[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 12.748654] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 15.251727] random: sshd: uninitialized urandom read (32 bytes read) [ 15.509982] random: sshd: uninitialized urandom read (32 bytes read) [ 16.398092] random: sshd: uninitialized urandom read (32 bytes read) [ 33.653067] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.0.49' (ECDSA) to the list of known hosts. [ 39.076198] random: sshd: uninitialized urandom read (32 bytes read) executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 40.566243] ================================================================== [ 40.574609] BUG: KASAN: use-after-free in disk_unblock_events+0x51/0x60 [ 40.581334] Read of size 8 at addr ffff8801d98b62e0 by task syz-executor737/3882 [ 40.588838] [ 40.590441] CPU: 1 PID: 3882 Comm: syz-executor737 Not tainted 4.9.99-gc2f9bce #22 [ 40.598117] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 40.607446] ffff8801b6eef6d8 ffffffff81eb0f09 ffffea0007662c00 ffff8801d98b62e0 [ 40.615429] 0000000000000000 ffff8801d98b62e0 0000000000000000 ffff8801b6eef710 [ 40.623434] ffffffff815652eb ffff8801d98b62e0 0000000000000008 0000000000000000 [ 40.631414] Call Trace: [ 40.633977] [] dump_stack+0xc1/0x128 [ 40.639317] [] print_address_description+0x6c/0x234 [ 40.645956] [] kasan_report.cold.6+0x242/0x2fe [ 40.652164] [] ? disk_unblock_events+0x51/0x60 [ 40.658372] [] __asan_report_load8_noabort+0x14/0x20 [ 40.665110] [] disk_unblock_events+0x51/0x60 [ 40.671147] [] __blkdev_get+0x6b6/0xd60 [ 40.676759] [] ? __blkdev_put+0x840/0x840 [ 40.682546] [] ? fsnotify+0x114/0x1100 [ 40.688067] [] blkdev_get+0x2da/0x920 [ 40.693491] [] ? bd_may_claim+0xd0/0xd0 [ 40.699086] [] ? bd_acquire+0x27/0x250 [ 40.704612] [] ? bd_acquire+0x88/0x250 [ 40.710143] [] ? _raw_spin_unlock+0x2c/0x50 [ 40.716089] [] blkdev_open+0x1a5/0x250 [ 40.721599] [] do_dentry_open+0x703/0xc80 [ 40.727369] [] ? blkdev_get_by_dev+0x70/0x70 [ 40.733397] [] vfs_open+0x11c/0x210 [ 40.738650] [] ? may_open.isra.57+0x14f/0x2a0 [ 40.744766] [] path_openat+0x758/0x3590 [ 40.750368] [] ? save_stack+0xa9/0xd0 [ 40.755800] [] ? path_lookupat.isra.41+0x410/0x410 [ 40.762353] [] ? __lock_is_held+0xa2/0xf0 [ 40.768122] [] do_filp_open+0x197/0x270 [ 40.773718] [] ? may_open_dev+0xe0/0xe0 [ 40.779314] [] ? _raw_spin_unlock+0x2c/0x50 [ 40.785258] [] ? __alloc_fd+0x1d7/0x4a0 [ 40.790863] [] do_sys_open+0x30d/0x5c0 [ 40.796374] [] ? filp_open+0x70/0x70 [ 40.801711] [] ? up_read+0x1a/0x40 [ 40.806876] [] ? __do_page_fault+0x183/0xd50 [ 40.812903] [] SyS_open+0x2d/0x40 [ 40.817976] [] ? do_sys_open+0x5c0/0x5c0 [ 40.823659] [] do_syscall_64+0x1a6/0x490 [ 40.829355] [] entry_SYSCALL_64_after_swapgs+0x5d/0xdb [ 40.836255] [ 40.837871] Allocated by task 3882: [ 40.841474] save_stack_trace+0x16/0x20 [ 40.845420] save_stack+0x43/0xd0 [ 40.848850] kasan_kmalloc+0xc7/0xe0 [ 40.852537] kmem_cache_alloc_trace+0xfd/0x2b0 [ 40.857090] alloc_disk_node+0x54/0x3a0 [ 40.861035] alloc_disk+0x18/0x20 [ 40.864461] loop_add+0x33b/0x770 [ 40.867887] loop_probe+0x14f/0x180 [ 40.871486] kobj_lookup+0x223/0x410 [ 40.875173] get_gendisk+0x39/0x2d0 [ 40.878776] __blkdev_get+0x351/0xd60 [ 40.882550] blkdev_get+0x2da/0x920 [ 40.886149] blkdev_open+0x1a5/0x250 [ 40.889837] do_dentry_open+0x703/0xc80 [ 40.893784] vfs_open+0x11c/0x210 [ 40.897212] path_openat+0x758/0x3590 [ 40.900981] do_filp_open+0x197/0x270 [ 40.904752] do_sys_open+0x30d/0x5c0 [ 40.908434] SyS_open+0x2d/0x40 [ 40.911684] do_syscall_64+0x1a6/0x490 [ 40.915546] entry_SYSCALL_64_after_swapgs+0x5d/0xdb [ 40.920617] [ 40.922231] Freed by task 3882: [ 40.925486] save_stack_trace+0x16/0x20 [ 40.929431] save_stack+0x43/0xd0 [ 40.932855] kasan_slab_free+0x72/0xc0 [ 40.936717] kfree+0xfb/0x310 [ 40.939796] disk_release+0x259/0x330 [ 40.943571] device_release+0x7e/0x220 [ 40.947431] kobject_release+0x103/0x1b0 [ 40.951462] kobject_put+0x6d/0xd0 [ 40.954978] put_disk+0x23/0x30 [ 40.958232] __blkdev_get+0x616/0xd60 [ 40.962003] blkdev_get+0x2da/0x920 [ 40.965598] blkdev_open+0x1a5/0x250 [ 40.969284] do_dentry_open+0x703/0xc80 [ 40.973230] vfs_open+0x11c/0x210 [ 40.976655] path_openat+0x758/0x3590 [ 40.980427] do_filp_open+0x197/0x270 [ 40.984199] do_sys_open+0x30d/0x5c0 [ 40.987884] SyS_open+0x2d/0x40 [ 40.991136] do_syscall_64+0x1a6/0x490 [ 40.994993] entry_SYSCALL_64_after_swapgs+0x5d/0xdb [ 41.000066] [ 41.001666] The buggy address belongs to the object at ffff8801d98b5d80 [ 41.001666] which belongs to the cache kmalloc-2048 of size 2048 [ 41.014467] The buggy address is located 1376 bytes inside of [ 41.014467] 2048-byte region [ffff8801d98b5d80, ffff8801d98b6580) [ 41.026490] The buggy address belongs to the page: [ 41.031397] page:ffffea0007662c00 count:1 mapcount:0 mapping: (null) index:0x0 compound_mapcount: 0 [ 41.041580] flags: 0x8000000000004080(slab|head) [ 41.046307] page dumped because: kasan: bad access detected [ 41.051988] [ 41.053588] Memory state around the buggy address: [ 41.058503] ffff8801d98b6180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 41.065833] ffff8801d98b6200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 41.073164] >ffff8801d98b6280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 41.080494] ^ [ 41.086956] ffff8801d98b6300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 41.094285] ffff8801d98b6380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 41.101613] ================================================================== [ 41.108942] Disabling lock debugging due to kernel taint executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 41.117189] Kernel panic - not syncing: panic_on_warn set ... [ 41.117189] [ 41.124552] CPU: 1 PID: 3882 Comm: syz-executor737 Tainted: G B 4.9.99-gc2f9bce #22 [ 41.133446] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 41.142771] ffff8801b6eef638 ffffffff81eb0f09 ffffffff843c5065 00000000ffffffff [ 41.150761] 0000000000000000 0000000000000001 0000000000000000 ffff8801b6eef6f8 [ 41.158744] ffffffff8141f855 0000000041b58ab3 ffffffff843b8768 ffffffff8141f696 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 41.166730] Call Trace: [ 41.169290] [] dump_stack+0xc1/0x128 [ 41.174627] [] panic+0x1bf/0x3bc [ 41.179627] [] ? add_taint.cold.6+0x16/0x16 [ 41.185571] [] ? ___preempt_schedule+0x16/0x18 [ 41.191775] [] kasan_end_report+0x47/0x4f [ 41.197554] [] kasan_report.cold.6+0x76/0x2fe [ 41.203673] [] ? disk_unblock_events+0x51/0x60 [ 41.209876] [] __asan_report_load8_noabort+0x14/0x20 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 41.216600] [] disk_unblock_events+0x51/0x60 [ 41.222630] [] __blkdev_get+0x6b6/0xd60 [ 41.228228] [] ? __blkdev_put+0x840/0x840 [ 41.233999] [] ? fsnotify+0x114/0x1100 [ 41.239510] [] blkdev_get+0x2da/0x920 [ 41.244931] [] ? bd_may_claim+0xd0/0xd0 [ 41.250527] [] ? bd_acquire+0x27/0x250 [ 41.256039] [] ? bd_acquire+0x88/0x250 [ 41.261552] [] ? _raw_spin_unlock+0x2c/0x50 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 41.267495] [] blkdev_open+0x1a5/0x250 [ 41.273005] [] do_dentry_open+0x703/0xc80 [ 41.278777] [] ? blkdev_get_by_dev+0x70/0x70 [ 41.284808] [] vfs_open+0x11c/0x210 [ 41.290056] [] ? may_open.isra.57+0x14f/0x2a0 [ 41.296175] [] path_openat+0x758/0x3590 [ 41.301769] [] ? save_stack+0xa9/0xd0 [ 41.307192] [] ? path_lookupat.isra.41+0x410/0x410 [ 41.313746] [] ? __lock_is_held+0xa2/0xf0 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 41.319866] [] do_filp_open+0x197/0x270 [ 41.325462] [] ? may_open_dev+0xe0/0xe0 [ 41.331058] [] ? _raw_spin_unlock+0x2c/0x50 [ 41.337010] [] ? __alloc_fd+0x1d7/0x4a0 [ 41.342615] [] do_sys_open+0x30d/0x5c0 [ 41.348133] [] ? filp_open+0x70/0x70 [ 41.353470] [] ? up_read+0x1a/0x40 [ 41.358635] [] ? __do_page_fault+0x183/0xd50 [ 41.364665] [] SyS_open+0x2d/0x40 executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 41.369738] [] ? do_sys_open+0x5c0/0x5c0 [ 41.375420] [] do_syscall_64+0x1a6/0x490 [ 41.381113] [] entry_SYSCALL_64_after_swapgs+0x5d/0xdb [ 41.388401] Dumping ftrace buffer: [ 41.391913] (ftrace buffer empty) [ 41.395597] Kernel Offset: disabled [ 41.399200] Rebooting in 86400 seconds..