[....] Starting enhanced syslogd: rsyslogd[ 14.790956] audit: type=1400 audit(1563356100.829:4): avc: denied { syslog } for pid=1919 comm="rsyslogd" capability=34 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:system_r:kernel_t:s0 tclass=capability2 permissive=1 [?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. Starting mcstransd: [....] Starting periodic command scheduler: cron[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. [....] Starting file context maintaining daemon: restorecond[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added '10.128.0.50' (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 syzkaller login: [ 47.850528] ================================================================== [ 47.857938] BUG: KASAN: use-after-free in disk_unblock_events+0x55/0x60 [ 47.864687] Read of size 8 at addr ffff8800b6f7e2e8 by task syz-executor280/2094 [ 47.872208] [ 47.873830] CPU: 0 PID: 2094 Comm: syz-executor280 Not tainted 4.4.174+ #17 [ 47.880916] 0000000000000000 933f5ee786ab420f ffff8800b65af6c0 ffffffff81aad1a1 [ 47.888983] 0000000000000000 ffffea0002dbde00 ffff8800b6f7e2e8 0000000000000008 executing program executing program executing program executing program executing program [ 47.897043] 0000000000000000 ffff8800b65af6f8 ffffffff81490120 0000000000000000 [ 47.905130] Call Trace: [ 47.907752] [] dump_stack+0xc1/0x120 [ 47.913113] [] print_address_description+0x6f/0x21b [ 47.919865] [] kasan_report.cold+0x8c/0x2be [ 47.925834] [] ? disk_unblock_events+0x55/0x60 [ 47.932066] [] __asan_report_load8_noabort+0x14/0x20 [ 47.938824] [] disk_unblock_events+0x55/0x60 [ 47.944877] [] __blkdev_get+0x70c/0xdf0 executing program executing program executing program executing program executing program [ 47.950500] [] ? __blkdev_put+0x840/0x840 [ 47.956300] [] ? blkdev_get_block+0x80/0x80 [ 47.962268] [] ? __might_sleep+0x90/0x1a0 [ 47.968090] [] blkdev_get+0x2e8/0x920 [ 47.973536] [] ? bd_may_claim+0xd0/0xd0 [ 47.979156] [] ? bd_acquire+0x133/0x370 [ 47.984779] [] ? _raw_spin_unlock+0x2d/0x50 [ 47.990747] [] blkdev_open+0x1aa/0x250 executing program executing program executing program executing program executing program [ 47.996283] [] do_dentry_open+0x38f/0xbd0 [ 48.002078] [] ? __inode_permission2+0x9e/0x250 [ 48.008395] [] ? blkdev_get_by_dev+0x80/0x80 [ 48.014456] [] vfs_open+0x10b/0x210 [ 48.019735] [] ? may_open.isra.0+0xe7/0x210 [ 48.025714] [] path_openat+0x136f/0x4470 [ 48.031432] [] ? kasan_kmalloc.part.0+0xc6/0xf0 [ 48.037757] [] ? may_open.isra.0+0x210/0x210 [ 48.043813] [] ? 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 [ 48.049873] [] do_filp_open+0x1a1/0x270 [ 48.055501] [] ? user_path_mountpoint_at+0x50/0x50 [ 48.062075] [] ? do_dup2+0x3d0/0x3d0 [ 48.067435] [] ? _raw_spin_unlock+0x2d/0x50 [ 48.073410] [] do_sys_open+0x2f8/0x600 [ 48.078944] [] ? filp_open+0x70/0x70 [ 48.084305] [] ? __do_page_fault+0x2b3/0x7f0 [ 48.090360] [] compat_SyS_open+0x2a/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 [ 48.096072] [] ? compat_SyS_getdents64+0x270/0x270 [ 48.102650] [] do_fast_syscall_32+0x32d/0xa90 [ 48.108804] [] sysenter_flags_fixed+0xd/0x1a [ 48.114851] [ 48.116470] Allocated by task 2094: [ 48.120089] [] save_stack_trace+0x26/0x50 [ 48.126022] [] kasan_kmalloc.part.0+0x62/0xf0 [ 48.132295] [] kasan_kmalloc+0xb7/0xd0 [ 48.137957] [] kmem_cache_alloc_trace+0x123/0x2d0 [ 48.144582] [] alloc_disk_node+0x50/0x3c0 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 48.150510] [] alloc_disk+0x1b/0x20 [ 48.155913] [] loop_add+0x380/0x830 [ 48.161318] [] loop_control_ioctl+0x138/0x2f0 [ 48.167589] [] compat_SyS_ioctl+0x403/0x2210 [ 48.173779] [] do_fast_syscall_32+0x32d/0xa90 [ 48.180054] [] sysenter_flags_fixed+0xd/0x1a [ 48.186254] [ 48.187874] Freed by task 2094: [ 48.191141] [] save_stack_trace+0x26/0x50 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 [ 48.197068] [] kasan_slab_free+0xb0/0x190 [ 48.202998] [] kfree+0xf4/0x310 [ 48.208054] [] disk_release+0x255/0x330 [ 48.213812] [] device_release+0x7d/0x220 [ 48.219655] [] kobject_put+0x14c/0x260 [ 48.225325] [] put_disk+0x23/0x30 [ 48.230559] [] __blkdev_get+0x66c/0xdf0 [ 48.236311] [] blkdev_get+0x2e8/0x920 [ 48.241891] [] blkdev_open+0x1aa/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 [ 48.247562] [] do_dentry_open+0x38f/0xbd0 [ 48.253580] [] vfs_open+0x10b/0x210 [ 48.258984] [] path_openat+0x136f/0x4470 [ 48.264824] [] do_filp_open+0x1a1/0x270 [ 48.270577] [] do_sys_open+0x2f8/0x600 [ 48.276256] [] compat_SyS_open+0x2a/0x40 [ 48.282604] [] do_fast_syscall_32+0x32d/0xa90 [ 48.289079] [] sysenter_flags_fixed+0xd/0x1a [ 48.295277] executing program executing program executing program executing program executing program executing program executing program executing program [ 48.296907] The buggy address belongs to the object at ffff8800b6f7dd80 [ 48.296907] which belongs to the cache kmalloc-2048 of size 2048 [ 48.309740] The buggy address is located 1384 bytes inside of [ 48.309740] 2048-byte region [ffff8800b6f7dd80, ffff8800b6f7e580) [ 48.322224] The buggy address belongs to the page: [[ 48.328253] kasan: CONFIG_KASAN_INLINE enabled [ 48.328260] kasan: GPF could be caused by NULL-ptr deref or user memory access [ 48.328265] general protection fault: 0000 [#1] PREEMPT SMP KASAN [ 48.328269] Modules linked in: [ 48.328277] CPU: 1 PID: -1225269888 Comm: @‡¶ Not tainted 4.4.174+ #17 [ 48.328282] task: ffff8800b61a8000 task.stack: ffffffff8142ac50 [ 48.328305] RIP: 0010:[] [] dump_page_badflags+0x30/0x70 [ 48.328310] RSP: 0018:ffff8800b614f410 EFLAGS: 00010007 [ 48.328314] RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000001 [ 48.328319] RDX: 0000000360adf29f RSI: ffffffff8142abdf RDI: 0000001b056f94fe [ 48.328323] RBP: ffff8800b614f440 R08: 0000000000000001 R09: 0000000000000000 [ 48.328327] R10: 0000000000000001 R11: ffffffff83fdf193 R12: 0000001b056f94fe [ 48.328331] R13: ffffffff82891be0 R14: 00000000000008fd R15: fffffbfff092dca5 [ 48.328337] FS: 0000000000000000(0000) GS:ffff8801db700000(0063) knlGS:00000000087cf840 [ 48.328342] CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 [ 48.328346] CR2: ffff8800b6537a00 CR3: 00000000b6fe5000 CR4: 00000000001606b0 [ 48.328352] Stack: [ 48.328362] ffff8800b614f450 0000001b056f9cd8 0000001b056f94fe ffffffff82891be0 [ 48.328370] 00000000000008fd fffffbfff092dca5 ffff8800b614f460 ffffffff8142ac50 [ 48.328379] 0000001b056f94fe 0000000000000001 ffff8800b614f4a0 ffffffff8142ac16 [ 48.328380] Call Trace: [ 48.328385] [ 48.328478] Code: 57 41 56 41 55 49 89 f5 41 54 49 89 fc 53 48 89 d3 48 83 ec 08 e8 11 ea ed ff 4c 89 e2 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <80> 3c 02 00 75 22 49 8b 04 24 a8 80 0f 84 fa 34 06 00 e8 e9 e9 [ 48.328486] RIP [] dump_page_badflags+0x30/0x70 [ 48.328489] RSP [ 48.328493] ---[ end trace 3c6aec468e5d4d6f ]--- [ 48.328497] Kernel panic - not syncing: Fatal exception [ 49.445659] Shutting down cpus with NMI [ 49.446536] Kernel Offset: disabled [ 49.628684] Rebooting in 86400 seconds..