====================================================== [ INFO: possible circular locking dependency detected ] 4.4.174+ #4 Not tainted ------------------------------------------------------- syz-executor.4/6898 is trying to acquire lock: (&pipe->mutex/1){+.+.+.}, at: [] __pipe_lock fs/pipe.c:86 [inline] (&pipe->mutex/1){+.+.+.}, at: [] fifo_open+0x15d/0xa00 fs/pipe.c:896 but task is already holding lock: (&sig->cred_guard_mutex){+.+.+.}, at: [] prepare_bprm_creds+0x55/0x120 fs/exec.c:1225 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 [] __mutex_lock_common kernel/locking/mutex.c:521 [inline] [] mutex_lock_interruptible_nested+0xd2/0xce0 kernel/locking/mutex.c:650 [] proc_pid_attr_write+0x1a8/0x2a0 fs/proc/base.c:2524 [] __vfs_write+0x116/0x3d0 fs/read_write.c:491 [] __kernel_write+0x112/0x370 fs/read_write.c:513 [] write_pipe_buf+0x15d/0x1f0 fs/splice.c:1074 [] splice_from_pipe_feed fs/splice.c:776 [inline] [] __splice_from_pipe+0x37e/0x7a0 fs/splice.c:901 [] splice_from_pipe+0x108/0x170 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+0xd71/0x13a0 fs/splice.c:1690 [] entry_SYSCALL_64_fastpath+0x1e/0x9a [] 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+0x37d6/0x4f50 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+0xc1/0xb80 kernel/locking/mutex.c:621 [] __pipe_lock fs/pipe.c:86 [inline] [] fifo_open+0x15d/0xa00 fs/pipe.c:896 [] do_dentry_open+0x38f/0xbd0 fs/open.c:749 [] vfs_open+0x10b/0x210 fs/open.c:862 [] do_last fs/namei.c:3269 [inline] [] path_openat+0x136f/0x4470 fs/namei.c:3406 [] do_filp_open+0x1a1/0x270 fs/namei.c:3440 [] do_open_execat+0x10c/0x6e0 fs/exec.c:805 [] do_execveat_common.isra.0+0x6f6/0x1e90 fs/exec.c:1577 [] do_execve fs/exec.c:1683 [inline] [] SYSC_execve fs/exec.c:1764 [inline] [] SyS_execve+0x42/0x50 fs/exec.c:1759 [] return_from_execve+0x0/0x23 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&sig->cred_guard_mutex); lock(&pipe->mutex/1); lock(&sig->cred_guard_mutex); lock(&pipe->mutex/1); *** DEADLOCK *** 1 lock held by syz-executor.4/6898: #0: (&sig->cred_guard_mutex){+.+.+.}, at: [] prepare_bprm_creds+0x55/0x120 fs/exec.c:1225 stack backtrace: CPU: 0 PID: 6898 Comm: syz-executor.4 Not tainted 4.4.174+ #4 0000000000000000 05a9da1f27697fc1 ffff8801af367530 ffffffff81aad1a1 ffffffff84057a80 ffff8800b7e62f80 ffffffff83abd610 ffffffff83ab6350 ffffffff83abd610 ffff8801af367580 ffffffff813abcda ffff8801af367660 Call Trace: [] __dump_stack lib/dump_stack.c:15 [inline] [] dump_stack+0xc1/0x120 lib/dump_stack.c:51 [] print_circular_bug.cold+0x2f7/0x44e 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+0x37d6/0x4f50 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+0xc1/0xb80 kernel/locking/mutex.c:621 [] __pipe_lock fs/pipe.c:86 [inline] [] fifo_open+0x15d/0xa00 fs/pipe.c:896 [] do_dentry_open+0x38f/0xbd0 fs/open.c:749 [] vfs_open+0x10b/0x210 fs/open.c:862 [] do_last fs/namei.c:3269 [inline] [] path_openat+0x136f/0x4470 fs/namei.c:3406 [] do_filp_open+0x1a1/0x270 fs/namei.c:3440 [] do_open_execat+0x10c/0x6e0 fs/exec.c:805 [] do_execveat_common.isra.0+0x6f6/0x1e90 fs/exec.c:1577 [] do_execve fs/exec.c:1683 [inline] [] SYSC_execve fs/exec.c:1764 [inline] [] SyS_execve+0x42/0x50 fs/exec.c:1759 [] stub_execve+0x5/0x5 arch/x86/entry/entry_64.S:440 audit_printk_skb: 6 callbacks suppressed audit: type=1400 audit(1574976931.087:1966): avc: denied { create } for pid=6878 comm="syz-executor.5" 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=0 audit: type=1400 audit(1574976931.097:1967): avc: denied { create } for pid=6878 comm="syz-executor.5" 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=0 audit: type=1400 audit(1574976931.117:1968): avc: denied { create } for pid=6889 comm="syz-executor.3" 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=0 audit: type=1400 audit(1574976931.427:1969): avc: denied { create } for pid=6897 comm="syz-executor.4" 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=0 SELinux: unrecognized netlink message: protocol=6 nlmsg_type=0 sclass=netlink_xfrm_socket audit: type=1400 audit(1574976931.687:1970): avc: denied { create } for pid=6897 comm="syz-executor.4" 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=0 audit: type=1400 audit(1574976931.877:1971): avc: denied { create } for pid=6922 comm="syz-executor.3" 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=0 audit: type=1400 audit(1574976931.977:1972): avc: denied { create } for pid=6955 comm="syz-executor.4" 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=0 audit: type=1400 audit(1574976932.587:1973): avc: denied { create } for pid=7005 comm="syz-executor.5" 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=0 audit: type=1400 audit(1574976932.727:1974): avc: denied { create } for pid=6988 comm="syz-executor.3" 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=0 audit: type=1400 audit(1574976932.757:1975): avc: denied { create } for pid=6987 comm="syz-executor.1" 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=0 IPv6: RTM_NEWROUTE with no NLM_F_CREATE or NLM_F_REPLACE audit_printk_skb: 45 callbacks suppressed audit: type=1400 audit(1574976936.297:1991): avc: denied { create } for pid=7307 comm="syz-executor.3" 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=0 audit: type=1400 audit(1574976936.497:1992): avc: denied { create } for pid=7307 comm="syz-executor.3" 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=0 audit: type=1400 audit(1574976936.737:1993): avc: denied { create } for pid=7353 comm="syz-executor.3" 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=0 audit: type=1400 audit(1574976936.757:1994): avc: denied { create } for pid=7294 comm="syz-executor.5" 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=0 audit: type=1400 audit(1574976937.607:1995): avc: denied { create } for pid=7410 comm="syz-executor.3" 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=0 audit: type=1400 audit(1574976938.067:1996): avc: denied { create } for pid=7428 comm="syz-executor.3" 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=0 audit: type=1400 audit(1574976938.117:1997): avc: denied { create } for pid=7426 comm="syz-executor.0" 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=0 audit: type=1400 audit(1574976938.547:1998): avc: denied { create } for pid=7428 comm="syz-executor.3" 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=0 audit: type=1400 audit(1574976939.137:1999): avc: denied { create } for pid=7504 comm="syz-executor.3" 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=0 audit: type=1400 audit(1574976939.187:2000): avc: denied { create } for pid=7499 comm="syz-executor.0" 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=0