[ 27.510761] random: sshd: uninitialized urandom read (32 bytes read) [....] Starting file context maintaining daemon: restorecond[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c[ 27.658268] random: sshd: uninitialized urandom read (32 bytes read) . [ 27.931328] random: sshd: uninitialized urandom read (32 bytes read) Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 40.131407] urandom_read: 1 callbacks suppressed [ 40.131411] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.0.188' (ECDSA) to the list of known hosts. [ 45.620292] random: sshd: uninitialized urandom read (32 bytes read) executing program [ 45.740675] kauditd_printk_skb: 10 callbacks suppressed [ 45.740682] audit: type=1400 audit(1571666211.649:36): avc: denied { map } for pid=6790 comm="syz-executor097" path="/root/syz-executor097621092" dev="sda1" ino=16482 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1 [ 45.798007] audit: type=1400 audit(1571666211.699:37): avc: denied { map } for pid=6791 comm="syz-executor097" path="/dev/usbmon0" dev="devtmpfs" ino=14947 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=system_u:object_r:usbmon_device_t:s0 tclass=chr_file permissive=1 [ 45.798113] [ 45.825293] ====================================================== [ 45.831588] WARNING: possible circular locking dependency detected [ 45.837979] 4.14.150 #0 Not tainted [ 45.841577] ------------------------------------------------------ [ 45.847870] syz-executor097/6793 is trying to acquire lock: [ 45.853596] (&rp->fetch_lock){+.+.}, at: [] mon_bin_vma_fault+0x6f/0x280 [ 45.862075] [ 45.862075] but task is already holding lock: [ 45.868019] (&mm->mmap_sem){++++}, at: [] __mm_populate+0x1e5/0x2c0 [ 45.876055] [ 45.876055] which lock already depends on the new lock. [ 45.876055] [ 45.884365] [ 45.884365] the existing dependency chain (in reverse order) is: [ 45.891960] [ 45.891960] -> #1 (&mm->mmap_sem){++++}: [ 45.897484] lock_acquire+0x16f/0x430 [ 45.901782] __might_fault+0x143/0x1d0 [ 45.906164] _copy_to_user+0x2c/0xd0 [ 45.910375] mon_bin_get_event+0x10a/0x430 [ 45.915108] mon_bin_ioctl+0x9b4/0xb50 [ 45.919494] do_vfs_ioctl+0x7ae/0x1060 [ 45.923877] SyS_ioctl+0x8f/0xc0 [ 45.927740] do_syscall_64+0x1e8/0x640 [ 45.932142] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 45.937838] [ 45.937838] -> #0 (&rp->fetch_lock){+.+.}: [ 45.943533] __lock_acquire+0x2cb3/0x4620 [ 45.948174] lock_acquire+0x16f/0x430 [ 45.952468] __mutex_lock+0xe8/0x1470 [ 45.956766] mutex_lock_nested+0x16/0x20 [ 45.961322] mon_bin_vma_fault+0x6f/0x280 [ 45.965966] __do_fault+0x104/0x390 [ 45.970090] __handle_mm_fault+0x2460/0x3470 [ 45.975001] handle_mm_fault+0x293/0x7c0 [ 45.979559] __get_user_pages+0x465/0x1220 [ 45.984291] populate_vma_page_range+0x18e/0x230 [ 45.989546] __mm_populate+0x198/0x2c0 [ 45.993931] vm_mmap_pgoff+0x1be/0x1d0 [ 45.998332] SyS_mmap_pgoff+0x3ca/0x520 [ 46.002815] SyS_mmap+0x16/0x20 [ 46.006597] do_syscall_64+0x1e8/0x640 [ 46.010995] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 46.016677] [ 46.016677] other info that might help us debug this: [ 46.016677] [ 46.024790] Possible unsafe locking scenario: [ 46.024790] [ 46.030820] CPU0 CPU1 [ 46.035459] ---- ---- [ 46.040106] lock(&mm->mmap_sem); [ 46.043621] lock(&rp->fetch_lock); [ 46.049825] lock(&mm->mmap_sem); [ 46.055859] lock(&rp->fetch_lock); [ 46.059553] [ 46.059553] *** DEADLOCK *** [ 46.059553] [ 46.065589] 1 lock held by syz-executor097/6793: [ 46.070319] #0: (&mm->mmap_sem){++++}, at: [] __mm_populate+0x1e5/0x2c0 [ 46.078798] [ 46.078798] stack backtrace: [ 46.083286] CPU: 1 PID: 6793 Comm: syz-executor097 Not tainted 4.14.150 #0 [ 46.090271] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 46.099600] Call Trace: [ 46.102186] dump_stack+0x138/0x197 [ 46.105798] print_circular_bug.isra.0.cold+0x1cc/0x28f [ 46.111139] __lock_acquire+0x2cb3/0x4620 [ 46.115264] ? trace_hardirqs_on_caller+0x400/0x590 [ 46.120256] ? trace_hardirqs_on+0x10/0x10 [ 46.124466] ? kasan_slab_alloc+0xf/0x20 [ 46.128520] ? kmem_cache_alloc+0x12e/0x780 [ 46.132815] ? ptlock_alloc+0x20/0x70 [ 46.136596] lock_acquire+0x16f/0x430 [ 46.140374] ? mon_bin_vma_fault+0x6f/0x280 [ 46.144673] ? mon_bin_vma_fault+0x6f/0x280 [ 46.148972] __mutex_lock+0xe8/0x1470 [ 46.152747] ? mon_bin_vma_fault+0x6f/0x280 [ 46.157060] ? save_trace+0x290/0x290 [ 46.160839] ? mon_bin_vma_fault+0x6f/0x280 [ 46.165136] ? mutex_trylock+0x1c0/0x1c0 [ 46.169171] ? ptlock_alloc+0x20/0x70 [ 46.172960] ? rcu_lockdep_current_cpu_online+0xf2/0x140 [ 46.178387] ? rcu_read_lock_sched_held+0x110/0x130 [ 46.183394] ? kmem_cache_alloc+0x611/0x780 [ 46.187691] ? __lock_acquire+0x5f7/0x4620 [ 46.191902] ? __lockdep_init_map+0x10c/0x570 [ 46.196388] mutex_lock_nested+0x16/0x20 [ 46.200426] ? mutex_lock_nested+0x16/0x20 [ 46.204655] mon_bin_vma_fault+0x6f/0x280 [ 46.208788] __do_fault+0x104/0x390 [ 46.212390] ? trace_hardirqs_on+0x10/0x10 [ 46.216604] __handle_mm_fault+0x2460/0x3470 [ 46.220990] ? vm_insert_mixed_mkwrite+0x40/0x40 [ 46.225727] ? find_held_lock+0x35/0x130 [ 46.229763] ? handle_mm_fault+0x1b6/0x7c0 [ 46.233974] handle_mm_fault+0x293/0x7c0 [ 46.238010] __get_user_pages+0x465/0x1220 [ 46.242220] ? follow_page_mask+0x1560/0x1560 [ 46.246711] ? memset+0x32/0x40 [ 46.249983] populate_vma_page_range+0x18e/0x230 [ 46.254717] __mm_populate+0x198/0x2c0 [ 46.258582] ? populate_vma_page_range+0x230/0x230 [ 46.263505] vm_mmap_pgoff+0x1be/0x1d0 [ 46.267386] ? vma_is_stack_for_current+0xa0/0xa0 [ 46.272212] ? __fget+0x237/0x370 [ 46.275660] SyS_mmap_pgoff+0x3ca/0x520 [ 46.279681] ? find_mergeable_anon_vma+0x2c0/0x2c0 [ 46.284592] ? do_syscall_64+0x53/0x640 [ 46.288543] ? align_vdso_addr+0x60/0x60 [ 46.292582] SyS_mmap+0x16/0x20 [ 46.295839] do_syscall_64+0x1e8/0x640 [ 46.299707] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 46.304527] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 46.309695] RIP: 0033:0x44a739 [ 46.312863] RSP: 002b:00007f6de595acd8 EFLAGS: 00000246 ORIG_RAX: 0000000000000009 [ 46.320601] RAX: ffffffffffffffda RBX: 00000000006dbc38 RCX: 000000000044a739 [ 46.327867] RDX: 0000000002000001 RSI: 0000000002000000 RDI: 0000000020ffd000 [ 46.335114] RBP: 00000000006dbc30 R08: 0000000000000005 R09: 0000000000000000 [ 46.342362] R10: 03eb6b06d1207692 R11: 0000000000000246 R12: 00000000006dbc3c [ 46.349616] R13: 00007fffafb3807f R14: 00007f6de595b9c0 R15: 20c49ba5e353f7cf executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program