INIT: Entering runlevel: 2 [[36minfo[39;49m] Using makefile-style concurrent boot in runlevel 2. [....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. [....] Starting periodic command scheduler: cron[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added '10.128.0.25' (ECDSA) to the list of known hosts. executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program syzkaller login: [ 29.128953] ================================================================== [ 29.136380] BUG: KASAN: use-after-free in disk_unblock_events+0x51/0x60 [ 29.143133] Read of size 8 at addr ffff8801c52b0560 by task syzkaller136360/3926 [ 29.150654] [ 29.152278] CPU: 0 PID: 3926 Comm: syzkaller136360 Not tainted 4.9.95-gee0bcd6 #3 [ 29.159892] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 29.169242] ffff8801b7a5f6d8 ffffffff81eb0f89 ffffea000714ac00 ffff8801c52b0560 [ 29.177305] 0000000000000000 ffff8801c52b0560 0000000000000000 ffff8801b7a5f710 [ 29.185367] ffffffff815653cb ffff8801c52b0560 0000000000000008 0000000000000000 [ 29.193433] Call Trace: [ 29.196011] [] dump_stack+0xc1/0x128 [ 29.201377] [] print_address_description+0x6c/0x234 [ 29.208234] [] kasan_report.cold.6+0x242/0x2fe [ 29.214506] [] ? disk_unblock_events+0x51/0x60 [ 29.220743] [] __asan_report_load8_noabort+0x14/0x20 [ 29.227500] [] disk_unblock_events+0x51/0x60 [ 29.233580] [] __blkdev_get+0x6b6/0xd60 [ 29.239209] [] ? __blkdev_put+0x840/0x840 [ 29.245013] [] ? fsnotify+0x114/0x1100 [ 29.250553] [] blkdev_get+0x2da/0x920 [ 29.256005] [] ? bd_may_claim+0xd0/0xd0 [ 29.261628] [] ? bd_acquire+0x27/0x250 [ 29.267167] [] ? bd_acquire+0x88/0x250 [ 29.272709] [] ? _raw_spin_unlock+0x2c/0x50 [ 29.278687] [] blkdev_open+0x1a5/0x250 [ 29.284227] [] do_dentry_open+0x703/0xc80 [ 29.290033] [] ? blkdev_get_by_dev+0x70/0x70 [ 29.296120] [] vfs_open+0x11c/0x210 [ 29.301398] [] ? may_open.isra.57+0x14f/0x2a0 [ 29.307554] [] path_openat+0x758/0x3590 [ 29.313179] [] ? save_stack+0xa9/0xd0 [ 29.318632] [] ? path_lookupat.isra.41+0x410/0x410 [ 29.325215] [] ? __lock_is_held+0xa2/0xf0 [ 29.331106] [] do_filp_open+0x197/0x270 [ 29.336731] [] ? may_open_dev+0xe0/0xe0 [ 29.342360] [] ? _raw_spin_unlock+0x2c/0x50 [ 29.348333] [] ? __alloc_fd+0x1d7/0x4a0 [ 29.353957] [] do_sys_open+0x30d/0x5c0 [ 29.359506] [] ? filp_open+0x70/0x70 [ 29.364957] [] ? up_read+0x1a/0x40 [ 29.370147] [] ? __do_page_fault+0x183/0xd50 [ 29.376232] [] SyS_open+0x2d/0x40 [ 29.381512] [] ? do_sys_open+0x5c0/0x5c0 [ 29.387227] [] do_syscall_64+0x1a6/0x490 [ 29.392943] [] entry_SYSCALL_64_after_swapgs+0x5d/0xdb [ 29.399858] [ 29.401479] Allocated by task 3926: [ 29.405105] save_stack_trace+0x16/0x20 [ 29.409072] save_stack+0x43/0xd0 [ 29.412525] kasan_kmalloc+0xc7/0xe0 [ 29.416235] kmem_cache_alloc_trace+0xfd/0x2b0 [ 29.420821] alloc_disk_node+0x54/0x3a0 [ 29.424797] alloc_disk+0x18/0x20 [ 29.428246] loop_add+0x33b/0x770 [ 29.431694] loop_probe+0x14f/0x180 [ 29.435317] kobj_lookup+0x223/0x410 [ 29.439028] get_gendisk+0x39/0x2d0 [ 29.442656] __blkdev_get+0x351/0xd60 [ 29.446457] blkdev_get+0x2da/0x920 [ 29.450083] blkdev_open+0x1a5/0x250 [ 29.453799] do_dentry_open+0x703/0xc80 [ 29.457781] vfs_open+0x11c/0x210 [ 29.461236] path_openat+0x758/0x3590 [ 29.465828] do_filp_open+0x197/0x270 [ 29.469624] do_sys_open+0x30d/0x5c0 [ 29.473335] SyS_open+0x2d/0x40 [ 29.476625] do_syscall_64+0x1a6/0x490 executing program executing program executing program executing program executing program executing program executing program executing program [ 29.480509] entry_SYSCALL_64_after_swapgs+0x5d/0xdb [ 29.486210] [ 29.487843] Freed by task 3926: [ 29.491127] save_stack_trace+0x16/0x20 [ 29.495119] save_stack+0x43/0xd0 [ 29.498575] kasan_slab_free+0x72/0xc0 [ 29.502465] kfree+0xfb/0x310 [ 29.505567] disk_release+0x259/0x330 [ 29.509361] device_release+0x7e/0x220 [ 29.513248] kobject_release+0x103/0x1b0 [ 29.517314] kobject_put+0x6d/0xd0 [ 29.520850] put_disk+0x23/0x30 [ 29.524540] __blkdev_get+0x616/0xd60 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 29.528342] blkdev_get+0x2da/0x920 [ 29.531969] blkdev_open+0x1a5/0x250 [ 29.535678] do_dentry_open+0x703/0xc80 [ 29.539654] vfs_open+0x11c/0x210 [ 29.543119] path_openat+0x758/0x3590 [ 29.546924] do_filp_open+0x197/0x270 [ 29.550718] do_sys_open+0x30d/0x5c0 [ 29.554430] SyS_open+0x2d/0x40 [ 29.558238] do_syscall_64+0x1a6/0x490 [ 29.562140] entry_SYSCALL_64_after_swapgs+0x5d/0xdb [ 29.567227] [ 29.568861] The buggy address belongs to the object at ffff8801c52b0000 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 29.568861] which belongs to the cache kmalloc-2048 of size 2048 [ 29.581701] The buggy address is located 1376 bytes inside of [ 29.581701] 2048-byte region [ffff8801c52b0000, ffff8801c52b0800) [ 29.593737] The buggy address belongs to the page: [ 29.598672] page:ffffea000714ac00 count:1 mapcount:0 mapping: (null) index:0x0 compound_mapcount: 0 [ 29.608915] flags: 0x8000000000004080(slab|head) [ 29.613669] page dumped because: kasan: bad access detected [ 29.619366] [ 29.620982] Memory state around the buggy address: executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 29.625902] ffff8801c52b0400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 29.633349] ffff8801c52b0480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 29.641954] >ffff8801c52b0500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 29.649303] ^ [ 29.655785] ffff8801c52b0580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 29.663139] ffff8801c52b0600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 29.670851] ================================================================== executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 29.678293] Disabling lock debugging due to kernel taint [ 29.703948] Kernel panic - not syncing: panic_on_warn set ... [ 29.703948] [ 29.711359] CPU: 0 PID: 3926 Comm: syzkaller136360 Tainted: G B 4.9.95-gee0bcd6 #3 [ 29.720197] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 29.729553] ffff8801b7a5f638 ffffffff81eb0f89 ffffffff841c45f5 00000000ffffffff [ 29.737656] 0000000000000000 0000000000000000 0000000000000000 ffff8801b7a5f6f8 [ 29.745696] ffffffff8141f945 0000000041b58ab3 ffffffff841b7cf8 ffffffff8141f786 [ 29.753746] Call Trace: [ 29.756325] [] dump_stack+0xc1/0x128 [ 29.761687] [] panic+0x1bf/0x3bc [ 29.766699] [] ? add_taint.cold.6+0x16/0x16 [ 29.772674] [] ? ___preempt_schedule+0x16/0x18 [ 29.778906] [] kasan_end_report+0x47/0x4f [ 29.784705] [] kasan_report.cold.6+0x76/0x2fe [ 29.790858] [] ? disk_unblock_events+0x51/0x60 [ 29.797118] [] __asan_report_load8_noabort+0x14/0x20 [ 29.803895] [] disk_unblock_events+0x51/0x60 [ 29.809967] [] __blkdev_get+0x6b6/0xd60 [ 29.815600] [] ? __blkdev_put+0x840/0x840 [ 29.821582] [] ? fsnotify+0x114/0x1100 [ 29.827126] [] blkdev_get+0x2da/0x920 [ 29.832591] [] ? bd_may_claim+0xd0/0xd0 [ 29.838224] [] ? bd_acquire+0x27/0x250 [ 29.843763] [] ? bd_acquire+0x88/0x250 [ 29.849303] [] ? _raw_spin_unlock+0x2c/0x50 [ 29.855286] [] blkdev_open+0x1a5/0x250 [ 29.860921] [] do_dentry_open+0x703/0xc80 [ 29.866717] [] ? blkdev_get_by_dev+0x70/0x70 [ 29.873038] [] vfs_open+0x11c/0x210 [ 29.878320] [] ? may_open.isra.57+0x14f/0x2a0 [ 29.884483] [] path_openat+0x758/0x3590 [ 29.890113] [] ? save_stack+0xa9/0xd0 [ 29.895564] [] ? path_lookupat.isra.41+0x410/0x410 [ 29.902145] [] ? __lock_is_held+0xa2/0xf0 [ 29.907943] [] do_filp_open+0x197/0x270 [ 29.913569] [] ? may_open_dev+0xe0/0xe0 [ 29.919198] [] ? _raw_spin_unlock+0x2c/0x50 [ 29.925170] [] ? __alloc_fd+0x1d7/0x4a0 [ 29.930794] [] do_sys_open+0x30d/0x5c0 [ 29.936337] [] ? filp_open+0x70/0x70 [ 29.941705] [] ? up_read+0x1a/0x40 [ 29.946894] [] ? __do_page_fault+0x183/0xd50 [ 29.952950] [] SyS_open+0x2d/0x40 [ 29.958056] [] ? do_sys_open+0x5c0/0x5c0 [ 29.963782] [] do_syscall_64+0x1a6/0x490 [ 29.969498] [] entry_SYSCALL_64_after_swapgs+0x5d/0xdb [ 29.977103] Dumping ftrace buffer: [ 29.980642] (ftrace buffer empty) [ 29.984327] Kernel Offset: disabled [ 29.987926] Rebooting in 86400 seconds..