[....] Starting file context maintaining daemon: restorecond[?25l[?1c7[[[ 15.911114] random: sshd: uninitialized urandom read (32 bytes read, 32 bits of entropy available) 32m ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 21.782784] random: sshd: uninitialized urandom read (32 bytes read, 37 bits of entropy available) [ 22.352059] random: sshd: uninitialized urandom read (32 bytes read, 37 bits of entropy available) [ 23.212702] random: sshd: uninitialized urandom read (32 bytes read, 100 bits of entropy available) [ 23.384327] random: sshd: uninitialized urandom read (32 bytes read, 104 bits of entropy available) Warning: Permanently added '10.128.0.16' (ECDSA) to the list of known hosts. [ 28.851234] random: sshd: uninitialized urandom read (32 bytes read, 114 bits of entropy available) executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 28.976864] [ 28.978524] ====================================================== [ 28.984808] [ INFO: possible circular locking dependency detected ] [ 28.991185] 4.4.112-g5f6325b #28 Not tainted [ 28.995556] ------------------------------------------------------- [ 29.001933] syzkaller714645/3318 is trying to acquire lock: [ 29.007610] (&sb->s_type->i_mutex_key#10){+.+.+.}, at: [] shmem_file_llseek+0xf1/0x240 [ 29.017865] [ 29.017865] but task is already holding lock: [ 29.023808] (ashmem_mutex){+.+.+.}, at: [] ashmem_llseek+0x56/0x1f0 [ 29.032294] [ 29.032294] which lock already depends on the new lock. [ 29.032294] [ 29.040575] [ 29.040575] the existing dependency chain (in reverse order) is: [ 29.048164] -> #2 (ashmem_mutex){+.+.+.}: [ 29.052915] [] lock_acquire+0x15e/0x460 [ 29.059140] [] mutex_lock_nested+0xbb/0x850 [ 29.065724] [] ashmem_mmap+0x53/0x400 [ 29.071786] [] mmap_region+0x94f/0x1250 [ 29.078016] [] do_mmap+0x4fd/0x9d0 [ 29.083808] [] vm_mmap_pgoff+0x16e/0x1c0 [ 29.090128] [] SyS_mmap_pgoff+0x33f/0x560 [ 29.096527] [] SyS_mmap+0x16/0x20 [ 29.102235] [] entry_SYSCALL_64_fastpath+0x16/0x92 [ 29.109422] -> #1 (&mm->mmap_sem){++++++}: [ 29.114257] [] lock_acquire+0x15e/0x460 [ 29.120485] [] __might_fault+0x14a/0x1d0 [ 29.126796] [] filldir+0x162/0x2d0 [ 29.132588] [] dcache_readdir+0x11e/0x7b0 [ 29.138992] [] iterate_dir+0x1c8/0x420 [ 29.145132] [] SyS_getdents+0x14a/0x270 [ 29.151357] [] entry_SYSCALL_64_fastpath+0x16/0x92 [ 29.158538] -> #0 (&sb->s_type->i_mutex_key#10){+.+.+.}: [ 29.164695] [] __lock_acquire+0x371f/0x4b50 [ 29.171266] [] lock_acquire+0x15e/0x460 [ 29.177495] [] mutex_lock_nested+0xbb/0x850 [ 29.184069] [] shmem_file_llseek+0xf1/0x240 [ 29.190645] [] vfs_llseek+0xa2/0xd0 [ 29.196525] [] ashmem_llseek+0xe7/0x1f0 [ 29.202750] [] SyS_lseek+0xeb/0x170 [ 29.208632] [] entry_SYSCALL_64_fastpath+0x16/0x92 [ 29.215816] [ 29.215816] other info that might help us debug this: [ 29.215816] [ 29.223923] Chain exists of: &sb->s_type->i_mutex_key#10 --> &mm->mmap_sem --> ashmem_mutex [ 29.233622] Possible unsafe locking scenario: [ 29.233622] [ 29.239645] CPU0 CPU1 [ 29.244296] ---- ---- [ 29.248938] lock(ashmem_mutex); [ 29.252592] lock(&mm->mmap_sem); [ 29.258849] lock(ashmem_mutex); [ 29.265015] lock(&sb->s_type->i_mutex_key#10); [ 29.270093] [ 29.270093] *** DEADLOCK *** [ 29.270093] [ 29.276121] 1 lock held by syzkaller714645/3318: [ 29.280844] #0: (ashmem_mutex){+.+.+.}, at: [] ashmem_llseek+0x56/0x1f0 [ 29.289882] [ 29.289882] stack backtrace: [ 29.294346] CPU: 1 PID: 3318 Comm: syzkaller714645 Not tainted 4.4.112-g5f6325b #28 [ 29.302103] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 29.311427] 0000000000000000 85750f6d4fcb2036 ffff8800b423fad8 ffffffff81d0579d [ 29.319384] ffffffff8519e370 ffffffff851a8060 ffffffff851bc970 ffff8800b537cfd8 [ 29.327345] ffff8800b537c740 ffff8800b423fb20 ffffffff81232c31 ffff8800b537cfd8 [ 29.335304] Call Trace: [ 29.337865] [] dump_stack+0xc1/0x124 [ 29.343199] [] print_circular_bug+0x271/0x310 [ 29.349318] [] __lock_acquire+0x371f/0x4b50 [ 29.355257] [] ? debug_check_no_locks_freed+0x2c0/0x2c0 [ 29.362236] [] ? do_futex+0x3e3/0x1670 [ 29.367743] [] ? __lock_is_held+0xa1/0xf0 [ 29.373512] [] lock_acquire+0x15e/0x460 [ 29.379106] [] ? shmem_file_llseek+0xf1/0x240 [ 29.385216] [] ? shmem_file_llseek+0xf1/0x240 [ 29.391338] [] mutex_lock_nested+0xbb/0x850 [ 29.397282] [] ? shmem_file_llseek+0xf1/0x240 [ 29.403395] [] ? mutex_lock_nested+0x5d4/0x850 [ 29.409607] [] ? __ww_mutex_lock+0x14f0/0x14f0 [ 29.415807] [] ? mutex_lock_nested+0x560/0x850 [ 29.422006] [] ? ashmem_llseek+0x56/0x1f0 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 29.427774] [] shmem_file_llseek+0xf1/0x240 [ 29.433713] [] ? shmem_mmap+0x90/0x90 [ 29.439131] [] vfs_llseek+0xa2/0xd0 [ 29.444373] [] ashmem_llseek+0xe7/0x1f0 [ 29.449961] [] ? ashmem_read+0x200/0x200 [ 29.455640] [] SyS_lseek+0xeb/0x170 [ 29.460883] [] entry_SYSCALL_64_fastpath+0x16/0x92 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 31.021767] random: nonblocking pool is initialized executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program