[ OK ] Reached target Graphical Interface. Starting Update UTMP about System Runlevel Changes... Starting Load/Save RF Kill Switch Status... [ OK ] Started Update UTMP about System Runlevel Changes. [ OK ] Started Load/Save RF Kill Switch Status. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.0.41' (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 syzkaller login: [ 29.069508] ================================================================== [ 29.077012] BUG: KASAN: use-after-free in ex_handler_refcount+0x164/0x1a0 [ 29.083920] Write of size 4 at addr ffff8880ab067658 by task systemd-udevd/8083 [ 29.091347] [ 29.092958] CPU: 1 PID: 8083 Comm: systemd-udevd Not tainted 4.14.228-syzkaller #0 [ 29.100640] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 29.110018] Call Trace: [ 29.112592] dump_stack+0x1b2/0x281 executing program [ 29.116201] print_address_description.cold+0x54/0x1d3 [ 29.121456] kasan_report_error.cold+0x8a/0x191 [ 29.126107] ? ex_handler_refcount+0x164/0x1a0 [ 29.130665] __asan_report_store4_noabort+0x68/0x70 [ 29.135663] ? ex_handler_refcount+0x164/0x1a0 [ 29.140223] ex_handler_refcount+0x164/0x1a0 [ 29.144610] ? ex_handler_clear_fs+0xb0/0xb0 [ 29.148996] fixup_exception+0x8a/0xd0 [ 29.152876] do_trap+0x61/0x250 [ 29.156139] ? do_error_trap+0x1d0/0x2d0 [ 29.160205] do_error_trap+0x132/0x2d0 [ 29.164095] ? math_error+0x2d0/0x2d0 [ 29.167876] ? flags_string.cold+0x1b15/0x6a9f [ 29.172443] ? __mutex_lock+0x360/0x1310 [ 29.176493] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 29.181324] invalid_op+0x1b/0x40 [ 29.184764] RIP: 0010:flags_string.cold+0x1b15/0x6a9f [ 29.189932] RSP: 0018:ffff8880b19dfcd0 EFLAGS: 00010296 [ 29.195272] RAX: 0000000000000000 RBX: ffff8880ab067658 RCX: ffff8880ab067658 [ 29.202519] RDX: 0000000000000004 RSI: 0000000000000003 RDI: 0000000000000001 [ 29.209763] RBP: ffffffff89512780 R08: 0000000000000000 R09: 0000000000000002 [ 29.217019] R10: 0000000000000000 R11: ffff8880954200c0 R12: 0000000000000000 [ 29.224263] R13: ffff88808df3b684 R14: ffffed1011be771e R15: dffffc0000000000 [ 29.231522] nbd_release+0xf3/0x150 [ 29.235126] ? nbd_queue_rq+0xc50/0xc50 [ 29.239081] __blkdev_put+0x5aa/0x800 [ 29.242862] ? revalidate_disk+0x1f0/0x1f0 [ 29.247077] ? locks_remove_file+0x2cd/0x420 [ 29.251464] ? blkdev_put+0x75/0x4c0 [ 29.255154] ? blkdev_put+0x4c0/0x4c0 [ 29.258935] blkdev_close+0x86/0xb0 [ 29.262547] __fput+0x25f/0x7a0 [ 29.265804] task_work_run+0x11f/0x190 [ 29.269671] exit_to_usermode_loop+0x1ad/0x200 [ 29.274233] do_syscall_64+0x4a3/0x640 [ 29.278100] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 29.283269] RIP: 0033:0x7f1d2eec9270 [ 29.286956] RSP: 002b:00007ffe7d15c498 EFLAGS: 00000246 ORIG_RAX: 0000000000000003 [ 29.294650] RAX: 0000000000000000 RBX: 0000000000000007 RCX: 00007f1d2eec9270 [ 29.301895] RDX: 000000000aba9500 RSI: 0000000000000000 RDI: 0000000000000007 [ 29.309141] RBP: 00007f1d2fd83710 R08: 0000563fcda09c40 R09: 0000000000000018 [ 29.316386] R10: 0000563fcda0ae28 R11: 0000000000000246 R12: 0000000000000000 [ 29.323630] R13: 0000563fcda09ee0 R14: 0000000000000003 R15: 000000000000000e [ 29.330880] [ 29.332486] Allocated by task 8065: [ 29.336265] kasan_kmalloc+0xeb/0x160 [ 29.340047] kmem_cache_alloc_trace+0x131/0x3d0 [ 29.344693] nbd_dev_add+0x7c/0x800 [ 29.348293] nbd_genl_connect+0x3a4/0x1400 [ 29.352503] genl_family_rcv_msg+0x572/0xb20 [ 29.356884] genl_rcv_msg+0xaf/0x140 [ 29.360572] netlink_rcv_skb+0x125/0x390 [ 29.364629] genl_rcv+0x24/0x40 [ 29.367884] netlink_unicast+0x437/0x610 [ 29.371925] netlink_sendmsg+0x62e/0xb80 [ 29.375968] sock_sendmsg+0xb5/0x100 [ 29.379669] ___sys_sendmsg+0x6c8/0x800 [ 29.383620] __sys_sendmsg+0xa3/0x120 [ 29.387395] SyS_sendmsg+0x27/0x40 [ 29.390923] do_syscall_64+0x1d5/0x640 [ 29.394786] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 29.399953] [ 29.401553] Freed by task 8074: [ 29.404809] kasan_slab_free+0xc3/0x1a0 [ 29.408781] kfree+0xc9/0x250 [ 29.411868] nbd_put.part.0+0x100/0x140 [ 29.415824] nbd_genl_connect+0xfa9/0x1400 [ 29.421247] genl_family_rcv_msg+0x572/0xb20 [ 29.425627] genl_rcv_msg+0xaf/0x140 [ 29.429315] netlink_rcv_skb+0x125/0x390 [ 29.433359] genl_rcv+0x24/0x40 [ 29.436632] netlink_unicast+0x437/0x610 [ 29.440668] netlink_sendmsg+0x62e/0xb80 [ 29.444702] sock_sendmsg+0xb5/0x100 [ 29.448389] ___sys_sendmsg+0x6c8/0x800 [ 29.452340] __sys_sendmsg+0xa3/0x120 [ 29.456114] SyS_sendmsg+0x27/0x40 [ 29.459630] do_syscall_64+0x1d5/0x640 [ 29.463495] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 29.468658] [ 29.470270] The buggy address belongs to the object at ffff8880ab067580 [ 29.470270] which belongs to the cache kmalloc-512 of size 512 [ 29.482913] The buggy address is located 216 bytes inside of [ 29.482913] 512-byte region [ffff8880ab067580, ffff8880ab067780) [ 29.494763] The buggy address belongs to the page: [ 29.499736] page:ffffea0002ac19c0 count:1 mapcount:0 mapping:ffff8880ab067080 index:0xffff8880ab067a80 [ 29.509160] flags: 0xfff00000000100(slab) [ 29.513287] raw: 00fff00000000100 ffff8880ab067080 ffff8880ab067a80 0000000100000005 [ 29.521146] raw: ffffea00026524e0 ffffea0002ad3160 ffff88813fe80940 0000000000000000 [ 29.529004] page dumped because: kasan: bad access detected [ 29.534687] [ 29.536289] Memory state around the buggy address: [ 29.541191] ffff8880ab067500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 29.548525] ffff8880ab067580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 29.555882] >ffff8880ab067600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 29.563215] ^ [ 29.569419] ffff8880ab067680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 29.576751] ffff8880ab067700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 29.584083] ================================================================== [ 29.591413] Disabling lock debugging due to kernel taint [ 29.600192] Kernel panic - not syncing: panic_on_warn set ... [ 29.600192] [ 29.607565] CPU: 0 PID: 8083 Comm: systemd-udevd Tainted: G B 4.14.228-syzkaller #0 [ 29.616477] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 29.625815] Call Trace: [ 29.628427] dump_stack+0x1b2/0x281 [ 29.632028] panic+0x1f9/0x42d [ 29.635192] ? add_taint.cold+0x16/0x16 [ 29.639140] ? ___preempt_schedule+0x16/0x18 [ 29.643521] kasan_end_report+0x43/0x49 [ 29.647466] kasan_report_error.cold+0xa7/0x191 [ 29.652109] ? ex_handler_refcount+0x164/0x1a0 [ 29.656665] __asan_report_store4_noabort+0x68/0x70 [ 29.661669] ? ex_handler_refcount+0x164/0x1a0 [ 29.666236] ex_handler_refcount+0x164/0x1a0 [ 29.670618] ? ex_handler_clear_fs+0xb0/0xb0 [ 29.674997] fixup_exception+0x8a/0xd0 [ 29.678859] do_trap+0x61/0x250 [ 29.682166] ? do_error_trap+0x1d0/0x2d0 [ 29.686221] do_error_trap+0x132/0x2d0 [ 29.690134] ? math_error+0x2d0/0x2d0 [ 29.693911] ? flags_string.cold+0x1b15/0x6a9f [ 29.698506] ? __mutex_lock+0x360/0x1310 [ 29.702554] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 29.707378] invalid_op+0x1b/0x40 [ 29.710806] RIP: 0010:flags_string.cold+0x1b15/0x6a9f [ 29.715966] RSP: 0018:ffff8880b19dfcd0 EFLAGS: 00010296 [ 29.721317] RAX: 0000000000000000 RBX: ffff8880ab067658 RCX: ffff8880ab067658 [ 29.728561] RDX: 0000000000000004 RSI: 0000000000000003 RDI: 0000000000000001 [ 29.735803] RBP: ffffffff89512780 R08: 0000000000000000 R09: 0000000000000002 [ 29.743045] R10: 0000000000000000 R11: ffff8880954200c0 R12: 0000000000000000 [ 29.750289] R13: ffff88808df3b684 R14: ffffed1011be771e R15: dffffc0000000000 [ 29.757543] nbd_release+0xf3/0x150 [ 29.761144] ? nbd_queue_rq+0xc50/0xc50 [ 29.765090] __blkdev_put+0x5aa/0x800 [ 29.768865] ? revalidate_disk+0x1f0/0x1f0 [ 29.773071] ? locks_remove_file+0x2cd/0x420 [ 29.777451] ? blkdev_put+0x75/0x4c0 [ 29.781137] ? blkdev_put+0x4c0/0x4c0 [ 29.784940] blkdev_close+0x86/0xb0 [ 29.788541] __fput+0x25f/0x7a0 [ 29.791795] task_work_run+0x11f/0x190 [ 29.795657] exit_to_usermode_loop+0x1ad/0x200 [ 29.800228] do_syscall_64+0x4a3/0x640 [ 29.804088] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 29.809251] RIP: 0033:0x7f1d2eec9270 [ 29.812986] RSP: 002b:00007ffe7d15c498 EFLAGS: 00000246 ORIG_RAX: 0000000000000003 [ 29.820666] RAX: 0000000000000000 RBX: 0000000000000007 RCX: 00007f1d2eec9270 [ 29.827909] RDX: 000000000aba9500 RSI: 0000000000000000 RDI: 0000000000000007 [ 29.835151] RBP: 00007f1d2fd83710 R08: 0000563fcda09c40 R09: 0000000000000018 [ 29.842403] R10: 0000563fcda0ae28 R11: 0000000000000246 R12: 0000000000000000 [ 29.849646] R13: 0000563fcda09ee0 R14: 0000000000000003 R15: 000000000000000e [ 29.857465] Kernel Offset: disabled [ 29.861072] Rebooting in 86400 seconds..