======================================================
[ INFO: possible circular locking dependency detected ]
4.4.162+ #7 Not tainted
-------------------------------------------------------
syz-executor2/9836 is trying to acquire lock:
(&sig->cred_guard_mutex){+.+.+.}, at: [<ffffffff815dce1b>] do_io_accounting+0x1fb/0x7e0 fs/proc/base.c:2661
but task is already holding lock:
(&p->lock){+.+.+.}, at: [<ffffffff8150127d>] seq_read+0xdd/0x12b0 fs/seq_file.c:178
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
[<ffffffff8150127d>] seq_read+0xdd/0x12b0 fs/seq_file.c:178
[<ffffffff815d862d>] proc_reg_read+0xfd/0x180 fs/proc/inode.c:202
[<ffffffff81491378>] do_loop_readv_writev+0x148/0x1e0 fs/read_write.c:680
[<ffffffff814931b1>] do_readv_writev+0x581/0x6f0 fs/read_write.c:810
audit: type=1400 audit(1541209333.147:454): avc: denied { create } for pid=9845 comm="syz-executor0" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_generic_socket permissive=1
audit: type=1400 audit(1541209333.147:455): avc: denied { write } for pid=9845 comm="syz-executor0" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_generic_socket permissive=1
audit: type=1400 audit(1541209333.147:456): avc: denied { read } for pid=9845 comm="syz-executor0" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_generic_socket permissive=1
audit: type=1400 audit(1541209333.147:457): avc: denied { create } for pid=9845 comm="syz-executor0" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_generic_socket permissive=1
audit: type=1400 audit(1541209333.147:458): avc: denied { write } for pid=9845 comm="syz-executor0" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_generic_socket permissive=1
audit: type=1400 audit(1541209333.147:459): avc: denied { read } for pid=9845 comm="syz-executor0" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_generic_socket permissive=1
audit: type=1400 audit(1541209333.147:460): avc: denied { create } for pid=9853 comm="syz-executor4" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_netfilter_socket permissive=1
audit: type=1400 audit(1541209333.147:461): avc: denied { setopt } for pid=9853 comm="syz-executor4" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_netfilter_socket permissive=1
audit: type=1400 audit(1541209333.147:462): avc: denied { create } for pid=9856 comm="syz-executor4" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_netfilter_socket permissive=1
audit: type=1400 audit(1541209333.147:463): avc: denied { setopt } for pid=9856 comm="syz-executor4" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_netfilter_socket permissive=1
[<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
[<ffffffff81496721>] C_SYSC_sendfile fs/read_write.c:1303 [inline]
[<ffffffff81496721>] compat_SyS_sendfile+0xd1/0x160 fs/read_write.c:1292
[<ffffffff8100629e>] do_syscall_32_irqs_on arch/x86/entry/common.c:396 [inline]
[<ffffffff8100629e>] do_fast_syscall_32+0x31e/0xa80 arch/x86/entry/common.c:463
[<ffffffff82707a50>] sysenter_flags_fixed+0xd/0x1a
[<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
[<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
[<ffffffff8100629e>] do_syscall_32_irqs_on arch/x86/entry/common.c:396 [inline]
[<ffffffff8100629e>] do_fast_syscall_32+0x31e/0xa80 arch/x86/entry/common.c:463
[<ffffffff82707a50>] sysenter_flags_fixed+0xd/0x1a
[<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
[<ffffffff814a9738>] compat_do_execve fs/exec.c:1706 [inline]
[<ffffffff814a9738>] C_SYSC_execve fs/exec.c:1781 [inline]
[<ffffffff814a9738>] compat_SyS_execve+0x48/0x60 fs/exec.c:1777
[<ffffffff8100629e>] do_syscall_32_irqs_on arch/x86/entry/common.c:396 [inline]
[<ffffffff8100629e>] do_fast_syscall_32+0x31e/0xa80 arch/x86/entry/common.c:463
[<ffffffff82707a50>] sysenter_flags_fixed+0xd/0x1a
[<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
[<ffffffff826fbf4c>] __mutex_lock_common kernel/locking/mutex.c:521 [inline]
[<ffffffff826fbf4c>] mutex_lock_killable_nested+0xcc/0xa10 kernel/locking/mutex.c:641
[<ffffffff815dce1b>] do_io_accounting+0x1fb/0x7e0 fs/proc/base.c:2661
[<ffffffff815dd422>] proc_tgid_io_accounting+0x22/0x30 fs/proc/base.c:2710
[<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
[<ffffffff81495135>] SYSC_pread64 fs/read_write.c:607 [inline]
[<ffffffff81495135>] SyS_pread64+0x145/0x170 fs/read_write.c:594
[<ffffffff810bf089>] sys32_pread+0x39/0x50 arch/x86/ia32/sys_ia32.c:179
[<ffffffff8100629e>] do_syscall_32_irqs_on arch/x86/entry/common.c:396 [inline]
[<ffffffff8100629e>] do_fast_syscall_32+0x31e/0xa80 arch/x86/entry/common.c:463
[<ffffffff82707a50>] sysenter_flags_fixed+0xd/0x1a
other info that might help us debug this:
Chain exists of:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&p->lock);
lock(sb_writers#4);
lock(&p->lock);
lock(&sig->cred_guard_mutex);
*** DEADLOCK ***
1 lock held by syz-executor2/9836:
#0: (&p->lock){+.+.+.}, at: [<ffffffff8150127d>] seq_read+0xdd/0x12b0 fs/seq_file.c:178
stack backtrace:
CPU: 1 PID: 9836 Comm: syz-executor2 Not tainted 4.4.162+ #7
0000000000000000 bad7716d15701ce8 ffff8800ac9bf608 ffffffff81a994bd
ffffffff83ab4190 ffffffff83aaffc0 ffffffff83aae670 ffff8801d09708e8
ffff8801d0970000 ffff8800ac9bf650 ffffffff813a834a 0000000000000001
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
[<ffffffff826fbf4c>] __mutex_lock_common kernel/locking/mutex.c:521 [inline]
[<ffffffff826fbf4c>] mutex_lock_killable_nested+0xcc/0xa10 kernel/locking/mutex.c:641
[<ffffffff815dce1b>] do_io_accounting+0x1fb/0x7e0 fs/proc/base.c:2661
[<ffffffff815dd422>] proc_tgid_io_accounting+0x22/0x30 fs/proc/base.c:2710
[<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
[<ffffffff81495135>] SYSC_pread64 fs/read_write.c:607 [inline]
[<ffffffff81495135>] SyS_pread64+0x145/0x170 fs/read_write.c:594
[<ffffffff810bf089>] sys32_pread+0x39/0x50 arch/x86/ia32/sys_ia32.c:179
[<ffffffff8100629e>] do_syscall_32_irqs_on arch/x86/entry/common.c:396 [inline]
[<ffffffff8100629e>] do_fast_syscall_32+0x31e/0xa80 arch/x86/entry/common.c:463
[<ffffffff82707a50>] sysenter_flags_fixed+0xd/0x1a
SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket
SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket
netlink: 192 bytes leftover after parsing attributes in process `syz-executor0'.
netlink: 192 bytes leftover after parsing attributes in process `syz-executor0'.
audit_printk_skb: 27 callbacks suppressed
audit: type=1400 audit(1541209338.377:473): avc: denied { create } for pid=10107 comm="syz-executor4" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_generic_socket permissive=1
audit: type=1400 audit(1541209338.457:474): avc: denied { write } for pid=10107 comm="syz-executor4" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_generic_socket permissive=1
audit: type=1400 audit(1541209338.507:475): avc: denied { read } for pid=10107 comm="syz-executor4" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_generic_socket permissive=1
audit: type=1400 audit(1541209338.557:476): avc: denied { create } for pid=10107 comm="syz-executor4" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_generic_socket permissive=1
audit: type=1400 audit(1541209339.677:477): avc: denied { create } for pid=10176 comm="syz-executor4" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_generic_socket permissive=1
audit: type=1400 audit(1541209339.697:478): avc: denied { write } for pid=10176 comm="syz-executor4" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_generic_socket permissive=1
audit: type=1400 audit(1541209339.737:479): avc: denied { read } for pid=10176 comm="syz-executor4" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_generic_socket permissive=1
audit: type=1400 audit(1541209339.777:480): avc: denied { create } for pid=10176 comm="syz-executor4" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_generic_socket permissive=1
audit: type=1400 audit(1541209339.797:481): avc: denied { write } for pid=10176 comm="syz-executor4" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_generic_socket permissive=1
audit: type=1400 audit(1541209340.257:482): avc: denied { setattr } for pid=10206 comm="syz-executor5" name="status" dev="proc" ino=30852 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=file permissive=1