[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 66.521124][ T25] audit: type=1800 audit(1575432790.631:25): pid=9061 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 66.541061][ T25] audit: type=1800 audit(1575432790.641:26): pid=9061 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 66.591216][ T25] audit: type=1800 audit(1575432790.641:27): pid=9061 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="restorecond" dev="sda1" ino=2436 res=0 [....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added '10.128.10.29' (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 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program 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: [ 91.263742][ T9474] ================================================================== [ 91.272055][ T9474] BUG: KASAN: use-after-free in tty_open+0x6f8/0xbb0 [ 91.279521][ T9474] Read of size 8 at addr ffff88809ff8d200 by task syz-executor163/9474 [ 91.287754][ T9474] [ 91.290080][ T9474] CPU: 0 PID: 9474 Comm: syz-executor163 Not tainted 5.4.0-syzkaller #0 [ 91.298384][ T9474] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 91.309207][ T9474] Call Trace: [ 91.312503][ T9474] dump_stack+0x197/0x210 [ 91.316970][ T9474] ? tty_open+0x6f8/0xbb0 [ 91.321312][ T9474] print_address_description.constprop.0.cold+0xd4/0x30b [ 91.328337][ T9474] ? tty_open+0x6f8/0xbb0 [ 91.332871][ T9474] ? tty_open+0x6f8/0xbb0 [ 91.337209][ T9474] __kasan_report.cold+0x1b/0x41 [ 91.342134][ T9474] ? tty_open+0x6f8/0xbb0 [ 91.346473][ T9474] kasan_report+0x12/0x20 [ 91.350994][ T9474] check_memory_region+0x134/0x1a0 [ 91.356094][ T9474] __kasan_check_read+0x11/0x20 [ 91.360938][ T9474] tty_open+0x6f8/0xbb0 [ 91.365096][ T9474] ? tty_init_dev+0x460/0x460 [ 91.370012][ T9474] ? do_raw_spin_unlock+0x178/0x270 [ 91.375321][ T9474] ? tty_init_dev+0x460/0x460 [ 91.380023][ T9474] chrdev_open+0x245/0x6b0 [ 91.384539][ T9474] ? cdev_put.part.0+0x50/0x50 [ 91.389313][ T9474] ? security_file_open+0x87/0x300 [ 91.394513][ T9474] do_dentry_open+0x4e6/0x1380 [ 91.399319][ T9474] ? __kasan_check_read+0x11/0x20 [ 91.404371][ T9474] ? cdev_put.part.0+0x50/0x50 [ 91.409145][ T9474] ? chown_common+0x5c0/0x5c0 [ 91.414020][ T9474] ? inode_permission+0xb4/0x520 [ 91.418991][ T9474] vfs_open+0xa0/0xd0 [ 91.422989][ T9474] path_openat+0x10e4/0x4710 [ 91.427578][ T9474] ? __kasan_kmalloc.constprop.0+0xcf/0xe0 [ 91.433446][ T9474] ? kasan_slab_alloc+0xf/0x20 [ 91.438225][ T9474] ? kmem_cache_alloc+0x121/0x710 [ 91.443253][ T9474] ? getname_flags+0xd6/0x5b0 [ 91.448240][ T9474] ? getname+0x1a/0x20 [ 91.452317][ T9474] ? do_sys_open+0x2c9/0x5d0 [ 91.457020][ T9474] ? path_lookupat.isra.0+0x8d0/0x8d0 [ 91.462387][ T9474] ? __alloc_fd+0x487/0x620 [ 91.466879][ T9474] do_filp_open+0x1a1/0x280 [ 91.471475][ T9474] ? may_open_dev+0x100/0x100 [ 91.476194][ T9474] ? do_raw_spin_unlock+0x178/0x270 [ 91.481518][ T9474] ? _raw_spin_unlock+0x28/0x40 [ 91.486668][ T9474] ? __alloc_fd+0x487/0x620 [ 91.491273][ T9474] do_sys_open+0x3fe/0x5d0 [ 91.496040][ T9474] ? filp_open+0x80/0x80 [ 91.500370][ T9474] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 91.505837][ T9474] ? do_syscall_64+0x26/0x790 [ 91.510511][ T9474] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 91.517019][ T9474] ? do_syscall_64+0x26/0x790 [ 91.521725][ T9474] __x64_sys_open+0x7e/0xc0 [ 91.526341][ T9474] do_syscall_64+0xfa/0x790 [ 91.531043][ T9474] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 91.536936][ T9474] RIP: 0033:0x401140 [ 91.540831][ T9474] Code: 01 f0 ff ff 0f 83 c0 0b 00 00 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 83 3d 8d 55 2d 00 00 75 14 b8 02 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 94 0b 00 00 c3 48 83 ec 08 e8 fa 00 00 00 [ 91.561984][ T9474] RSP: 002b:00007ffda2635c48 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 [ 91.570418][ T9474] RAX: ffffffffffffffda RBX: 6666666666666667 RCX: 0000000000401140 [ 91.578562][ T9474] RDX: 0000000000000000 RSI: 0000000000101000 RDI: 00007ffda2635c70 [ 91.586985][ T9474] RBP: 000000000001640b R08: 000000000000000f R09: 00000000004002e0 [ 91.595178][ T9474] R10: 000000000000000f R11: 0000000000000246 R12: 0000000000402160 [ 91.603417][ T9474] R13: 00000000004021f0 R14: 0000000000000000 R15: 0000000000000000 [ 91.611500][ T9474] [ 91.614102][ T9474] Allocated by task 9472: [ 91.618978][ T9474] save_stack+0x23/0x90 [ 91.623147][ T9474] __kasan_kmalloc.constprop.0+0xcf/0xe0 [ 91.629158][ T9474] kasan_kmalloc+0x9/0x10 [ 91.633500][ T9474] kmem_cache_alloc_trace+0x158/0x790 [ 91.638877][ T9474] vc_allocate+0x1fc/0x760 [ 91.643278][ T9474] con_install+0x52/0x410 [ 91.647589][ T9474] tty_init_dev+0xf7/0x460 [ 91.652017][ T9474] tty_open+0x4a5/0xbb0 [ 91.656325][ T9474] chrdev_open+0x245/0x6b0 [ 91.660741][ T9474] do_dentry_open+0x4e6/0x1380 [ 91.665500][ T9474] vfs_open+0xa0/0xd0 [ 91.669473][ T9474] path_openat+0x10e4/0x4710 [ 91.674043][ T9474] do_filp_open+0x1a1/0x280 [ 91.678526][ T9474] do_sys_open+0x3fe/0x5d0 [ 91.682926][ T9474] __x64_sys_open+0x7e/0xc0 [ 91.687608][ T9474] do_syscall_64+0xfa/0x790 [ 91.692097][ T9474] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 91.697977][ T9474] [ 91.700298][ T9474] Freed by task 9477: [ 91.704263][ T9474] save_stack+0x23/0x90 [ 91.708404][ T9474] __kasan_slab_free+0x102/0x150 [ 91.713322][ T9474] kasan_slab_free+0xe/0x10 [ 91.717812][ T9474] kfree+0x10a/0x2c0 [ 91.721711][ T9474] vt_disallocate_all+0x2bd/0x3e0 [ 91.726735][ T9474] vt_ioctl+0xc38/0x26d0 [ 91.730962][ T9474] tty_ioctl+0xa37/0x14f0 [ 91.735275][ T9474] do_vfs_ioctl+0x977/0x14e0 [ 91.739850][ T9474] ksys_ioctl+0xab/0xd0 [ 91.744003][ T9474] __x64_sys_ioctl+0x73/0xb0 [ 91.748578][ T9474] do_syscall_64+0xfa/0x790 [ 91.753071][ T9474] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 91.758963][ T9474] [ 91.761275][ T9474] The buggy address belongs to the object at ffff88809ff8d000 [ 91.761275][ T9474] which belongs to the cache kmalloc-2k of size 2048 [ 91.775310][ T9474] The buggy address is located 512 bytes inside of [ 91.775310][ T9474] 2048-byte region [ffff88809ff8d000, ffff88809ff8d800) [ 91.788651][ T9474] The buggy address belongs to the page: [ 91.794303][ T9474] page:ffffea00027fe340 refcount:1 mapcount:0 mapping:ffff8880aa400e00 index:0x0 [ 91.803439][ T9474] raw: 00fffe0000000200 ffffea0002664b08 ffffea00028b8d48 ffff8880aa400e00 [ 91.812118][ T9474] raw: 0000000000000000 ffff88809ff8d000 0000000100000001 0000000000000000 [ 91.820776][ T9474] page dumped because: kasan: bad access detected [ 91.827230][ T9474] [ 91.829554][ T9474] Memory state around the buggy address: [ 91.835207][ T9474] ffff88809ff8d100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 91.843290][ T9474] ffff88809ff8d180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 91.851362][ T9474] >ffff88809ff8d200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 91.859423][ T9474] ^ [ 91.863486][ T9474] ffff88809ff8d280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 91.871571][ T9474] ffff88809ff8d300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 91.879648][ T9474] ================================================================== [ 91.887697][ T9474] Disabling lock debugging due to kernel taint [ 91.902775][ T9474] Kernel panic - not syncing: panic_on_warn set ... [ 91.909473][ T9474] CPU: 0 PID: 9474 Comm: syz-executor163 Tainted: G B 5.4.0-syzkaller #0 [ 91.919194][ T9474] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 91.929262][ T9474] Call Trace: [ 91.932577][ T9474] dump_stack+0x197/0x210 [ 91.936932][ T9474] panic+0x2e3/0x75c [ 91.940853][ T9474] ? add_taint.cold+0x16/0x16 [ 91.945547][ T9474] ? tty_open+0x6f8/0xbb0 [ 91.949896][ T9474] ? preempt_schedule+0x4b/0x60 [ 91.954768][ T9474] ? ___preempt_schedule+0x16/0x18 [ 91.959911][ T9474] ? trace_hardirqs_on+0x5e/0x240 [ 91.964959][ T9474] ? tty_open+0x6f8/0xbb0 [ 91.969305][ T9474] end_report+0x47/0x4f [ 91.973482][ T9474] ? tty_open+0x6f8/0xbb0 [ 91.977843][ T9474] __kasan_report.cold+0xe/0x41 [ 91.982720][ T9474] ? tty_open+0x6f8/0xbb0 [ 91.987075][ T9474] kasan_report+0x12/0x20 [ 91.991429][ T9474] check_memory_region+0x134/0x1a0 [ 91.996573][ T9474] __kasan_check_read+0x11/0x20 [ 92.001446][ T9474] tty_open+0x6f8/0xbb0 [ 92.005623][ T9474] ? tty_init_dev+0x460/0x460 [ 92.010325][ T9474] ? do_raw_spin_unlock+0x178/0x270 [ 92.015545][ T9474] ? tty_init_dev+0x460/0x460 [ 92.020248][ T9474] chrdev_open+0x245/0x6b0 [ 92.024680][ T9474] ? cdev_put.part.0+0x50/0x50 [ 92.029442][ T9474] ? security_file_open+0x87/0x300 [ 92.034540][ T9474] do_dentry_open+0x4e6/0x1380 [ 92.039298][ T9474] ? __kasan_check_read+0x11/0x20 [ 92.044319][ T9474] ? cdev_put.part.0+0x50/0x50 [ 92.049090][ T9474] ? chown_common+0x5c0/0x5c0 [ 92.053781][ T9474] ? inode_permission+0xb4/0x520 [ 92.058994][ T9474] vfs_open+0xa0/0xd0 [ 92.062993][ T9474] path_openat+0x10e4/0x4710 [ 92.067586][ T9474] ? __kasan_kmalloc.constprop.0+0xcf/0xe0 [ 92.073398][ T9474] ? kasan_slab_alloc+0xf/0x20 [ 92.078163][ T9474] ? kmem_cache_alloc+0x121/0x710 [ 92.083219][ T9474] ? getname_flags+0xd6/0x5b0 [ 92.087889][ T9474] ? getname+0x1a/0x20 [ 92.091974][ T9474] ? do_sys_open+0x2c9/0x5d0 [ 92.096569][ T9474] ? path_lookupat.isra.0+0x8d0/0x8d0 [ 92.101942][ T9474] ? __alloc_fd+0x487/0x620 [ 92.106437][ T9474] do_filp_open+0x1a1/0x280 [ 92.110967][ T9474] ? may_open_dev+0x100/0x100 [ 92.115631][ T9474] ? do_raw_spin_unlock+0x178/0x270 [ 92.121083][ T9474] ? _raw_spin_unlock+0x28/0x40 [ 92.125950][ T9474] ? __alloc_fd+0x487/0x620 [ 92.130575][ T9474] do_sys_open+0x3fe/0x5d0 [ 92.135152][ T9474] ? filp_open+0x80/0x80 [ 92.139387][ T9474] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 92.144936][ T9474] ? do_syscall_64+0x26/0x790 [ 92.149648][ T9474] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 92.155853][ T9474] ? do_syscall_64+0x26/0x790 [ 92.160541][ T9474] __x64_sys_open+0x7e/0xc0 [ 92.165036][ T9474] do_syscall_64+0xfa/0x790 [ 92.169527][ T9474] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 92.175413][ T9474] RIP: 0033:0x401140 [ 92.179291][ T9474] Code: 01 f0 ff ff 0f 83 c0 0b 00 00 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 83 3d 8d 55 2d 00 00 75 14 b8 02 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 94 0b 00 00 c3 48 83 ec 08 e8 fa 00 00 00 [ 92.198879][ T9474] RSP: 002b:00007ffda2635c48 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 [ 92.207277][ T9474] RAX: ffffffffffffffda RBX: 6666666666666667 RCX: 0000000000401140 [ 92.215228][ T9474] RDX: 0000000000000000 RSI: 0000000000101000 RDI: 00007ffda2635c70 [ 92.223231][ T9474] RBP: 000000000001640b R08: 000000000000000f R09: 00000000004002e0 [ 92.231231][ T9474] R10: 000000000000000f R11: 0000000000000246 R12: 0000000000402160 [ 92.239329][ T9474] R13: 00000000004021f0 R14: 0000000000000000 R15: 0000000000000000 [ 92.248867][ T9474] Kernel Offset: disabled [ 92.253224][ T9474] Rebooting in 86400 seconds..