possible deadlock in sel_commit_bools_write
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syzbot
Apr 11, 2019, 4:44:36 AM4/11/19
to syzkaller-a...@googlegroups.com
Hello,
syzbot found the following crash on:
HEAD commit: c4b00eb7 Revert "BACKPORT, FROMLIST: fscrypt: add Speck128..
git tree: android-4.4
console output: https://syzkaller.appspot.com/x/log.txt?x=168a357b400000
kernel config: https://syzkaller.appspot.com/x/.config?x=88f924cb59937510
dashboard link: https://syzkaller.appspot.com/bug?extid=ce459bafcb68ff272f48
compiler: gcc (GCC) 8.0.1 20180413 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1301ab13400000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=158878b9400000
IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+ce459b...@syzkaller.appspotmail.com
======================================================
[ INFO: possible circular locking dependency detected ]
4.4.162+ #117 Not tainted
-------------------------------------------------------
syz-executor023/2087 is trying to acquire lock:
(sel_mutex){+.+.+.}, at: [<ffffffff81963767>]
sel_commit_bools_write+0x87/0x250 security/selinux/selinuxfs.c:1142
but task is already holding lock:
(&pipe->mutex/1){+.+.+.}, at: [<ffffffff814a9afe>] pipe_lock_nested
fs/pipe.c:65 [inline]
(&pipe->mutex/1){+.+.+.}, at: [<ffffffff814a9afe>] pipe_lock+0x5e/0x70
fs/pipe.c:73
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
[<ffffffff81202cde>] lock_acquire+0x15e/0x450
kernel/locking/lockdep.c:3592
[<ffffffff826fad9b>] __mutex_lock_common kernel/locking/mutex.c:521
[inline]
[<ffffffff826fad9b>] mutex_lock_nested+0xbb/0x8d0
kernel/locking/mutex.c:621
[<ffffffff814aca0c>] __pipe_lock fs/pipe.c:86 [inline]
[<ffffffff814aca0c>] fifo_open+0x15c/0x9e0 fs/pipe.c:896
[<ffffffff8148ba0d>] do_dentry_open+0x38d/0xbd0 fs/open.c:749
[<ffffffff8148f17a>] vfs_open+0x12a/0x210 fs/open.c:862
[<ffffffff814bed5c>] do_last fs/namei.c:3222 [inline]
[<ffffffff814bed5c>] path_openat+0x50c/0x39a0 fs/namei.c:3359
[<ffffffff814c5e87>] do_filp_open+0x197/0x270 fs/namei.c:3393
[<ffffffff814a1eef>] do_open_execat+0x10f/0x6f0 fs/exec.c:800
[<ffffffff814a74a1>] do_execveat_common.isra.14+0x6a1/0x1f00
fs/exec.c:1573
[<ffffffff814a9672>] do_execve fs/exec.c:1679 [inline]
[<ffffffff814a9672>] SYSC_execve fs/exec.c:1760 [inline]
[<ffffffff814a9672>] SyS_execve+0x42/0x50 fs/exec.c:1755
[<ffffffff827065f5>] return_from_execve+0x0/0x23
[<ffffffff81202cde>] lock_acquire+0x15e/0x450
kernel/locking/lockdep.c:3592
[<ffffffff826fbf4c>] __mutex_lock_common kernel/locking/mutex.c:521
[inline]
[<ffffffff826fbf4c>] mutex_lock_killable_nested+0xcc/0xa10
kernel/locking/mutex.c:641
[<ffffffff815e2b54>] lock_trace+0x44/0xc0 fs/proc/base.c:448
[<ffffffff815e33a9>] proc_pid_syscall+0xa9/0x260 fs/proc/base.c:683
[<ffffffff815daffd>] proc_single_show+0xfd/0x170 fs/proc/base.c:805
[<ffffffff81501656>] seq_read+0x4b6/0x12b0 fs/seq_file.c:240
[<ffffffff8149084c>] __vfs_read+0x11c/0x3d0 fs/read_write.c:432
[<ffffffff81492520>] vfs_read+0x130/0x360 fs/read_write.c:454
[<ffffffff81494d49>] SYSC_read fs/read_write.c:569 [inline]
[<ffffffff81494d49>] SyS_read+0xd9/0x1c0 fs/read_write.c:562
[<ffffffff827062e1>] entry_SYSCALL_64_fastpath+0x1e/0x9a
[<ffffffff81202cde>] lock_acquire+0x15e/0x450
kernel/locking/lockdep.c:3592
[<ffffffff826fad9b>] __mutex_lock_common kernel/locking/mutex.c:521
[inline]
[<ffffffff826fad9b>] mutex_lock_nested+0xbb/0x8d0
kernel/locking/mutex.c:621
[<ffffffff8150127d>] seq_read+0xdd/0x12b0 fs/seq_file.c:178
[<ffffffff81491378>] do_loop_readv_writev+0x148/0x1e0
fs/read_write.c:680
[<ffffffff814931b1>] do_readv_writev+0x581/0x6f0 fs/read_write.c:810
[<ffffffff81493398>] vfs_readv+0x78/0xb0 fs/read_write.c:834
[<ffffffff8152f53f>] kernel_readv fs/splice.c:586 [inline]
[<ffffffff8152f53f>] default_file_splice_read+0x50f/0x8f0
fs/splice.c:662
[<ffffffff8152b417>] do_splice_to+0xf7/0x140 fs/splice.c:1154
[<ffffffff8152b6a2>] splice_direct_to_actor+0x242/0x830
fs/splice.c:1226
[<ffffffff8152be33>] do_splice_direct+0x1a3/0x270 fs/splice.c:1337
[<ffffffff814945d4>] do_sendfile+0x4e4/0xb80 fs/read_write.c:1227
[<ffffffff814965c3>] SYSC_sendfile64 fs/read_write.c:1282 [inline]
[<ffffffff814965c3>] SyS_sendfile64+0xc3/0x150 fs/read_write.c:1274
[<ffffffff827062e1>] entry_SYSCALL_64_fastpath+0x1e/0x9a
[<ffffffff81202cde>] lock_acquire+0x15e/0x450
kernel/locking/lockdep.c:3592
[<ffffffff81498cae>] percpu_down_read
include/linux/percpu-rwsem.h:26 [inline]
[<ffffffff81498cae>] __sb_start_write+0x1ae/0x310 fs/super.c:1221
[<ffffffff816bafc7>] sb_start_write include/linux/fs.h:1515 [inline]
[<ffffffff816bafc7>] ext4_run_li_request fs/ext4/super.c:2674
[inline]
[<ffffffff816bafc7>] ext4_lazyinit_thread+0x1a7/0x750
fs/ext4/super.c:2773
[<ffffffff81133e18>] kthread+0x268/0x300 kernel/kthread.c:211
[<ffffffff827066c5>] ret_from_fork+0x55/0x80
arch/x86/entry/entry_64.S:510
[<ffffffff81202cde>] lock_acquire+0x15e/0x450
kernel/locking/lockdep.c:3592
[<ffffffff826fad9b>] __mutex_lock_common kernel/locking/mutex.c:521
[inline]
[<ffffffff826fad9b>] mutex_lock_nested+0xbb/0x8d0
kernel/locking/mutex.c:621
[<ffffffff816c50c4>] ext4_register_li_request+0x304/0x7a0
fs/ext4/super.c:2961
[<ffffffff816c68c8>] ext4_remount+0x1368/0x1bb0 fs/ext4/super.c:4911
[<ffffffff8149bf58>] do_remount_sb2+0x428/0x7d0 fs/super.c:771
[<ffffffff814fbe9e>] do_remount fs/namespace.c:2335 [inline]
[<ffffffff814fbe9e>] do_mount+0x101e/0x2a10 fs/namespace.c:2848
[<ffffffff814fe3e1>] SYSC_mount fs/namespace.c:3051 [inline]
[<ffffffff814fe3e1>] SyS_mount+0x191/0x1c0 fs/namespace.c:3029
[<ffffffff827062e1>] entry_SYSCALL_64_fastpath+0x1e/0x9a
[<ffffffff81202cde>] lock_acquire+0x15e/0x450
kernel/locking/lockdep.c:3592
[<ffffffff826fad9b>] __mutex_lock_common kernel/locking/mutex.c:521
[inline]
[<ffffffff826fad9b>] mutex_lock_nested+0xbb/0x8d0
kernel/locking/mutex.c:621
[<ffffffff816c4e47>] ext4_register_li_request+0x87/0x7a0
fs/ext4/super.c:2934
[<ffffffff816c68c8>] ext4_remount+0x1368/0x1bb0 fs/ext4/super.c:4911
[<ffffffff8149bf58>] do_remount_sb2+0x428/0x7d0 fs/super.c:771
[<ffffffff814fbe9e>] do_remount fs/namespace.c:2335 [inline]
[<ffffffff814fbe9e>] do_mount+0x101e/0x2a10 fs/namespace.c:2848
[<ffffffff814fe3e1>] SYSC_mount fs/namespace.c:3051 [inline]
[<ffffffff814fe3e1>] SyS_mount+0x191/0x1c0 fs/namespace.c:3029
[<ffffffff827062e1>] entry_SYSCALL_64_fastpath+0x1e/0x9a
[<ffffffff81202cde>] lock_acquire+0x15e/0x450
kernel/locking/lockdep.c:3592
[<ffffffff82701312>] down_read+0x42/0x60 kernel/locking/rwsem.c:22
[<ffffffff8149b671>] iterate_supers+0xe1/0x260 fs/super.c:537
[<ffffffff8199e104>] selinux_complete_init+0x2f/0x31
security/selinux/hooks.c:6154
[<ffffffff8198fd56>] security_load_policy+0x886/0x9b0
security/selinux/ss/services.c:2060
[<ffffffff81965c81>] sel_write_load+0x191/0xfc0
security/selinux/selinuxfs.c:535
[<ffffffff81490c1c>] __vfs_write+0x11c/0x3e0 fs/read_write.c:489
[<ffffffff814928ce>] vfs_write+0x17e/0x4e0 fs/read_write.c:538
[<ffffffff81494f09>] SYSC_write fs/read_write.c:585 [inline]
[<ffffffff81494f09>] SyS_write+0xd9/0x1c0 fs/read_write.c:577
[<ffffffff827062e1>] entry_SYSCALL_64_fastpath+0x1e/0x9a
[<ffffffff811ff0fc>] check_prev_add kernel/locking/lockdep.c:1853
[inline]
[<ffffffff811ff0fc>] check_prevs_add kernel/locking/lockdep.c:1958
[inline]
[<ffffffff811ff0fc>] validate_chain kernel/locking/lockdep.c:2144
[inline]
[<ffffffff811ff0fc>] __lock_acquire+0x3e6c/0x5f10
kernel/locking/lockdep.c:3213
[<ffffffff81202cde>] lock_acquire+0x15e/0x450
kernel/locking/lockdep.c:3592
[<ffffffff826fad9b>] __mutex_lock_common kernel/locking/mutex.c:521
[inline]
[<ffffffff826fad9b>] mutex_lock_nested+0xbb/0x8d0
kernel/locking/mutex.c:621
[<ffffffff81963767>] sel_commit_bools_write+0x87/0x250
security/selinux/selinuxfs.c:1142
[<ffffffff81490c1c>] __vfs_write+0x11c/0x3e0 fs/read_write.c:489
[<ffffffff81490fea>] __kernel_write+0x10a/0x350 fs/read_write.c:511
[<ffffffff8152c05d>] write_pipe_buf+0x15d/0x1f0 fs/splice.c:1074
[<ffffffff8152cef4>] splice_from_pipe_feed fs/splice.c:776 [inline]
[<ffffffff8152cef4>] __splice_from_pipe+0x364/0x790 fs/splice.c:901
[<ffffffff8152ffb9>] splice_from_pipe+0xf9/0x170 fs/splice.c:936
[<ffffffff815300bc>] default_file_splice_write+0x3c/0x80
fs/splice.c:1086
[<ffffffff81531181>] do_splice_from fs/splice.c:1128 [inline]
[<ffffffff81531181>] do_splice fs/splice.c:1404 [inline]
[<ffffffff81531181>] SYSC_splice fs/splice.c:1707 [inline]
[<ffffffff81531181>] SyS_splice+0xde1/0x1430 fs/splice.c:1690
[<ffffffff827062e1>] entry_SYSCALL_64_fastpath+0x1e/0x9a
other info that might help us debug this:
Chain exists of:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&pipe->mutex/1);
lock(&sig->cred_guard_mutex);
lock(&pipe->mutex/1);
lock(sel_mutex);
*** DEADLOCK ***
2 locks held by syz-executor023/2087:
#0: (sb_writers#3){.+.+.+}, at: [<ffffffff8153134a>] file_start_write
include/linux/fs.h:2541 [inline]
#0: (sb_writers#3){.+.+.+}, at: [<ffffffff8153134a>] do_splice
fs/splice.c:1403 [inline]
#0: (sb_writers#3){.+.+.+}, at: [<ffffffff8153134a>] SYSC_splice
fs/splice.c:1707 [inline]
#0: (sb_writers#3){.+.+.+}, at: [<ffffffff8153134a>]
SyS_splice+0xfaa/0x1430 fs/splice.c:1690
#1: (&pipe->mutex/1){+.+.+.}, at: [<ffffffff814a9afe>] pipe_lock_nested
fs/pipe.c:65 [inline]
#1: (&pipe->mutex/1){+.+.+.}, at: [<ffffffff814a9afe>]
pipe_lock+0x5e/0x70 fs/pipe.c:73
stack backtrace:
CPU: 0 PID: 2087 Comm: syz-executor023 Not tainted 4.4.162+ #117
0000000000000000 3f5b8160f0f4f9e9 ffff8801d3f4f5f8 ffffffff81a994bd
ffffffff83aae4c0 ffffffff83ab50c0 ffffffff83ab0680 ffff8801d5d4e810
ffff8801d5d4df00 ffff8801d3f4f640 ffffffff813a834a 0000000000000002
Call Trace:
[<ffffffff81a994bd>] __dump_stack lib/dump_stack.c:15 [inline]
[<ffffffff81a994bd>] dump_stack+0xc1/0x124 lib/dump_stack.c:51
[<ffffffff813a834a>] print_circular_bug.cold.34+0x2f7/0x432
kernel/locking/lockdep.c:1226
[<ffffffff811ff0fc>] check_prev_add kernel/locking/lockdep.c:1853 [inline]
[<ffffffff811ff0fc>] check_prevs_add kernel/locking/lockdep.c:1958 [inline]
[<ffffffff811ff0fc>] validate_chain kernel/locking/lockdep.c:2144 [inline]
[<ffffffff811ff0fc>] __lock_acquire+0x3e6c/0x5f10
kernel/locking/lockdep.c:3213
[<ffffffff81202cde>] lock_acquire+0x15e/0x450 kernel/locking/lockdep.c:3592
[<ffffffff826fad9b>] __mutex_lock_common kernel/locking/mutex.c:521
[inline]
[<ffffffff826fad9b>] mutex_lock_nested+0xbb/0x8d0
kernel/locking/mutex.c:621
[<ffffffff81963767>] sel_commit_bools_write+0x87/0x250
security/selinux/selinuxfs.c:1142
[<ffffffff81490c1c>] __vfs_write+0x11c/0x3e0 fs/read_write.c:489
[<ffffffff81490fea>] __kernel_write+0x10a/0x350 fs/read_write.c:511
[<ffffffff8152c05d>] write_pipe_buf+0x15d/0x1f0 fs/splice.c:1074
[<ffffffff8152cef4>] splice_from_pipe_feed fs/splice.c:776 [inline]
[<ffffffff8152cef4>] __splice_from_pipe+0x364/0x790 fs/splice.c:901
[<ffffffff8152ffb9>] splice_from_pipe+0xf9/0x170 fs/splice.c:936
[<ffffffff815300bc>] default_file_splice_write+0x3c/0x80 fs/splice.c:1086
[<ffffffff81531181>] do_splice_from fs/splice.c:1128 [inline]
[<ffffffff81531181>] do_splice fs/splice.c:1404 [inline]
[<ffffffff81531181>] SYSC_splice fs/splice.c:1707 [inline]
[<ffffffff81531181>] SyS_splice+0xde1/0x1430 fs/splice.c:1690
[<ffffffff827062e1>] entry_SYSCALL_64_fastpath+0x1e/0x9a
---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.
syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
syzbot can test patches for this bug, for details see:
https://goo.gl/tpsmEJ#testing-patches
syzbot found the following crash on:
HEAD commit: c4b00eb7 Revert "BACKPORT, FROMLIST: fscrypt: add Speck128..
git tree: android-4.4
console output: https://syzkaller.appspot.com/x/log.txt?x=168a357b400000
kernel config: https://syzkaller.appspot.com/x/.config?x=88f924cb59937510
dashboard link: https://syzkaller.appspot.com/bug?extid=ce459bafcb68ff272f48
compiler: gcc (GCC) 8.0.1 20180413 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1301ab13400000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=158878b9400000
IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+ce459b...@syzkaller.appspotmail.com
======================================================
[ INFO: possible circular locking dependency detected ]
4.4.162+ #117 Not tainted
-------------------------------------------------------
syz-executor023/2087 is trying to acquire lock:
(sel_mutex){+.+.+.}, at: [<ffffffff81963767>]
sel_commit_bools_write+0x87/0x250 security/selinux/selinuxfs.c:1142
but task is already holding lock:
(&pipe->mutex/1){+.+.+.}, at: [<ffffffff814a9afe>] pipe_lock_nested
fs/pipe.c:65 [inline]
(&pipe->mutex/1){+.+.+.}, at: [<ffffffff814a9afe>] pipe_lock+0x5e/0x70
fs/pipe.c:73
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
[<ffffffff81202cde>] lock_acquire+0x15e/0x450
kernel/locking/lockdep.c:3592
[<ffffffff826fad9b>] __mutex_lock_common kernel/locking/mutex.c:521
[inline]
[<ffffffff826fad9b>] mutex_lock_nested+0xbb/0x8d0
kernel/locking/mutex.c:621
[<ffffffff814aca0c>] __pipe_lock fs/pipe.c:86 [inline]
[<ffffffff814aca0c>] fifo_open+0x15c/0x9e0 fs/pipe.c:896
[<ffffffff8148ba0d>] do_dentry_open+0x38d/0xbd0 fs/open.c:749
[<ffffffff8148f17a>] vfs_open+0x12a/0x210 fs/open.c:862
[<ffffffff814bed5c>] do_last fs/namei.c:3222 [inline]
[<ffffffff814bed5c>] path_openat+0x50c/0x39a0 fs/namei.c:3359
[<ffffffff814c5e87>] do_filp_open+0x197/0x270 fs/namei.c:3393
[<ffffffff814a1eef>] do_open_execat+0x10f/0x6f0 fs/exec.c:800
[<ffffffff814a74a1>] do_execveat_common.isra.14+0x6a1/0x1f00
fs/exec.c:1573
[<ffffffff814a9672>] do_execve fs/exec.c:1679 [inline]
[<ffffffff814a9672>] SYSC_execve fs/exec.c:1760 [inline]
[<ffffffff814a9672>] SyS_execve+0x42/0x50 fs/exec.c:1755
[<ffffffff827065f5>] return_from_execve+0x0/0x23
[<ffffffff81202cde>] lock_acquire+0x15e/0x450
kernel/locking/lockdep.c:3592
[<ffffffff826fbf4c>] __mutex_lock_common kernel/locking/mutex.c:521
[inline]
[<ffffffff826fbf4c>] mutex_lock_killable_nested+0xcc/0xa10
kernel/locking/mutex.c:641
[<ffffffff815e2b54>] lock_trace+0x44/0xc0 fs/proc/base.c:448
[<ffffffff815e33a9>] proc_pid_syscall+0xa9/0x260 fs/proc/base.c:683
[<ffffffff815daffd>] proc_single_show+0xfd/0x170 fs/proc/base.c:805
[<ffffffff81501656>] seq_read+0x4b6/0x12b0 fs/seq_file.c:240
[<ffffffff8149084c>] __vfs_read+0x11c/0x3d0 fs/read_write.c:432
[<ffffffff81492520>] vfs_read+0x130/0x360 fs/read_write.c:454
[<ffffffff81494d49>] SYSC_read fs/read_write.c:569 [inline]
[<ffffffff81494d49>] SyS_read+0xd9/0x1c0 fs/read_write.c:562
[<ffffffff827062e1>] entry_SYSCALL_64_fastpath+0x1e/0x9a
[<ffffffff81202cde>] lock_acquire+0x15e/0x450
kernel/locking/lockdep.c:3592
[<ffffffff826fad9b>] __mutex_lock_common kernel/locking/mutex.c:521
[inline]
[<ffffffff826fad9b>] mutex_lock_nested+0xbb/0x8d0
kernel/locking/mutex.c:621
[<ffffffff8150127d>] seq_read+0xdd/0x12b0 fs/seq_file.c:178
[<ffffffff81491378>] do_loop_readv_writev+0x148/0x1e0
fs/read_write.c:680
[<ffffffff814931b1>] do_readv_writev+0x581/0x6f0 fs/read_write.c:810
[<ffffffff81493398>] vfs_readv+0x78/0xb0 fs/read_write.c:834
[<ffffffff8152f53f>] kernel_readv fs/splice.c:586 [inline]
[<ffffffff8152f53f>] default_file_splice_read+0x50f/0x8f0
fs/splice.c:662
[<ffffffff8152b417>] do_splice_to+0xf7/0x140 fs/splice.c:1154
[<ffffffff8152b6a2>] splice_direct_to_actor+0x242/0x830
fs/splice.c:1226
[<ffffffff8152be33>] do_splice_direct+0x1a3/0x270 fs/splice.c:1337
[<ffffffff814945d4>] do_sendfile+0x4e4/0xb80 fs/read_write.c:1227
[<ffffffff814965c3>] SYSC_sendfile64 fs/read_write.c:1282 [inline]
[<ffffffff814965c3>] SyS_sendfile64+0xc3/0x150 fs/read_write.c:1274
[<ffffffff827062e1>] entry_SYSCALL_64_fastpath+0x1e/0x9a
[<ffffffff81202cde>] lock_acquire+0x15e/0x450
kernel/locking/lockdep.c:3592
[<ffffffff81498cae>] percpu_down_read
include/linux/percpu-rwsem.h:26 [inline]
[<ffffffff81498cae>] __sb_start_write+0x1ae/0x310 fs/super.c:1221
[<ffffffff816bafc7>] sb_start_write include/linux/fs.h:1515 [inline]
[<ffffffff816bafc7>] ext4_run_li_request fs/ext4/super.c:2674
[inline]
[<ffffffff816bafc7>] ext4_lazyinit_thread+0x1a7/0x750
fs/ext4/super.c:2773
[<ffffffff81133e18>] kthread+0x268/0x300 kernel/kthread.c:211
[<ffffffff827066c5>] ret_from_fork+0x55/0x80
arch/x86/entry/entry_64.S:510
[<ffffffff81202cde>] lock_acquire+0x15e/0x450
kernel/locking/lockdep.c:3592
[<ffffffff826fad9b>] __mutex_lock_common kernel/locking/mutex.c:521
[inline]
[<ffffffff826fad9b>] mutex_lock_nested+0xbb/0x8d0
kernel/locking/mutex.c:621
[<ffffffff816c50c4>] ext4_register_li_request+0x304/0x7a0
fs/ext4/super.c:2961
[<ffffffff816c68c8>] ext4_remount+0x1368/0x1bb0 fs/ext4/super.c:4911
[<ffffffff8149bf58>] do_remount_sb2+0x428/0x7d0 fs/super.c:771
[<ffffffff814fbe9e>] do_remount fs/namespace.c:2335 [inline]
[<ffffffff814fbe9e>] do_mount+0x101e/0x2a10 fs/namespace.c:2848
[<ffffffff814fe3e1>] SYSC_mount fs/namespace.c:3051 [inline]
[<ffffffff814fe3e1>] SyS_mount+0x191/0x1c0 fs/namespace.c:3029
[<ffffffff827062e1>] entry_SYSCALL_64_fastpath+0x1e/0x9a
[<ffffffff81202cde>] lock_acquire+0x15e/0x450
kernel/locking/lockdep.c:3592
[<ffffffff826fad9b>] __mutex_lock_common kernel/locking/mutex.c:521
[inline]
[<ffffffff826fad9b>] mutex_lock_nested+0xbb/0x8d0
kernel/locking/mutex.c:621
[<ffffffff816c4e47>] ext4_register_li_request+0x87/0x7a0
fs/ext4/super.c:2934
[<ffffffff816c68c8>] ext4_remount+0x1368/0x1bb0 fs/ext4/super.c:4911
[<ffffffff8149bf58>] do_remount_sb2+0x428/0x7d0 fs/super.c:771
[<ffffffff814fbe9e>] do_remount fs/namespace.c:2335 [inline]
[<ffffffff814fbe9e>] do_mount+0x101e/0x2a10 fs/namespace.c:2848
[<ffffffff814fe3e1>] SYSC_mount fs/namespace.c:3051 [inline]
[<ffffffff814fe3e1>] SyS_mount+0x191/0x1c0 fs/namespace.c:3029
[<ffffffff827062e1>] entry_SYSCALL_64_fastpath+0x1e/0x9a
[<ffffffff81202cde>] lock_acquire+0x15e/0x450
kernel/locking/lockdep.c:3592
[<ffffffff82701312>] down_read+0x42/0x60 kernel/locking/rwsem.c:22
[<ffffffff8149b671>] iterate_supers+0xe1/0x260 fs/super.c:537
[<ffffffff8199e104>] selinux_complete_init+0x2f/0x31
security/selinux/hooks.c:6154
[<ffffffff8198fd56>] security_load_policy+0x886/0x9b0
security/selinux/ss/services.c:2060
[<ffffffff81965c81>] sel_write_load+0x191/0xfc0
security/selinux/selinuxfs.c:535
[<ffffffff81490c1c>] __vfs_write+0x11c/0x3e0 fs/read_write.c:489
[<ffffffff814928ce>] vfs_write+0x17e/0x4e0 fs/read_write.c:538
[<ffffffff81494f09>] SYSC_write fs/read_write.c:585 [inline]
[<ffffffff81494f09>] SyS_write+0xd9/0x1c0 fs/read_write.c:577
[<ffffffff827062e1>] entry_SYSCALL_64_fastpath+0x1e/0x9a
[<ffffffff811ff0fc>] check_prev_add kernel/locking/lockdep.c:1853
[inline]
[<ffffffff811ff0fc>] check_prevs_add kernel/locking/lockdep.c:1958
[inline]
[<ffffffff811ff0fc>] validate_chain kernel/locking/lockdep.c:2144
[inline]
[<ffffffff811ff0fc>] __lock_acquire+0x3e6c/0x5f10
kernel/locking/lockdep.c:3213
[<ffffffff81202cde>] lock_acquire+0x15e/0x450
kernel/locking/lockdep.c:3592
[<ffffffff826fad9b>] __mutex_lock_common kernel/locking/mutex.c:521
[inline]
[<ffffffff826fad9b>] mutex_lock_nested+0xbb/0x8d0
kernel/locking/mutex.c:621
[<ffffffff81963767>] sel_commit_bools_write+0x87/0x250
security/selinux/selinuxfs.c:1142
[<ffffffff81490c1c>] __vfs_write+0x11c/0x3e0 fs/read_write.c:489
[<ffffffff81490fea>] __kernel_write+0x10a/0x350 fs/read_write.c:511
[<ffffffff8152c05d>] write_pipe_buf+0x15d/0x1f0 fs/splice.c:1074
[<ffffffff8152cef4>] splice_from_pipe_feed fs/splice.c:776 [inline]
[<ffffffff8152cef4>] __splice_from_pipe+0x364/0x790 fs/splice.c:901
[<ffffffff8152ffb9>] splice_from_pipe+0xf9/0x170 fs/splice.c:936
[<ffffffff815300bc>] default_file_splice_write+0x3c/0x80
fs/splice.c:1086
[<ffffffff81531181>] do_splice_from fs/splice.c:1128 [inline]
[<ffffffff81531181>] do_splice fs/splice.c:1404 [inline]
[<ffffffff81531181>] SYSC_splice fs/splice.c:1707 [inline]
[<ffffffff81531181>] SyS_splice+0xde1/0x1430 fs/splice.c:1690
[<ffffffff827062e1>] entry_SYSCALL_64_fastpath+0x1e/0x9a
other info that might help us debug this:
Chain exists of:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&pipe->mutex/1);
lock(&sig->cred_guard_mutex);
lock(&pipe->mutex/1);
lock(sel_mutex);
*** DEADLOCK ***
2 locks held by syz-executor023/2087:
#0: (sb_writers#3){.+.+.+}, at: [<ffffffff8153134a>] file_start_write
include/linux/fs.h:2541 [inline]
#0: (sb_writers#3){.+.+.+}, at: [<ffffffff8153134a>] do_splice
fs/splice.c:1403 [inline]
#0: (sb_writers#3){.+.+.+}, at: [<ffffffff8153134a>] SYSC_splice
fs/splice.c:1707 [inline]
#0: (sb_writers#3){.+.+.+}, at: [<ffffffff8153134a>]
SyS_splice+0xfaa/0x1430 fs/splice.c:1690
#1: (&pipe->mutex/1){+.+.+.}, at: [<ffffffff814a9afe>] pipe_lock_nested
fs/pipe.c:65 [inline]
#1: (&pipe->mutex/1){+.+.+.}, at: [<ffffffff814a9afe>]
pipe_lock+0x5e/0x70 fs/pipe.c:73
stack backtrace:
CPU: 0 PID: 2087 Comm: syz-executor023 Not tainted 4.4.162+ #117
0000000000000000 3f5b8160f0f4f9e9 ffff8801d3f4f5f8 ffffffff81a994bd
ffffffff83aae4c0 ffffffff83ab50c0 ffffffff83ab0680 ffff8801d5d4e810
ffff8801d5d4df00 ffff8801d3f4f640 ffffffff813a834a 0000000000000002
Call Trace:
[<ffffffff81a994bd>] __dump_stack lib/dump_stack.c:15 [inline]
[<ffffffff81a994bd>] dump_stack+0xc1/0x124 lib/dump_stack.c:51
[<ffffffff813a834a>] print_circular_bug.cold.34+0x2f7/0x432
kernel/locking/lockdep.c:1226
[<ffffffff811ff0fc>] check_prev_add kernel/locking/lockdep.c:1853 [inline]
[<ffffffff811ff0fc>] check_prevs_add kernel/locking/lockdep.c:1958 [inline]
[<ffffffff811ff0fc>] validate_chain kernel/locking/lockdep.c:2144 [inline]
[<ffffffff811ff0fc>] __lock_acquire+0x3e6c/0x5f10
kernel/locking/lockdep.c:3213
[<ffffffff81202cde>] lock_acquire+0x15e/0x450 kernel/locking/lockdep.c:3592
[<ffffffff826fad9b>] __mutex_lock_common kernel/locking/mutex.c:521
[inline]
[<ffffffff826fad9b>] mutex_lock_nested+0xbb/0x8d0
kernel/locking/mutex.c:621
[<ffffffff81963767>] sel_commit_bools_write+0x87/0x250
security/selinux/selinuxfs.c:1142
[<ffffffff81490c1c>] __vfs_write+0x11c/0x3e0 fs/read_write.c:489
[<ffffffff81490fea>] __kernel_write+0x10a/0x350 fs/read_write.c:511
[<ffffffff8152c05d>] write_pipe_buf+0x15d/0x1f0 fs/splice.c:1074
[<ffffffff8152cef4>] splice_from_pipe_feed fs/splice.c:776 [inline]
[<ffffffff8152cef4>] __splice_from_pipe+0x364/0x790 fs/splice.c:901
[<ffffffff8152ffb9>] splice_from_pipe+0xf9/0x170 fs/splice.c:936
[<ffffffff815300bc>] default_file_splice_write+0x3c/0x80 fs/splice.c:1086
[<ffffffff81531181>] do_splice_from fs/splice.c:1128 [inline]
[<ffffffff81531181>] do_splice fs/splice.c:1404 [inline]
[<ffffffff81531181>] SYSC_splice fs/splice.c:1707 [inline]
[<ffffffff81531181>] SyS_splice+0xde1/0x1430 fs/splice.c:1690
[<ffffffff827062e1>] entry_SYSCALL_64_fastpath+0x1e/0x9a
---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.
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syzbot can test patches for this bug, for details see:
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