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 '10.128.0.37' (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 syzkaller login: [ 29.395993] ================================================================== [ 29.403405] BUG: KASAN: use-after-free in disk_unblock_events+0x51/0x60 [ 29.410159] Read of size 8 at addr ffff8801d8b89660 by task syzkaller757873/3896 [ 29.417683] [ 29.419301] CPU: 0 PID: 3896 Comm: syzkaller757873 Not tainted 4.9.93-g2ba4887 #2 [ 29.426900] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 29.436238] ffff8801d89a76d8 ffffffff81d9aa29 ffffea000762e200 ffff8801d8b89660 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 29.444271] 0000000000000000 ffff8801d8b89660 0000000000000000 ffff8801d89a7710 [ 29.452298] ffffffff81564acb ffff8801d8b89660 0000000000000008 0000000000000000 [ 29.460332] Call Trace: [ 29.462911] [] dump_stack+0xc1/0x128 [ 29.468273] [] print_address_description+0x6c/0x234 [ 29.474939] [] kasan_report.cold.6+0x242/0x2fe [ 29.481164] [] ? disk_unblock_events+0x51/0x60 [ 29.487387] [] __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 [ 29.494141] [] disk_unblock_events+0x51/0x60 [ 29.500198] [] __blkdev_get+0x6b6/0xd60 [ 29.505811] [] ? __blkdev_put+0x840/0x840 [ 29.511597] [] ? fsnotify+0x114/0x1100 [ 29.517136] [] blkdev_get+0x2da/0x920 [ 29.522579] [] ? bd_may_claim+0xd0/0xd0 [ 29.528196] [] ? bd_acquire+0x27/0x250 [ 29.533726] [] ? bd_acquire+0x88/0x250 [ 29.539261] [] ? _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 [ 29.545230] [] blkdev_open+0x1a5/0x250 [ 29.550761] [] do_dentry_open+0x703/0xc80 [ 29.556553] [] ? blkdev_get_by_dev+0x70/0x70 [ 29.562607] [] vfs_open+0x11c/0x210 [ 29.567885] [] ? may_open.isra.57+0x14f/0x2a0 [ 29.574030] [] path_openat+0x758/0x3590 [ 29.579651] [] ? save_stack+0xa9/0xd0 [ 29.585108] [] ? path_lookupat.isra.41+0x410/0x410 executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 29.591683] [] ? __lock_is_held+0xa2/0xf0 [ 29.597477] [] do_filp_open+0x197/0x270 [ 29.603108] [] ? may_open_dev+0xe0/0xe0 [ 29.608730] [] ? _raw_spin_unlock+0x2c/0x50 [ 29.614705] [] ? __alloc_fd+0x1d7/0x4a0 [ 29.620327] [] do_sys_open+0x30d/0x5c0 [ 29.625864] [] ? filp_open+0x70/0x70 [ 29.631221] [] ? up_read+0x1a/0x40 [ 29.636407] [] ? __do_page_fault+0x183/0xd50 executing program executing program executing program executing program executing program executing program executing program [ 29.642633] [] SyS_open+0x2d/0x40 [ 29.647727] [] ? do_sys_open+0x5c0/0x5c0 [ 29.653432] [] do_syscall_64+0x1a6/0x490 [ 29.659139] [] entry_SYSCALL_64_after_swapgs+0x5d/0xdb [ 29.666052] [ 29.667678] Allocated by task 3896: [ 29.671315] save_stack_trace+0x16/0x20 [ 29.675289] save_stack+0x43/0xd0 [ 29.678734] kasan_kmalloc+0xc7/0xe0 [ 29.682436] kmem_cache_alloc_trace+0xfd/0x2b0 [ 29.687009] alloc_disk_node+0x54/0x3a0 [ 29.690971] alloc_disk+0x18/0x20 executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 29.694412] loop_add+0x33b/0x770 [ 29.697851] loop_probe+0x14f/0x180 [ 29.701468] kobj_lookup+0x223/0x410 [ 29.705173] get_gendisk+0x39/0x2d0 [ 29.708789] __blkdev_get+0x351/0xd60 [ 29.712673] blkdev_get+0x2da/0x920 [ 29.716294] blkdev_open+0x1a5/0x250 [ 29.719996] do_dentry_open+0x703/0xc80 [ 29.723960] vfs_open+0x11c/0x210 [ 29.727413] path_openat+0x758/0x3590 [ 29.731203] do_filp_open+0x197/0x270 [ 29.734995] do_sys_open+0x30d/0x5c0 [ 29.738695] SyS_open+0x2d/0x40 [ 29.741963] do_syscall_64+0x1a6/0x490 executing program executing program executing program executing program executing program executing program executing program [ 29.745838] entry_SYSCALL_64_after_swapgs+0x5d/0xdb [ 29.750933] [ 29.752551] Freed by task 3896: [ 29.755817] save_stack_trace+0x16/0x20 [ 29.759779] save_stack+0x43/0xd0 [ 29.763226] kasan_slab_free+0x72/0xc0 [ 29.767109] kfree+0xfb/0x310 [ 29.770202] disk_release+0x259/0x330 [ 29.773988] device_release+0x7e/0x220 [ 29.777867] kobject_release+0x103/0x1b0 [ 29.781922] kobject_put+0x6d/0xd0 [ 29.785454] put_disk+0x23/0x30 [ 29.788725] __blkdev_get+0x616/0xd60 [ 29.792510] blkdev_get+0x2da/0x920 executing program executing program executing program executing program executing program executing program [ 29.796126] blkdev_open+0x1a5/0x250 [ 29.799825] do_dentry_open+0x703/0xc80 [ 29.803789] vfs_open+0x11c/0x210 [ 29.807230] path_openat+0x758/0x3590 [ 29.811025] do_filp_open+0x197/0x270 [ 29.814820] do_sys_open+0x30d/0x5c0 [ 29.818519] SyS_open+0x2d/0x40 [ 29.821786] do_syscall_64+0x1a6/0x490 [ 29.825664] entry_SYSCALL_64_after_swapgs+0x5d/0xdb [ 29.830754] [ 29.832367] The buggy address belongs to the object at ffff8801d8b89100 [ 29.832367] which belongs to the cache kmalloc-2048 of size 2048 executing program executing program executing program executing program executing program executing program [ 29.845186] The buggy address is located 1376 bytes inside of [ 29.845186] 2048-byte region [ffff8801d8b89100, ffff8801d8b89900) [ 29.857232] The buggy address belongs to the page: [ 29.862155] page:ffffea000762e200 count:1 mapcount:0 mapping: (null) index:0x0 compound_mapcount: 0 [ 29.872389] flags: 0x8000000000004080(slab|head) [ 29.877127] page dumped because: kasan: bad access detected [ 29.882824] [ 29.884434] Memory state around the buggy address: [ 29.889350] ffff8801d8b89500: 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 [ 29.896701] ffff8801d8b89580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 29.904144] >ffff8801d8b89600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 29.911491] ^ [ 29.917974] ffff8801d8b89680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 29.925347] ffff8801d8b89700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 29.932703] ================================================================== [ 29.940058] 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 [ 29.984264] Kernel panic - not syncing: panic_on_warn set ... [ 29.984264] [ 29.991666] CPU: 0 PID: 3896 Comm: syzkaller757873 Tainted: G B 4.9.93-g2ba4887 #2 [ 30.000488] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 30.009833] ffff8801d89a7638 ffffffff81d9aa29 ffffffff841a8661 00000000ffffffff [ 30.017923] 0000000000000000 0000000000000000 0000000000000000 ffff8801d89a76f8 [ 30.025974] ffffffff8141f015 0000000041b58ab3 ffffffff8419bd98 ffffffff8141ee56 executing program executing program executing program executing program executing program executing program executing program [ 30.034005] Call Trace: [ 30.036588] [] dump_stack+0xc1/0x128 [ 30.041943] [] panic+0x1bf/0x3bc [ 30.046952] [] ? add_taint.cold.6+0x16/0x16 [ 30.052918] [] ? ___preempt_schedule+0x16/0x18 [ 30.059145] [] kasan_end_report+0x47/0x4f [ 30.064938] [] kasan_report.cold.6+0x76/0x2fe [ 30.071106] [] ? disk_unblock_events+0x51/0x60 [ 30.077339] [] __asan_report_load8_noabort+0x14/0x20 executing program executing program executing program executing program executing program executing program executing program [ 30.084090] [] disk_unblock_events+0x51/0x60 [ 30.090144] [] __blkdev_get+0x6b6/0xd60 [ 30.095763] [] ? __blkdev_put+0x840/0x840 [ 30.101559] [] ? fsnotify+0x114/0x1100 [ 30.107093] [] blkdev_get+0x2da/0x920 [ 30.112543] [] ? bd_may_claim+0xd0/0xd0 [ 30.118160] [] ? bd_acquire+0x27/0x250 [ 30.123692] [] ? bd_acquire+0x88/0x250 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 30.129235] [] ? _raw_spin_unlock+0x2c/0x50 [ 30.135209] [] blkdev_open+0x1a5/0x250 [ 30.140750] [] do_dentry_open+0x703/0xc80 [ 30.146541] [] ? blkdev_get_by_dev+0x70/0x70 [ 30.152592] [] vfs_open+0x11c/0x210 [ 30.157869] [] ? may_open.isra.57+0x14f/0x2a0 [ 30.164051] [] path_openat+0x758/0x3590 [ 30.169678] [] ? save_stack+0xa9/0xd0 [ 30.175128] [] ? path_lookupat.isra.41+0x410/0x410 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 30.181702] [] ? __lock_is_held+0xa2/0xf0 [ 30.187501] [] do_filp_open+0x197/0x270 [ 30.193124] [] ? may_open_dev+0xe0/0xe0 [ 30.198748] [] ? _raw_spin_unlock+0x2c/0x50 [ 30.204721] [] ? __alloc_fd+0x1d7/0x4a0 [ 30.210340] [] do_sys_open+0x30d/0x5c0 [ 30.215874] [] ? filp_open+0x70/0x70 [ 30.221234] [] ? up_read+0x1a/0x40 [ 30.226420] [] ? __do_page_fault+0x183/0xd50 executing program executing program executing program [ 30.232487] [] SyS_open+0x2d/0x40 [ 30.237590] [] ? do_sys_open+0x5c0/0x5c0 [ 30.243296] [] do_syscall_64+0x1a6/0x490 [ 30.249010] [] entry_SYSCALL_64_after_swapgs+0x5d/0xdb [ 30.256409] Dumping ftrace buffer: [ 30.259927] (ftrace buffer empty) [ 30.263609] Kernel Offset: disabled [ 30.267205] Rebooting in 86400 seconds..