INIT: Entering runlevel: 2 [info] Using makefile-style concurrent boot in runlevel 2. [....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added '10.128.10.11' (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 syzkaller login: [ 20.918683] ================================================================== [ 20.919735] BUG: KASAN: use-after-free in disk_unblock_events+0x51/0x60 [ 20.921228] Read of size 8 at addr ffff8801d97b7c60 by task syzkaller257901/3811 [ 20.922989] [ 20.923524] CPU: 1 PID: 3811 Comm: syzkaller257901 Not tainted 4.9.94-g8683408 #3 [ 20.925351] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 20.927059] ffff8801d92c76d8 ffffffff81d9b509 ffffea000765ec00 ffff8801d97b7c60 [ 20.929131] 0000000000000000 ffff8801d97b7c60 0000000000000000 ffff8801d92c7710 [ 20.930688] ffffffff815652cb ffff8801d97b7c60 0000000000000008 0000000000000000 [ 20.932758] Call Trace: [ 20.933341] [] dump_stack+0xc1/0x128 [ 20.934652] [] print_address_description+0x6c/0x234 [ 20.936171] [] kasan_report.cold.6+0x242/0x2fe [ 20.937159] [] ? disk_unblock_events+0x51/0x60 [ 20.940045] [] __asan_report_load8_noabort+0x14/0x20 [ 20.946782] [] disk_unblock_events+0x51/0x60 [ 20.952825] [] __blkdev_get+0x6b6/0xd60 [ 20.958438] [] ? __blkdev_put+0x840/0x840 executing program executing program executing program executing program executing program executing program executing program [ 20.964223] [] ? fsnotify+0x114/0x1100 [ 20.969748] [] blkdev_get+0x2da/0x920 [ 20.975183] [] ? bd_may_claim+0xd0/0xd0 [ 20.980795] [] ? bd_acquire+0x27/0x250 [ 20.986321] [] ? bd_acquire+0x88/0x250 [ 20.991846] [] ? _raw_spin_unlock+0x2c/0x50 [ 20.997805] [] blkdev_open+0x1a5/0x250 [ 21.003327] [] do_dentry_open+0x703/0xc80 [ 21.009110] [] ? blkdev_get_by_dev+0x70/0x70 [ 21.015153] [] vfs_open+0x11c/0x210 [ 21.020416] [] ? may_open.isra.57+0x14f/0x2a0 [ 21.026548] [] path_openat+0x758/0x3590 [ 21.032159] [] ? save_stack+0xa9/0xd0 [ 21.037599] [] ? path_lookupat.isra.41+0x410/0x410 [ 21.044169] [] ? __lock_is_held+0xa2/0xf0 [ 21.049959] [] do_filp_open+0x197/0x270 [ 21.055577] [] ? may_open_dev+0xe0/0xe0 [ 21.061189] [] ? _raw_spin_unlock+0x2c/0x50 [ 21.067147] [] ? __alloc_fd+0x1d7/0x4a0 [ 21.072761] [] do_sys_open+0x30d/0x5c0 [ 21.078287] [] ? filp_open+0x70/0x70 [ 21.083642] [] ? up_read+0x1a/0x40 [ 21.088819] [] ? __do_page_fault+0x183/0xd50 [ 21.094864] [] SyS_open+0x2d/0x40 [ 21.099953] [] ? do_sys_open+0x5c0/0x5c0 [ 21.105653] [] do_syscall_64+0x1a6/0x490 [ 21.111355] [] entry_SYSCALL_64_after_swapgs+0x5d/0xdb [ 21.118261] [ 21.119871] Allocated by task 3811: [ 21.123495] save_stack_trace+0x16/0x20 [ 21.127454] save_stack+0x43/0xd0 [ 21.130896] kasan_kmalloc+0xc7/0xe0 [ 21.134597] kmem_cache_alloc_trace+0xfd/0x2b0 [ 21.139165] alloc_disk_node+0x54/0x3a0 [ 21.143135] alloc_disk+0x18/0x20 [ 21.146575] loop_add+0x33b/0x770 [ 21.150017] loop_probe+0x14f/0x180 [ 21.153638] kobj_lookup+0x223/0x410 [ 21.157344] get_gendisk+0x39/0x2d0 [ 21.160955] __blkdev_get+0x351/0xd60 [ 21.164741] blkdev_get+0x2da/0x920 [ 21.168354] blkdev_open+0x1a5/0x250 [ 21.172052] do_dentry_open+0x703/0xc80 [ 21.176015] vfs_open+0x11c/0x210 [ 21.179459] path_openat+0x758/0x3590 [ 21.183245] do_filp_open+0x197/0x270 [ 21.187034] do_sys_open+0x30d/0x5c0 [ 21.190735] SyS_open+0x2d/0x40 [ 21.194002] do_syscall_64+0x1a6/0x490 [ 21.197880] entry_SYSCALL_64_after_swapgs+0x5d/0xdb [ 21.202965] [ 21.204575] Freed by task 3811: [ 21.207843] save_stack_trace+0x16/0x20 [ 21.211801] save_stack+0x43/0xd0 [ 21.215239] kasan_slab_free+0x72/0xc0 [ 21.219110] kfree+0xfb/0x310 [ 21.222202] disk_release+0x259/0x330 [ 21.225991] device_release+0x7e/0x220 [ 21.229866] kobject_release+0x103/0x1b0 [ 21.233936] kobject_put+0x6d/0xd0 [ 21.237463] put_disk+0x23/0x30 [ 21.240729] __blkdev_get+0x616/0xd60 [ 21.244516] blkdev_get+0x2da/0x920 [ 21.248131] blkdev_open+0x1a5/0x250 [ 21.251833] do_dentry_open+0x703/0xc80 [ 21.255793] vfs_open+0x11c/0x210 [ 21.259232] path_openat+0x758/0x3590 [ 21.263021] do_filp_open+0x197/0x270 [ 21.266803] do_sys_open+0x30d/0x5c0 [ 21.270501] SyS_open+0x2d/0x40 [ 21.273767] do_syscall_64+0x1a6/0x490 [ 21.277641] entry_SYSCALL_64_after_swapgs+0x5d/0xdb [ 21.282720] [ 21.284336] The buggy address belongs to the object at ffff8801d97b7700 [ 21.284336] which belongs to the cache kmalloc-2048 of size 2048 [ 21.297149] The buggy address is located 1376 bytes inside of [ 21.297149] 2048-byte region [ffff8801d97b7700, ffff8801d97b7f00) [ 21.309181] The buggy address belongs to the page: [ 21.314099] page:ffffea000765ec00 count:1 mapcount:0 mapping: (null) index:0x0 compound_mapcount: 0 [ 21.324313] flags: 0x8000000000004080(slab|head) [ 21.329050] page dumped because: kasan: bad access detected [ 21.334741] [ 21.336351] Memory state around the buggy address: [ 21.341263] ffff8801d97b7b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 21.348610] ffff8801d97b7b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 21.355955] >ffff8801d97b7c00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 21.363295] ^ executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 21.369770] ffff8801d97b7c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 21.377113] ffff8801d97b7d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 21.384455] ================================================================== [ 21.391825] 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 [ 21.426089] Kernel panic - not syncing: panic_on_warn set ... [ 21.426089] [ 21.433485] CPU: 1 PID: 3811 Comm: syzkaller257901 Tainted: G B 4.9.94-g8683408 #3 [ 21.442306] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 21.451650] ffff8801d92c7638 ffffffff81d9b509 ffffffff841a8a65 00000000ffffffff [ 21.459679] 0000000000000000 0000000000000001 0000000000000000 ffff8801d92c76f8 [ 21.467711] ffffffff8141f845 0000000041b58ab3 ffffffff8419c168 ffffffff8141f686 executing program [ 21.475737] Call Trace: [ 21.478312] [] dump_stack+0xc1/0x128 [ 21.483665] [] panic+0x1bf/0x3bc [ 21.488670] [] ? add_taint.cold.6+0x16/0x16 [ 21.494631] [] ? ___preempt_schedule+0x16/0x18 [ 21.500852] [] kasan_end_report+0x47/0x4f [ 21.506637] [] kasan_report.cold.6+0x76/0x2fe [ 21.512771] [] ? disk_unblock_events+0x51/0x60 [ 21.519000] [] __asan_report_load8_noabort+0x14/0x20 [ 21.525742] [] disk_unblock_events+0x51/0x60 [ 21.531796] [] __blkdev_get+0x6b6/0xd60 [ 21.537413] [] ? __blkdev_put+0x840/0x840 [ 21.543204] [] ? fsnotify+0x114/0x1100 [ 21.548739] [] blkdev_get+0x2da/0x920 [ 21.554184] [] ? bd_may_claim+0xd0/0xd0 [ 21.559801] [] ? bd_acquire+0x27/0x250 [ 21.565331] [] ? bd_acquire+0x88/0x250 [ 21.570866] [] ? _raw_spin_unlock+0x2c/0x50 [ 21.576837] [] blkdev_open+0x1a5/0x250 [ 21.582374] [] do_dentry_open+0x703/0xc80 [ 21.588170] [] ? blkdev_get_by_dev+0x70/0x70 [ 21.594224] [] vfs_open+0x11c/0x210 [ 21.599502] [] ? may_open.isra.57+0x14f/0x2a0 [ 21.605640] [] path_openat+0x758/0x3590 [ 21.611257] [] ? save_stack+0xa9/0xd0 [ 21.616703] [] ? path_lookupat.isra.41+0x410/0x410 [ 21.623278] [] ? __lock_is_held+0xa2/0xf0 [ 21.629066] [] do_filp_open+0x197/0x270 [ 21.634682] [] ? may_open_dev+0xe0/0xe0 [ 21.640297] [] ? _raw_spin_unlock+0x2c/0x50 [ 21.646259] [] ? __alloc_fd+0x1d7/0x4a0 [ 21.651876] [] do_sys_open+0x30d/0x5c0 [ 21.657400] [] ? filp_open+0x70/0x70 [ 21.662752] [] ? up_read+0x1a/0x40 [ 21.667928] [] ? __do_page_fault+0x183/0xd50 [ 21.673973] [] SyS_open+0x2d/0x40 [ 21.679062] [] ? do_sys_open+0x5c0/0x5c0 [ 21.684765] [] do_syscall_64+0x1a6/0x490 [ 21.690467] [] entry_SYSCALL_64_after_swapgs+0x5d/0xdb [ 21.697767] Dumping ftrace buffer: [ 21.701290] (ftrace buffer empty) [ 21.704968] Kernel Offset: disabled [ 21.708562] Rebooting in 86400 seconds..