[....] Starting file context maintaining daemon: restorecond[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 27.999333] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. [ 28.256646] random: sshd: uninitialized urandom read (32 bytes read) [ 28.497849] random: sshd: uninitialized urandom read (32 bytes read) [ 29.035371] random: sshd: uninitialized urandom read (32 bytes read) Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 35.803173] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.10.55' (ECDSA) to the list of known hosts. [ 41.409515] random: sshd: uninitialized urandom read (32 bytes read) [ 41.521617] kauditd_printk_skb: 10 callbacks suppressed [ 41.521625] audit: type=1400 audit(1571647750.698:36): avc: denied { map } for pid=6825 comm="syz-executor083" path="/root/syz-executor083339609" dev="sda1" ino=16483 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1 [ 41.790910] IPVS: ftp: loaded support on port[0] = 21 executing program [ 42.606500] audit: type=1400 audit(1571647751.778:37): avc: denied { map } for pid=6826 comm="syz-executor083" path="/dev/usbmon0" dev="devtmpfs" ino=14994 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 [ 42.766638] [ 42.768429] ====================================================== [ 42.774738] WARNING: possible circular locking dependency detected [ 42.781036] 4.14.150 #0 Not tainted [ 42.784637] ------------------------------------------------------ [ 42.790954] syz-executor083/6827 is trying to acquire lock: [ 42.796639] (&mm->mmap_sem){++++}, at: [] __might_fault+0xe0/0x1d0 [ 42.804729] [ 42.804729] but task is already holding lock: [ 42.810674] (&rp->fetch_lock){+.+.}, at: [] mon_bin_get_event+0x3c/0x430 [ 42.819250] [ 42.819250] which lock already depends on the new lock. [ 42.819250] [ 42.827540] [ 42.827540] the existing dependency chain (in reverse order) is: [ 42.835137] [ 42.835137] -> #1 (&rp->fetch_lock){+.+.}: [ 42.840846] lock_acquire+0x16f/0x430 [ 42.845167] __mutex_lock+0xe8/0x1470 [ 42.849462] mutex_lock_nested+0x16/0x20 [ 42.854025] mon_bin_vma_fault+0x6f/0x280 [ 42.858673] __do_fault+0x104/0x390 [ 42.862796] __handle_mm_fault+0xde1/0x3470 [ 42.867611] handle_mm_fault+0x293/0x7c0 [ 42.872169] __get_user_pages+0x465/0x1220 [ 42.876916] populate_vma_page_range+0x18e/0x230 [ 42.882344] __mm_populate+0x198/0x2c0 [ 42.886749] vm_mmap_pgoff+0x1be/0x1d0 [ 42.891160] SyS_mmap_pgoff+0x3ca/0x520 [ 42.896676] SyS_mmap+0x16/0x20 [ 42.900457] do_syscall_64+0x1e8/0x640 [ 42.904842] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 42.910536] [ 42.910536] -> #0 (&mm->mmap_sem){++++}: [ 42.916056] __lock_acquire+0x2cb3/0x4620 [ 42.920700] lock_acquire+0x16f/0x430 [ 42.924998] __might_fault+0x143/0x1d0 [ 42.929436] _copy_to_user+0x2c/0xd0 [ 42.933660] mon_bin_get_event+0x10a/0x430 [ 42.938436] mon_bin_ioctl+0x9b4/0xb50 [ 42.942826] do_vfs_ioctl+0x7ae/0x1060 [ 42.947212] SyS_ioctl+0x8f/0xc0 [ 42.951076] do_syscall_64+0x1e8/0x640 [ 42.955461] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 42.961162] [ 42.961162] other info that might help us debug this: [ 42.961162] [ 42.969278] Possible unsafe locking scenario: [ 42.969278] [ 42.975310] CPU0 CPU1 [ 42.979950] ---- ---- [ 42.984590] lock(&rp->fetch_lock); [ 42.988292] lock(&mm->mmap_sem); [ 42.994340] lock(&rp->fetch_lock); [ 43.000558] lock(&mm->mmap_sem); [ 43.004080] [ 43.004080] *** DEADLOCK *** [ 43.004080] [ 43.010123] 1 lock held by syz-executor083/6827: [ 43.014851] #0: (&rp->fetch_lock){+.+.}, at: [] mon_bin_get_event+0x3c/0x430 [ 43.023761] [ 43.023761] stack backtrace: [ 43.028232] CPU: 0 PID: 6827 Comm: syz-executor083 Not tainted 4.14.150 #0 [ 43.035220] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 43.044554] Call Trace: [ 43.047128] dump_stack+0x138/0x197 [ 43.050734] print_circular_bug.isra.0.cold+0x1cc/0x28f [ 43.056162] __lock_acquire+0x2cb3/0x4620 [ 43.060285] ? remove_wait_queue+0x10f/0x190 [ 43.064672] ? trace_hardirqs_on+0x10/0x10 [ 43.068885] lock_acquire+0x16f/0x430 [ 43.072677] ? __might_fault+0xe0/0x1d0 [ 43.076629] __might_fault+0x143/0x1d0 [ 43.080494] ? __might_fault+0xe0/0x1d0 [ 43.084447] _copy_to_user+0x2c/0xd0 [ 43.088138] mon_bin_get_event+0x10a/0x430 [ 43.092351] mon_bin_ioctl+0x9b4/0xb50 [ 43.096215] ? mon_bin_read+0x5e0/0x5e0 [ 43.100168] ? __might_sleep+0x93/0xb0 [ 43.104050] ? __fget+0x210/0x370 [ 43.107480] ? mon_bin_read+0x5e0/0x5e0 [ 43.111431] do_vfs_ioctl+0x7ae/0x1060 [ 43.115295] ? selinux_file_mprotect+0x5d0/0x5d0 [ 43.120048] ? lock_downgrade+0x740/0x740 [ 43.124201] ? ioctl_preallocate+0x1c0/0x1c0 [ 43.128592] ? __fget+0x237/0x370 [ 43.132034] ? security_file_ioctl+0x7d/0xb0 [ 43.136438] ? security_file_ioctl+0x89/0xb0 [ 43.140833] SyS_ioctl+0x8f/0xc0 [ 43.144181] ? do_vfs_ioctl+0x1060/0x1060 [ 43.148310] do_syscall_64+0x1e8/0x640 [ 43.152176] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 43.157001] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 43.162167] RIP: 0033:0x44a209 [ 43.165335] RSP: 002b:00007f9826c50ce8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 43.173020] RAX: ffffffffffffffda RBX: 00000000006dcc28 RCX: 000000000044a209 [ 43.180268] RDX: 00000000200000c0 RSI: 0000000040189206 RDI: 0000000000000004 [ 43.187647] RBP: 00000000006dcc20 R08: 0000000000000000 R09: 0000000000000000 [ 43.194944] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dcc2c [ 43.202204] R13: 00007ffd110d4d8f R14: 00007f9826c519c0 R15: 0000000000000000