[ OK ] Started Serial Getty on ttyS0. [ OK ] Started Getty on tty3. [ OK ] Started Getty on tty2. [ OK ] Reached target Login Prompts. [ OK ] Reached target Multi-User System. [ OK ] Reached target Graphical Interface. Starting Update UTMP about System Runlevel Changes... Starting Load/Save RF Kill Switch Status... [ OK ] Started Load/Save RF Kill Switch Status. [ OK ] Started Update UTMP about System Runlevel Changes. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.1.126' (ECDSA) to the list of known hosts. executing program executing program executing program executing program executing program executing program syzkaller login: [ 27.230498] netlink: 4 bytes leftover after parsing attributes in process `syz-executor146'. executing program [ 27.286415] netlink: 4 bytes leftover after parsing attributes in process `syz-executor146'. executing program [ 27.335993] netlink: 4 bytes leftover after parsing attributes in process `syz-executor146'. executing program [ 27.385904] netlink: 4 bytes leftover after parsing attributes in process `syz-executor146'. executing program [ 27.435667] netlink: 4 bytes leftover after parsing attributes in process `syz-executor146'. executing program [ 27.495430] netlink: 4 bytes leftover after parsing attributes in process `syz-executor146'. executing program [ 27.555637] netlink: 4 bytes leftover after parsing attributes in process `syz-executor146'. executing program [ 27.605546] netlink: 4 bytes leftover after parsing attributes in process `syz-executor146'. executing program [ 27.655586] netlink: 4 bytes leftover after parsing attributes in process `syz-executor146'. executing program executing program [ 27.715680] netlink: 4 bytes leftover after parsing attributes in process `syz-executor146'. executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 29.135061] ================================================================== [ 29.142539] BUG: KASAN: use-after-free in ex_handler_refcount+0x164/0x1a0 [ 29.149440] Write of size 4 at addr ffff88809b42ad58 by task systemd-udevd/8264 [ 29.156856] [ 29.158462] CPU: 0 PID: 8264 Comm: systemd-udevd Not tainted 4.14.280-syzkaller #0 [ 29.166140] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 29.175467] Call Trace: [ 29.178031] dump_stack+0x1b2/0x281 [ 29.181633] print_address_description.cold+0x54/0x1d3 [ 29.186882] kasan_report_error.cold+0x8a/0x191 [ 29.191525] ? ex_handler_refcount+0x164/0x1a0 [ 29.196097] __asan_report_store4_noabort+0x68/0x70 [ 29.201100] ? ex_handler_refcount+0x164/0x1a0 [ 29.205655] ex_handler_refcount+0x164/0x1a0 [ 29.210038] ? ex_handler_clear_fs+0xb0/0xb0 [ 29.214419] fixup_exception+0x8a/0xd0 [ 29.218289] do_trap+0x61/0x250 [ 29.221542] ? do_error_trap+0x1d0/0x2d0 [ 29.225581] do_error_trap+0x132/0x2d0 [ 29.229441] ? math_error+0x2d0/0x2d0 [ 29.233215] ? flags_string.cold+0x1b2c/0x6beb [ 29.237769] ? __mutex_lock+0x360/0x1310 [ 29.241812] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 29.246628] invalid_op+0x1b/0x40 [ 29.250055] RIP: 0010:flags_string.cold+0x1b2c/0x6beb [ 29.255217] RSP: 0018:ffff8880afe4fcd0 EFLAGS: 00010296 [ 29.260552] RAX: 0000000000000000 RBX: ffff88809b42ad58 RCX: ffff88809b42ad58 [ 29.267795] RDX: 0000000000000004 RSI: 0000000000000003 RDI: 0000000000000001 [ 29.275037] RBP: ffffffff89513ce0 R08: 0000000000000000 R09: 0000000000000002 [ 29.282280] R10: 0000000000000000 R11: ffff8880af3065c0 R12: 0000000000000000 [ 29.289524] R13: ffff88808ad20984 R14: ffffed10115a417e R15: dffffc0000000000 [ 29.296780] nbd_release+0xf3/0x150 [ 29.300381] ? nbd_queue_rq+0xc50/0xc50 [ 29.304330] __blkdev_put+0x5aa/0x800 [ 29.308111] ? revalidate_disk+0x1f0/0x1f0 [ 29.312317] ? locks_remove_file+0x2cd/0x420 [ 29.316701] ? blkdev_put+0x75/0x4c0 [ 29.320391] ? blkdev_put+0x4c0/0x4c0 [ 29.324172] blkdev_close+0x86/0xb0 [ 29.327774] __fput+0x25f/0x7a0 [ 29.331030] task_work_run+0x11f/0x190 [ 29.334895] exit_to_usermode_loop+0x1ad/0x200 [ 29.339456] do_syscall_64+0x4a3/0x640 [ 29.343319] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 29.348482] RIP: 0033:0x7f6c60611270 [ 29.352163] RSP: 002b:00007ffde6e24078 EFLAGS: 00000246 ORIG_RAX: 0000000000000003 [ 29.359844] RAX: 0000000000000000 RBX: 0000000000000007 RCX: 00007f6c60611270 [ 29.367093] RDX: 000000000aba9500 RSI: 0000000000000000 RDI: 0000000000000007 [ 29.374336] RBP: 00007f6c614cb710 R08: 0000000000000045 R09: 0000000000000018 [ 29.381580] R10: 000055ec17911fb8 R11: 0000000000000246 R12: 0000000000000000 [ 29.388822] R13: 000055ec17911e20 R14: 0000000000000003 R15: 000000000000000e [ 29.396071] [ 29.397679] Allocated by task 8224: [ 29.401283] kasan_kmalloc+0xeb/0x160 [ 29.405085] kmem_cache_alloc_trace+0x131/0x3d0 [ 29.409726] nbd_dev_add+0x7c/0x800 [ 29.413324] nbd_genl_connect+0x3a4/0x1400 [ 29.417530] genl_family_rcv_msg+0x572/0xb20 [ 29.421909] genl_rcv_msg+0xaf/0x140 [ 29.425593] netlink_rcv_skb+0x125/0x390 [ 29.429626] genl_rcv+0x24/0x40 [ 29.432878] netlink_unicast+0x437/0x610 [ 29.436912] netlink_sendmsg+0x648/0xbc0 [ 29.440945] sock_sendmsg+0xb5/0x100 [ 29.444631] ___sys_sendmsg+0x6c8/0x800 [ 29.448581] __sys_sendmsg+0xa3/0x120 [ 29.452351] SyS_sendmsg+0x27/0x40 [ 29.455862] do_syscall_64+0x1d5/0x640 [ 29.459722] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 29.464881] [ 29.466483] Freed by task 8246: [ 29.469738] kasan_slab_free+0xc3/0x1a0 [ 29.473683] kfree+0xc9/0x250 [ 29.476763] nbd_put.part.0+0x100/0x140 [ 29.480709] nbd_genl_connect+0xfa9/0x1400 [ 29.484915] genl_family_rcv_msg+0x572/0xb20 [ 29.489294] genl_rcv_msg+0xaf/0x140 [ 29.492984] netlink_rcv_skb+0x125/0x390 [ 29.497026] genl_rcv+0x24/0x40 [ 29.500279] netlink_unicast+0x437/0x610 [ 29.504312] netlink_sendmsg+0x648/0xbc0 [ 29.508343] sock_sendmsg+0xb5/0x100 [ 29.512026] ___sys_sendmsg+0x6c8/0x800 [ 29.515972] __sys_sendmsg+0xa3/0x120 [ 29.519750] SyS_sendmsg+0x27/0x40 [ 29.523268] do_syscall_64+0x1d5/0x640 [ 29.527130] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 29.532288] [ 29.533891] The buggy address belongs to the object at ffff88809b42ac80 [ 29.533891] which belongs to the cache kmalloc-512 of size 512 [ 29.546525] The buggy address is located 216 bytes inside of [ 29.546525] 512-byte region [ffff88809b42ac80, ffff88809b42ae80) [ 29.558376] The buggy address belongs to the page: [ 29.563277] page:ffffea00026d0a80 count:1 mapcount:0 mapping:ffff88809b42a000 index:0xffff88809b42a780 [ 29.572694] flags: 0xfff00000000100(slab) [ 29.576816] raw: 00fff00000000100 ffff88809b42a000 ffff88809b42a780 0000000100000002 [ 29.584668] raw: ffffea0002738ea0 ffffea00026c9f60 ffff88813fe74940 0000000000000000 [ 29.592516] page dumped because: kasan: bad access detected [ 29.598195] [ 29.599800] Memory state around the buggy address: [ 29.604708] ffff88809b42ac00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 29.612039] ffff88809b42ac80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 29.619379] >ffff88809b42ad00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 29.626714] ^ executing program [ 29.632927] ffff88809b42ad80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 29.640261] ffff88809b42ae00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 29.647591] ================================================================== [ 29.654926] Disabling lock debugging due to kernel taint [ 29.665227] Kernel panic - not syncing: panic_on_warn set ... [ 29.665227] [ 29.672593] CPU: 1 PID: 8264 Comm: systemd-udevd Tainted: G B 4.14.280-syzkaller #0 [ 29.681496] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 29.690828] Call Trace: [ 29.693389] dump_stack+0x1b2/0x281 [ 29.696991] panic+0x1f9/0x42d [ 29.700155] ? add_taint.cold+0x16/0x16 [ 29.704105] ? ___preempt_schedule+0x16/0x18 [ 29.708485] kasan_end_report+0x43/0x49 [ 29.712432] kasan_report_error.cold+0xa7/0x191 [ 29.717074] ? ex_handler_refcount+0x164/0x1a0 [ 29.721629] __asan_report_store4_noabort+0x68/0x70 [ 29.726619] ? ex_handler_refcount+0x164/0x1a0 [ 29.731172] ex_handler_refcount+0x164/0x1a0 [ 29.735556] ? ex_handler_clear_fs+0xb0/0xb0 [ 29.739934] fixup_exception+0x8a/0xd0 [ 29.743794] do_trap+0x61/0x250 [ 29.747044] ? do_error_trap+0x1d0/0x2d0 [ 29.751076] do_error_trap+0x132/0x2d0 [ 29.754932] ? math_error+0x2d0/0x2d0 [ 29.758706] ? flags_string.cold+0x1b2c/0x6beb [ 29.763260] ? __mutex_lock+0x360/0x1310 [ 29.767292] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 29.772105] invalid_op+0x1b/0x40 [ 29.775530] RIP: 0010:flags_string.cold+0x1b2c/0x6beb [ 29.780690] RSP: 0018:ffff8880afe4fcd0 EFLAGS: 00010296 [ 29.786024] RAX: 0000000000000000 RBX: ffff88809b42ad58 RCX: ffff88809b42ad58 [ 29.793264] RDX: 0000000000000004 RSI: 0000000000000003 RDI: 0000000000000001 [ 29.800506] RBP: ffffffff89513ce0 R08: 0000000000000000 R09: 0000000000000002 [ 29.807750] R10: 0000000000000000 R11: ffff8880af3065c0 R12: 0000000000000000 [ 29.814991] R13: ffff88808ad20984 R14: ffffed10115a417e R15: dffffc0000000000 [ 29.822241] nbd_release+0xf3/0x150 [ 29.825842] ? nbd_queue_rq+0xc50/0xc50 [ 29.829795] __blkdev_put+0x5aa/0x800 [ 29.833568] ? revalidate_disk+0x1f0/0x1f0 [ 29.837799] ? locks_remove_file+0x2cd/0x420 [ 29.842179] ? blkdev_put+0x75/0x4c0 [ 29.845865] ? blkdev_put+0x4c0/0x4c0 [ 29.849635] blkdev_close+0x86/0xb0 [ 29.853235] __fput+0x25f/0x7a0 [ 29.856486] task_work_run+0x11f/0x190 [ 29.860347] exit_to_usermode_loop+0x1ad/0x200 [ 29.864902] do_syscall_64+0x4a3/0x640 [ 29.868763] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 29.873924] RIP: 0033:0x7f6c60611270 [ 29.877605] RSP: 002b:00007ffde6e24078 EFLAGS: 00000246 ORIG_RAX: 0000000000000003 [ 29.885281] RAX: 0000000000000000 RBX: 0000000000000007 RCX: 00007f6c60611270 [ 29.892545] RDX: 000000000aba9500 RSI: 0000000000000000 RDI: 0000000000000007 [ 29.899787] RBP: 00007f6c614cb710 R08: 0000000000000045 R09: 0000000000000018 [ 29.907026] R10: 000055ec17911fb8 R11: 0000000000000246 R12: 0000000000000000 [ 29.914267] R13: 000055ec17911e20 R14: 0000000000000003 R15: 000000000000000e [ 29.921685] Kernel Offset: disabled [ 29.925291] Rebooting in 86400 seconds..