[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. Starting mcstransd: [ 10.581278] random: sshd: uninitialized urandom read (32 bytes read) [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting file context maintaining daemon: restorecond[?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 24.139813] random: crng init done Warning: Permanently added '10.128.10.8' (ECDSA) to the list of known hosts. net.ipv6.conf.syz_tun.accept_dad = 0 net.ipv6.conf.syz_tun.router_solicitations = 0 RTNETLINK answers: Operation not supported RTNETLINK answers: Operation not supported RTNETLINK answers: Operation not supported RTNETLINK answers: Operation not supported RTNETLINK answers: Operation not supported RTNETLINK answers: Operation not supported RTNETLINK answers: Operation not supported RTNETLINK answers: Operation not supported Error: argument "bridge0" is wrong: Device does not exist Error: argument "bridge0" is wrong: Device does not exist Cannot find device "veth0_to_bridge" Cannot find device "veth1_to_bridge" RTNETLINK answers: Operation not supported RTNETLINK answers: Operation not supported Error: argument "bond0" is wrong: Device does not exist Error: argument "bond0" is wrong: Device does not exist Cannot find device "veth0_to_bond" Cannot find device "veth1_to_bond" RTNETLINK answers: Operation not supported RTNETLINK answers: Operation not supported Error: argument "team0" is wrong: Device does not exist Error: argument "team0" is wrong: Device does not exist Cannot find device "veth0_to_team" Cannot find device "veth1_to_team" Cannot find device "bridge_slave_0" Cannot find device "bridge_slave_1" RTNETLINK answers: Operation not supported Cannot find device "bridge0" Cannot find device "bridge0" Cannot find device "bridge0" Cannot find device "bridge0" Cannot find device "vcan0" Cannot find device "vcan0" Cannot find device "vcan0" Cannot find device "vcan0" Cannot find device "tunl0" Cannot find device "tunl0" Cannot find device "tunl0" Cannot find device "tunl0" Cannot find device "gre0" Cannot find device "gre0" Cannot find device "gre0" Cannot find device "gre0" Cannot find device "gretap0" Cannot find device "gretap0" Cannot find device "gretap0" Cannot find device "gretap0" RTNETLINK answers: Operation not supported RTNETLINK answers: Invalid argument RTNETLINK answers: Invalid argument Cannot find device "ip6gre0" Cannot find device "ip6gre0" Cannot find device "ip6gre0" Cannot find device "ip6gre0" Cannot find device "ip6gretap0" Cannot find device "ip6gretap0" Cannot find device "ip6gretap0" Cannot find device "ip6gretap0" Cannot find device "erspan0" Cannot find device "erspan0" Cannot find device "erspan0" Cannot find device "erspan0" Cannot find device "bond0" Cannot find device "bond0" Cannot find device "bond0" Cannot find device "bond0" Cannot find device "veth0" Cannot find device "veth0" Cannot find device "veth0" Cannot find device "veth0" Cannot find device "veth1" Cannot find device "veth1" Cannot find device "veth1" Cannot find device "veth1" Cannot find device "team0" Cannot find device "team0" Cannot find device "team0" Cannot find device "team0" Cannot find device "veth0_to_bridge" Cannot find device "veth0_to_bridge" Cannot find device "veth0_to_bridge" Cannot find device "veth0_to_bridge" Cannot find device "veth1_to_bridge" Cannot find device "veth1_to_bridge" Cannot find device "veth1_to_bridge" Cannot find device "veth1_to_bridge" Cannot find device "veth0_to_bond" Cannot find device "veth0_to_bond" Cannot find device "veth0_to_bond" Cannot find device "veth0_to_bond" Cannot find device "veth1_to_bond" Cannot find device "veth1_to_bond" Cannot find device "veth1_to_bond" Cannot find device "veth1_to_bond" Cannot find device "veth0_to_team" Cannot find device "veth0_to_team" Cannot find device "veth0_to_team" Cannot find device "veth0_to_team" Cannot find device "veth1_to_team" Cannot find device "veth1_to_team" Cannot find device "veth1_to_team" Cannot find device "veth1_to_team" executing program [ 40.286901] audit: type=1400 audit(1545407617.118:5): avc: denied { associate } for pid=2054 comm="syz-executor846" name="syz0" scontext=unconfined_u:object_r:unlabeled_t:s0 tcontext=system_u:object_r:unlabeled_t:s0 tclass=filesystem permissive=1 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 50.874410] [ 50.876072] ====================================================== [ 50.882363] [ INFO: possible circular locking dependency detected ] [ 50.888741] 4.9.147+ #86 Not tainted [ 50.892423] ------------------------------------------------------- [ 50.898798] syz-executor846/3043 is trying to acquire lock: [ 50.904480] (&mm->mmap_sem){++++++}, at: [] __do_page_fault+0x7db/0xa60 [ 50.913238] but task is already holding lock: [ 50.917877] (&sb->s_type->i_mutex_key#10){+.+.+.}, at: [] generic_file_write_iter+0x9d/0x620 [ 50.928563] which lock already depends on the new lock. [ 50.928563] [ 50.935560] [ 50.935560] the existing dependency chain (in reverse order) is: [ 50.943152] -> #2 (&sb->s_type->i_mutex_key#10){+.+.+.}: [ 50.949390] lock_acquire+0x130/0x3e0 [ 50.953700] down_write+0x41/0xa0 [ 50.957663] shmem_fallocate+0x13c/0xb10 [ 50.962225] ashmem_shrink_scan+0x1b9/0x4c0 [ 50.967052] ashmem_ioctl+0x2c3/0xf00 [ 50.971350] do_vfs_ioctl+0x1ac/0x11a0 [ 50.975736] SyS_ioctl+0x8f/0xc0 [ 50.979601] do_syscall_64+0x19f/0x550 [ 50.983996] entry_SYSCALL_64_after_swapgs+0x5d/0xdb [ 50.989592] -> #1 (ashmem_mutex){+.+.+.}: [ 50.994374] lock_acquire+0x130/0x3e0 [ 50.998669] mutex_lock_nested+0xc0/0x900 [ 51.003314] ashmem_mmap+0x55/0x480 [ 51.007439] mmap_region+0x80c/0xf90 [ 51.011646] do_mmap+0x53d/0xbb0 [ 51.015511] vm_mmap_pgoff+0x168/0x1b0 [ 51.019892] SyS_mmap_pgoff+0xfe/0x1b0 [ 51.024286] SyS_mmap+0x16/0x20 [ 51.028093] do_syscall_64+0x19f/0x550 [ 51.032476] entry_SYSCALL_64_after_swapgs+0x5d/0xdb [ 51.038071] -> #0 (&mm->mmap_sem){++++++}: [ 51.042952] __lock_acquire+0x3189/0x4a10 [ 51.047596] lock_acquire+0x130/0x3e0 [ 51.051908] down_read+0x44/0xb0 [ 51.055777] __do_page_fault+0x7db/0xa60 [ 51.060337] do_page_fault+0x27/0x30 [ 51.064553] page_fault+0x25/0x30 [ 51.068503] generic_perform_write+0x1c7/0x500 [ 51.073599] __generic_file_write_iter+0x352/0x540 [ 51.079021] generic_file_write_iter+0x37a/0x620 [ 51.084277] __vfs_write+0x3d7/0x580 [ 51.088509] vfs_write+0x187/0x520 [ 51.092545] SyS_write+0xd9/0x1c0 [ 51.096506] do_syscall_64+0x19f/0x550 [ 51.100890] entry_SYSCALL_64_after_swapgs+0x5d/0xdb [ 51.106487] [ 51.106487] other info that might help us debug this: [ 51.106487] [ 51.114601] Chain exists of: &mm->mmap_sem --> ashmem_mutex --> &sb->s_type->i_mutex_key#10 [ 51.124362] Possible unsafe locking scenario: [ 51.124362] [ 51.130400] CPU0 CPU1 [ 51.135040] ---- ---- [ 51.139677] lock(&sb->s_type->i_mutex_key#10); [ 51.144767] lock(ashmem_mutex); [ 51.150985] lock(&sb->s_type->i_mutex_key#10); [ 51.158648] lock(&mm->mmap_sem); [ 51.162395] [ 51.162395] *** DEADLOCK *** [ 51.162395] [ 51.168460] 2 locks held by syz-executor846/3043: [ 51.173272] #0: (sb_writers#6){.+.+.+}, at: [] vfs_write+0x3eb/0x520 [ 51.182143] #1: (&sb->s_type->i_mutex_key#10){+.+.+.}, at: [] generic_file_write_iter+0x9d/0x620 [ 51.193463] [ 51.193463] stack backtrace: [ 51.197934] CPU: 1 PID: 3043 Comm: syz-executor846 Not tainted 4.9.147+ #86 [ 51.205007] ffff8801d9f57548 ffffffff81b43be9 ffffffff83cc9790 ffffffff83cb2960 [ 51.213018] ffffffff83ca9180 ffff8801c4f488f8 ffff8801c4f48000 ffff8801d9f57590 [ 51.221029] ffffffff813ff460 0000000000000002 00000000c4f488d8 0000000000000002 [ 51.229031] Call Trace: [ 51.231606] [] dump_stack+0xc1/0x128 [ 51.236949] [] print_circular_bug.cold.36+0x2f7/0x432 [ 51.243762] [] __lock_acquire+0x3189/0x4a10 [ 51.249719] [] ? get_page_from_freelist+0xda3/0x1d80 [ 51.256460] [] ? trace_hardirqs_on+0x10/0x10 [ 51.262512] [] ? rcu_read_lock_sched_held+0x103/0x120 [ 51.269326] [] lock_acquire+0x130/0x3e0 [ 51.274928] [] ? __do_page_fault+0x7db/0xa60 [ 51.280965] [] down_read+0x44/0xb0 [ 51.286131] [] ? __do_page_fault+0x7db/0xa60 [ 51.292164] [] __do_page_fault+0x7db/0xa60 [ 51.298022] [] ? bad_area_access_error+0x3a0/0x3a0 [ 51.304576] [] ? debug_lockdep_rcu_enabled+0x77/0x90 [ 51.311306] [] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 51.317945] [] do_page_fault+0x27/0x30 [ 51.323455] [] page_fault+0x25/0x30 [ 51.328706] [] ? shmem_put_link+0xe0/0xe0 [ 51.334482] [] ? iov_iter_fault_in_readable+0x330/0x400 [ 51.341472] [] ? iov_iter_fault_in_readable+0x323/0x400 [ 51.348474] [] ? flex_array_free_parts+0xe0/0xe0 [ 51.354854] [] ? do_writepages+0x1c0/0x1d0 [ 51.360718] [] ? do_writepages+0x1d0/0x1d0 [ 51.366586] [] ? iov_iter_advance+0x216/0xd40 [ 51.372706] [] generic_perform_write+0x1c7/0x500 [ 51.379084] [] ? filemap_page_mkwrite+0x280/0x280 [ 51.385551] [] ? file_update_time+0xbc/0x390 [ 51.391585] [] ? current_time+0xd0/0xd0 [ 51.397185] [] __generic_file_write_iter+0x352/0x540 [ 51.403911] [] generic_file_write_iter+0x37a/0x620 [ 51.410468] [] __vfs_write+0x3d7/0x580 [ 51.415979] [] ? __vfs_read+0x560/0x560 [ 51.421577] [] ? retint_kernel+0x2d/0x2d [ 51.427268] [] ? rcu_sync_lockdep_assert+0x73/0xb0 [ 51.433829] [] ? __sb_start_write+0x161/0x300 [ 51.439964] [] vfs_write+0x187/0x520 [ 51.445304] [] SyS_write+0xd9/0x1c0 [ 51.450553] [] ? SyS_read+0x1c0/0x1c0 [ 51.455978] [] ? do_syscall_64+0x48/0x550 [ 51.461760] [] ? SyS_read+0x1c0/0x1c0 [ 51.467204] [] do_syscall_64+0x19f/0x550 executing program executing program [ 51.472893] [] entry_SYSCALL_64_after_swapgs+0x5d/0xdb executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program