random: sshd: uninitialized urandom read (32 bytes read) random: sshd: uninitialized urandom read (32 bytes read) random: sshd: uninitialized urandom read (32 bytes read) ====================================================== [ INFO: possible circular locking dependency detected ] 4.9.109-ga4230be #48 Not tainted ------------------------------------------------------- syz-executor240/3796 is trying to acquire lock: (sk_lock-AF_INET){+.+.+.}, at: [] lock_sock include/net/sock.h:1404 [inline] (sk_lock-AF_INET){+.+.+.}, at: [] do_ip_setsockopt.isra.13+0x12a/0x2b10 net/ipv4/ip_sockglue.c:636 but task is already holding lock: (rtnl_mutex){+.+.+.}, at: [] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:70 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: lock_acquire+0x130/0x3e0 kernel/locking/lockdep.c:3756 __mutex_lock_common kernel/locking/mutex.c:521 [inline] mutex_lock_nested+0xc0/0x870 kernel/locking/mutex.c:621 rtnl_lock+0x17/0x20 net/core/rtnetlink.c:70 mrtsock_destruct+0x3b/0x1e0 net/ipv4/ipmr.c:1231 ip_ra_control+0x2c2/0x420 net/ipv4/ip_sockglue.c:360 do_ip_setsockopt.isra.13+0x15ff/0x2b10 net/ipv4/ip_sockglue.c:1137 ip_setsockopt+0x3a/0xb0 net/ipv4/ip_sockglue.c:1240 raw_setsockopt+0xb7/0xd0 net/ipv4/raw.c:833 sock_common_setsockopt+0x9a/0xe0 net/core/sock.c:2706 SYSC_setsockopt net/socket.c:1772 [inline] SyS_setsockopt+0x166/0x260 net/socket.c:1751 do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282 entry_SYSCALL_64_after_swapgs+0x5d/0xdb check_prev_add kernel/locking/lockdep.c:1828 [inline] check_prevs_add kernel/locking/lockdep.c:1938 [inline] validate_chain kernel/locking/lockdep.c:2265 [inline] __lock_acquire+0x3019/0x4070 kernel/locking/lockdep.c:3345 lock_acquire+0x130/0x3e0 kernel/locking/lockdep.c:3756 lock_sock_nested+0xc6/0x120 net/core/sock.c:2511 lock_sock include/net/sock.h:1404 [inline] do_ip_setsockopt.isra.13+0x12a/0x2b10 net/ipv4/ip_sockglue.c:636 ip_setsockopt+0x3a/0xb0 net/ipv4/ip_sockglue.c:1240 udp_setsockopt+0x4a/0x90 net/ipv4/udp.c:2091 sock_common_setsockopt+0x9a/0xe0 net/core/sock.c:2706 SYSC_setsockopt net/socket.c:1772 [inline] SyS_setsockopt+0x166/0x260 net/socket.c:1751 do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282 entry_SYSCALL_64_after_swapgs+0x5d/0xdb other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(rtnl_mutex); lock(sk_lock-AF_INET); lock(rtnl_mutex); lock(sk_lock-AF_INET); *** DEADLOCK *** 1 lock held by syz-executor240/3796: #0: (rtnl_mutex){+.+.+.}, at: [] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:70 stack backtrace: CPU: 1 PID: 3796 Comm: syz-executor240 Not tainted 4.9.109-ga4230be #48 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ffff8801da3b7758 ffffffff81eb3e29 ffffffff855e7b60 ffffffff8559cef0 ffffffff855e7b60 ffff8801c81508e8 ffff8801c8150000 ffff8801da3b77a0 ffffffff814262d4 0000000000000001 00000000c8150000 0000000000000001 Call Trace: [] __dump_stack lib/dump_stack.c:15 [inline] [] dump_stack+0xc1/0x128 lib/dump_stack.c:51 [] print_circular_bug.cold.51+0x1bd/0x27d kernel/locking/lockdep.c:1202 [] check_prev_add kernel/locking/lockdep.c:1828 [inline] [] check_prevs_add kernel/locking/lockdep.c:1938 [inline] [] validate_chain kernel/locking/lockdep.c:2265 [inline] [] __lock_acquire+0x3019/0x4070 kernel/locking/lockdep.c:3345 [] lock_acquire+0x130/0x3e0 kernel/locking/lockdep.c:3756 [] lock_sock_nested+0xc6/0x120 net/core/sock.c:2511 [] lock_sock include/net/sock.h:1404 [inline] [] do_ip_setsockopt.isra.13+0x12a/0x2b10 net/ipv4/ip_sockglue.c:636 [] ip_setsockopt+0x3a/0xb0 net/ipv4/ip_sockglue.c:1240 [] udp_setsockopt+0x4a/0x90 net/ipv4/udp.c:2091 [] sock_common_setsockopt+0x9a/0xe0 net/core/sock.c:2706 [] SYSC_setsockopt net/socket.c:1772 [inline] [] SyS_setsockopt+0x166/0x260 net/socket.c:1751