[ OK ] Started Getty on tty2. [ OK ] Started Serial Getty on ttyS0. [ OK ] Started Getty on tty1. [ OK ] Reached target Login Prompts. [ OK ] Reached target Multi-User System. [ OK ] Reached target Graphical Interface. Starting Update UTMP about System Runlevel Changes... [ OK ] Started Update UTMP about System Runlevel Changes. Starting Load/Save RF Kill Switch Status... [ OK ] Started Load/Save RF Kill Switch Status. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.1.75' (ECDSA) to the list of known hosts. executing program executing program executing program executing program executing program executing program syzkaller login: [ 30.864494] netlink: 4 bytes leftover after parsing attributes in process `syz-executor038'. [ 30.877225] netlink: 4 bytes leftover after parsing attributes in process `syz-executor038'. executing program [ 30.934793] netlink: 4 bytes leftover after parsing attributes in process `syz-executor038'. [ 30.946907] netlink: 4 bytes leftover after parsing attributes in process `syz-executor038'. executing program [ 30.993882] netlink: 4 bytes leftover after parsing attributes in process `syz-executor038'. [ 31.003351] netlink: 4 bytes leftover after parsing attributes in process `syz-executor038'. executing program [ 31.043724] netlink: 4 bytes leftover after parsing attributes in process `syz-executor038'. [ 31.052593] netlink: 4 bytes leftover after parsing attributes in process `syz-executor038'. executing program [ 31.103713] netlink: 4 bytes leftover after parsing attributes in process `syz-executor038'. [ 31.112614] netlink: 4 bytes leftover after parsing attributes in process `syz-executor038'. executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 31.883201] ================================================================== [ 31.890739] BUG: KASAN: use-after-free in ex_handler_refcount+0x164/0x1a0 [ 31.897759] Write of size 4 at addr ffff8880a9bb1698 by task systemd-udevd/8090 [ 31.905639] [ 31.907273] CPU: 1 PID: 8090 Comm: systemd-udevd Not tainted 4.14.228-syzkaller #0 [ 31.914980] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 31.924344] Call Trace: [ 31.926944] dump_stack+0x1b2/0x281 [ 31.930651] print_address_description.cold+0x54/0x1d3 [ 31.936013] kasan_report_error.cold+0x8a/0x191 [ 31.940670] ? ex_handler_refcount+0x164/0x1a0 [ 31.945520] __asan_report_store4_noabort+0x68/0x70 [ 31.950539] ? ex_handler_refcount+0x164/0x1a0 [ 31.955126] ex_handler_refcount+0x164/0x1a0 [ 31.959690] ? ex_handler_clear_fs+0xb0/0xb0 [ 31.964110] fixup_exception+0x8a/0xd0 [ 31.968005] do_trap+0x61/0x250 [ 31.971287] ? do_error_trap+0x1d0/0x2d0 [ 31.975339] do_error_trap+0x132/0x2d0 [ 31.979227] ? math_error+0x2d0/0x2d0 [ 31.983016] ? flags_string.cold+0x1b15/0x6a9f [ 31.987795] ? __mutex_lock+0x360/0x1310 [ 31.991876] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 31.996711] invalid_op+0x1b/0x40 [ 32.000157] RIP: 0010:flags_string.cold+0x1b15/0x6a9f [ 32.005388] RSP: 0018:ffff8880962a7cd0 EFLAGS: 00010296 [ 32.010762] RAX: 0000000000000000 RBX: ffff8880a9bb1698 RCX: ffff8880a9bb1698 [ 32.018113] RDX: 0000000000000004 RSI: 0000000000000003 RDI: 0000000000000001 [ 32.025588] RBP: ffffffff89512780 R08: 0000000000000000 R09: 0000000000000002 [ 32.032874] R10: 0000000000000000 R11: ffff88809578a440 R12: 0000000000000000 [ 32.040152] R13: ffff88808deb3784 R14: ffffed1011bd673e R15: dffffc0000000000 [ 32.047428] nbd_release+0xf3/0x150 [ 32.051452] ? nbd_queue_rq+0xc50/0xc50 [ 32.055529] __blkdev_put+0x5aa/0x800 [ 32.059382] ? revalidate_disk+0x1f0/0x1f0 [ 32.063727] ? locks_remove_file+0x2cd/0x420 [ 32.068265] ? blkdev_put+0x75/0x4c0 [ 32.071968] ? blkdev_put+0x4c0/0x4c0 [ 32.075858] blkdev_close+0x86/0xb0 [ 32.080301] __fput+0x25f/0x7a0 [ 32.083811] task_work_run+0x11f/0x190 [ 32.087791] exit_to_usermode_loop+0x1ad/0x200 [ 32.092413] do_syscall_64+0x4a3/0x640 [ 32.096385] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 32.101757] RIP: 0033:0x7f9928c69270 [ 32.105495] RSP: 002b:00007fffb96a8378 EFLAGS: 00000246 ORIG_RAX: 0000000000000003 [ 32.113211] RAX: 0000000000000000 RBX: 0000000000000007 RCX: 00007f9928c69270 [ 32.120471] RDX: 000000000aba9500 RSI: 0000000000000000 RDI: 0000000000000007 [ 32.128112] RBP: 00007f9929b23710 R08: 0000557dee822d30 R09: 0000000000000018 [ 32.135542] R10: 0000557dee80fe38 R11: 0000000000000246 R12: 0000000000000000 [ 32.142812] R13: 0000557dee81e860 R14: 0000000000000003 R15: 000000000000000e [ 32.150076] [ 32.151686] Allocated by task 8087: [ 32.155366] kasan_kmalloc+0xeb/0x160 [ 32.159186] kmem_cache_alloc_trace+0x131/0x3d0 [ 32.163845] nbd_dev_add+0x7c/0x800 [ 32.167474] nbd_genl_connect+0x3a4/0x1400 [ 32.171693] genl_family_rcv_msg+0x572/0xb20 [ 32.176098] genl_rcv_msg+0xaf/0x140 [ 32.179795] netlink_rcv_skb+0x125/0x390 [ 32.183842] genl_rcv+0x24/0x40 [ 32.187189] netlink_unicast+0x437/0x610 [ 32.191229] netlink_sendmsg+0x62e/0xb80 [ 32.195273] sock_sendmsg+0xb5/0x100 [ 32.198965] ___sys_sendmsg+0x6c8/0x800 [ 32.202927] __sys_sendmsg+0xa3/0x120 [ 32.206752] SyS_sendmsg+0x27/0x40 [ 32.210397] do_syscall_64+0x1d5/0x640 [ 32.214281] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 32.219450] [ 32.221168] Freed by task 8095: [ 32.224433] kasan_slab_free+0xc3/0x1a0 [ 32.228661] kfree+0xc9/0x250 [ 32.231751] nbd_put.part.0+0x100/0x140 [ 32.235728] nbd_genl_connect+0xfa9/0x1400 [ 32.239958] genl_family_rcv_msg+0x572/0xb20 [ 32.244408] genl_rcv_msg+0xaf/0x140 [ 32.248225] netlink_rcv_skb+0x125/0x390 [ 32.252416] genl_rcv+0x24/0x40 [ 32.255684] netlink_unicast+0x437/0x610 [ 32.259907] netlink_sendmsg+0x62e/0xb80 [ 32.263947] sock_sendmsg+0xb5/0x100 [ 32.267804] ___sys_sendmsg+0x6c8/0x800 [ 32.271776] __sys_sendmsg+0xa3/0x120 [ 32.275572] SyS_sendmsg+0x27/0x40 [ 32.279106] do_syscall_64+0x1d5/0x640 [ 32.282973] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 32.288156] [ 32.289774] The buggy address belongs to the object at ffff8880a9bb15c0 [ 32.289774] which belongs to the cache kmalloc-512 of size 512 [ 32.302539] The buggy address is located 216 bytes inside of [ 32.302539] 512-byte region [ffff8880a9bb15c0, ffff8880a9bb17c0) [ 32.314414] The buggy address belongs to the page: [ 32.319348] page:ffffea0002a6ec40 count:1 mapcount:0 mapping:ffff8880a9bb10c0 index:0x0 [ 32.327490] flags: 0xfff00000000100(slab) [ 32.331635] raw: 00fff00000000100 ffff8880a9bb10c0 0000000000000000 0000000100000006 [ 32.339523] raw: ffffea0002a6e7a0 ffffea0002d38a60 ffff88813fe80940 0000000000000000 [ 32.347819] page dumped because: kasan: bad access detected [ 32.353541] [ 32.355148] Memory state around the buggy address: [ 32.360170] ffff8880a9bb1580: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb [ 32.367857] ffff8880a9bb1600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 32.375219] >ffff8880a9bb1680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb executing program [ 32.382578] ^ [ 32.386789] ffff8880a9bb1700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 32.394147] ffff8880a9bb1780: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc [ 32.401603] ================================================================== [ 32.408945] Disabling lock debugging due to kernel taint [ 32.418103] Kernel panic - not syncing: panic_on_warn set ... [ 32.418103] [ 32.425484] CPU: 1 PID: 8090 Comm: systemd-udevd Tainted: G B 4.14.228-syzkaller #0 [ 32.434404] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 32.443757] Call Trace: [ 32.446348] dump_stack+0x1b2/0x281 [ 32.449974] panic+0x1f9/0x42d [ 32.454116] ? add_taint.cold+0x16/0x16 [ 32.458141] ? ___preempt_schedule+0x16/0x18 [ 32.462542] kasan_end_report+0x43/0x49 [ 32.466508] kasan_report_error.cold+0xa7/0x191 [ 32.471169] ? ex_handler_refcount+0x164/0x1a0 [ 32.475761] __asan_report_store4_noabort+0x68/0x70 [ 32.480763] ? ex_handler_refcount+0x164/0x1a0 [ 32.485449] ex_handler_refcount+0x164/0x1a0 [ 32.489842] ? ex_handler_clear_fs+0xb0/0xb0 [ 32.494246] fixup_exception+0x8a/0xd0 [ 32.498135] do_trap+0x61/0x250 [ 32.501404] ? do_error_trap+0x1d0/0x2d0 [ 32.505500] do_error_trap+0x132/0x2d0 [ 32.509380] ? math_error+0x2d0/0x2d0 [ 32.513183] ? flags_string.cold+0x1b15/0x6a9f [ 32.517830] ? __mutex_lock+0x360/0x1310 [ 32.521887] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 32.526712] invalid_op+0x1b/0x40 [ 32.530149] RIP: 0010:flags_string.cold+0x1b15/0x6a9f [ 32.535336] RSP: 0018:ffff8880962a7cd0 EFLAGS: 00010296 [ 32.540687] RAX: 0000000000000000 RBX: ffff8880a9bb1698 RCX: ffff8880a9bb1698 [ 32.547938] RDX: 0000000000000004 RSI: 0000000000000003 RDI: 0000000000000001 [ 32.555189] RBP: ffffffff89512780 R08: 0000000000000000 R09: 0000000000000002 [ 32.562448] R10: 0000000000000000 R11: ffff88809578a440 R12: 0000000000000000 [ 32.569697] R13: ffff88808deb3784 R14: ffffed1011bd673e R15: dffffc0000000000 [ 32.576979] nbd_release+0xf3/0x150 [ 32.580608] ? nbd_queue_rq+0xc50/0xc50 [ 32.584560] __blkdev_put+0x5aa/0x800 [ 32.588363] ? revalidate_disk+0x1f0/0x1f0 [ 32.592607] ? locks_remove_file+0x2cd/0x420 [ 32.597001] ? blkdev_put+0x75/0x4c0 [ 32.600704] ? blkdev_put+0x4c0/0x4c0 [ 32.604504] blkdev_close+0x86/0xb0 [ 32.608115] __fput+0x25f/0x7a0 [ 32.611374] task_work_run+0x11f/0x190 [ 32.615242] exit_to_usermode_loop+0x1ad/0x200 [ 32.619803] do_syscall_64+0x4a3/0x640 [ 32.623687] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 32.628873] RIP: 0033:0x7f9928c69270 [ 32.632583] RSP: 002b:00007fffb96a8378 EFLAGS: 00000246 ORIG_RAX: 0000000000000003 [ 32.640278] RAX: 0000000000000000 RBX: 0000000000000007 RCX: 00007f9928c69270 [ 32.647659] RDX: 000000000aba9500 RSI: 0000000000000000 RDI: 0000000000000007 [ 32.655087] RBP: 00007f9929b23710 R08: 0000557dee822d30 R09: 0000000000000018 [ 32.662350] R10: 0000557dee80fe38 R11: 0000000000000246 R12: 0000000000000000 [ 32.669660] R13: 0000557dee81e860 R14: 0000000000000003 R15: 000000000000000e [ 32.677480] Kernel Offset: disabled [ 32.681097] Rebooting in 86400 seconds..