[ 17.012441] random: sshd: uninitialized urandom read (32 bytes read, 32 bits of entropy available) [....] Starting file context maintaining daemon: restorecond[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 20.855574] random: sshd: uninitialized urandom read (32 bytes read, 37 bits of entropy available) [ 21.212428] random: sshd: uninitialized urandom read (32 bytes read, 37 bits of entropy available) [ 21.892181] random: sshd: uninitialized urandom read (32 bytes read, 74 bits of entropy available) [ 22.066317] random: sshd: uninitialized urandom read (32 bytes read, 79 bits of entropy available) Warning: Permanently added '10.128.0.6' (ECDSA) to the list of known hosts. [ 27.447950] random: sshd: uninitialized urandom read (32 bytes read, 85 bits of entropy available) executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 27.577278] [ 27.578919] ====================================================== [ 27.585200] [ INFO: possible circular locking dependency detected ] [ 27.591569] 4.4.110-g618a510 #15 Not tainted [ 27.595941] ------------------------------------------------------- [ 27.602322] syzkaller415171/3320 is trying to acquire lock: [ 27.607993] (&sb->s_type->i_mutex_key#10){+.+.+.}, at: [] shmem_file_llseek+0xf1/0x240 [ 27.618224] [ 27.618224] but task is already holding lock: executing program [ 27.624159] (ashmem_mutex){+.+.+.}, at: [] ashmem_llseek+0x56/0x1f0 [ 27.632628] [ 27.632628] which lock already depends on the new lock. [ 27.632628] [ 27.640907] [ 27.640907] the existing dependency chain (in reverse order) is: [ 27.648491] -> #2 (ashmem_mutex){+.+.+.}: [ 27.653231] [] lock_acquire+0x15e/0x460 [ 27.659457] [] mutex_lock_nested+0xbb/0x850 [ 27.666025] [] ashmem_mmap+0x53/0x400 [ 27.672080] [] mmap_region+0x94f/0x1250 [ 27.678305] [] do_mmap+0x4fd/0x9d0 [ 27.684095] [] vm_mmap_pgoff+0x16e/0x1c0 [ 27.690407] [] SyS_mmap_pgoff+0x33f/0x560 [ 27.696804] [] do_fast_syscall_32+0x314/0x890 [ 27.703545] [] sysenter_flags_fixed+0xd/0x17 [ 27.710199] -> #1 (&mm->mmap_sem){++++++}: [ 27.715032] [] lock_acquire+0x15e/0x460 [ 27.721257] [] __might_fault+0x14a/0x1d0 [ 27.727565] [] filldir+0x162/0x2d0 [ 27.733353] [] dcache_readdir+0x11e/0x7b0 [ 27.739753] [] iterate_dir+0x1c8/0x420 [ 27.745885] [] SyS_getdents+0x14a/0x270 [ 27.752113] [] entry_SYSCALL_64_fastpath+0x16/0x92 [ 27.759294] -> #0 (&sb->s_type->i_mutex_key#10){+.+.+.}: [ 27.765447] [] __lock_acquire+0x371f/0x4b50 [ 27.772013] [] lock_acquire+0x15e/0x460 [ 27.778234] [] mutex_lock_nested+0xbb/0x850 [ 27.784802] [] shmem_file_llseek+0xf1/0x240 [ 27.791382] [] vfs_llseek+0xa2/0xd0 [ 27.797259] [] ashmem_llseek+0xe7/0x1f0 [ 27.803572] [] compat_SyS_lseek+0xeb/0x170 [ 27.810053] [] do_fast_syscall_32+0x314/0x890 [ 27.816811] [] sysenter_flags_fixed+0xd/0x17 [ 27.823471] [ 27.823471] other info that might help us debug this: [ 27.823471] [ 27.831581] Chain exists of: &sb->s_type->i_mutex_key#10 --> &mm->mmap_sem --> ashmem_mutex [ 27.841260] Possible unsafe locking scenario: [ 27.841260] [ 27.847285] CPU0 CPU1 [ 27.851929] ---- ---- [ 27.856558] lock(ashmem_mutex); [ 27.860199] lock(&mm->mmap_sem); [ 27.866445] lock(ashmem_mutex); [ 27.872601] lock(&sb->s_type->i_mutex_key#10); [ 27.877655] [ 27.877655] *** DEADLOCK *** [ 27.877655] [ 27.883678] 1 lock held by syzkaller415171/3320: [ 27.888394] #0: (ashmem_mutex){+.+.+.}, at: [] ashmem_llseek+0x56/0x1f0 [ 27.897416] [ 27.897416] stack backtrace: [ 27.901886] CPU: 1 PID: 3320 Comm: syzkaller415171 Not tainted 4.4.110-g618a510 #15 [ 27.909649] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 27.918971] 0000000000000000 1837b920fa41bc9d ffff8801d0a1fa58 ffffffff81d04e3d [ 27.926924] ffffffff8519d1c0 ffffffff851a6eb0 ffffffff851bada0 ffff8800b5496798 [ 27.934885] ffff8800b5495f00 ffff8801d0a1faa0 ffffffff81232af1 ffff8800b5496798 [ 27.942845] Call Trace: [ 27.945400] [] dump_stack+0xc1/0x124 [ 27.950730] [] print_circular_bug+0x271/0x310 [ 27.956838] [] __lock_acquire+0x371f/0x4b50 [ 27.962780] [] ? hash_futex+0x210/0x210 [ 27.968379] [] ? debug_check_no_locks_freed+0x2c0/0x2c0 [ 27.975358] [] ? do_futex+0x3e3/0x1670 [ 27.980862] [] ? __lock_is_held+0xa1/0xf0 [ 27.986625] [] lock_acquire+0x15e/0x460 [ 27.992214] [] ? shmem_file_llseek+0xf1/0x240 [ 27.998343] [] ? shmem_file_llseek+0xf1/0x240 [ 28.004465] [] mutex_lock_nested+0xbb/0x850 [ 28.010412] [] ? shmem_file_llseek+0xf1/0x240 [ 28.016527] [] ? mutex_lock_nested+0x5d4/0x850 [ 28.022733] [] ? __ww_mutex_lock+0x14f0/0x14f0 [ 28.028928] [] ? mutex_lock_nested+0x560/0x850 [ 28.035135] [] ? ashmem_llseek+0x56/0x1f0 [ 28.040913] [] shmem_file_llseek+0xf1/0x240 [ 28.046865] [] ? shmem_mmap+0x90/0x90 [ 28.052292] [] vfs_llseek+0xa2/0xd0 [ 28.057534] [] ashmem_llseek+0xe7/0x1f0 [ 28.063134] [] ? ashmem_read+0x200/0x200 [ 28.068997] [] compat_SyS_lseek+0xeb/0x170 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 28.074849] [] ? SyS_lseek+0x170/0x170 [ 28.080350] [] do_fast_syscall_32+0x314/0x890 [ 28.086464] [] sysenter_flags_fixed+0xd/0x17 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program