====================================================== [ INFO: possible circular locking dependency detected ] 4.4.167+ #4 Not tainted ------------------------------------------------------- syz-executor4/20916 is trying to acquire lock: (&pipe->mutex/1){+.+.+.}, at: [] pipe_lock_nested fs/pipe.c:65 [inline] (&pipe->mutex/1){+.+.+.}, at: [] pipe_lock+0x5e/0x70 fs/pipe.c:73 but task is already holding lock: (sb_writers#4){.+.+.+}, at: [] file_start_write include/linux/fs.h:2543 [inline] (sb_writers#4){.+.+.+}, at: [] do_splice fs/splice.c:1403 [inline] (sb_writers#4){.+.+.+}, at: [] SYSC_splice fs/splice.c:1707 [inline] (sb_writers#4){.+.+.+}, at: [] SyS_splice+0xfaa/0x1430 fs/splice.c:1690 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: [] lock_acquire+0x15e/0x450 kernel/locking/lockdep.c:3592 [] percpu_down_read include/linux/percpu-rwsem.h:26 [inline] [] __sb_start_write+0x1ae/0x310 fs/super.c:1221 [] sb_start_write include/linux/fs.h:1517 [inline] [] ext4_run_li_request fs/ext4/super.c:2674 [inline] [] ext4_lazyinit_thread+0x1a7/0x750 fs/ext4/super.c:2773 [] kthread+0x268/0x300 kernel/kthread.c:211 [] ret_from_fork+0x55/0x80 arch/x86/entry/entry_64.S:537 [] lock_acquire+0x15e/0x450 kernel/locking/lockdep.c:3592 [] __mutex_lock_common kernel/locking/mutex.c:521 [inline] [] mutex_lock_nested+0xc2/0xb60 kernel/locking/mutex.c:621 [] ext4_register_li_request+0x304/0x7a0 fs/ext4/super.c:2961 [] ext4_remount+0x1368/0x1bb0 fs/ext4/super.c:4911 [] do_remount_sb2+0x428/0x7d0 fs/super.c:771 [] do_remount fs/namespace.c:2347 [inline] [] do_mount+0x101e/0x2a10 fs/namespace.c:2860 [] SYSC_mount fs/namespace.c:3063 [inline] [] SyS_mount+0x191/0x1c0 fs/namespace.c:3041 [] entry_SYSCALL_64_fastpath+0x1e/0x9a [] lock_acquire+0x15e/0x450 kernel/locking/lockdep.c:3592 [] __mutex_lock_common kernel/locking/mutex.c:521 [inline] [] mutex_lock_nested+0xc2/0xb60 kernel/locking/mutex.c:621 [] ext4_register_li_request+0x87/0x7a0 fs/ext4/super.c:2934 [] ext4_remount+0x1368/0x1bb0 fs/ext4/super.c:4911 [] do_remount_sb2+0x428/0x7d0 fs/super.c:771 [] do_remount fs/namespace.c:2347 [inline] [] do_mount+0x101e/0x2a10 fs/namespace.c:2860 [] SYSC_mount fs/namespace.c:3063 [inline] [] SyS_mount+0x191/0x1c0 fs/namespace.c:3041 [] entry_SYSCALL_64_fastpath+0x1e/0x9a [] lock_acquire+0x15e/0x450 kernel/locking/lockdep.c:3592 [] down_read+0x42/0x60 kernel/locking/rwsem.c:22 [] iterate_supers+0xe1/0x260 fs/super.c:537 [] selinux_complete_init+0x2f/0x31 security/selinux/hooks.c:6154 [] security_load_policy+0x886/0x9b0 security/selinux/ss/services.c:2060 [] sel_write_load+0x191/0xfc0 security/selinux/selinuxfs.c:535 [] __vfs_write+0x11c/0x3e0 fs/read_write.c:489 [] vfs_write+0x17e/0x4e0 fs/read_write.c:538 [] SYSC_write fs/read_write.c:585 [inline] [] SyS_write+0xd9/0x1c0 fs/read_write.c:577 [] entry_SYSCALL_64_fastpath+0x1e/0x9a [] lock_acquire+0x15e/0x450 kernel/locking/lockdep.c:3592 [] __mutex_lock_common kernel/locking/mutex.c:521 [inline] [] mutex_lock_nested+0xc2/0xb60 kernel/locking/mutex.c:621 [] sel_commit_bools_write+0x87/0x250 security/selinux/selinuxfs.c:1142 [] __vfs_write+0x11c/0x3e0 fs/read_write.c:489 [ 604.216187] audit: type=1400 audit(1545109027.138:1437): avc: denied { create } for pid=20912 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(1545109027.138:1438): avc: denied { getattr } for pid=20912 comm="syz-executor4" path="socket:[65671]" dev="sockfs" ino=65671 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 [] __kernel_write+0x10a/0x350 fs/read_write.c:511 [] write_pipe_buf+0x15d/0x1f0 fs/splice.c:1074 [] splice_from_pipe_feed fs/splice.c:776 [inline] [] __splice_from_pipe+0x364/0x790 fs/splice.c:901 [] splice_from_pipe+0xf9/0x170 fs/splice.c:936 [] default_file_splice_write+0x3c/0x80 fs/splice.c:1086 [] do_splice_from fs/splice.c:1128 [inline] [] do_splice fs/splice.c:1404 [inline] [] SYSC_splice fs/splice.c:1707 [inline] [] SyS_splice+0xde1/0x1430 fs/splice.c:1690 [] do_syscall_32_irqs_on arch/x86/entry/common.c:330 [inline] [] do_fast_syscall_32+0x31e/0xa80 arch/x86/entry/common.c:397 [] sysenter_flags_fixed+0xd/0x1a [] check_prev_add kernel/locking/lockdep.c:1853 [inline] [] check_prevs_add kernel/locking/lockdep.c:1958 [inline] [] validate_chain kernel/locking/lockdep.c:2144 [inline] [] __lock_acquire+0x3cd4/0x5530 kernel/locking/lockdep.c:3213 [] lock_acquire+0x15e/0x450 kernel/locking/lockdep.c:3592 [] __mutex_lock_common kernel/locking/mutex.c:521 [inline] [] mutex_lock_nested+0xc2/0xb60 kernel/locking/mutex.c:621 [] pipe_lock_nested fs/pipe.c:65 [inline] [] pipe_lock+0x5e/0x70 fs/pipe.c:73 [] iter_file_splice_write+0x160/0xb90 fs/splice.c:974 [] do_splice_from fs/splice.c:1128 [inline] [] do_splice fs/splice.c:1404 [inline] [] SYSC_splice fs/splice.c:1707 [inline] [] SyS_splice+0xde1/0x1430 fs/splice.c:1690 [] do_syscall_32_irqs_on arch/x86/entry/common.c:330 [inline] [] do_fast_syscall_32+0x31e/0xa80 arch/x86/entry/common.c:397 [] sysenter_flags_fixed+0xd/0x1a other info that might help us debug this: audit: type=1400 audit(1545109027.308:1440): avc: denied { create } for pid=20912 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(1545109027.308:1441): avc: denied { getattr } for pid=20912 comm="syz-executor4" path="socket:[65679]" dev="sockfs" ino=65679 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(1545109027.258:1439): avc: denied { create } for pid=20921 comm="syz-executor2" 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 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 audit: type=1400 audit(1545109027.338:1442): avc: denied { write } for pid=20921 comm="syz-executor2" 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 SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket Chain exists of: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(sb_writers#4); lock(&eli->li_list_mtx); lock(sb_writers#4); lock(&pipe->mutex/1); *** DEADLOCK *** 1 lock held by syz-executor4/20916: #0: (sb_writers#4){.+.+.+}, at: [] file_start_write include/linux/fs.h:2543 [inline] #0: (sb_writers#4){.+.+.+}, at: [] do_splice fs/splice.c:1403 [inline] #0: (sb_writers#4){.+.+.+}, at: [] SYSC_splice fs/splice.c:1707 [inline] #0: (sb_writers#4){.+.+.+}, at: [] SyS_splice+0xfaa/0x1430 fs/splice.c:1690 stack backtrace: CPU: 1 PID: 20916 Comm: syz-executor4 Not tainted 4.4.167+ #4 0000000000000000 ccc002263c34a9a4 ffff8800b3f77860 ffffffff81aa62cd ffffffff83ac2080 ffffffff83ab72b0 ffff8800a75caf80 ffffffff83ab6380 ffff8800a75cb868 ffff8800b3f778b0 ffffffff813a9559 ffff8800a75caf80 Call Trace: [] __dump_stack lib/dump_stack.c:15 [inline] [] dump_stack+0xc1/0x124 lib/dump_stack.c:51 [] print_circular_bug.cold.31+0x2f6/0x435 kernel/locking/lockdep.c:1226 [] check_prev_add kernel/locking/lockdep.c:1853 [inline] [] check_prevs_add kernel/locking/lockdep.c:1958 [inline] [] validate_chain kernel/locking/lockdep.c:2144 [inline] [] __lock_acquire+0x3cd4/0x5530 kernel/locking/lockdep.c:3213 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 [] lock_acquire+0x15e/0x450 kernel/locking/lockdep.c:3592 [] __mutex_lock_common kernel/locking/mutex.c:521 [inline] [] mutex_lock_nested+0xc2/0xb60 kernel/locking/mutex.c:621 [] pipe_lock_nested fs/pipe.c:65 [inline] [] pipe_lock+0x5e/0x70 fs/pipe.c:73 [] iter_file_splice_write+0x160/0xb90 fs/splice.c:974 [] do_splice_from fs/splice.c:1128 [inline] [] do_splice fs/splice.c:1404 [inline] [] SYSC_splice fs/splice.c:1707 [inline] [] SyS_splice+0xde1/0x1430 fs/splice.c:1690 [] do_syscall_32_irqs_on arch/x86/entry/common.c:330 [inline] [] do_fast_syscall_32+0x31e/0xa80 arch/x86/entry/common.c:397 [] sysenter_flags_fixed+0xd/0x1a blk_update_request: 120 callbacks suppressed blk_update_request: I/O error, dev loop5, sector 0 buffer_io_error: 120 callbacks suppressed Buffer I/O error on dev loop5, logical block 0, lost async page write blk_update_request: I/O error, dev loop5, sector 8 Buffer I/O error on dev loop5, logical block 1, lost async page write blk_update_request: I/O error, dev loop5, sector 16 Buffer I/O error on dev loop5, logical block 2, lost async page write blk_update_request: I/O error, dev loop5, sector 24 Buffer I/O error on dev loop5, logical block 3, lost async page write blk_update_request: I/O error, dev loop5, sector 32 Buffer I/O error on dev loop5, logical block 4, lost async page write blk_update_request: I/O error, dev loop5, sector 40 Buffer I/O error on dev loop5, logical block 5, lost async page write blk_update_request: I/O error, dev loop5, sector 48 Buffer I/O error on dev loop5, logical block 6, lost async page write blk_update_request: I/O error, dev loop5, sector 56 Buffer I/O error on dev loop5, logical block 7, lost async page write blk_update_request: I/O error, dev loop5, sector 64 Buffer I/O error on dev loop5, logical block 8, lost async page write blk_update_request: I/O error, dev loop5, sector 72 Buffer I/O error on dev loop5, logical block 9, lost async page write audit_printk_skb: 75 callbacks suppressed audit: type=1400 audit(1545109030.018:1469): avc: denied { create } for pid=20998 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(1545109029.968:1468): avc: denied { create } for pid=20999 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(1545109030.108:1470): avc: denied { create } for pid=20998 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(1545109030.158:1471): avc: denied { write } for pid=20998 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(1545109030.208:1472): avc: denied { write } for pid=20999 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(1545109030.288:1473): avc: denied { write } for pid=20998 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(1545109030.448:1474): avc: denied { read } for pid=20998 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(1545109030.498:1475): avc: denied { read } for pid=20999 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(1545109030.598:1476): avc: denied { read } for pid=20998 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(1545109030.918:1477): avc: denied { create } for pid=20999 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 blk_update_request: 509 callbacks suppressed blk_update_request: I/O error, dev loop5, sector 0 buffer_io_error: 509 callbacks suppressed Buffer I/O error on dev loop5, logical block 0, lost async page write blk_update_request: I/O error, dev loop5, sector 8 Buffer I/O error on dev loop5, logical block 1, lost async page write blk_update_request: I/O error, dev loop5, sector 16 Buffer I/O error on dev loop5, logical block 2, lost async page write blk_update_request: I/O error, dev loop5, sector 24 Buffer I/O error on dev loop5, logical block 3, lost async page write blk_update_request: I/O error, dev loop5, sector 32 Buffer I/O error on dev loop5, logical block 4, lost async page write blk_update_request: I/O error, dev loop5, sector 40 Buffer I/O error on dev loop5, logical block 5, lost async page write blk_update_request: I/O error, dev loop5, sector 48 Buffer I/O error on dev loop5, logical block 6, lost async page write blk_update_request: I/O error, dev loop5, sector 56 Buffer I/O error on dev loop5, logical block 7, lost async page write blk_update_request: I/O error, dev loop5, sector 64 Buffer I/O error on dev loop5, logical block 8, lost async page write blk_update_request: I/O error, dev loop5, sector 72 Buffer I/O error on dev loop5, logical block 9, lost async page write audit_printk_skb: 72 callbacks suppressed audit: type=1400 audit(1545109035.078:1503): avc: denied { create } for pid=21071 comm="syz-executor2" 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(1545109034.948:1502): avc: denied { write } for pid=21071 comm="syz-executor2" 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(1545109035.178:1504): avc: denied { write } for pid=21071 comm="syz-executor2" 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(1545109035.308:1505): avc: denied { read } for pid=21071 comm="syz-executor2" 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(1545109035.378:1506): avc: denied { read } for pid=21071 comm="syz-executor2" 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(1545109035.628:1507): avc: denied { create } for pid=21125 comm="syz-executor3" 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(1545109035.658:1508): avc: denied { write } for pid=21125 comm="syz-executor3" 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(1545109035.748:1509): avc: denied { read } for pid=21125 comm="syz-executor3" 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(1545109036.338:1510): avc: denied { create } for pid=21134 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(1545109036.438:1511): avc: denied { create } for pid=21137 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