[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 11.805595] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 22.385334] random: sshd: uninitialized urandom read (32 bytes read) [ 22.806349] random: sshd: uninitialized urandom read (32 bytes read) [ 23.430999] random: sshd: uninitialized urandom read (32 bytes read) [ 27.134267] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.0.35' (ECDSA) to the list of known hosts. [ 32.585457] random: sshd: uninitialized urandom read (32 bytes read) executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 38.125712] ================================================================== [ 38.133128] BUG: KASAN: use-after-free in disk_unblock_events+0x51/0x60 [ 38.139865] Read of size 8 at addr ffff8801d5792fe0 by task blkid/4016 [ 38.146501] [ 38.148114] CPU: 1 PID: 4016 Comm: blkid Not tainted 4.9.98-g9731a2d #22 [ 38.154924] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 38.164251] ffff8801d53ff6d8 ffffffff81eb0ee9 ffffea000755e400 ffff8801d5792fe0 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 38.172250] 0000000000000000 ffff8801d5792fe0 0000000000000000 ffff8801d53ff710 [ 38.180232] ffffffff815652cb ffff8801d5792fe0 0000000000000008 0000000000000000 [ 38.188226] Call Trace: [ 38.190800] [] dump_stack+0xc1/0x128 [ 38.196139] [] print_address_description+0x6c/0x234 [ 38.202778] [] kasan_report.cold.6+0x242/0x2fe [ 38.208986] [] ? disk_unblock_events+0x51/0x60 [ 38.215190] [] __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 executing program executing program executing program executing program executing program executing program executing program executing program [ 38.221917] [] disk_unblock_events+0x51/0x60 [ 38.227953] [] __blkdev_get+0x6b6/0xd60 [ 38.233551] [] ? __blkdev_put+0x840/0x840 [ 38.239332] [] ? fsnotify+0x114/0x1100 [ 38.244854] [] blkdev_get+0x2da/0x920 [ 38.250278] [] ? bd_may_claim+0xd0/0xd0 [ 38.255872] [] ? bd_acquire+0x27/0x250 [ 38.261380] [] ? bd_acquire+0x88/0x250 [ 38.266891] [] ? _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 [ 38.272837] [] blkdev_open+0x1a5/0x250 [ 38.278349] [] do_dentry_open+0x703/0xc80 [ 38.284120] [] ? blkdev_get_by_dev+0x70/0x70 [ 38.290154] [] vfs_open+0x11c/0x210 [ 38.295405] [] ? may_open.isra.57+0x14f/0x2a0 [ 38.301524] [] path_openat+0x758/0x3590 [ 38.307119] [] ? save_stack+0xa9/0xd0 [ 38.312542] [] ? path_lookupat.isra.41+0x410/0x410 [ 38.319096] [] ? __lock_is_held+0xa2/0xf0 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 38.324871] [] do_filp_open+0x197/0x270 [ 38.330472] [] ? may_open_dev+0xe0/0xe0 [ 38.336083] [] ? _raw_spin_unlock+0x2c/0x50 [ 38.342118] [] ? __alloc_fd+0x1d7/0x4a0 [ 38.347733] [] do_sys_open+0x30d/0x5c0 [ 38.353606] [] ? filp_open+0x70/0x70 [ 38.358957] [] ? up_read+0x1a/0x40 [ 38.364142] [] ? __do_page_fault+0x183/0xd50 [ 38.370178] [] SyS_open+0x2d/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 [ 38.375257] [] ? do_sys_open+0x5c0/0x5c0 [ 38.380946] [] do_syscall_64+0x1a6/0x490 [ 38.386630] [] entry_SYSCALL_64_after_swapgs+0x5d/0xdb [ 38.393526] [ 38.395124] Allocated by task 4004: [ 38.398736] save_stack_trace+0x16/0x20 [ 38.402693] save_stack+0x43/0xd0 [ 38.406124] kasan_kmalloc+0xc7/0xe0 [ 38.409820] kmem_cache_alloc_trace+0xfd/0x2b0 [ 38.414460] alloc_disk_node+0x54/0x3a0 [ 38.418410] alloc_disk+0x18/0x20 [ 38.421852] loop_add+0x33b/0x770 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 38.425281] loop_probe+0x14f/0x180 [ 38.428879] kobj_lookup+0x223/0x410 [ 38.432567] get_gendisk+0x39/0x2d0 [ 38.436167] blkdev_get+0xf6/0x920 [ 38.439692] blkdev_open+0x1a5/0x250 [ 38.443380] do_dentry_open+0x703/0xc80 [ 38.447325] vfs_open+0x11c/0x210 [ 38.450751] path_openat+0x758/0x3590 [ 38.454523] do_filp_open+0x197/0x270 [ 38.458301] do_sys_open+0x30d/0x5c0 [ 38.461986] SyS_open+0x2d/0x40 [ 38.465239] do_syscall_64+0x1a6/0x490 [ 38.469099] entry_SYSCALL_64_after_swapgs+0x5d/0xdb [ 38.474177] executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 38.475775] Freed by task 4016: [ 38.479039] save_stack_trace+0x16/0x20 [ 38.482984] save_stack+0x43/0xd0 [ 38.486410] kasan_slab_free+0x72/0xc0 [ 38.490270] kfree+0xfb/0x310 [ 38.493347] disk_release+0x259/0x330 [ 38.497130] device_release+0x7e/0x220 [ 38.500992] kobject_release+0x103/0x1b0 [ 38.505025] kobject_put+0x6d/0xd0 [ 38.508537] put_disk+0x23/0x30 [ 38.511790] __blkdev_get+0x616/0xd60 [ 38.515573] blkdev_get+0x2da/0x920 [ 38.519171] blkdev_open+0x1a5/0x250 [ 38.522859] do_dentry_open+0x703/0xc80 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 38.526820] vfs_open+0x11c/0x210 [ 38.530249] path_openat+0x758/0x3590 [ 38.534021] do_filp_open+0x197/0x270 [ 38.537794] do_sys_open+0x30d/0x5c0 [ 38.541490] SyS_open+0x2d/0x40 [ 38.544743] do_syscall_64+0x1a6/0x490 [ 38.548612] entry_SYSCALL_64_after_swapgs+0x5d/0xdb [ 38.553685] [ 38.555286] The buggy address belongs to the object at ffff8801d5792a80 [ 38.555286] which belongs to the cache kmalloc-2048 of size 2048 [ 38.568096] The buggy address is located 1376 bytes inside of executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 38.568096] 2048-byte region [ffff8801d5792a80, ffff8801d5793280) [ 38.580113] The buggy address belongs to the page: [ 38.585016] page:ffffea000755e400 count:1 mapcount:0 mapping: (null) index:0x0 compound_mapcount: 0 [ 38.595195] flags: 0x8000000000004080(slab|head) [ 38.599920] page dumped because: kasan: bad access detected [ 38.605597] [ 38.607197] Memory state around the buggy address: [ 38.612097] ffff8801d5792e80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 38.619426] ffff8801d5792f00: 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 [ 38.626756] >ffff8801d5792f80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 38.634085] ^ [ 38.640548] ffff8801d5793000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 38.647878] ffff8801d5793080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 38.655211] ================================================================== [ 38.662540] 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 [ 38.686986] Kernel panic - not syncing: panic_on_warn set ... [ 38.686986] [ 38.694372] CPU: 1 PID: 4016 Comm: blkid Tainted: G B 4.9.98-g9731a2d #22 [ 38.702396] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 38.711726] ffff8801d53ff638 ffffffff81eb0ee9 ffffffff843c4fe5 00000000ffffffff [ 38.719710] 0000000000000000 0000000000000001 0000000000000000 ffff8801d53ff6f8 [ 38.727690] ffffffff8141f835 0000000041b58ab3 ffffffff843b86e8 ffffffff8141f676 [ 38.735673] Call Trace: [ 38.738342] [] dump_stack+0xc1/0x128 [ 38.743681] [] panic+0x1bf/0x3bc [ 38.748669] [] ? add_taint.cold.6+0x16/0x16 [ 38.754613] [] ? ___preempt_schedule+0x16/0x18 [ 38.760816] [] kasan_end_report+0x47/0x4f [ 38.766585] [] kasan_report.cold.6+0x76/0x2fe [ 38.772706] [] ? disk_unblock_events+0x51/0x60 [ 38.778912] [] __asan_report_load8_noabort+0x14/0x20 [ 38.785639] [] disk_unblock_events+0x51/0x60 [ 38.791669] [] __blkdev_get+0x6b6/0xd60 [ 38.797269] [] ? __blkdev_put+0x840/0x840 [ 38.803049] [] ? fsnotify+0x114/0x1100 [ 38.808559] [] blkdev_get+0x2da/0x920 [ 38.813984] [] ? bd_may_claim+0xd0/0xd0 [ 38.819579] [] ? bd_acquire+0x27/0x250 [ 38.825088] [] ? bd_acquire+0x88/0x250 [ 38.830602] [] ? _raw_spin_unlock+0x2c/0x50 [ 38.836547] [] blkdev_open+0x1a5/0x250 [ 38.842056] [] do_dentry_open+0x703/0xc80 [ 38.847825] [] ? blkdev_get_by_dev+0x70/0x70 [ 38.853855] [] vfs_open+0x11c/0x210 [ 38.859103] [] ? may_open.isra.57+0x14f/0x2a0 [ 38.865221] [] path_openat+0x758/0x3590 [ 38.870820] [] ? save_stack+0xa9/0xd0 [ 38.876331] [] ? path_lookupat.isra.41+0x410/0x410 [ 38.882892] [] ? __lock_is_held+0xa2/0xf0 [ 38.888666] [] do_filp_open+0x197/0x270 [ 38.894263] [] ? may_open_dev+0xe0/0xe0 [ 38.899861] [] ? _raw_spin_unlock+0x2c/0x50 [ 38.905806] [] ? __alloc_fd+0x1d7/0x4a0 [ 38.911401] [] do_sys_open+0x30d/0x5c0 [ 38.916911] [] ? filp_open+0x70/0x70 [ 38.922258] [] ? up_read+0x1a/0x40 [ 38.927424] [] ? __do_page_fault+0x183/0xd50 [ 38.933454] [] SyS_open+0x2d/0x40 [ 38.938530] [] ? do_sys_open+0x5c0/0x5c0 [ 38.944216] [] do_syscall_64+0x1a6/0x490 [ 38.949901] [] entry_SYSCALL_64_after_swapgs+0x5d/0xdb [ 38.957214] Dumping ftrace buffer: [ 38.960729] (ftrace buffer empty) [ 38.964414] Kernel Offset: disabled [ 38.968026] Rebooting in 86400 seconds..