[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 19.412258] random: sshd: uninitialized urandom read (32 bytes read, 32 bits of entropy available) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 26.112367] random: sshd: uninitialized urandom read (32 bytes read, 38 bits of entropy available) [ 26.362400] random: sshd: uninitialized urandom read (32 bytes read, 38 bits of entropy available) [ 27.556587] random: sshd: uninitialized urandom read (32 bytes read, 100 bits of entropy available) [ 72.851850] random: sshd: uninitialized urandom read (32 bytes read, 119 bits of entropy available) Warning: Permanently added '10.128.0.53' (ECDSA) to the list of known hosts. [ 78.332988] random: sshd: uninitialized urandom read (32 bytes read, 123 bits of entropy available) 2018/07/16 04:58:07 parsed 1 programs [ 79.886800] random: cc1: uninitialized urandom read (8 bytes read, 126 bits of entropy available) [ 80.738040] random: nonblocking pool is initialized 2018/07/16 04:58:09 executed programs: 0 [ 80.944521] IPVS: Creating netns size=2552 id=1 [ 81.134404] syz-executor0 (3914) used greatest stack depth: 23424 bytes left [ 81.782511] syz-executor0 (3962) used greatest stack depth: 23120 bytes left 2018/07/16 04:58:14 executed programs: 102 [ 86.054287] ------------[ cut here ]------------ [ 86.059055] kernel BUG at fs/ext4/inode.c:2474! [ 86.063695] invalid opcode: 0000 [#1] PREEMPT SMP KASAN [ 86.069519] Dumping ftrace buffer: [ 86.073038] (ftrace buffer empty) [ 86.076720] Modules linked in: [ 86.080003] CPU: 0 PID: 4323 Comm: syz-executor0 Not tainted 4.4.140-ged9bdc8 #4 [ 86.087511] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 86.096846] task: ffff8801d3f99800 task.stack: ffff8800b64a0000 [ 86.102881] RIP: 0010:[] [] mpage_prepare_extent_to_map+0x74f/0x970 [ 86.112599] RSP: 0018:ffff8800b64a77e0 EFLAGS: 00010293 [ 86.118018] RAX: ffff8801d3f99800 RBX: ffffea00070ae100 RCX: 0000000000000000 [ 86.125266] RDX: 0000000000000000 RSI: ffffffff816d7fcf RDI: ffffea00070ae108 [ 86.132506] RBP: ffff8800b64a79a8 R08: ffff8801d3f9a128 R09: 0000000000000001 [ 86.139750] R10: 0000000000000000 R11: ffff8801d3f99800 R12: 0000000000000001 [ 86.147002] R13: 0000000000000000 R14: ffff8800b64a7af0 R15: dffffc0000000000 [ 86.154255] FS: 0000000000000000(0000) GS:ffff8801db200000(0063) knlGS:000000000892e900 [ 86.162454] CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 [ 86.168306] CR2: 000000000814b009 CR3: 00000000b754c000 CR4: 00000000001606f0 [ 86.175551] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 86.182793] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 86.190035] Stack: [ 86.192155] ffff8800b64a7908 1ffff10016c94f0c ffff8800b64a7af8 ffff8800b64a7880 [ 86.200143] ffff8800b64a7b00 00000000d3473c68 ffff8800ab5653d8 000000090000000c [ 86.208111] 7fffffffffffffff ffff8800b64a78c0 ffff8800b64a7b08 ffffea00070ae110 [ 86.216104] Call Trace: [ 86.218688] [] ? ext4_journalled_zero_new_buffers+0x350/0x350 [ 86.226198] [] ? __lock_is_held+0xa2/0xf0 [ 86.231977] [] ? __lock_is_held+0xa2/0xf0 [ 86.237750] [] ext4_writepages+0xbb0/0x2c80 [ 86.243693] [] ? ext4_mark_inode_dirty+0xb80/0xb80 [ 86.250254] [] ? debug_check_no_locks_freed+0x210/0x210 [ 86.257237] [] ? __lock_acquire+0xa86/0x5270 [ 86.263267] [] ? trace_hardirqs_on_caller+0x38b/0x590 [ 86.270081] [] ? ext4_mark_inode_dirty+0xb80/0xb80 [ 86.276639] [] do_writepages+0xef/0x1d0 [ 86.282232] [] ? ratelimit_handler+0x50/0x50 [ 86.288280] [] __filemap_fdatawrite_range+0x1b3/0x250 [ 86.295090] [] ? replace_page_cache_page+0x440/0x440 [ 86.301813] [] ? ext4_check_all_de+0xf0/0xf0 [ 86.307840] [] filemap_flush+0x23/0x30 [ 86.313352] [] ext4_alloc_da_blocks+0x108/0x3c0 [ 86.319641] [] ? ext4_check_all_de+0xf0/0xf0 [ 86.325685] [] ext4_release_file+0x1ff/0x2e0 [ 86.331724] [] __fput+0x235/0x6f0 [ 86.336804] [] ____fput+0x15/0x20 [ 86.341880] [] task_work_run+0x10f/0x190 [ 86.347561] [] exit_to_usermode_loop+0x13d/0x160 [ 86.353936] [] do_fast_syscall_32+0x620/0x8b0 [ 86.360052] [] sysenter_flags_fixed+0xd/0x17 [ 86.366078] Code: ff 48 8b 75 d0 65 48 33 34 25 28 00 00 00 0f 85 2e 02 00 00 48 81 c4 a0 01 00 00 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 21 95 c7 ff <0f> 0b e8 1a 95 c7 ff 8b 95 18 ff ff ff 85 d2 75 7f e8 0b 95 c7 [ 86.392828] RIP [] mpage_prepare_extent_to_map+0x74f/0x970 [ 86.400195] RSP [ 86.404243] ---[ end trace ab4668f08f63fb58 ]--- [ 86.409068] Kernel panic - not syncing: Fatal exception [ 86.414832] Dumping ftrace buffer: [ 86.418339] (ftrace buffer empty) [ 86.422029] Kernel Offset: disabled [ 86.425628] Rebooting in 86400 seconds..