[....] Starting enhanced syslogd: rsyslogd[ 12.895949] audit: type=1400 audit(1514560604.576:4): avc: denied { syslog } for pid=3171 comm="rsyslogd" capability=34 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:system_r:kernel_t:s0 tclass=capability2 permissive=1 [?25l[?1c7[ ok 8[?25h[?0c. [....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. Starting mcstransd: [....] Starting file context maintaining daemon: restorecond[?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 '10.128.15.201' (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 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program 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: [ 33.808906] ================================================================== [ 33.816297] BUG: KASAN: use-after-free in disk_unblock_events+0x51/0x60 [ 33.823015] Read of size 8 at addr ffff8801d8ed40e0 by task blkid/3666 [ 33.829644] [ 33.831243] CPU: 1 PID: 3666 Comm: blkid Not tainted 4.9.72-gcb7518e #10 [ 33.838051] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 33.847372] ffff8801d888f790 ffffffff81d922b9 ffffea000763b400 ffff8801d8ed40e0 [ 33.855327] 0000000000000000 ffff8801d8ed40e0 0000000000000000 ffff8801d888f7c8 [ 33.863278] ffffffff8153bab3 ffff8801d8ed40e0 0000000000000008 0000000000000000 [ 33.871238] Call Trace: [ 33.873791] [] dump_stack+0xc1/0x128 [ 33.879129] [] print_address_description+0x73/0x280 [ 33.885776] [] kasan_report+0x275/0x360 [ 33.891453] [] ? disk_unblock_events+0x51/0x60 [ 33.897653] [] __asan_report_load8_noabort+0x14/0x20 [ 33.904371] [] disk_unblock_events+0x51/0x60 [ 33.910396] [] __blkdev_get+0x4b5/0xd50 [ 33.915985] [] ? __blkdev_put+0x7e0/0x7e0 [ 33.921749] [] blkdev_get+0x33b/0x960 [ 33.927163] [] ? bd_link_disk_holder+0x6c0/0x6c0 [ 33.933533] [] ? bd_acquire+0x27/0x250 [ 33.939037] [] ? bd_acquire+0x88/0x250 [ 33.944542] [] ? _raw_spin_unlock+0x2c/0x50 [ 33.950478] [] blkdev_open+0x1a5/0x250 [ 33.955982] [] do_dentry_open+0x607/0xc60 [ 33.961745] [] ? blkdev_get_by_dev+0x60/0x60 [ 33.967779] [] vfs_open+0x105/0x220 [ 33.973027] [] ? may_open+0x231/0x2e0 [ 33.978443] [] path_openat+0x5ac/0x2910 [ 33.984038] [] ? path_lookupat+0x3f0/0x3f0 [ 33.989904] [] ? debug_check_no_locks_freed+0x2c0/0x2c0 [ 33.996882] [] ? __lock_is_held+0xa1/0xf0 [ 34.002645] [] do_filp_open+0x197/0x290 [ 34.008233] [] ? may_open_dev+0xe0/0xe0 [ 34.013825] [] ? _raw_spin_unlock+0x2c/0x50 [ 34.019764] [] ? __alloc_fd+0x1d7/0x510 [ 34.025353] [] do_sys_open+0x352/0x4c0 [ 34.030868] [] ? filp_open+0x70/0x70 [ 34.036196] [] ? entry_SYSCALL_64_fastpath+0x5/0xc6 [ 34.042828] [] ? trace_hardirqs_on_caller+0x38b/0x590 [ 34.049634] [] SyS_open+0x2d/0x40 [ 34.054789] [] entry_SYSCALL_64_fastpath+0x23/0xc6 [ 34.061331] [ 34.062923] Allocated by task 3638: [ 34.066516] save_stack_trace+0x16/0x20 [ 34.070460] save_stack+0x43/0xd0 [ 34.073881] kasan_kmalloc+0xad/0xe0 [ 34.077561] kmem_cache_alloc_trace+0xfb/0x2a0 [ 34.082109] alloc_disk_node+0x54/0x3b0 [ 34.086049] alloc_disk+0x18/0x20 [ 34.089467] loop_add+0x324/0x770 [ 34.092885] loop_probe+0x155/0x180 [ 34.096486] kobj_lookup+0x2ac/0x410 [ 34.100165] get_gendisk+0x37/0x2d0 [ 34.103765] __blkdev_get+0x34f/0xd50 [ 34.107532] blkdev_get+0x4bf/0x960 [ 34.111121] blkdev_open+0x1a5/0x250 [ 34.114801] do_dentry_open+0x607/0xc60 [ 34.118740] vfs_open+0x105/0x220 [ 34.122157] path_openat+0x5ac/0x2910 [ 34.125923] do_filp_open+0x197/0x290 [ 34.129687] do_sys_open+0x352/0x4c0 [ 34.133368] compat_SyS_open+0x2a/0x40 [ 34.137221] do_fast_syscall_32+0x2f7/0x890 [ 34.141507] entry_SYSENTER_compat+0x51/0x60 [ 34.145878] [ 34.147472] Freed by task 3666: [ 34.150716] save_stack_trace+0x16/0x20 [ 34.154657] save_stack+0x43/0xd0 [ 34.158075] kasan_slab_free+0x72/0xc0 [ 34.161925] kfree+0x103/0x300 [ 34.165084] disk_release+0x259/0x330 [ 34.168868] device_release+0x7c/0x210 [ 34.172721] kobject_release+0xed/0x1a0 [ 34.176670] kobject_put+0x63/0xc0 [ 34.180176] put_disk+0x23/0x30 [ 34.183420] __blkdev_get+0x415/0xd50 [ 34.187187] blkdev_get+0x33b/0x960 [ 34.190781] blkdev_open+0x1a5/0x250 [ 34.194460] do_dentry_open+0x607/0xc60 [ 34.198408] vfs_open+0x105/0x220 [ 34.201827] path_openat+0x5ac/0x2910 [ 34.205592] do_filp_open+0x197/0x290 [ 34.209357] do_sys_open+0x352/0x4c0 [ 34.213052] SyS_open+0x2d/0x40 [ 34.216305] entry_SYSCALL_64_fastpath+0x23/0xc6 [ 34.221023] [ 34.222616] The buggy address belongs to the object at ffff8801d8ed3b80 [ 34.222616] which belongs to the cache kmalloc-2048 of size 2048 [ 34.235411] The buggy address is located 1376 bytes inside of [ 34.235411] 2048-byte region [ffff8801d8ed3b80, ffff8801d8ed4380) [ 34.247421] The buggy address belongs to the page: [ 34.252405] page:ffffea000763b400 count:1 mapcount:0 mapping: (null) index:0x0 compound_mapcount: 0 [ 34.262560] flags: 0x8000000000004080(slab|head) [ 34.267279] page dumped because: kasan: bad access detected [ 34.272954] [ 34.274546] Memory state around the buggy address: [ 34.279440] ffff8801d8ed3f80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 34.286764] ffff8801d8ed4000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 34.294088] >ffff8801d8ed4080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 34.301411] ^ executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 34.307877] ffff8801d8ed4100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 34.315216] ffff8801d8ed4180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 34.322553] ================================================================== [ 34.329877] Disabling lock debugging due to kernel taint [ 34.337321] Kernel panic - not syncing: panic_on_warn set ... [ 34.337321] [ 34.344670] CPU: 1 PID: 3666 Comm: blkid Tainted: G B 4.9.72-gcb7518e #10 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 34.352698] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 34.362019] ffff8801d888f6e8 ffffffff81d922b9 ffffffff841955bf ffff8801d888f7c0 [ 34.369975] 0000000000000000 ffff8801d8ed40e0 0000000000000000 ffff8801d888f7b0 [ 34.377933] ffffffff8142d741 0000000041b58ab3 ffffffff84189000 ffffffff8142d585 [ 34.385884] Call Trace: [ 34.388438] [] dump_stack+0xc1/0x128 [ 34.393769] [] panic+0x1bc/0x3a8 [ 34.398753] [] ? percpu_up_read_preempt_enable.constprop.53+0xd7/0xd7 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 34.406947] [] ? preempt_schedule+0x25/0x30 [ 34.412885] [] ? ___preempt_schedule+0x16/0x18 [ 34.419082] [] kasan_end_report+0x50/0x50 [ 34.424847] [] kasan_report+0x167/0x360 [ 34.430440] [] ? disk_unblock_events+0x51/0x60 [ 34.436641] [] __asan_report_load8_noabort+0x14/0x20 [ 34.443362] [] disk_unblock_events+0x51/0x60 [ 34.449387] [] __blkdev_get+0x4b5/0xd50 [ 34.454984] [] ? __blkdev_put+0x7e0/0x7e0 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 34.460749] [] blkdev_get+0x33b/0x960 [ 34.466169] [] ? bd_link_disk_holder+0x6c0/0x6c0 [ 34.472549] [] ? bd_acquire+0x27/0x250 [ 34.478051] [] ? bd_acquire+0x88/0x250 [ 34.483565] [] ? _raw_spin_unlock+0x2c/0x50 [ 34.489521] [] blkdev_open+0x1a5/0x250 [ 34.495026] [] do_dentry_open+0x607/0xc60 [ 34.500790] [] ? blkdev_get_by_dev+0x60/0x60 [ 34.506814] [] vfs_open+0x105/0x220 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 34.512062] [] ? may_open+0x231/0x2e0 [ 34.517480] [] path_openat+0x5ac/0x2910 [ 34.523068] [] ? path_lookupat+0x3f0/0x3f0 [ 34.528927] [] ? debug_check_no_locks_freed+0x2c0/0x2c0 [ 34.535916] [] ? __lock_is_held+0xa1/0xf0 [ 34.541678] [] do_filp_open+0x197/0x290 [ 34.547267] [] ? may_open_dev+0xe0/0xe0 [ 34.552859] [] ? _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 executing program executing program [ 34.558805] [] ? __alloc_fd+0x1d7/0x510 [ 34.564395] [] do_sys_open+0x352/0x4c0 [ 34.569900] [] ? filp_open+0x70/0x70 [ 34.575230] [] ? entry_SYSCALL_64_fastpath+0x5/0xc6 [ 34.581864] [] ? trace_hardirqs_on_caller+0x38b/0x590 [ 34.588668] [] SyS_open+0x2d/0x40 [ 34.593738] [] entry_SYSCALL_64_fastpath+0x23/0xc6 [ 34.600655] Dumping ftrace buffer: [ 34.604169] (ftrace buffer empty) [ 34.607847] Kernel Offset: disabled [ 34.611443] Rebooting in 86400 seconds..