binder: BINDER_SET_CONTEXT_MGR already set
binder: 15073:15075 ioctl 40046207 0 returned -16
======================================================
[ INFO: possible circular locking dependency detected ]
4.4.174+ #17 Not tainted
-------------------------------------------------------
syz-executor.4/15084 is trying to acquire lock:
 (sel_mutex){+.+.+.}, at: [<ffffffff81979d7e>] sel_write_load+0x9e/0xf90 security/selinux/selinuxfs.c:511

but task is already holding lock:
 (&pipe->mutex/1){+.+.+.}, at: [<ffffffff814af8b3>] pipe_lock_nested fs/pipe.c:65 [inline]
 (&pipe->mutex/1){+.+.+.}, at: [<ffffffff814af8b3>] pipe_lock+0x63/0x80 fs/pipe.c:73

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #5 (&pipe->mutex/1){+.+.+.}:
       [<ffffffff81205f6e>] lock_acquire+0x15e/0x450 kernel/locking/lockdep.c:3592
       [<ffffffff8270c191>] __mutex_lock_common kernel/locking/mutex.c:521 [inline]
       [<ffffffff8270c191>] mutex_lock_nested+0xc1/0xb80 kernel/locking/mutex.c:621
       [<ffffffff814af8b3>] pipe_lock_nested fs/pipe.c:65 [inline]
       [<ffffffff814af8b3>] pipe_lock+0x63/0x80 fs/pipe.c:73
       [<ffffffff815342e9>] iter_file_splice_write+0x179/0xb30 fs/splice.c:974
       [<ffffffff81537d31>] do_splice_from fs/splice.c:1128 [inline]
       [<ffffffff81537d31>] do_splice fs/splice.c:1404 [inline]
       [<ffffffff81537d31>] SYSC_splice fs/splice.c:1707 [inline]
       [<ffffffff81537d31>] SyS_splice+0xd71/0x13a0 fs/splice.c:1690
       [<ffffffff8100603d>] do_syscall_32_irqs_on arch/x86/entry/common.c:330 [inline]
       [<ffffffff8100603d>] do_fast_syscall_32+0x32d/0xa90 arch/x86/entry/common.c:397
       [<ffffffff8271a350>] sysenter_flags_fixed+0xd/0x1a

-> #4 (sb_writers#4){.+.+.+}:
       [<ffffffff81205f6e>] lock_acquire+0x15e/0x450 kernel/locking/lockdep.c:3592
       [<ffffffff8149ea2f>] percpu_down_read include/linux/percpu-rwsem.h:26 [inline]
       [<ffffffff8149ea2f>] __sb_start_write+0x1af/0x310 fs/super.c:1239
       [<ffffffff816c3af4>] sb_start_write include/linux/fs.h:1517 [inline]
       [<ffffffff816c3af4>] ext4_run_li_request fs/ext4/super.c:2685 [inline]
       [<ffffffff816c3af4>] ext4_lazyinit_thread fs/ext4/super.c:2784 [inline]
       [<ffffffff816c3af4>] ext4_lazyinit_thread+0x1e4/0x7b0 fs/ext4/super.c:2760
       [<ffffffff811342c3>] kthread+0x273/0x310 kernel/kthread.c:211
       [<ffffffff82718fc5>] ret_from_fork+0x55/0x80 arch/x86/entry/entry_64.S:537

-> #3 (&eli->li_list_mtx){+.+...}:
       [<ffffffff81205f6e>] lock_acquire+0x15e/0x450 kernel/locking/lockdep.c:3592
       [<ffffffff8270c191>] __mutex_lock_common kernel/locking/mutex.c:521 [inline]
       [<ffffffff8270c191>] mutex_lock_nested+0xc1/0xb80 kernel/locking/mutex.c:621
       [<ffffffff816cdacd>] ext4_register_li_request+0x2fd/0x7d0 fs/ext4/super.c:2972
       [<ffffffff816cf306>] ext4_remount+0x1366/0x1b90 fs/ext4/super.c:4922
       [<ffffffff814a1ccb>] do_remount_sb2+0x41b/0x7a0 fs/super.c:781
       [<ffffffff815028ab>] do_remount fs/namespace.c:2347 [inline]
       [<ffffffff815028ab>] do_mount+0xfdb/0x2a40 fs/namespace.c:2860
       [<ffffffff81504d00>] SYSC_mount fs/namespace.c:3063 [inline]
       [<ffffffff81504d00>] SyS_mount+0x130/0x1d0 fs/namespace.c:3041
       [<ffffffff82718ba1>] entry_SYSCALL_64_fastpath+0x1e/0x9a

-> #2 (&ext4_li_mtx){+.+.+.}:
       [<ffffffff81205f6e>] lock_acquire+0x15e/0x450 kernel/locking/lockdep.c:3592
       [<ffffffff8270c191>] __mutex_lock_common kernel/locking/mutex.c:521 [inline]
       [<ffffffff8270c191>] mutex_lock_nested+0xc1/0xb80 kernel/locking/mutex.c:621
       [<ffffffff816cd859>] ext4_register_li_request+0x89/0x7d0 fs/ext4/super.c:2945
       [<ffffffff816cf306>] ext4_remount+0x1366/0x1b90 fs/ext4/super.c:4922
       [<ffffffff814a1ccb>] do_remount_sb2+0x41b/0x7a0 fs/super.c:781
       [<ffffffff815028ab>] do_remount fs/namespace.c:2347 [inline]
       [<ffffffff815028ab>] do_mount+0xfdb/0x2a40 fs/namespace.c:2860
       [<ffffffff81504d00>] SYSC_mount fs/namespace.c:3063 [inline]
       [<ffffffff81504d00>] SyS_mount+0x130/0x1d0 fs/namespace.c:3041
       [<ffffffff82718ba1>] entry_SYSCALL_64_fastpath+0x1e/0x9a

-> #1 (&type->s_umount_key#34){++++++}:
       [<ffffffff81205f6e>] lock_acquire+0x15e/0x450 kernel/locking/lockdep.c:3592
       [<ffffffff827139a2>] down_read+0x42/0x60 kernel/locking/rwsem.c:22
       [<ffffffff814a1411>] iterate_supers+0xe1/0x250 fs/super.c:547
       [<ffffffff819b19f7>] selinux_complete_init+0x2f/0x31 security/selinux/hooks.c:6154
       [<ffffffff819a353d>] security_load_policy+0x69d/0x9c0 security/selinux/ss/services.c:2060
       [<ffffffff81979e55>] sel_write_load+0x175/0xf90 security/selinux/selinuxfs.c:535
       [<ffffffff81496916>] __vfs_write+0x116/0x3d0 fs/read_write.c:491
       [<ffffffff81498612>] vfs_write+0x182/0x4e0 fs/read_write.c:540
       [<ffffffff8149ac4c>] SYSC_write fs/read_write.c:587 [inline]
       [<ffffffff8149ac4c>] SyS_write+0xdc/0x1c0 fs/read_write.c:579
       [<ffffffff82718ba1>] entry_SYSCALL_64_fastpath+0x1e/0x9a

-> #0 (sel_mutex){+.+.+.}:
       [<ffffffff81202d86>] check_prev_add kernel/locking/lockdep.c:1853 [inline]
       [<ffffffff81202d86>] check_prevs_add kernel/locking/lockdep.c:1958 [inline]
       [<ffffffff81202d86>] validate_chain kernel/locking/lockdep.c:2144 [inline]
       [<ffffffff81202d86>] __lock_acquire+0x37d6/0x4f50 kernel/locking/lockdep.c:3213
       [<ffffffff81205f6e>] lock_acquire+0x15e/0x450 kernel/locking/lockdep.c:3592
       [<ffffffff8270c191>] __mutex_lock_common kernel/locking/mutex.c:521 [inline]
       [<ffffffff8270c191>] mutex_lock_nested+0xc1/0xb80 kernel/locking/mutex.c:621
       [<ffffffff81979d7e>] sel_write_load+0x9e/0xf90 security/selinux/selinuxfs.c:511
       [<ffffffff81496916>] __vfs_write+0x116/0x3d0 fs/read_write.c:491
       [<ffffffff81496ce2>] __kernel_write+0x112/0x370 fs/read_write.c:513
       [<ffffffff81532e6d>] write_pipe_buf+0x15d/0x1f0 fs/splice.c:1074
       [<ffffffff81533b6e>] splice_from_pipe_feed fs/splice.c:776 [inline]
       [<ffffffff81533b6e>] __splice_from_pipe+0x37e/0x7a0 fs/splice.c:901
       [<ffffffff81536be8>] splice_from_pipe+0x108/0x170 fs/splice.c:936
       [<ffffffff81536cdc>] default_file_splice_write+0x3c/0x80 fs/splice.c:1086
       [<ffffffff81537d31>] do_splice_from fs/splice.c:1128 [inline]
       [<ffffffff81537d31>] do_splice fs/splice.c:1404 [inline]
       [<ffffffff81537d31>] SYSC_splice fs/splice.c:1707 [inline]
       [<ffffffff81537d31>] SyS_splice+0xd71/0x13a0 fs/splice.c:1690
       [<ffffffff8100603d>] do_syscall_32_irqs_on arch/x86/entry/common.c:330 [inline]
       [<ffffffff8100603d>] do_fast_syscall_32+0x32d/0xa90 arch/x86/entry/common.c:397
       [<ffffffff8271a350>] sysenter_flags_fixed+0xd/0x1a

other info that might help us debug this:

Chain exists of:
  sel_mutex --> sb_writers#4 --> &pipe->mutex/1

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&pipe->mutex/1);
                               lock(sb_writers#4);
                               lock(&pipe->mutex/1);
  lock(sel_mutex);

 *** DEADLOCK ***

2 locks held by syz-executor.4/15084:
 #0:  (sb_writers#3){.+.+.+}, at: [<ffffffff81537eed>] file_start_write include/linux/fs.h:2543 [inline]
 #0:  (sb_writers#3){.+.+.+}, at: [<ffffffff81537eed>] do_splice fs/splice.c:1403 [inline]
 #0:  (sb_writers#3){.+.+.+}, at: [<ffffffff81537eed>] SYSC_splice fs/splice.c:1707 [inline]
 #0:  (sb_writers#3){.+.+.+}, at: [<ffffffff81537eed>] SyS_splice+0xf2d/0x13a0 fs/splice.c:1690
 #1:  (&pipe->mutex/1){+.+.+.}, at: [<ffffffff814af8b3>] pipe_lock_nested fs/pipe.c:65 [inline]
 #1:  (&pipe->mutex/1){+.+.+.}, at: [<ffffffff814af8b3>] pipe_lock+0x63/0x80 fs/pipe.c:73

stack backtrace:
CPU: 0 PID: 15084 Comm: syz-executor.4 Not tainted 4.4.174+ #17
 0000000000000000 b1d8cb0793f51ddb ffff88005d68f4b0 ffffffff81aad1a1
 ffffffff84057a80 ffff88006de8af80 ffffffff83ab8870 ffffffff83abd460
 ffffffff83abc1d0 ffff88005d68f500 ffffffff813abcda ffffffff83e25b00
Call Trace:
 [<ffffffff81aad1a1>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81aad1a1>] dump_stack+0xc1/0x120 lib/dump_stack.c:51
 [<ffffffff813abcda>] print_circular_bug.cold+0x2f7/0x44e kernel/locking/lockdep.c:1226
 [<ffffffff81202d86>] check_prev_add kernel/locking/lockdep.c:1853 [inline]
 [<ffffffff81202d86>] check_prevs_add kernel/locking/lockdep.c:1958 [inline]
 [<ffffffff81202d86>] validate_chain kernel/locking/lockdep.c:2144 [inline]
 [<ffffffff81202d86>] __lock_acquire+0x37d6/0x4f50 kernel/locking/lockdep.c:3213
 [<ffffffff81205f6e>] lock_acquire+0x15e/0x450 kernel/locking/lockdep.c:3592
 [<ffffffff8270c191>] __mutex_lock_common kernel/locking/mutex.c:521 [inline]
 [<ffffffff8270c191>] mutex_lock_nested+0xc1/0xb80 kernel/locking/mutex.c:621
 [<ffffffff81979d7e>] sel_write_load+0x9e/0xf90 security/selinux/selinuxfs.c:511
 [<ffffffff81496916>] __vfs_write+0x116/0x3d0 fs/read_write.c:491
 [<ffffffff81496ce2>] __kernel_write+0x112/0x370 fs/read_write.c:513
 [<ffffffff81532e6d>] write_pipe_buf+0x15d/0x1f0 fs/splice.c:1074
 [<ffffffff81533b6e>] splice_from_pipe_feed fs/splice.c:776 [inline]
 [<ffffffff81533b6e>] __splice_from_pipe+0x37e/0x7a0 fs/splice.c:901
 [<ffffffff81536be8>] splice_from_pipe+0x108/0x170 fs/splice.c:936
 [<ffffffff81536cdc>] default_file_splice_write+0x3c/0x80 fs/splice.c:1086
 [<ffffffff81537d31>] do_splice_from fs/splice.c:1128 [inline]
 [<ffffffff81537d31>] do_splice fs/splice.c:1404 [inline]
 [<ffffffff81537d31>] SYSC_splice fs/splice.c:1707 [inline]
 [<ffffffff81537d31>] SyS_splice+0xd71/0x13a0 fs/splice.c:1690
 [<ffffffff8100603d>] do_syscall_32_irqs_on arch/x86/entry/common.c:330 [inline]
 [<ffffffff8100603d>] do_fast_syscall_32+0x32d/0xa90 arch/x86/entry/common.c:397
 [<ffffffff8271a350>] sysenter_flags_fixed+0xd/0x1a
SELinux:  policydb magic number 0x30307830 does not match expected magic number 0xf97cff8c
binder: 15073:15088 BC_ACQUIRE_DONE u0000000000000000 no match
binder: 15073:15088 DecRefs 0 refcount change on invalid ref 0 ret -22
binder: 15073:15088 BC_FREE_BUFFER u0000000000000000 no match
binder: 15073:15088 got new transaction with bad transaction stack, transaction 242 has target 14692:0
binder: 15073:15088 transaction failed 29201/-71, size 0-16 line 3041
binder: release 15073:15088 transaction 241 out, still active
binder: undelivered TRANSACTION_COMPLETE
binder: release 15073:15088 transaction 244 out, still active
binder: undelivered TRANSACTION_COMPLETE
binder: release 15073:15088 transaction 242 out, still active
binder: undelivered TRANSACTION_COMPLETE
binder: undelivered TRANSACTION_ERROR: 29201
SELinux:  policydb magic number 0x30307830 does not match expected magic number 0xf97cff8c
binder: BINDER_SET_CONTEXT_MGR already set
binder: 15123:15125 ioctl 40046207 0 returned -16
binder: 15123:15125 BC_ACQUIRE_DONE u0000000000000000 no match
binder: 15123:15125 DecRefs 0 refcount change on invalid ref 0 ret -22
binder: 15123:15125 BC_FREE_BUFFER u0000000000000000 no match
binder: 15123:15125 got new transaction with bad transaction stack, transaction 246 has target 14692:0
binder: 15123:15125 transaction failed 29201/-71, size 0-16 line 3041
binder: release 15123:15125 transaction 246 out, still active
binder: undelivered TRANSACTION_COMPLETE
binder: undelivered TRANSACTION_ERROR: 29201
binder: release 15123:15125 transaction 245 out, still active
binder: undelivered TRANSACTION_COMPLETE
binder: BINDER_SET_CONTEXT_MGR already set
binder: 15145:15146 ioctl 40046207 0 returned -16
binder: 15145:15146 BC_ACQUIRE_DONE u0000000000000000 no match
binder: 15145:15146 DecRefs 0 refcount change on invalid ref 0 ret -22
binder: 15145:15146 BC_FREE_BUFFER u0000000000000000 no match
binder: 15145:15146 got new transaction with bad transaction stack, transaction 249 has target 14692:0
binder: 15145:15146 transaction failed 29201/-71, size 0-16 line 3041
binder: release 15145:15146 transaction 248 out, still active
binder: undelivered TRANSACTION_COMPLETE
binder: release 15145:15146 transaction 249 out, still active
binder: undelivered TRANSACTION_COMPLETE
binder: BINDER_SET_CONTEXT_MGR already set
binder: undelivered TRANSACTION_ERROR: 29201
binder: 15161:15162 ioctl 40046207 0 returned -16
binder: 15161:15162 BC_ACQUIRE_DONE u0000000000000000 no match
binder: 15161:15162 DecRefs 0 refcount change on invalid ref 0 ret -22
binder: 15161:15162 BC_FREE_BUFFER u0000000000000000 no match
SELinux:  policydb magic number 0x30307830 does not match expected magic number 0xf97cff8c
binder: 15161:15162 got new transaction with bad transaction stack, transaction 252 has target 14692:0
binder: 15161:15162 transaction failed 29201/-71, size 0-16 line 3041
binder: release 15161:15162 transaction 252 out, still active
binder: undelivered TRANSACTION_COMPLETE
binder: undelivered TRANSACTION_ERROR: 29201
binder: release 15161:15162 transaction 251 out, still active
binder: undelivered TRANSACTION_COMPLETE
binder: BINDER_SET_CONTEXT_MGR already set
binder: 15176:15180 ioctl 40046207 0 returned -16
binder: 15176:15180 BC_ACQUIRE_DONE u0000000000000000 no match
binder: 15176:15180 DecRefs 0 refcount change on invalid ref 0 ret -22
binder: 15176:15180 BC_FREE_BUFFER u0000000000000000 no match
binder: 15176:15180 got new transaction with bad transaction stack, transaction 255 has target 14692:0
binder: 15176:15180 transaction failed 29201/-71, size 0-16 line 3041
binder: release 15176:15180 transaction 255 out, still active
binder: undelivered TRANSACTION_COMPLETE
binder: undelivered TRANSACTION_ERROR: 29201
binder: release 15176:15180 transaction 254 out, still active
binder: undelivered TRANSACTION_COMPLETE
binder: BINDER_SET_CONTEXT_MGR already set
binder: 15183:15184 ioctl 40046207 0 returned -16
binder: 15183:15184 BC_ACQUIRE_DONE u0000000000000000 no match
binder: 15183:15184 DecRefs 0 refcount change on invalid ref 0 ret -22
binder: 15183:15184 BC_FREE_BUFFER u0000000000000000 no match
binder: 15183:15184 got new transaction with bad transaction stack, transaction 258 has target 14692:0
binder: 15183:15184 transaction failed 29201/-71, size 0-16 line 3041
binder: release 15183:15184 transaction 258 out, still active
binder: undelivered TRANSACTION_COMPLETE
binder: undelivered TRANSACTION_ERROR: 29201
binder: release 15183:15184 transaction 257 out, still active
binder: undelivered TRANSACTION_COMPLETE
binder: BINDER_SET_CONTEXT_MGR already set
binder: 15197:15198 ioctl 40046207 0 returned -16
binder: release 15197:15198 transaction 260 out, still active
binder: undelivered TRANSACTION_COMPLETE
binder: BINDER_SET_CONTEXT_MGR already set
binder: 15204:15205 ioctl 40046207 0 returned -16
binder: release 15204:15205 transaction 261 out, still active
binder: undelivered TRANSACTION_COMPLETE
SELinux:  policydb magic number 0x30307830 does not match expected magic number 0xf97cff8c
binder: BINDER_SET_CONTEXT_MGR already set
binder: 15216:15217 ioctl 40046207 0 returned -16
binder: release 15216:15217 transaction 262 out, still active
binder: undelivered TRANSACTION_COMPLETE
binder: BINDER_SET_CONTEXT_MGR already set
binder: 15228:15231 ioctl 40046207 0 returned -16
binder: release 15228:15231 transaction 263 out, still active
binder: undelivered TRANSACTION_COMPLETE
binder: BINDER_SET_CONTEXT_MGR already set
binder: 15243:15245 ioctl 40046207 0 returned -16
binder: release 15243:15245 transaction 264 out, still active
binder: undelivered TRANSACTION_COMPLETE
SELinux:  policydb magic number 0x30307830 does not match expected magic number 0xf97cff8c
SELinux:  policydb magic number 0x30307830 does not match expected magic number 0xf97cff8c
binder: release 15257:15260 transaction 265 out, still active
binder: undelivered TRANSACTION_COMPLETE
SELinux:  policydb magic number 0x30307830 does not match expected magic number 0xf97cff8c
binder: release 15270:15274 transaction 266 out, still active
binder: undelivered TRANSACTION_COMPLETE
binder: release 15332:15333 transaction 267 out, still active
binder: undelivered TRANSACTION_COMPLETE
binder: release 15340:15344 transaction 268 out, still active
binder: undelivered TRANSACTION_COMPLETE
binder: release 15363:15366 transaction 269 out, still active
binder: undelivered TRANSACTION_COMPLETE
binder: release 15378:15381 transaction 270 out, still active
binder: undelivered TRANSACTION_COMPLETE
binder: release 15401:15408 transaction 271 out, still active
binder: undelivered TRANSACTION_COMPLETE
SELinux:  policydb magic number 0x30307830 does not match expected magic number 0xf97cff8c
binder: release 15421:15423 transaction 272 out, still active
binder: undelivered TRANSACTION_COMPLETE
binder: release 15442:15443 transaction 273 out, still active
binder: undelivered TRANSACTION_COMPLETE
binder: release 15451:15452 transaction 274 out, still active
binder: undelivered TRANSACTION_COMPLETE
binder: release 15459:15463 transaction 275 out, still active
binder: undelivered TRANSACTION_COMPLETE