Warning: Permanently added '10.128.0.64' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 44.827491] [ 44.829235] ====================================================== [ 44.835529] [ INFO: possible circular locking dependency detected ] [ 44.841904] 4.4.162+ #7 Not tainted [ 44.845510] ------------------------------------------------------- [ 44.851938] syz-executor067/2085 is trying to acquire lock: [ 44.857627] (rtnl_mutex){+.+.+.}, at: [] rtnl_lock+0x17/0x20 [ 44.866500] [ 44.866500] but task is already holding lock: [ 44.872442] (sk_lock-AF_INET6){+.+.+.}, at: [] do_ipv6_setsockopt.isra.4+0x252/0x2d50 [ 44.882526] [ 44.882526] which lock already depends on the new lock. [ 44.882526] [ 44.890813] [ 44.890813] the existing dependency chain (in reverse order) is: [ 44.898519] -> #1 (sk_lock-AF_INET6){+.+.+.}: [ 44.903642] [] lock_acquire+0x15e/0x450 [ 44.909883] [] lock_sock_nested+0xc6/0x120 [ 44.916387] [] do_ipv6_setsockopt.isra.4+0x1d2/0x2d50 [ 44.923895] [] compat_ipv6_setsockopt+0xe9/0x1d0 [ 44.930941] [] compat_udpv6_setsockopt+0x4a/0x90 [ 44.937971] [] compat_sock_common_setsockopt+0xb4/0x150 [ 44.945601] [] compat_SyS_setsockopt+0x169/0x700 [ 44.952623] [] do_fast_syscall_32+0x31e/0xa80 [ 44.959450] [] sysenter_flags_fixed+0xd/0x1a [ 44.966141] -> #0 (rtnl_mutex){+.+.+.}: [ 44.970764] [] __lock_acquire+0x3e6c/0x5f10 [ 44.977356] [] lock_acquire+0x15e/0x450 [ 44.983602] [] mutex_lock_nested+0xbb/0x8d0 [ 44.990195] [] rtnl_lock+0x17/0x20 [ 44.996001] [] ipv6_sock_mc_close+0x10e/0x350 [ 45.003124] [] do_ipv6_setsockopt.isra.4+0xd07/0x2d50 [ 45.010585] [] compat_ipv6_setsockopt+0xe9/0x1d0 [ 45.017684] [] compat_udpv6_setsockopt+0x4a/0x90 [ 45.024759] [] compat_sock_common_setsockopt+0xb4/0x150 [ 45.032389] [] compat_SyS_setsockopt+0x169/0x700 [ 45.039468] [] do_fast_syscall_32+0x31e/0xa80 [ 45.046228] [] sysenter_flags_fixed+0xd/0x1a [ 45.052901] [ 45.052901] other info that might help us debug this: [ 45.052901] [ 45.061024] Possible unsafe locking scenario: [ 45.061024] [ 45.067057] CPU0 CPU1 [ 45.071694] ---- ---- [ 45.076332] lock(sk_lock-AF_INET6); [ 45.080355] lock(rtnl_mutex); [ 45.086418] lock(sk_lock-AF_INET6); [ 45.092948] lock(rtnl_mutex); [ 45.096433] [ 45.096433] *** DEADLOCK *** [ 45.096433] [ 45.102466] 1 lock held by syz-executor067/2085: [ 45.107188] #0: (sk_lock-AF_INET6){+.+.+.}, at: [] do_ipv6_setsockopt.isra.4+0x252/0x2d50 [ 45.117931] [ 45.117931] stack backtrace: [ 45.122404] CPU: 0 PID: 2085 Comm: syz-executor067 Not tainted 4.4.162+ #7 [ 45.129385] 0000000000000000 d21c4fc6f4c45630 ffff8801d43d7538 ffffffff81a994bd [ 45.137373] ffffffff83a85b10 ffffffff83ac48d0 ffffffff83a85b10 ffff8801d59967e8 [ 45.145355] ffff8801d5995f00 ffff8801d43d7580 ffffffff813a834a 0000000000000001 [ 45.153346] Call Trace: [ 45.155916] [] dump_stack+0xc1/0x124 [ 45.161263] [] print_circular_bug.cold.34+0x2f7/0x432 [ 45.168188] [] __lock_acquire+0x3e6c/0x5f10 [ 45.174136] [] ? trace_hardirqs_on+0x10/0x10 [ 45.180434] [] lock_acquire+0x15e/0x450 [ 45.186040] [] ? rtnl_lock+0x17/0x20 [ 45.191381] [] ? rtnl_lock+0x17/0x20 [ 45.196724] [] mutex_lock_nested+0xbb/0x8d0 [ 45.202675] [] ? rtnl_lock+0x17/0x20 [ 45.208025] [] ? debug_lockdep_rcu_enabled+0x77/0x90 [ 45.214948] [] ? debug_lockdep_rcu_enabled+0x77/0x90 [ 45.221680] [] ? mutex_trylock+0x3e0/0x3e0 [ 45.227542] [] ? mark_held_locks+0xc7/0x130 [ 45.233715] [] ? __local_bh_enable_ip+0x6a/0xd0 [ 45.240012] [] rtnl_lock+0x17/0x20 [ 45.245174] [] ipv6_sock_mc_close+0x10e/0x350 [ 45.251297] [] ? fl6_free_socklist+0xb7/0x240 [ 45.257435] [] do_ipv6_setsockopt.isra.4+0xd07/0x2d50 [ 45.264262] [] ? ip6_ra_control+0x430/0x430 [ 45.270320] [] ? trace_hardirqs_on+0x10/0x10 [ 45.276445] [] ? __lock_acquire+0xa85/0x5f10 [ 45.282481] [] ? __local_bh_enable_ip+0x6a/0xd0 [ 45.288780] [] ? debug_lockdep_rcu_enabled+0x77/0x90 [ 45.295612] [] ? avc_has_perm+0x15a/0x3a0 [ 45.301391] [] ? avc_has_perm+0x1cc/0x3a0 [ 45.307168] [] ? avc_has_perm+0x9e/0x3a0 [ 45.312856] [] ? avc_has_perm_noaudit+0x2f0/0x2f0 [ 45.319575] [] ? check_preemption_disabled+0x3b/0x170 [ 45.326393] [] ? sock_has_perm+0x1c1/0x3f0 [ 45.332257] [] ? sock_has_perm+0x2a1/0x3f0 [ 45.338122] [] ? sock_has_perm+0x9f/0x3f0 [ 45.343946] [] ? selinux_msg_queue_alloc_security+0x2e0/0x2e0 [ 45.351463] [] ? __fget+0x12f/0x3d0 [ 45.356725] [] compat_ipv6_setsockopt+0xe9/0x1d0 [ 45.363110] [] compat_udpv6_setsockopt+0x4a/0x90 [ 45.369576] [] compat_sock_common_setsockopt+0xb4/0x150 [ 45.376572] [] ? udpv6_setsockopt+0x90/0x90 [ 45.382522] [] compat_SyS_setsockopt+0x169/0x700 [ 45.388918] [] ? sock_common_setsockopt+0xe0/0xe0 [ 45.395392] [] ? scm_detach_fds_compat+0x3b0/0x3b0 [ 45.401947] [] ? __do_page_fault+0x2b6/0x7e0 [ 45.407981] [] ? do_fast_syscall_32+0xdb/0xa80 [ 45.414297] [] ? scm_detach_fds_compat+0x3b0/0x3b0 [ 45.420853] [] do_fast_syscall_32+0x31e/0xa80 [ 45.426974] []