[....] 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[ 10.516473] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. [ 11.637652] random: crng init done Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added '10.128.0.27' (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 syzkaller login: [ 39.422682] ================================================================== [ 39.423792] BUG: KASAN: use-after-free in disk_unblock_events+0x51/0x60 [ 39.424767] Read of size 8 at addr ffff8801cbd4b860 by task blkid/2269 [ 39.425719] [ 39.425958] CPU: 1 PID: 2269 Comm: blkid Not tainted 4.9.141+ #23 [ 39.426786] ffff8801cbacf6f8 ffffffff81b42e79 ffffea00072f5200 ffff8801cbd4b860 [ 39.428021] 0000000000000000 ffff8801cbd4b860 0000000000000000 ffff8801cbacf730 [ 39.429200] ffffffff815009b8 ffff8801cbd4b860 0000000000000008 0000000000000000 [ 39.430444] Call Trace: [ 39.430827] [] dump_stack+0xc1/0x128 [ 39.431567] [] print_address_description+0x6c/0x234 [ 39.432568] [] kasan_report.cold.6+0x242/0x2fe [ 39.433510] [] ? disk_unblock_events+0x51/0x60 [ 39.434462] [] __asan_report_load8_noabort+0x14/0x20 [ 39.435492] [] disk_unblock_events+0x51/0x60 [ 39.436455] [] __blkdev_get+0x6b6/0xd60 [ 39.437279] [] ? __blkdev_put+0x840/0x840 [ 39.438324] [] ? fsnotify+0x114/0x1100 [ 39.439220] [] blkdev_get+0x2da/0x920 [ 39.440083] [] ? debug_lockdep_rcu_enabled+0x77/0x90 [ 39.441036] [] ? bd_may_claim+0xd0/0xd0 [ 39.441845] [] ? bd_acquire+0x27/0x250 [ 39.442720] [] ? bd_acquire+0x88/0x250 [ 39.447940] [] ? _raw_spin_unlock+0x2c/0x50 [ 39.453885] [] blkdev_open+0x1a5/0x250 [ 39.459394] [] do_dentry_open+0x3ef/0xc90 [ 39.465179] [] ? blkdev_get_by_dev+0x70/0x70 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 39.471207] [] vfs_open+0x11c/0x210 [ 39.476459] [] ? may_open.isra.20+0x14f/0x2a0 [ 39.482579] [] path_openat+0x542/0x2790 [ 39.488176] [] ? path_mountpoint+0x6c0/0x6c0 [ 39.494206] [] ? trace_hardirqs_on+0x10/0x10 [ 39.500235] [] ? expand_files.part.3+0x3a9/0x6d0 [ 39.506619] [] do_filp_open+0x197/0x270 [ 39.512222] [] ? may_open_dev+0xe0/0xe0 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 39.517822] [] ? _raw_spin_unlock+0x2c/0x50 [ 39.523767] [] ? __alloc_fd+0x1d7/0x4a0 [ 39.529366] [] do_sys_open+0x30d/0x5c0 [ 39.534874] [] ? filp_open+0x70/0x70 [ 39.540244] [] ? up_read+0x1a/0x40 [ 39.545409] [] SyS_open+0x2d/0x40 [ 39.550485] [] ? do_sys_open+0x5c0/0x5c0 [ 39.556168] [] do_syscall_64+0x19f/0x550 [ 39.561851] [] entry_SYSCALL_64_after_swapgs+0x5d/0xdb [ 39.568745] executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 39.570345] Allocated by task 2256: [ 39.573947] save_stack_trace+0x16/0x20 [ 39.577894] kasan_kmalloc.part.1+0x62/0xf0 [ 39.582185] kasan_kmalloc+0xaf/0xc0 [ 39.585869] kmem_cache_alloc_trace+0x117/0x2e0 [ 39.590517] alloc_disk_node+0x54/0x3a0 [ 39.594465] alloc_disk+0x18/0x20 [ 39.598044] loop_add+0x368/0x7a0 [ 39.601473] loop_control_ioctl+0x136/0x300 [ 39.605766] compat_SyS_ioctl+0x12d/0x1fd0 [ 39.609975] do_fast_syscall_32+0x2f1/0xa10 [ 39.614272] entry_SYSENTER_compat+0x90/0xa2 [ 39.618651] [ 39.620266] Freed by task 2269: executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 39.623524] save_stack_trace+0x16/0x20 [ 39.627477] kasan_slab_free+0xac/0x190 [ 39.631426] kfree+0xfb/0x310 [ 39.634505] disk_release+0x259/0x330 [ 39.638298] device_release+0x7e/0x220 [ 39.642175] kobject_put+0x148/0x250 [ 39.645874] put_disk+0x23/0x30 [ 39.649128] __blkdev_get+0x616/0xd60 [ 39.652899] blkdev_get+0x2da/0x920 [ 39.656496] blkdev_open+0x1a5/0x250 [ 39.660184] do_dentry_open+0x3ef/0xc90 [ 39.664127] vfs_open+0x11c/0x210 [ 39.667560] path_openat+0x542/0x2790 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 39.671332] do_filp_open+0x197/0x270 [ 39.675106] do_sys_open+0x30d/0x5c0 [ 39.678803] SyS_open+0x2d/0x40 [ 39.682058] do_syscall_64+0x19f/0x550 [ 39.685916] entry_SYSCALL_64_after_swapgs+0x5d/0xdb [ 39.690989] [ 39.692599] The buggy address belongs to the object at ffff8801cbd4b300 [ 39.692599] which belongs to the cache kmalloc-2048 of size 2048 [ 39.705444] The buggy address is located 1376 bytes inside of [ 39.705444] 2048-byte region [ffff8801cbd4b300, ffff8801cbd4bb00) [ 39.717476] The buggy address belongs to the page: executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 39.722382] page:ffffea00072f5200 count:1 mapcount:0 mapping: (null) index:0x0 compound_mapcount: 0 [ 39.732558] flags: 0x4000000000004080(slab|head) [ 39.737283] page dumped because: kasan: bad access detected [ 39.742964] [ 39.744579] Memory state around the buggy address: [ 39.749489] ffff8801cbd4b700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 39.756826] ffff8801cbd4b780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 39.764157] >ffff8801cbd4b800: 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 [ 39.771488] ^ [ 39.777971] ffff8801cbd4b880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 39.785300] ffff8801cbd4b900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 39.792631] ================================================================== [ 39.799957] Disabling lock debugging due to kernel taint [ 39.807666] Kernel panic - not syncing: panic_on_warn set ... [ 39.807666] [ 39.815017] CPU: 1 PID: 2269 Comm: blkid Tainted: G B 4.9.141+ #23 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 39.822468] ffff8801cbacf658 ffffffff81b42e79 ffffffff82e37630 00000000ffffffff [ 39.830478] 0000000000000000 0000000000000001 0000000000000000 ffff8801cbacf718 [ 39.838457] ffffffff813f7125 0000000041b58ab3 ffffffff82e2b62b ffffffff813f6f66 [ 39.846465] Call Trace: [ 39.849059] [] dump_stack+0xc1/0x128 [ 39.854406] [] panic+0x1bf/0x39f [ 39.859392] [] ? add_taint.cold.5+0x16/0x16 [ 39.865335] [] ? ___preempt_schedule+0x16/0x18 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 39.871546] [] kasan_end_report+0x47/0x4f [ 39.877325] [] kasan_report.cold.6+0x76/0x2fe [ 39.883443] [] ? disk_unblock_events+0x51/0x60 [ 39.889649] [] __asan_report_load8_noabort+0x14/0x20 [ 39.896375] [] disk_unblock_events+0x51/0x60 [ 39.902403] [] __blkdev_get+0x6b6/0xd60 [ 39.907999] [] ? __blkdev_put+0x840/0x840 [ 39.913769] [] ? fsnotify+0x114/0x1100 [ 39.919274] [] blkdev_get+0x2da/0x920 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 39.924696] [] ? debug_lockdep_rcu_enabled+0x77/0x90 [ 39.931451] [] ? bd_may_claim+0xd0/0xd0 [ 39.937145] [] ? bd_acquire+0x27/0x250 [ 39.942662] [] ? bd_acquire+0x88/0x250 [ 39.948168] [] ? _raw_spin_unlock+0x2c/0x50 [ 39.954108] [] blkdev_open+0x1a5/0x250 [ 39.959615] [] do_dentry_open+0x3ef/0xc90 [ 39.965391] [] ? blkdev_get_by_dev+0x70/0x70 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 39.971428] [] vfs_open+0x11c/0x210 [ 39.976677] [] ? may_open.isra.20+0x14f/0x2a0 [ 39.982909] [] path_openat+0x542/0x2790 [ 39.988524] [] ? path_mountpoint+0x6c0/0x6c0 [ 39.994564] [] ? trace_hardirqs_on+0x10/0x10 [ 40.000595] [] ? expand_files.part.3+0x3a9/0x6d0 [ 40.006988] [] do_filp_open+0x197/0x270 [ 40.012600] [] ? may_open_dev+0xe0/0xe0 [ 40.018196] [] ? _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 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 40.024139] [] ? __alloc_fd+0x1d7/0x4a0 [ 40.029735] [] do_sys_open+0x30d/0x5c0 [ 40.035247] [] ? filp_open+0x70/0x70 [ 40.040601] [] ? up_read+0x1a/0x40 [ 40.045780] [] SyS_open+0x2d/0x40 [ 40.050854] [] ? do_sys_open+0x5c0/0x5c0 [ 40.056539] [] do_syscall_64+0x19f/0x550 [ 40.062221] [] entry_SYSCALL_64_after_swapgs+0x5d/0xdb [ 40.069388] Kernel Offset: disabled [ 40.072997] Rebooting in 86400 seconds..