[....] Starting OpenBSD Secure Shell server: sshd[ 11.841069] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 27.518003] random: sshd: uninitialized urandom read (32 bytes read) [ 27.951176] audit: type=1400 audit(1549216895.840:6): avc: denied { map } for pid=1776 comm="bash" path="/bin/bash" dev="sda1" ino=1457 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 [ 27.986764] random: sshd: uninitialized urandom read (32 bytes read) [ 28.444290] random: sshd: uninitialized urandom read (32 bytes read) [ 28.592492] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.0.133' (ECDSA) to the list of known hosts. [ 34.119116] random: sshd: uninitialized urandom read (32 bytes read) executing program executing program executing program executing program executing program executing program [ 34.206200] audit: type=1400 audit(1549216902.090:7): avc: denied { map } for pid=1794 comm="syz-executor992" path="/root/syz-executor992209004" dev="sda1" ino=16481 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1 [ 34.257163] audit: type=1400 audit(1549216902.120:8): avc: denied { map } for pid=1799 comm="syz-executor992" path="/dev/ashmem" dev="devtmpfs" ino=5422 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=system_u:object_r:device_t:s0 tclass=chr_file permissive=1 [ 34.298040] [ 34.299695] ====================================================== [ 34.306010] WARNING: possible circular locking dependency detected [ 34.312323] 4.14.97+ #1 Not tainted [ 34.315940] ------------------------------------------------------ [ 34.322252] syz-executor992/1812 is trying to acquire lock: [ 34.327966] (&mm->mmap_sem){++++}, at: [] __do_page_fault+0x871/0xb80 [ 34.336206] [ 34.336206] but task is already holding lock: [ 34.342176] (&sb->s_type->i_mutex_key#10){+.+.}, at: [] generic_file_write_iter+0x99/0x650 [ 34.352247] [ 34.352247] which lock already depends on the new lock. [ 34.352247] [ 34.360554] [ 34.360554] the existing dependency chain (in reverse order) is: [ 34.368167] [ 34.368167] -> #2 (&sb->s_type->i_mutex_key#10){+.+.}: [ 34.374921] [ 34.374921] -> #1 (ashmem_mutex){+.+.}: [ 34.380372] [ 34.380372] -> #0 (&mm->mmap_sem){++++}: [ 34.385909] [ 34.385909] other info that might help us debug this: [ 34.385909] [ 34.394043] Chain exists of: executing program [ 34.394043] &mm->mmap_sem --> ashmem_mutex --> &sb->s_type->i_mutex_key#10 [ 34.394043] [ 34.405580] Possible unsafe locking scenario: [ 34.405580] [ 34.411640] CPU0 CPU1 [ 34.416304] ---- ---- [ 34.420961] lock(&sb->s_type->i_mutex_key#10); [ 34.425715] lock(ashmem_mutex); [ 34.431682] lock(&sb->s_type->i_mutex_key#10); [ 34.439057] lock(&mm->mmap_sem); [ 34.442679] [ 34.442679] *** DEADLOCK *** [ 34.442679] executing program executing program [ 34.448730] 2 locks held by syz-executor992/1812: [ 34.453558] #0: (sb_writers#6){.+.+}, at: [] vfs_write+0x3d8/0x4d0 [ 34.461623] #1: (&sb->s_type->i_mutex_key#10){+.+.}, at: [] generic_file_write_iter+0x99/0x650 [ 34.472133] [ 34.472133] stack backtrace: [ 34.476631] CPU: 0 PID: 1812 Comm: syz-executor992 Not tainted 4.14.97+ #1 [ 34.483637] Call Trace: [ 34.486229] dump_stack+0xb9/0x10e [ 34.489769] print_circular_bug.isra.0.cold+0x2dc/0x425 [ 34.495132] ? __lock_acquire+0x2d83/0x3fa0 [ 34.499457] ? trace_hardirqs_on+0x10/0x10 [ 34.503698] ? trace_hardirqs_on+0x10/0x10 [ 34.507927] ? cmp_ex_search+0x71/0x90 [ 34.511806] ? bsearch+0x87/0xa0 [ 34.515162] ? lock_acquire+0x10f/0x380 [ 34.519131] ? __do_page_fault+0x871/0xb80 [ 34.523365] ? down_read+0x37/0xa0 [ 34.526896] ? __do_page_fault+0x871/0xb80 [ 34.531562] ? __do_page_fault+0x871/0xb80 [ 34.535972] ? mark_held_locks+0xa6/0xf0 [ 34.540046] ? bad_area_access_error+0x340/0x340 executing program executing program [ 34.544790] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 34.549624] ? page_fault+0x22/0x50 [ 34.553245] ? iov_iter_fault_in_readable+0x29c/0x350 [ 34.558437] ? iov_iter_fault_in_readable+0x296/0x350 [ 34.563627] ? iov_iter_init+0x1c0/0x1c0 [ 34.567773] ? generic_perform_write+0x158/0x450 [ 34.572528] ? filemap_page_mkwrite+0x2d0/0x2d0 [ 34.577200] ? current_time+0xb0/0xb0 [ 34.581012] ? lock_acquire+0x10f/0x380 [ 34.584986] ? __generic_file_write_iter+0x32e/0x550 [ 34.590089] ? generic_file_write_iter+0x36f/0x650 [ 34.595019] ? iov_iter_init+0xa6/0x1c0 [ 34.598992] ? __vfs_write+0x401/0x5a0 [ 34.602877] ? kernel_read+0x110/0x110 [ 34.606861] ? rcu_lockdep_current_cpu_online+0xed/0x140 [ 34.612310] ? rcu_read_lock_sched_held+0x10a/0x130 [ 34.617323] ? vfs_write+0x17f/0x4d0 [ 34.621033] ? SyS_write+0xc0/0x1a0 [ 34.624781] ? SyS_read+0x1a0/0x1a0 [ 34.628400] ? SyS_memfd_create+0x2a0/0x310 [ 34.633064] ? kfree+0xf5/0x310 [ 34.636337] ? do_syscall_64+0x43/0x4b0 [ 34.640307] ? SyS_read+0x1a0/0x1a0 [ 34.643945] ? do_syscall_64+0x19b/0x4b0 executing program executing program executing program executing program executing program executing program [ 34.648006] ? entry_SYSCALL_64_after_hwframe+0x42/0xb7 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program