[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. Starting mcstransd: [ 9.668395] random: sshd: uninitialized urandom read (32 bytes read) [....] 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 syzkaller login: [ 34.605257] random: sshd: uninitialized urandom read (32 bytes read) [ 34.862585] random: crng init done Warning: Permanently added '10.128.0.127' (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 [ 57.731010] ================================================================== [ 57.738409] BUG: KASAN: use-after-free in disk_unblock_events+0x55/0x60 [ 57.745187] Read of size 8 at addr ffff8801cd9851e0 by task syz-executor373/2139 [ 57.752704] [ 57.754321] CPU: 0 PID: 2139 Comm: syz-executor373 Not tainted 4.9.180+ #4 [ 57.761319] ffff8801cc5e7730 ffffffff81b577f1 0000000000000000 ffffea0007366000 [ 57.769345] ffff8801cd9851e0 0000000000000008 ffffffff81b29db5 ffff8801cc5e7768 executing program executing program executing program executing program executing program executing program [ 57.777470] ffffffff8150a828 0000000000000000 ffff8801cd9851e0 ffff8801cd9851e0 [ 57.785802] Call Trace: [ 57.788374] [<0000000091cc273a>] dump_stack+0xc1/0x120 [ 57.793725] [<000000009adf56b8>] ? disk_unblock_events+0x55/0x60 [ 57.799946] [<000000009e85b44b>] print_address_description+0x6f/0x23a [ 57.806600] [<000000009adf56b8>] ? disk_unblock_events+0x55/0x60 [ 57.812966] [<000000003c53c5da>] kasan_report.cold+0x8c/0x2ba [ 57.818927] [<0000000021172718>] __asan_report_load8_noabort+0x14/0x20 executing program executing program [ 57.825666] [<000000009adf56b8>] disk_unblock_events+0x55/0x60 [ 57.831713] [<00000000dba0208b>] __blkdev_get+0x6ba/0xeb0 [ 57.837335] [<0000000081dbc2ef>] ? __blkdev_put+0x840/0x840 [ 57.843126] [<000000000a3fb96e>] blkdev_get+0x2e8/0x920 [ 57.848679] [<0000000058abefee>] ? debug_lockdep_rcu_enabled+0x71/0xa0 [ 57.855420] [<00000000278d59c1>] ? bd_may_claim+0xd0/0xd0 [ 57.861251] [<000000007e67af46>] ? bd_acquire+0x26/0x250 [ 57.866772] [<000000006ffd8677>] ? bd_acquire+0x88/0x250 [ 57.872313] [<00000000a5c8e1e7>] ? _raw_spin_unlock+0x2d/0x50 [ 57.878426] [<000000003af2277f>] blkdev_open+0x1aa/0x250 [ 57.884272] [<00000000809a2ae2>] do_dentry_open+0x422/0xd20 [ 57.890058] [<0000000044f4fa7a>] ? blkdev_get_by_dev+0x80/0x80 [ 57.896199] [<0000000000074afb>] vfs_open+0x105/0x230 [ 57.901474] [<000000003c620abb>] ? may_open.isra.0+0x139/0x290 [ 57.907693] [<00000000860a18a7>] path_openat+0xbf5/0x2f60 [ 57.913401] [<000000006cbf6915>] ? path_mountpoint+0x6d0/0x6d0 [ 57.919516] [<000000002ff33d60>] do_filp_open+0x1a1/0x280 [ 57.925300] [<00000000b8f15f68>] ? may_open_dev+0xe0/0xe0 [ 57.931040] [<0000000072a02f99>] ? __alloc_fd+0x1d4/0x490 [ 57.936925] [<00000000a5c8e1e7>] ? _raw_spin_unlock+0x2d/0x50 [ 57.942906] [<0000000072a02f99>] ? __alloc_fd+0x1d4/0x490 [ 57.948664] [<000000007ec3c4e6>] do_sys_open+0x2f0/0x610 [ 57.954289] [<000000005e599dc7>] ? filp_open+0x70/0x70 [ 57.959641] [<0000000098b73b40>] ? __do_page_fault+0x545/0xa60 [ 57.965688] [<0000000029bb6277>] SyS_open+0x2d/0x40 [ 57.970776] [<000000002beb2728>] ? do_sys_open+0x610/0x610 [ 57.976585] [<00000000157ea0a4>] do_syscall_64+0x1ad/0x5c0 [ 57.982292] [<0000000000fe8c12>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb [ 57.989302] [ 57.990923] Allocated by task 2139: [ 57.994539] save_stack_trace+0x16/0x20 [ 57.998501] kasan_kmalloc.part.0+0x62/0xf0 [ 58.002899] kasan_kmalloc+0xb7/0xd0 [ 58.006592] kmem_cache_alloc_trace+0x115/0x2d0 [ 58.011339] alloc_disk_node+0x50/0x3c0 [ 58.015300] alloc_disk+0x1b/0x20 [ 58.018775] loop_add+0x37e/0x7d0 [ 58.022231] loop_control_ioctl+0x220/0x320 [ 58.026539] do_vfs_ioctl+0xb87/0x11d0 [ 58.030627] SyS_ioctl+0x8f/0xc0 [ 58.033980] do_syscall_64+0x1ad/0x5c0 [ 58.037854] entry_SYSCALL_64_after_swapgs+0x5d/0xdb [ 58.042935] [ 58.044582] Freed by task 2139: [ 58.047853] save_stack_trace+0x16/0x20 [ 58.052105] kasan_slab_free+0xb0/0x190 [ 58.056104] kfree+0xfc/0x310 [ 58.059209] disk_release+0x255/0x330 [ 58.062993] device_release+0x7d/0x220 [ 58.066865] kobject_put+0x150/0x260 [ 58.070558] put_disk+0x23/0x30 [ 58.073828] __blkdev_get+0x61a/0xeb0 [ 58.077700] blkdev_get+0x2e8/0x920 [ 58.081311] blkdev_open+0x1aa/0x250 [ 58.085011] do_dentry_open+0x422/0xd20 [ 58.088976] vfs_open+0x105/0x230 [ 58.092430] path_openat+0xbf5/0x2f60 [ 58.096223] do_filp_open+0x1a1/0x280 [ 58.100012] do_sys_open+0x2f0/0x610 [ 58.103723] SyS_open+0x2d/0x40 [ 58.107025] do_syscall_64+0x1ad/0x5c0 [ 58.110951] entry_SYSCALL_64_after_swapgs+0x5d/0xdb [ 58.116253] [ 58.117886] The buggy address belongs to the object at ffff8801cd984c80 [ 58.117886] which belongs to the cache kmalloc-2048 of size 2048 [ 58.130719] The buggy address is located 1376 bytes inside of [ 58.130719] 2048-byte region [ffff8801cd984c80, ffff8801cd985480) [ 58.142762] The buggy address belongs to the page: [ 58.147691] page:ffffea0007366000 count:1 mapcount:0 mapping: (null) index:0x0 compound_mapcount: 0 [ 58.157933] flags: 0x4000000000010200(slab|head) [ 58.162681] page dumped because: kasan: bad access detected [ 58.168385] [ 58.170016] Memory state around the buggy address: [ 58.174951] ffff8801cd985080: 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 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 58.182310] ffff8801cd985100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 58.189679] >ffff8801cd985180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 58.197031] ^ [ 58.203538] ffff8801cd985200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 58.210904] ffff8801cd985280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 58.218346] ================================================================== [ 58.225701] Disabling lock debugging due to kernel taint executing program executing program executing program executing program executing program executing program executing program [ 58.241639] Kernel panic - not syncing: panic_on_warn set ... [ 58.241639] [ 58.249024] CPU: 0 PID: 2139 Comm: syz-executor373 Tainted: G B 4.9.180+ #4 [ 58.257246] ffff8801cc5e7670 ffffffff81b577f1 ffff8801cc5e7700 ffffffff82e3eca7 [ 58.265364] 00000000ffffffff 0000000000000000 ffffffff81b29db5 ffff8801cc5e7750 [ 58.273459] ffffffff813fd2fa 0000000041b58ab3 ffffffff82e30d0a ffffffff813fd121 [ 58.281559] Call Trace: [ 58.284234] [<0000000091cc273a>] dump_stack+0xc1/0x120 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 58.289601] [<000000009adf56b8>] ? disk_unblock_events+0x55/0x60 [ 58.295834] [<00000000fc28ff8c>] panic+0x1d9/0x3bd [ 58.300940] [<000000007dfb7481>] ? add_taint.cold+0x16/0x16 [ 58.306741] [<000000003c9e80bf>] ? preempt_schedule_common+0x4f/0xe0 [ 58.313330] [<000000009adf56b8>] ? disk_unblock_events+0x55/0x60 [ 58.319655] [<000000001a4cab86>] ? preempt_schedule+0x26/0x30 [ 58.325635] [<00000000a263bb63>] ? ___preempt_schedule+0x16/0x18 [ 58.331874] [<0000000047786566>] kasan_end_report+0x47/0x4f executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 58.337677] [<00000000f3d58200>] kasan_report.cold+0xa9/0x2ba [ 58.343655] [<0000000021172718>] __asan_report_load8_noabort+0x14/0x20 [ 58.350414] [<000000009adf56b8>] disk_unblock_events+0x55/0x60 [ 58.356481] [<00000000dba0208b>] __blkdev_get+0x6ba/0xeb0 [ 58.362195] [<0000000081dbc2ef>] ? __blkdev_put+0x840/0x840 [ 58.368009] [<000000000a3fb96e>] blkdev_get+0x2e8/0x920 [ 58.373469] [<0000000058abefee>] ? debug_lockdep_rcu_enabled+0x71/0xa0 [ 58.380230] [<00000000278d59c1>] ? bd_may_claim+0xd0/0xd0 [ 58.385855] [<000000007e67af46>] ? bd_acquire+0x26/0x250 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 [ 58.391390] [<000000006ffd8677>] ? bd_acquire+0x88/0x250 [ 58.396927] [<00000000a5c8e1e7>] ? _raw_spin_unlock+0x2d/0x50 [ 58.402906] [<000000003af2277f>] blkdev_open+0x1aa/0x250 [ 58.408445] [<00000000809a2ae2>] do_dentry_open+0x422/0xd20 [ 58.414250] [<0000000044f4fa7a>] ? blkdev_get_by_dev+0x80/0x80 [ 58.420308] [<0000000000074afb>] vfs_open+0x105/0x230 [ 58.425589] [<000000003c620abb>] ? may_open.isra.0+0x139/0x290 [ 58.431650] [<00000000860a18a7>] path_openat+0xbf5/0x2f60 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 58.437276] [<000000006cbf6915>] ? path_mountpoint+0x6d0/0x6d0 [ 58.443341] [<000000002ff33d60>] do_filp_open+0x1a1/0x280 [ 58.448966] [<00000000b8f15f68>] ? may_open_dev+0xe0/0xe0 [ 58.454596] [<0000000072a02f99>] ? __alloc_fd+0x1d4/0x490 [ 58.460266] [<00000000a5c8e1e7>] ? _raw_spin_unlock+0x2d/0x50 [ 58.466239] [<0000000072a02f99>] ? __alloc_fd+0x1d4/0x490 [ 58.471864] [<000000007ec3c4e6>] do_sys_open+0x2f0/0x610 [ 58.477414] [<000000005e599dc7>] ? filp_open+0x70/0x70 [ 58.482785] [<0000000098b73b40>] ? __do_page_fault+0x545/0xa60 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 58.488852] [<0000000029bb6277>] SyS_open+0x2d/0x40 [ 58.493952] [<000000002beb2728>] ? do_sys_open+0x610/0x610 [ 58.499666] [<00000000157ea0a4>] do_syscall_64+0x1ad/0x5c0 [ 58.505392] [<0000000000fe8c12>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb [ 58.512690] Kernel Offset: disabled [ 58.516418] Rebooting in 86400 seconds..