====================================================== WARNING: possible circular locking dependency detected 4.14.94+ #13 Not tainted ------------------------------------------------------ syz-executor4/14627 is trying to acquire lock: (&pipe->mutex/1){+.+.}, at: [] __pipe_lock fs/pipe.c:88 [inline] (&pipe->mutex/1){+.+.}, at: [] fifo_open+0x156/0x9b0 fs/pipe.c:921 but task is already holding lock: (&sig->cred_guard_mutex){+.+.}, at: [] prepare_bprm_creds+0x51/0x110 fs/exec.c:1389 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&sig->cred_guard_mutex){+.+.}: -> #1 (&p->lock){+.+.}: -> #0 (&pipe->mutex/1){+.+.}: other info that might help us debug this: Chain exists of: &pipe->mutex/1 --> &p->lock --> &sig->cred_guard_mutex Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&sig->cred_guard_mutex); lock(&p->lock); lock(&sig->cred_guard_mutex); lock(&pipe->mutex/1); *** DEADLOCK *** 1 lock held by syz-executor4/14627: #0: (&sig->cred_guard_mutex){+.+.}, at: [] prepare_bprm_creds+0x51/0x110 fs/exec.c:1389 stack backtrace: CPU: 0 PID: 14627 Comm: syz-executor4 Not tainted 4.14.94+ #13 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0xb9/0x10e lib/dump_stack.c:53 print_circular_bug.isra.0.cold+0x2dc/0x425 kernel/locking/lockdep.c:1258 ip6_tunnel: ip6tnl3 xmit: Local address not yet configured! ip6_tunnel: ip6tnl3 xmit: Local address not yet configured! ip6_tunnel: ip6tnl3 xmit: Local address not yet configured! ip6_tunnel: ip6tnl2 xmit: Local address not yet configured! ip6_tunnel: ip6tnl1 xmit: Local address not yet configured! ip6_tunnel: ip6tnl3 xmit: Local address not yet configured! ip6_tunnel: ip6tnl2 xmit: Local address not yet configured! ip6_tunnel: ip6tnl1 xmit: Local address not yet configured! ip6_tunnel: ip6tnl3 xmit: Local address not yet configured! ip6_tunnel: ip6tnl3 xmit: Local address not yet configured! ip6_tunnel: ip6tnl2 xmit: Local address not yet configured! ip6_tunnel: ip6tnl1 xmit: Local address not yet configured! ip6_tunnel: ip6tnl3 xmit: Local address not yet configured! ip6_tunnel: ip6tnl2 xmit: Local address not yet configured! ip6_tunnel: ip6tnl1 xmit: Local address not yet configured! binder: 14665:14672 ioctl c018620c 20000000 returned -1 kauditd_printk_skb: 102 callbacks suppressed audit: type=1400 audit(1548222429.462:10596): avc: denied { map } for pid=14676 comm="blkid" path="/sbin/blkid" dev="sda1" ino=16128 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 ip6_tunnel: ip6tnl1 xmit: Local address not yet configured! ip6_tunnel: ip6tnl1 xmit: Local address not yet configured! ip6_tunnel: ip6tnl1 xmit: Local address not yet configured! audit: type=1400 audit(1548222429.492:10597): avc: denied { map } for pid=14676 comm="blkid" path="/sbin/blkid" dev="sda1" ino=16128 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 ip6_tunnel: ip6tnl3 xmit: Local address not yet configured! ip6_tunnel: ip6tnl2 xmit: Local address not yet configured! ip6_tunnel: ip6tnl1 xmit: Local address not yet configured! audit: type=1400 audit(1548222429.502:10598): avc: denied { map } for pid=14676 comm="blkid" path="/lib/x86_64-linux-gnu/ld-2.13.so" dev="sda1" ino=2668 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 binder: 14688:14690 ioctl c018620c 20000000 returned -1 audit: type=1400 audit(1548222429.512:10599): avc: denied { map } for pid=14676 comm="blkid" path="/lib/x86_64-linux-gnu/ld-2.13.so" dev="sda1" ino=2668 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 ip6_tunnel: ip6tnl1 xmit: Local address not yet configured! audit: type=1400 audit(1548222429.542:10600): avc: denied { map } for pid=14676 comm="blkid" path="/etc/ld.so.cache" dev="sda1" ino=2503 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 ip6_tunnel: ip6tnl3 xmit: Local address not yet configured! audit: type=1400 audit(1548222429.562:10601): avc: denied { map } for pid=14676 comm="blkid" path="/lib/x86_64-linux-gnu/libblkid.so.1.1.0" dev="sda1" ino=2825 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 ip6_tunnel: ip6tnl1 xmit: Local address not yet configured! audit: type=1400 audit(1548222429.562:10602): avc: denied { map } for pid=14676 comm="blkid" path="/lib/x86_64-linux-gnu/libblkid.so.1.1.0" dev="sda1" ino=2825 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 ip6_tunnel: ip6tnl3 xmit: Local address not yet configured! ip6_tunnel: ip6tnl2 xmit: Local address not yet configured! ip6_tunnel: ip6tnl1 xmit: Local address not yet configured! binder: 14702:14706 ioctl c018620c 20000000 returned -1 audit: type=1400 audit(1548222429.582:10603): avc: denied { map } for pid=14676 comm="blkid" path="/lib/x86_64-linux-gnu/libc-2.13.so" dev="sda1" ino=2784 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 audit: audit_backlog=65 > audit_backlog_limit=64 audit: audit_backlog=65 > audit_backlog_limit=64 ip6_tunnel: ip6tnl1 xmit: Local address not yet configured! ip6_tunnel: ip6tnl1 xmit: Local address not yet configured! ip6_tunnel: ip6tnl2 xmit: Local address not yet configured! ip6_tunnel: ip6tnl3 xmit: Local address not yet configured! binder: 14722:14727 ioctl c018620c 20000000 returned -1 ip6_tunnel: ip6tnl1 xmit: Local address not yet configured! ip6_tunnel: ip6tnl3 xmit: Local address not yet configured! ip6_tunnel: ip6tnl2 xmit: Local address not yet configured! ip6_tunnel: ip6tnl1 xmit: Local address not yet configured! ip6_tunnel: ip6tnl1 xmit: Local address not yet configured! binder: 14735:14740 ioctl c018620c 20000000 returned -1 ip6_tunnel: ip6tnl3 xmit: Local address not yet configured! ip6_tunnel: ip6tnl2 xmit: Local address not yet configured! ip6_tunnel: ip6tnl3 xmit: Local address not yet configured! ip6_tunnel: ip6tnl2 xmit: Local address not yet configured! ip6_tunnel: ip6tnl1 xmit: Local address not yet configured! binder: 14750:14756 ioctl c018620c 20000000 returned -1 ip6_tunnel: ip6tnl2 xmit: Local address not yet configured! ip6_tunnel: ip6tnl1 xmit: Local address not yet configured! ip6_tunnel: ip6tnl1 xmit: Local address not yet configured! ip6_tunnel: ip6tnl1 xmit: Local address not yet configured! binder: 14768:14772 ioctl c018620c 20000000 returned -1 ip6_tunnel: ip6tnl3 xmit: Local address not yet configured! ip6_tunnel: ip6tnl2 xmit: Local address not yet configured! ip6_tunnel: ip6tnl1 xmit: Local address not yet configured! ip6_tunnel: ip6tnl2 xmit: Local address not yet configured! ip6_tunnel: ip6tnl1 xmit: Local address not yet configured! binder: 14785:14787 ioctl c018620c 20000000 returned -1 ip6_tunnel: ip6tnl3 xmit: Local address not yet configured! ip6_tunnel: ip6tnl2 xmit: Local address not yet configured! ip6_tunnel: ip6tnl1 xmit: Local address not yet configured! ip6_tunnel: ip6tnl2 xmit: Local address not yet configured! kauditd_printk_skb: 337 callbacks suppressed audit: type=1400 audit(1548222434.532:10934): avc: denied { map } for pid=14791 comm="blkid" path="/sbin/blkid" dev="sda1" ino=16128 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 audit: type=1400 audit(1548222434.532:10935): avc: denied { map } for pid=14791 comm="blkid" path="/sbin/blkid" dev="sda1" ino=16128 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 audit: type=1400 audit(1548222434.532:10936): avc: denied { map } for pid=14791 comm="blkid" path="/lib/x86_64-linux-gnu/ld-2.13.so" dev="sda1" ino=2668 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 audit: type=1400 audit(1548222434.552:10937): avc: denied { map } for pid=14791 comm="blkid" path="/lib/x86_64-linux-gnu/ld-2.13.so" dev="sda1" ino=2668 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 audit: type=1400 audit(1548222434.552:10938): avc: denied { map } for pid=14791 comm="blkid" path="/etc/ld.so.cache" dev="sda1" ino=2503 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 audit: type=1400 audit(1548222434.552:10939): avc: denied { map } for pid=14791 comm="blkid" path="/lib/x86_64-linux-gnu/libblkid.so.1.1.0" dev="sda1" ino=2825 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 audit: type=1400 audit(1548222434.552:10940): avc: denied { map } for pid=14791 comm="blkid" path="/lib/x86_64-linux-gnu/libblkid.so.1.1.0" dev="sda1" ino=2825 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 audit: type=1400 audit(1548222434.552:10941): avc: denied { map } for pid=14791 comm="blkid" path="/lib/x86_64-linux-gnu/libc-2.13.so" dev="sda1" ino=2784 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 audit: type=1400 audit(1548222434.552:10942): avc: denied { map } for pid=14791 comm="blkid" path="/lib/x86_64-linux-gnu/libc-2.13.so" dev="sda1" ino=2784 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 audit: type=1400 audit(1548222434.552:10943): avc: denied { map } for pid=14791 comm="blkid" path="/lib/x86_64-linux-gnu/libuuid.so.1.3.0" dev="sda1" ino=2819 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 ip6_tunnel: ip6tnl3 xmit: Local address not yet configured! ip6_tunnel: ip6tnl1 xmit: Local address not yet configured! ip6_tunnel: ip6tnl1 xmit: Local address not yet configured!