[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 14.839741] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 19.026145] random: sshd: uninitialized urandom read (32 bytes read) [ 19.357741] random: sshd: uninitialized urandom read (32 bytes read) [ 20.278086] random: sshd: uninitialized urandom read (32 bytes read) [ 29.405489] random: sshd: uninitialized urandom read (32 bytes read) [ 34.848024] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.0.46' (ECDSA) to the list of known hosts. 2018/07/16 04:59:36 parsed 1 programs [ 36.415987] random: cc1: uninitialized urandom read (8 bytes read) 2018/07/16 04:59:38 executed programs: 0 [ 37.347765] IPVS: Creating netns size=2536 id=1 [ 37.487507] syz-executor0 (3808) used greatest stack depth: 23368 bytes left 2018/07/16 04:59:43 executed programs: 126 2018/07/16 04:59:48 executed programs: 248 [ 48.140253] random: crng init done 2018/07/16 04:59:53 executed programs: 377 2018/07/16 04:59:58 executed programs: 511 2018/07/16 05:00:03 executed programs: 644 [ 66.051117] ------------[ cut here ]------------ [ 66.056098] kernel BUG at fs/ext4/inode.c:2630! [ 66.062406] invalid opcode: 0000 [#1] PREEMPT SMP KASAN [ 66.067777] Dumping ftrace buffer: [ 66.071307] (ftrace buffer empty) [ 66.075032] Modules linked in: [ 66.078325] CPU: 1 PID: 6714 Comm: syz-executor0 Not tainted 4.9.112-g9e79039 #11 [ 66.085944] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 66.095294] task: ffff8801d3976000 task.stack: ffff8801d8a50000 [ 66.101328] RIP: 0010:[] [] mpage_prepare_extent_to_map+0x7f8/0xa40 [ 66.111081] RSP: 0018:ffff8801d8a577f0 EFLAGS: 00010293 [ 66.116527] RAX: ffff8801d3976000 RBX: ffffea0007125200 RCX: 0000000000000000 [ 66.123777] RDX: 0000000000000000 RSI: ffffffff81740088 RDI: ffffea0007125208 [ 66.131025] RBP: ffff8801d8a579b8 R08: ffff8801d3976938 R09: 0000000000000001 [ 66.138285] R10: 0000000000000000 R11: 1ffff1003a72ed22 R12: 0000000000000008 [ 66.145544] R13: 0000000000000000 R14: ffff8801d8a57b20 R15: dffffc0000000000 [ 66.152884] FS: 0000000000000000(0000) GS:ffff8801db300000(0063) knlGS:00000000084e0900 [ 66.161091] CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 [ 66.166959] CR2: 00007f3c3687c000 CR3: 00000001d6cea000 CR4: 00000000001606f0 [ 66.174210] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 66.181459] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 66.188703] Stack: [ 66.190828] 1ffff1003b14af0e ffff8801d8a57b28 ffff8801d8a57890 ffff8801d8a57b30 [ 66.198843] 00000000d39768c0 ffff8801c0161c30 000000020000000c 7fffffffffffffff [ 66.207048] ffff8801d8a578d0 ffff8801d8a57b38 ffffea0007125210 ffffed003b14af65 [ 66.215067] Call Trace: [ 66.217635] [] ? ext4_journalled_zero_new_buffers+0x3a0/0x3a0 [ 66.225161] [] ? __lock_is_held+0xa2/0xf0 [ 66.230936] [] ? __lock_is_held+0xa2/0xf0 [ 66.236713] [] ext4_writepages+0xdb9/0x2e50 [ 66.242661] [] ? do_writepages+0xef/0x1d0 [ 66.248434] [] ? ext4_mark_inode_dirty+0xb40/0xb40 [ 66.254995] [] ? debug_check_no_locks_freed+0x210/0x210 [ 66.261985] [] ? __lock_acquire+0x654/0x4070 [ 66.268020] [] ? __lock_acquire+0x654/0x4070 [ 66.274054] [] ? trace_hardirqs_on_caller+0x38b/0x590 [ 66.280880] [] ? ext4_mark_inode_dirty+0xb40/0xb40 [ 66.287450] [] do_writepages+0xef/0x1d0 [ 66.293058] [] ? page_writeback_cpu_online+0x20/0x20 [ 66.300320] [] ? trace_hardirqs_on_caller+0x38b/0x590 [ 66.307144] [] __filemap_fdatawrite_range+0x1b3/0x250 [ 66.313968] [] ? replace_page_cache_page+0x620/0x620 [ 66.320705] [] ? ext4_check_all_de+0xf0/0xf0 [ 66.326739] [] filemap_flush+0x23/0x30 [ 66.332254] [] ext4_alloc_da_blocks+0xd9/0x330 [ 66.338462] [] ext4_release_file+0x1ff/0x2e0 [ 66.344513] [] __fput+0x263/0x700 [ 66.349589] [] ____fput+0x15/0x20 [ 66.354684] [] task_work_run+0x10c/0x180 [ 66.360377] [] exit_to_usermode_loop+0xfc/0x120 [ 66.366681] [] do_fast_syscall_32+0x5c3/0x870 [ 66.372800] [] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 66.379451] [] entry_SYSENTER_compat+0x90/0xa2 [ 66.385662] Code: ff 48 8b 75 d0 65 48 33 34 25 28 00 00 00 0f 85 50 02 00 00 48 81 c4 a0 01 00 00 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 e8 e9 c1 ff <0f> 0b e8 e1 e9 c1 ff 8b 95 18 ff ff ff 85 d2 75 7a e8 d2 e9 c1 [ 66.412604] RIP [] mpage_prepare_extent_to_map+0x7f8/0xa40 [ 66.419982] RSP [ 66.423931] ---[ end trace 06bcbc3f18199d83 ]--- [ 66.428699] Kernel panic - not syncing: Fatal exception [ 66.434649] Dumping ftrace buffer: [ 66.438179] (ftrace buffer empty) [ 66.441873] Kernel Offset: disabled [ 66.445485] Rebooting in 86400 seconds..