[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 15.644160] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 21.421685] random: sshd: uninitialized urandom read (32 bytes read) [ 22.077696] random: sshd: uninitialized urandom read (32 bytes read) [ 22.822611] random: sshd: uninitialized urandom read (32 bytes read) [ 52.022773] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.0.40' (ECDSA) to the list of known hosts. [ 57.480753] random: sshd: uninitialized urandom read (32 bytes read) executing program [ 57.569225] IPVS: Creating netns size=2536 id=1 executing program [ 57.641735] syz-executor172 (3826) used greatest stack depth: 23448 bytes left executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 64.317643] ------------[ cut here ]------------ [ 64.322423] kernel BUG at fs/ext4/inode.c:2630! [ 64.327070] invalid opcode: 0000 [#1] PREEMPT SMP KASAN [ 64.332409] Dumping ftrace buffer: [ 64.335919] (ftrace buffer empty) [ 64.339603] Modules linked in: [ 64.342884] CPU: 0 PID: 4270 Comm: syz-executor172 Not tainted 4.9.100-ge14d1a3 #27 [ 64.351189] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 64.360555] task: ffff8801d90dc800 task.stack: ffff8801b6350000 [ 64.366841] RIP: 0010:[] [] mpage_prepare_extent_to_map+0x7f8/0xa40 [ 64.376572] RSP: 0018:ffff8801b63573c0 EFLAGS: 00010293 [ 64.382014] RAX: ffff8801d90dc800 RBX: ffffea0006f19a80 RCX: 0000000000000000 [ 64.389254] RDX: 0000000000000000 RSI: ffffffff8173cde8 RDI: ffffea0006f19a88 [ 64.396495] RBP: ffff8801b6357588 R08: ffff8801d90dd138 R09: 0000000000000001 [ 64.403839] R10: 0000000000000000 R11: 1ffff1003b21ba22 R12: 0000000000000009 [ 64.411086] R13: 0000000000000000 R14: ffff8801b63576f0 R15: dffffc0000000000 [ 64.418328] FS: 0000000000000000(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000 [ 64.426531] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 64.432383] CR2: 00007f9f07c21e78 CR3: 000000000461e000 CR4: 00000000001606f0 [ 64.439626] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 64.446868] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 64.454106] Stack: [ 64.456231] 1ffff10036c6ae88 ffff8801b63576f8 ffff8801b6357460 ffff8801b6357700 [ 64.464210] 00000000d90dd0c0 ffff8801b6f37538 000000010000000c 7fffffffffffffff [ 64.472188] ffff8801b63574a0 ffff8801b6357708 ffffea0006f19a90 ffffed0036c6aedf [ 64.480192] Call Trace: [ 64.482771] [] ? ext4_journalled_zero_new_buffers+0x3a0/0x3a0 [ 64.490296] [] ? __lock_is_held+0xa2/0xf0 [ 64.496068] [] ? __lock_is_held+0xa2/0xf0 [ 64.501840] [] ext4_writepages+0xdb9/0x2e50 [ 64.507798] [] ? do_writepages+0xef/0x1d0 [ 64.513579] [] ? __unwind_start+0x14d/0x3c0 [ 64.519523] [] ? unwind_next_frame+0x86/0xe0 [ 64.525552] [] ? ext4_mark_inode_dirty+0xb40/0xb40 [ 64.532103] [] ? __unwind_start+0x14d/0x3c0 [ 64.538056] [] ? depot_save_stack+0x132/0x460 [ 64.544180] [] ? ext4_mark_inode_dirty+0xb40/0xb40 [ 64.550733] [] do_writepages+0xef/0x1d0 [ 64.556327] [] ? page_writeback_cpu_online+0x20/0x20 [ 64.563051] [] ? exit_fs+0xe9/0x120 [ 64.568296] [] ? do_exit+0x9bb/0x27c0 [ 64.573725] [] ? do_group_exit+0x111/0x340 [ 64.579590] [] ? get_signal+0x4cf/0x1450 [ 64.585276] [] ? do_signal+0x87/0x19f0 [ 64.590798] [] ? exit_to_usermode_loop+0xe1/0x120 [ 64.597271] [] ? do_syscall_64+0x364/0x490 [ 64.603127] [] ? entry_SYSCALL_64_after_swapgs+0x5d/0xdb [ 64.610204] [] __filemap_fdatawrite_range+0x1b3/0x250 [ 64.617027] [] ? replace_page_cache_page+0x620/0x620 [ 64.623760] [] ? ext4_check_all_de+0xf0/0xf0 [ 64.629790] [] filemap_flush+0x23/0x30 [ 64.635296] [] ext4_alloc_da_blocks+0xd9/0x330 [ 64.641496] [] ext4_release_file+0x1ff/0x2e0 [ 64.647523] [] __fput+0x263/0x700 [ 64.652597] [] ____fput+0x15/0x20 [ 64.657670] [] task_work_run+0x10c/0x180 [ 64.663353] [] do_exit+0x9e1/0x27c0 [ 64.668600] [] ? debug_check_no_locks_freed+0x210/0x210 [ 64.675586] [] ? release_task.part.19+0x1210/0x1210 [ 64.682384] [] ? generic_file_read_iter+0x487/0x1a90 [ 64.689107] [] ? recalc_sigpending+0x72/0x90 [ 64.695140] [] do_group_exit+0x111/0x340 [ 64.700823] [] get_signal+0x4cf/0x1450 [ 64.706339] [] do_signal+0x87/0x19f0 [ 64.711677] [] ? __fsnotify_update_child_dentry_flags.part.1+0x300/0x300 [ 64.720162] [] ? selinux_file_permission+0x82/0x470 [ 64.726807] [] ? setup_sigcontext+0x7d0/0x7d0 [ 64.732928] [] ? do_futex+0x1770/0x1770 [ 64.738526] [] ? SyS_pread64+0xe8/0x170 [ 64.744121] [] ? exit_to_usermode_loop+0xac/0x120 [ 64.750600] [] exit_to_usermode_loop+0xe1/0x120 [ 64.756907] [] do_syscall_64+0x364/0x490 [ 64.762601] [] entry_SYSCALL_64_after_swapgs+0x5d/0xdb [ 64.769498] 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 18 fc c1 ff <0f> 0b e8 11 fc c1 ff 8b 95 18 ff ff ff 85 d2 75 7a e8 02 fc c1 [ 64.796486] RIP [] mpage_prepare_extent_to_map+0x7f8/0xa40 [ 64.803864] RSP [ 64.808276] ---[ end trace d5cdce8e0c2c007b ]--- [ 64.813065] Kernel panic - not syncing: Fatal exception [ 64.818790] Dumping ftrace buffer: [ 64.822303] (ftrace buffer empty) [ 64.825984] Kernel Offset: disabled [ 64.829601] Rebooting in 86400 seconds..