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 ] 4.9.103-g7fd4075 #36 Not tainted ------------------------------------------------------- syz-executor670/3804 is trying to acquire lock: (rtnl_mutex){+.+.+.}, at: [] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:70 but task is already holding lock: (sk_lock-AF_INET){+.+.+.}, at: [] lock_sock include/net/sock.h:1404 [inline] (sk_lock-AF_INET){+.+.+.}, at: [] do_ip_setsockopt.isra.13+0x269/0x2b10 net/ipv4/ip_sockglue.c:638 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 lock_sock_nested+0xc6/0x120 net/core/sock.c:2511 lock_sock include/net/sock.h:1404 [inline] do_ip_getsockopt+0x167/0x1600 net/ipv4/ip_sockglue.c:1319 ip_getsockopt+0x91/0x180 net/ipv4/ip_sockglue.c:1547 udp_getsockopt+0x4a/0x80 net/ipv4/udp.c:2163 sock_common_getsockopt+0x9a/0xe0 net/core/sock.c:2665 SYSC_getsockopt net/socket.c:1803 [inline] SyS_getsockopt+0x150/0x240 net/socket.c:1785 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 __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:1139 ip_setsockopt+0x3a/0xb0 net/ipv4/ip_sockglue.c:1242 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 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(sk_lock-AF_INET); lock(rtnl_mutex); lock(sk_lock-AF_INET); lock(rtnl_mutex); *** DEADLOCK *** 1 lock held by syz-executor670/3804: #0: (sk_lock-AF_INET){+.+.+.}, at: [] lock_sock include/net/sock.h:1404 [inline] #0: (sk_lock-AF_INET){+.+.+.}, at: [] do_ip_setsockopt.isra.13+0x269/0x2b10 net/ipv4/ip_sockglue.c:638 stack backtrace: CPU: 0 PID: 3804 Comm: syz-executor670 Not tainted 4.9.103-g7fd4075 #36 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ffff8801b5ebf5f8 ffffffff81eb34a9 ffffffff8559cf30 ffffffff855e79f0 ffffffff8559cf30 ffff8801b7b288e8 ffff8801b7b28000 ffff8801b5ebf640 ffffffff8142642d 0000000000000001 00000000b7b28000 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 [] __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:1139 [] ip_setsockopt+0x3a/0xb0 net/ipv4/ip_sockglue.c:1242 [] 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 [] ? move_addr_to_kernel+0x5