Warning: Permanently added '10.128.15.193' (ECDSA) to the list of known hosts. executing program [ 40.424161] [ 40.425803] ====================================================== [ 40.432097] [ INFO: possible circular locking dependency detected ] [ 40.438518] 4.4.174+ #17 Not tainted [ 40.442207] ------------------------------------------------------- [ 40.448583] syz-executor192/2076 is trying to acquire lock: [ 40.454264] (rtnl_mutex){+.+.+.}, at: [] rtnl_lock+0x17/0x20 [ 40.462168] [ 40.462168] but task is already holding lock: [ 40.468112] (sk_lock-AF_INET6){+.+.+.}, at: [] do_ipv6_setsockopt.isra.0+0x28a/0x30c0 [ 40.478239] [ 40.478239] which lock already depends on the new lock. [ 40.478239] [ 40.486578] [ 40.486578] the existing dependency chain (in reverse order) is: [ 40.494215] -> #1 (sk_lock-AF_INET6){+.+.+.}: [ 40.499351] [] lock_acquire+0x15e/0x450 [ 40.505592] [] lock_sock_nested+0xc6/0x120 [ 40.512096] [] do_ipv6_setsockopt.isra.0+0x2eba/0x30c0 [ 40.519680] [] ipv6_setsockopt+0xda/0x140 [ 40.526144] [] compat_mc_setsockopt+0x4f7/0x690 [ 40.533122] [] compat_ipv6_setsockopt+0x124/0x1d0 [ 40.540233] [] inet_csk_compat_setsockopt+0x99/0x120 [ 40.547602] [] compat_tcp_setsockopt+0x40/0x70 [ 40.554463] [] compat_sock_common_setsockopt+0xb4/0x150 [ 40.562097] [] compat_SyS_setsockopt+0x15c/0x720 [ 40.569121] [] do_fast_syscall_32+0x32d/0xa90 [ 40.575877] [] sysenter_flags_fixed+0xd/0x1a [ 40.582554] -> #0 (rtnl_mutex){+.+.+.}: [ 40.587150] [] __lock_acquire+0x37d6/0x4f50 [ 40.593731] [] lock_acquire+0x15e/0x450 [ 40.599964] [] mutex_lock_nested+0xc1/0xb80 [ 40.606553] [] rtnl_lock+0x17/0x20 [ 40.612353] [] ipv6_sock_mc_close+0x10e/0x350 [ 40.619195] [] do_ipv6_setsockopt.isra.0+0x1bd1/0x30c0 [ 40.626739] [] compat_ipv6_setsockopt+0xe7/0x1d0 [ 40.633865] [] inet_csk_compat_setsockopt+0x99/0x120 [ 40.641234] [] compat_tcp_setsockopt+0x40/0x70 [ 40.648078] [] compat_sock_common_setsockopt+0xb4/0x150 [ 40.655700] [] compat_SyS_setsockopt+0x15c/0x720 [ 40.662715] [] do_fast_syscall_32+0x32d/0xa90 [ 40.669469] [] sysenter_flags_fixed+0xd/0x1a [ 40.676148] [ 40.676148] other info that might help us debug this: [ 40.676148] [ 40.684323] Possible unsafe locking scenario: [ 40.684323] [ 40.690355] CPU0 CPU1 [ 40.694991] ---- ---- [ 40.699631] lock(sk_lock-AF_INET6); [ 40.703683] lock(rtnl_mutex); [ 40.709690] lock(sk_lock-AF_INET6); [ 40.716218] lock(rtnl_mutex); [ 40.719702] [ 40.719702] *** DEADLOCK *** [ 40.719702] [ 40.725734] 1 lock held by syz-executor192/2076: [ 40.730569] #0: (sk_lock-AF_INET6){+.+.+.}, at: [] do_ipv6_setsockopt.isra.0+0x28a/0x30c0 [ 40.741186] [ 40.741186] stack backtrace: [ 40.745662] CPU: 0 PID: 2076 Comm: syz-executor192 Not tainted 4.4.174+ #17 [ 40.752739] 0000000000000000 47a3d5c23c6a39f8 ffff8800b6be7500 ffffffff81aad1a1 [ 40.760720] ffffffff84057a80 ffff8801d4964740 ffffffff83a8db50 ffffffff83acc910 [ 40.768707] ffffffff83a8db50 ffff8800b6be7550 ffffffff813abcda ffff8800b6be7630 [ 40.776742] Call Trace: [ 40.779312] [] dump_stack+0xc1/0x120 [ 40.784651] [] print_circular_bug.cold+0x2f7/0x44e [ 40.791205] [] __lock_acquire+0x37d6/0x4f50 [ 40.797149] [] ? check_irq_usage+0xb1/0xe0 [ 40.803004] [] ? trace_hardirqs_on+0x10/0x10 [ 40.809151] [] ? trace_hardirqs_on+0x10/0x10 [ 40.815184] [] lock_acquire+0x15e/0x450 [ 40.820782] [] ? rtnl_lock+0x17/0x20 [ 40.826118] [] ? rtnl_lock+0x17/0x20 [ 40.831462] [] mutex_lock_nested+0xc1/0xb80 [ 40.837406] [] ? rtnl_lock+0x17/0x20 [ 40.842743] [] ? kvm_clock_read+0x23/0x40 [ 40.848510] [] ? kvm_clock_get_cycles+0x9/0x10 [ 40.854714] [] ? ktime_get_with_offset+0x176/0x240 [ 40.861266] [] ? debug_lockdep_rcu_enabled+0x71/0xa0 [ 40.868001] [] ? mutex_trylock+0x500/0x500 [ 40.873861] [] ? mark_held_locks+0xb1/0x100 [ 40.879870] [] ? __local_bh_enable_ip+0x6a/0xe0 [ 40.886172] [] rtnl_lock+0x17/0x20 [ 40.891438] [] ipv6_sock_mc_close+0x10e/0x350 [ 40.897671] [] ? fl6_free_socklist+0xb7/0x240 [ 40.903795] [] do_ipv6_setsockopt.isra.0+0x1bd1/0x30c0 [ 40.910704] [] ? ip6_ra_control+0x3c0/0x3c0 [ 40.916659] [] ? trace_hardirqs_on+0x10/0x10 [ 40.922697] [] ? tcp_v4_connect+0x1070/0x1930 [ 40.928819] [] ? debug_lockdep_rcu_enabled+0x71/0xa0 [ 40.935934] [] ? avc_has_perm+0x164/0x3a0 [ 40.942833] [] ? avc_has_perm+0x1d2/0x3a0 [ 40.948604] [] ? avc_has_perm+0xac/0x3a0 [ 40.954324] [] ? avc_has_perm_noaudit+0x300/0x300 [ 40.960797] [] ? debug_lockdep_rcu_enabled+0x71/0xa0 [ 40.967522] [] ? check_preemption_disabled+0x3c/0x200 [ 40.974335] [] ? check_preemption_disabled+0x3c/0x200 [ 40.981145] [] ? sock_has_perm+0x1c8/0x400 [ 40.986998] [] ? sock_has_perm+0x2a8/0x400 [ 40.992851] [] ? sock_has_perm+0xa6/0x400 [ 40.998640] [] ? selinux_msg_queue_alloc_security+0x2e0/0x2e0 [ 41.006253] [] ? check_preemption_disabled+0x3c/0x200 [ 41.013073] [] compat_ipv6_setsockopt+0xe7/0x1d0 [ 41.019466] [] inet_csk_compat_setsockopt+0x99/0x120 [ 41.026196] [] ? ipv6_setsockopt+0x140/0x140 [ 41.032235] [] compat_tcp_setsockopt+0x40/0x70 [ 41.038440] [] compat_sock_common_setsockopt+0xb4/0x150 [ 41.045440] [] ? do_tcp_setsockopt.isra.0+0x19a0/0x19a0 [ 41.052445] [] compat_SyS_setsockopt+0x15c/0x720 [ 41.058831] [] ? sock_common_setsockopt+0xe0/0xe0 [ 41.065304] [] ? scm_detach_fds_compat+0x3b0/0x3b0 [ 41.071978] [] ? __do_page_fault+0x2b3/0