
autofs4:pid:5584:check_dev_ioctl_version: ioctl control interface version mismatch: kernel(1.1), user(0.256), cmd(0x0000937e)
QAT: Invalid ioctl
autofs4:pid:5584:validate_dev_ioctl: invalid device control module version supplied for cmd(0x0000937e)
QAT: Invalid ioctl
autofs4:pid:5584:check_dev_ioctl_version: ioctl control interface version mismatch: kernel(1.1), user(0.256), cmd(0x0000937e)
autofs4:pid:5584:validate_dev_ioctl: invalid device control module version supplied for cmd(0x0000937e)
syz-executor7 (5644): /proc/5637/oom_adj is deprecated, please use /proc/5637/oom_score_adj instead.
binder: 5645:5651 unknown command 0
binder: 5645:5651 ioctl c0306201 2000a000 returned -22
sctp: [Deprecated]: syz-executor2 (pid 5651) Use of int in max_burst socket option.
Use struct sctp_assoc_value instead
binder: BINDER_SET_CONTEXT_MGR already set
binder: 5645:5651 ioctl 40046207 0 returned -16
binder: 5645:5651 unknown command 0
binder: 5645:5651 ioctl c0306201 2000a000 returned -22
sctp: [Deprecated]: syz-executor2 (pid 5664) Use of int in max_burst socket option.
Use struct sctp_assoc_value instead
netlink: 8 bytes leftover after parsing attributes in process `syz-executor2'.
netlink: 8 bytes leftover after parsing attributes in process `syz-executor2'.
netlink: 25 bytes leftover after parsing attributes in process `syz-executor5'.
netlink: 25 bytes leftover after parsing attributes in process `syz-executor5'.
netlink: 8 bytes leftover after parsing attributes in process `syz-executor7'.
binder: 5901:5904 DecRefs 0 refcount change on invalid ref 0 ret -22
binder: 5904 RLIMIT_NICE not set
binder: 5901:5913 BC_REQUEST_DEATH_NOTIFICATION invalid ref 0
binder: 5901:5913 got transaction to invalid handle
binder: 5901:5913 transaction failed 29201/-22, size 32-8 line 2755
binder: 5901:5922 ioctl 40046205 7f returned -22
binder: 5904 RLIMIT_NICE not set
binder: 5901:5904 unknown command 2002922117
binder: 5901:5904 ioctl c0306201 204f0000 returned -22
binder: 5901:5913 got transaction to invalid handle
binder: 5901:5913 transaction failed 29201/-22, size 0-0 line 2755
binder: 5901:5913 got reply transaction with bad transaction stack, transaction 18 has target 5901:5904
binder: 5901:5913 transaction failed 29201/-71, size 48-8 line 2685
binder: release 5901:5913 transaction 18 out, still active
binder: 5901:5922 DecRefs 0 refcount change on invalid ref 0 ret -22
binder: BINDER_SET_CONTEXT_MGR already set
binder: 5901:5913 ioctl 40046207 0 returned -16
binder: 5901:5922 BC_REQUEST_DEATH_NOTIFICATION invalid ref 0
binder: 5901:5922 got transaction to invalid handle
binder: 5901:5922 transaction failed 29201/-22, size 32-8 line 2755
binder: 5901:5913 ioctl 40046205 7f returned -22
binder_alloc: 5901: binder_alloc_buf, no vma
binder: 5901:5922 transaction failed 29189/-3, size 0-0 line 2870
binder: 5901:5913 BC_FREE_BUFFER u0000000020000000 no match
binder: 5901:5913 got transaction to invalid handle
binder: 5901:5913 transaction failed 29201/-22, size 0-0 line 2755
binder: 5901:5922 ERROR: BC_REGISTER_LOOPER called without request
binder: 5901:5922 got transaction to invalid handle
binder: 5901:5922 transaction failed 29201/-22, size 72-16 line 2755
binder: 5901:5922 got reply transaction with no transaction stack
binder: 5901:5922 transaction failed 29201/-71, size 48-8 line 2670
netlink: 3 bytes leftover after parsing attributes in process `syz-executor2'.
binder: undelivered TRANSACTION_ERROR: 29201
binder: release 5901:5904 transaction 18 in, still active
binder: send failed reply for transaction 18, target dead
device gre0 entered promiscuous mode
SELinux: unrecognized netlink message: protocol=0 nlmsg_type=256 sclass=netlink_route_socket pig=6144 comm=syz-executor7
SELinux: unrecognized netlink message: protocol=0 nlmsg_type=256 sclass=netlink_route_socket pig=6173 comm=syz-executor7
SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket pig=6213 comm=syz-executor4
SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket pig=6219 comm=syz-executor4
tmpfs: Bad mount option �peUѐ�%0���1D�#	0t�Pe�����?�9�(B��ڐg8)����W<k�
SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket pig=6364 comm=syz-executor5
QAT: Invalid ioctl
QAT: Invalid ioctl
QAT: Invalid ioctl
SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket pig=6364 comm=syz-executor5
QAT: Invalid ioctl
dccp_v4_rcv: dropped packet with invalid checksum
dccp_v4_rcv: dropped packet with invalid checksum
FAULT_FLAG_ALLOW_RETRY missing 30
CPU: 0 PID: 6424 Comm: syz-executor3 Not tainted 4.15.0-rc1-next-20171128+ #54
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+0x12fa/0x24c0 fs/userfaultfd.c:427
 do_anonymous_page mm/memory.c:3109 [inline]
 handle_pte_fault mm/memory.c:3922 [inline]
 __handle_mm_fault+0x3402/0x3dd0 mm/memory.c:4048
 handle_mm_fault+0x38f/0x930 mm/memory.c:4085
 __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:1230
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:ffff8801c107f928 EFLAGS: 00010246
RAX: 0000000000010000 RBX: 0000000020011fd2 RCX: ffffffff8250d6b1
RDX: 00000000000000c0 RSI: ffffc90002fee000 RDI: ffff8801c107fd28
RBP: ffff8801c107fa08 R08: 1ffff10038782cc2 R09: 1ffff1003820ff1a
R10: ffff8801d5a244c0 R11: ffff8801d5a244c0 R12: 1ffff1003820ff28
R13: ffff8801c107f9e0 R14: 0000000000000000 R15: ffff8801c107fd20
 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:1772 [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: 0033:0x4529d9
RSP: 002b:00007fed297b8c58 EFLAGS: 00000212 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000758020 RCX: 00000000004529d9
RDX: 0000000000000030 RSI: 0000000020011fd2 RDI: 0000000000000015
RBP: 0000000000000058 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006ed8e0
R13: 00000000ffffffff R14: 00007fed297b96d4 R15: 0000000000000000
QAT: Invalid ioctl
QAT: Invalid ioctl
QAT: Invalid ioctl
QAT: Invalid ioctl
QAT: Invalid ioctl
QAT: Invalid ioctl
ALSA: seq fatal error: cannot create timer (-19)
QAT: Invalid ioctl
QAT: Invalid ioctl
ALSA: seq fatal error: cannot create timer (-19)
9pnet_virtio: no channels available for device H
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9pnet_virtio: no channels available for device H
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device syz2 entered promiscuous mode
audit: type=1326 audit(1511907942.179:102): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=kernel pid=6673 comm="syz-executor4" exe="/root/syz-executor4" sig=31 arch=c000003e syscall=202 compat=0 ip=0x4529d9 code=0xffff0000
SELinux: unrecognized netlink message: protocol=0 nlmsg_type=5 sclass=netlink_route_socket pig=6688 comm=syz-executor6
SELinux: unrecognized netlink message: protocol=0 nlmsg_type=5 sclass=netlink_route_socket pig=6688 comm=syz-executor6
audit: type=1326 audit(1511907942.241:103): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=kernel pid=6689 comm="syz-executor2" exe="/root/syz-executor2" sig=0 arch=c000003e syscall=202 compat=0 ip=0x4529d9 code=0x7ffc0000
audit: type=1326 audit(1511907942.242:104): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=kernel pid=6689 comm="syz-executor2" exe="/root/syz-executor2" sig=0 arch=c000003e syscall=202 compat=0 ip=0x4529d9 code=0x7ffc0000
audit: type=1326 audit(1511907942.242:105): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=kernel pid=6689 comm="syz-executor2" exe="/root/syz-executor2" sig=0 arch=c000003e syscall=41 compat=0 ip=0x4529d9 code=0x7ffc0000
audit: type=1326 audit(1511907942.243:106): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=kernel pid=6689 comm="syz-executor2" exe="/root/syz-executor2" sig=0 arch=c000003e syscall=202 compat=0 ip=0x4529d9 code=0x7ffc0000
audit: type=1326 audit(1511907942.243:107): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=kernel pid=6689 comm="syz-executor2" exe="/root/syz-executor2" sig=0 arch=c000003e syscall=202 compat=0 ip=0x4529d9 code=0x7ffc0000
audit: type=1326 audit(1511907942.244:108): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=kernel pid=6689 comm="syz-executor2" exe="/root/syz-executor2" sig=0 arch=c000003e syscall=257 compat=0 ip=0x4529d9 code=0x7ffc0000
audit: type=1326 audit(1511907942.244:109): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=kernel pid=6689 comm="syz-executor2" exe="/root/syz-executor2" sig=0 arch=c000003e syscall=202 compat=0 ip=0x4529d9 code=0x7ffc0000
audit: type=1326 audit(1511907942.244:110): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=kernel pid=6689 comm="syz-executor2" exe="/root/syz-executor2" sig=0 arch=c000003e syscall=202 compat=0 ip=0x4529d9 code=0x7ffc0000
audit: type=1326 audit(1511907942.244:111): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=kernel pid=6689 comm="syz-executor2" exe="/root/syz-executor2" sig=0 arch=c000003e syscall=16 compat=0 ip=0x4529d9 code=0x7ffc0000
nla_parse: 4 callbacks suppressed
netlink: 1 bytes leftover after parsing attributes in process `syz-executor7'.
netlink: 1 bytes leftover after parsing attributes in process `syz-executor7'.
netlink: 1 bytes leftover after parsing attributes in process `syz-executor7'.
device gre0 entered promiscuous mode