[....] 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[ 10.043054] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. [ 11.288684] random: crng init done Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added '10.128.0.117' (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 syzkaller login: [ 34.063101] ================================================================== [ 34.064640] BUG: KASAN: use-after-free in disk_unblock_events+0x51/0x60 [ 34.065820] Read of size 8 at addr ffff8801d77f5a60 by task syz-executor902/2068 [ 34.066931] [ 34.067353] CPU: 0 PID: 2068 Comm: syz-executor902 Not tainted 4.9.142+ #73 [ 34.068435] ffff8801ce1a76f0 ffffffff81b43969 ffffea00075dfc00 ffff8801d77f5a60 [ 34.069875] 0000000000000000 ffff8801d77f5a60 0000000000000000 ffff8801ce1a7728 [ 34.071156] ffffffff81500a28 ffff8801d77f5a60 0000000000000008 0000000000000000 [ 34.072470] Call Trace: [ 34.072853] [] dump_stack+0xc1/0x128 [ 34.073704] [] print_address_description+0x6c/0x234 [ 34.074939] [] kasan_report.cold.6+0x242/0x2fe [ 34.076371] [] ? disk_unblock_events+0x51/0x60 [ 34.077604] [] __asan_report_load8_noabort+0x14/0x20 [ 34.078889] [] disk_unblock_events+0x51/0x60 [ 34.079996] [] __blkdev_get+0x6b6/0xd60 [ 34.080938] [] ? trace_hardirqs_on+0x10/0x10 [ 34.082093] [] ? __blkdev_put+0x840/0x840 [ 34.083192] [] ? fsnotify+0x114/0x1100 [ 34.088387] [] blkdev_get+0x2da/0x920 [ 34.093830] [] ? debug_lockdep_rcu_enabled+0x77/0x90 [ 34.100581] [] ? bd_may_claim+0xd0/0xd0 [ 34.106227] [] ? bd_acquire+0x27/0x250 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 34.111802] [] ? bd_acquire+0x88/0x250 [ 34.117350] [] ? _raw_spin_unlock+0x2c/0x50 [ 34.123313] [] blkdev_open+0x1a5/0x250 [ 34.128842] [] do_dentry_open+0x3ef/0xc90 [ 34.134634] [] ? blkdev_get_by_dev+0x70/0x70 [ 34.140686] [] vfs_open+0x11c/0x210 [ 34.145962] [] ? may_open.isra.21+0x14f/0x2a0 [ 34.152102] [] path_openat+0x661/0x2d90 [ 34.157719] [] ? path_mountpoint+0x6c0/0x6c0 [ 34.163778] [] ? trace_hardirqs_on+0x10/0x10 [ 34.169837] [] ? expand_files.part.3+0x3a9/0x6d0 [ 34.176248] [] do_filp_open+0x197/0x270 [ 34.181867] [] ? may_open_dev+0xe0/0xe0 [ 34.187488] [] ? _raw_spin_unlock+0x2c/0x50 [ 34.193444] [] ? __alloc_fd+0x1d7/0x4a0 [ 34.199064] [] do_sys_open+0x30d/0x5c0 [ 34.204597] [] ? filp_open+0x70/0x70 [ 34.209958] [] ? up_read+0x1a/0x40 [ 34.215146] [] SyS_open+0x2d/0x40 [ 34.220247] [] ? do_sys_open+0x5c0/0x5c0 [ 34.225938] [] do_syscall_64+0x19f/0x550 [ 34.231754] [] entry_SYSCALL_64_after_swapgs+0x5d/0xdb [ 34.238681] [ 34.240303] Allocated by task 2068: [ 34.243918] save_stack_trace+0x16/0x20 [ 34.247876] kasan_kmalloc.part.1+0x62/0xf0 [ 34.252174] kasan_kmalloc+0xaf/0xc0 [ 34.255875] kmem_cache_alloc_trace+0x117/0x2e0 [ 34.260536] alloc_disk_node+0x54/0x3a0 [ 34.264507] alloc_disk+0x18/0x20 [ 34.267938] loop_add+0x368/0x7a0 [ 34.271369] loop_probe+0x14f/0x180 [ 34.274980] kobj_lookup+0x223/0x410 [ 34.278685] get_gendisk+0x39/0x2d0 [ 34.282300] __blkdev_get+0x351/0xd60 [ 34.286082] blkdev_get+0x2da/0x920 [ 34.289701] blkdev_open+0x1a5/0x250 [ 34.293406] do_dentry_open+0x3ef/0xc90 [ 34.297379] vfs_open+0x11c/0x210 [ 34.300842] path_openat+0x661/0x2d90 [ 34.304630] do_filp_open+0x197/0x270 [ 34.308418] do_sys_open+0x30d/0x5c0 [ 34.312124] SyS_open+0x2d/0x40 [ 34.315399] do_syscall_64+0x19f/0x550 [ 34.319284] entry_SYSCALL_64_after_swapgs+0x5d/0xdb [ 34.324369] [ 34.325977] Freed by task 2068: [ 34.329258] save_stack_trace+0x16/0x20 [ 34.333234] kasan_slab_free+0xac/0x190 [ 34.337204] kfree+0xfb/0x310 [ 34.340313] disk_release+0x259/0x330 [ 34.344108] device_release+0x7e/0x220 [ 34.347989] kobject_put+0x148/0x250 [ 34.351712] put_disk+0x23/0x30 [ 34.355000] __blkdev_get+0x616/0xd60 [ 34.358795] blkdev_get+0x2da/0x920 [ 34.362449] blkdev_open+0x1a5/0x250 [ 34.366150] do_dentry_open+0x3ef/0xc90 [ 34.370117] vfs_open+0x11c/0x210 [ 34.373607] path_openat+0x661/0x2d90 [ 34.377410] do_filp_open+0x197/0x270 [ 34.381201] do_sys_open+0x30d/0x5c0 [ 34.384924] SyS_open+0x2d/0x40 [ 34.388190] do_syscall_64+0x19f/0x550 [ 34.392076] entry_SYSCALL_64_after_swapgs+0x5d/0xdb [ 34.397166] [ 34.398782] The buggy address belongs to the object at ffff8801d77f5500 [ 34.398782] which belongs to the cache kmalloc-2048 of size 2048 [ 34.411591] The buggy address is located 1376 bytes inside of [ 34.411591] 2048-byte region [ffff8801d77f5500, ffff8801d77f5d00) [ 34.423628] The buggy address belongs to the page: [ 34.428543] page:ffffea00075dfc00 count:1 mapcount:0 mapping: (null) index:0x0 compound_mapcount: 0 [ 34.438824] flags: 0x4000000000004080(slab|head) [ 34.443557] page dumped because: kasan: bad access detected [ 34.449267] [ 34.450883] Memory state around the buggy address: [ 34.455817] ffff8801d77f5900: 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 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 34.463170] ffff8801d77f5980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 34.470533] >ffff8801d77f5a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 34.477873] ^ [ 34.484348] ffff8801d77f5a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 34.491703] ffff8801d77f5b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 34.499052] ================================================================== [ 34.506405] 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 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 34.517179] Kernel panic - not syncing: panic_on_warn set ... [ 34.517179] [ 34.524557] CPU: 0 PID: 2068 Comm: syz-executor902 Tainted: G B 4.9.142+ #73 [ 34.532860] ffff8801ce1a7650 ffffffff81b43969 ffffffff82e3a8a8 00000000ffffffff [ 34.540938] 0000000000000000 0000000000000000 0000000000000000 ffff8801ce1a7710 [ 34.549016] ffffffff813f71f5 0000000041b58ab3 ffffffff82e2e8a3 ffffffff813f7036 [ 34.557083] Call Trace: [ 34.559665] [] dump_stack+0xc1/0x128 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 34.565036] [] panic+0x1bf/0x39f [ 34.570060] [] ? add_taint.cold.5+0x16/0x16 [ 34.576058] [] ? ___preempt_schedule+0x16/0x18 [ 34.582287] [] kasan_end_report+0x47/0x4f [ 34.588080] [] kasan_report.cold.6+0x76/0x2fe [ 34.594506] [] ? disk_unblock_events+0x51/0x60 [ 34.600735] [] __asan_report_load8_noabort+0x14/0x20 [ 34.607488] [] disk_unblock_events+0x51/0x60 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 34.613549] [] __blkdev_get+0x6b6/0xd60 [ 34.619155] [] ? trace_hardirqs_on+0x10/0x10 [ 34.625288] [] ? __blkdev_put+0x840/0x840 [ 34.631067] [] ? fsnotify+0x114/0x1100 [ 34.636583] [] blkdev_get+0x2da/0x920 [ 34.642018] [] ? debug_lockdep_rcu_enabled+0x77/0x90 [ 34.648751] [] ? bd_may_claim+0xd0/0xd0 [ 34.654359] [] ? bd_acquire+0x27/0x250 [ 34.659982] [] ? 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 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 34.665606] [] ? _raw_spin_unlock+0x2c/0x50 [ 34.671563] [] blkdev_open+0x1a5/0x250 [ 34.677080] [] do_dentry_open+0x3ef/0xc90 [ 34.682857] [] ? blkdev_get_by_dev+0x70/0x70 [ 34.688896] [] vfs_open+0x11c/0x210 [ 34.694156] [] ? may_open.isra.21+0x14f/0x2a0 [ 34.700286] [] path_openat+0x661/0x2d90 [ 34.705889] [] ? path_mountpoint+0x6c0/0x6c0 [ 34.711928] [] ? trace_hardirqs_on+0x10/0x10 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 34.717963] [] ? expand_files.part.3+0x3a9/0x6d0 [ 34.724344] [] do_filp_open+0x197/0x270 [ 34.730094] [] ? may_open_dev+0xe0/0xe0 [ 34.735812] [] ? _raw_spin_unlock+0x2c/0x50 [ 34.741921] [] ? __alloc_fd+0x1d7/0x4a0 [ 34.747538] [] do_sys_open+0x30d/0x5c0 [ 34.753146] [] ? filp_open+0x70/0x70 [ 34.758496] [] ? up_read+0x1a/0x40 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 34.763767] [] SyS_open+0x2d/0x40 [ 34.768960] [] ? do_sys_open+0x5c0/0x5c0 [ 34.774647] [] do_syscall_64+0x19f/0x550 [ 34.780337] [] entry_SYSCALL_64_after_swapgs+0x5d/0xdb [ 34.787535] Kernel Offset: disabled [ 34.791142] Rebooting in 86400 seconds..