[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 23.318857] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. [ 24.368380] random: sshd: uninitialized urandom read (32 bytes read) Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 24.763405] random: sshd: uninitialized urandom read (32 bytes read) [ 25.317308] random: sshd: uninitialized urandom read (32 bytes read) [ 86.544776] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.0.18' (ECDSA) to the list of known hosts. [ 92.068615] random: sshd: uninitialized urandom read (32 bytes read) 2018/08/27 18:59:13 parsed 1 programs [ 93.379835] random: cc1: uninitialized urandom read (8 bytes read) 2018/08/27 18:59:15 executed programs: 0 [ 94.873838] IPVS: ftp: loaded support on port[0] = 21 [ 95.090133] bridge0: port 1(bridge_slave_0) entered blocking state [ 95.096580] bridge0: port 1(bridge_slave_0) entered disabled state [ 95.104511] device bridge_slave_0 entered promiscuous mode [ 95.120802] bridge0: port 2(bridge_slave_1) entered blocking state [ 95.127145] bridge0: port 2(bridge_slave_1) entered disabled state [ 95.134349] device bridge_slave_1 entered promiscuous mode [ 95.149500] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 95.165869] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 95.208829] bond0: Enslaving bond_slave_0 as an active interface with an up link [ 95.228200] bond0: Enslaving bond_slave_1 as an active interface with an up link [ 95.291270] IPv6: ADDRCONF(NETDEV_UP): team_slave_0: link is not ready [ 95.298521] team0: Port device team_slave_0 added [ 95.314352] IPv6: ADDRCONF(NETDEV_UP): team_slave_1: link is not ready [ 95.321456] team0: Port device team_slave_1 added [ 95.337200] IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_0: link becomes ready [ 95.354968] IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_1: link becomes ready [ 95.373034] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 95.390400] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 95.478324] ip (4577) used greatest stack depth: 16280 bytes left [ 95.518961] bridge0: port 2(bridge_slave_1) entered blocking state [ 95.525379] bridge0: port 2(bridge_slave_1) entered forwarding state [ 95.532243] bridge0: port 1(bridge_slave_0) entered blocking state [ 95.538624] bridge0: port 1(bridge_slave_0) entered forwarding state [ 95.976230] IPv6: ADDRCONF(NETDEV_UP): bond0: link is not ready [ 95.982363] 8021q: adding VLAN 0 to HW filter on device bond0 [ 96.027705] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 96.043621] IPv6: ADDRCONF(NETDEV_CHANGE): bond0: link becomes ready [ 96.082453] IPv6: ADDRCONF(NETDEV_UP): veth1: link is not ready [ 96.088632] IPv6: ADDRCONF(NETDEV_CHANGE): veth1: link becomes ready [ 96.097029] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 96.138806] 8021q: adding VLAN 0 to HW filter on device team0 [ 97.423934] [ 97.425598] ===================================== [ 97.430414] WARNING: bad unlock balance detected! [ 97.435246] 4.19.0-rc1+ #211 Not tainted [ 97.439291] ------------------------------------- [ 97.444108] syz-executor0/5177 is trying to release lock (&file->mut) at: [ 97.451020] [] ucma_destroy_id+0x2cb/0x550 [ 97.456807] but there are no more locks to release! [ 97.461797] [ 97.461797] other info that might help us debug this: [ 97.468441] 1 lock held by syz-executor0/5177: [ 97.473007] #0: 00000000c4b79a5e (&file->mut){+.+.}, at: ucma_destroy_id+0x26b/0x550 [ 97.480965] [ 97.480965] stack backtrace: [ 97.485469] CPU: 0 PID: 5177 Comm: syz-executor0 Not tainted 4.19.0-rc1+ #211 [ 97.492741] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 97.502071] Call Trace: [ 97.504641] dump_stack+0x1c9/0x2b4 [ 97.508247] ? dump_stack_print_info.cold.2+0x52/0x52 [ 97.513446] ? vprintk_func+0x81/0x117 [ 97.517313] ? ucma_destroy_id+0x2cb/0x550 [ 97.521530] print_unlock_imbalance_bug.cold.49+0xcc/0xd8 [ 97.527044] lock_release+0x76e/0x9f0 [ 97.530823] ? ucma_destroy_id+0x2cb/0x550 [ 97.535033] ? lock_downgrade+0x8f0/0x8f0 [ 97.539157] ? radix_tree_descend+0x2e0/0x2e0 [ 97.543637] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 97.549154] ? node_tag_set+0xc4/0x160 [ 97.553025] __mutex_unlock_slowpath+0x102/0x8c0 [ 97.557778] ? wait_for_completion+0x8d0/0x8d0 [ 97.562343] ? radix_tree_delete_item+0x188/0x350 [ 97.567165] ? radix_tree_lookup+0x30/0x30 [ 97.571381] mutex_unlock+0xd/0x10 [ 97.574903] ucma_destroy_id+0x2cb/0x550 [ 97.578948] ? ucma_close+0x300/0x300 [ 97.582747] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 97.588265] ? _copy_from_user+0xdf/0x150 [ 97.592394] ? ucma_close+0x300/0x300 [ 97.596171] ucma_write+0x336/0x420 [ 97.599778] ? ucma_close_id+0x60/0x60 [ 97.603645] ? kasan_check_read+0x11/0x20 [ 97.607770] ? do_raw_spin_unlock+0xa7/0x2f0 [ 97.612163] __vfs_write+0x117/0x9d0 [ 97.615855] ? __fget_light+0x2f7/0x440 [ 97.619815] ? ucma_close_id+0x60/0x60 [ 97.623692] ? kernel_read+0x120/0x120 [ 97.627645] ? trace_hardirqs_on+0x2c0/0x2c0 [ 97.632033] ? kasan_check_read+0x11/0x20 [ 97.636177] ? schedule+0xfb/0x450 [ 97.639714] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 97.645232] ? security_file_permission+0x1c2/0x230 [ 97.650227] ? rw_verify_area+0x118/0x360 [ 97.654354] vfs_write+0x1fc/0x560 [ 97.657879] ksys_write+0x101/0x260 [ 97.661495] ? __ia32_sys_read+0xb0/0xb0 [ 97.665537] ? trace_hardirqs_off_caller+0x2b0/0x2b0 [ 97.670618] __x64_sys_write+0x73/0xb0 [ 97.674485] do_syscall_64+0x1b9/0x820 [ 97.678356] ? entry_SYSCALL_64_after_hwframe+0x3e/0xbe [ 97.683698] ? syscall_return_slowpath+0x5e0/0x5e0 [ 97.688604] ? trace_hardirqs_on_caller+0x2b0/0x2b0 [ 97.693598] ? prepare_exit_to_usermode+0x3b0/0x3b0 [ 97.698595] ? recalc_sigpending_tsk+0x180/0x180 [ 97.703348] ? kasan_check_write+0x14/0x20 [ 97.707567] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 97.712389] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 97.717557] RIP: 0033:0x457089 [ 97.720735] Code: fd b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 cb b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 [ 97.739632] RSP: 002b:00007fd982a36c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 [ 97.747323] RAX: ffffffffffffffda RBX: 00007fd982a376d4 RCX: 0000000000457089 [ 97.754570] RDX: 0000000000000018 RSI: 0000000020000480 RDI: 0000000000000005 [ 97.761829] RBP: 0000000000930140 R08: 0000000000000000 R09: 0000000000000000 [ 97.769074] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff [ 97.776322] R13: 00000000004d7470 R14: 00000000004c17a8 R15: 0000000000000001