[ 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 '10.128.0.161' (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 syzkaller login: [ 37.438771] ================================================================== [ 37.446489] BUG: KASAN: use-after-free in refcount_dec_not_one+0x71/0x1d0 [ 37.453419] Read of size 4 at addr ffff8880a32498d8 by task syz-executor167/8184 [ 37.461054] [ 37.462681] CPU: 1 PID: 8184 Comm: syz-executor167 Not tainted 4.19.194-syzkaller #0 [ 37.470580] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 37.479933] Call Trace: [ 37.482529] dump_stack+0x1fc/0x2ef [ 37.486180] print_address_description.cold+0x54/0x219 [ 37.491461] kasan_report_error.cold+0x8a/0x1b9 [ 37.496148] ? refcount_dec_not_one+0x71/0x1d0 [ 37.500762] kasan_report+0x8f/0xa0 [ 37.504395] ? refcount_dec_not_one+0x71/0x1d0 [ 37.509085] refcount_dec_not_one+0x71/0x1d0 [ 37.513613] ? refcount_dec_and_test_checked+0x20/0x20 [ 37.518912] ? nbd_config_put+0x5da/0x870 [ 37.523064] refcount_dec_and_mutex_lock+0x1c/0x80 [ 37.528052] nbd_genl_connect+0x11ee/0x1630 [ 37.532421] ? nbd_xmit_timeout+0x730/0x730 [ 37.536805] ? __sanitizer_cov_trace_switch+0x4b/0x80 [ 37.542005] ? validate_nla+0x270/0x820 [ 37.546176] ? nla_parse+0x1b2/0x290 [ 37.549913] genl_family_rcv_msg+0x642/0xc40 [ 37.554458] ? genl_rcv+0x40/0x40 [ 37.557943] ? genl_rcv_msg+0x12f/0x160 [ 37.561916] ? mutex_trylock+0x1a0/0x1a0 [ 37.565985] ? __radix_tree_lookup+0x216/0x370 [ 37.570667] genl_rcv_msg+0xbf/0x160 [ 37.574515] netlink_rcv_skb+0x160/0x440 [ 37.578664] ? genl_family_rcv_msg+0xc40/0xc40 [ 37.583234] ? netlink_ack+0xae0/0xae0 [ 37.587110] ? genl_rcv+0x15/0x40 [ 37.590555] genl_rcv+0x24/0x40 [ 37.593910] netlink_unicast+0x4d5/0x690 [ 37.597996] ? netlink_sendskb+0x110/0x110 [ 37.602256] ? _copy_from_iter_full+0x229/0x7c0 [ 37.607653] ? __phys_addr_symbol+0x2c/0x70 [ 37.611966] ? __check_object_size+0x17b/0x3e0 [ 37.616540] netlink_sendmsg+0x6bb/0xc40 [ 37.620602] ? aa_af_perm+0x230/0x230 [ 37.624416] ? nlmsg_notify+0x1a0/0x1a0 [ 37.628426] ? kernel_recvmsg+0x220/0x220 [ 37.632584] ? nlmsg_notify+0x1a0/0x1a0 [ 37.636571] sock_sendmsg+0xc3/0x120 [ 37.640299] ___sys_sendmsg+0x7bb/0x8e0 [ 37.644281] ? copy_msghdr_from_user+0x440/0x440 [ 37.649050] ? netlink_dump+0xc10/0xc10 [ 37.653042] ? nlmsg_notify+0x1a0/0x1a0 [ 37.657012] ? security_socket_recvmsg+0x8f/0xc0 [ 37.661761] ? __sys_recvfrom+0x2cd/0x3a0 [ 37.665901] ? __ia32_sys_send+0x100/0x100 [ 37.670244] ? __fdget+0x1a0/0x230 [ 37.673787] __x64_sys_sendmsg+0x132/0x220 [ 37.678030] ? __sys_sendmsg+0x1b0/0x1b0 [ 37.682104] ? entry_SYSCALL_64_after_hwframe+0x3e/0xbe [ 37.687470] ? trace_hardirqs_off_caller+0x6e/0x210 [ 37.692477] ? do_syscall_64+0x21/0x620 [ 37.696582] do_syscall_64+0xf9/0x620 [ 37.700421] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 37.706012] RIP: 0033:0x4407c9 [ 37.709196] Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 14 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48 [ 37.728191] RSP: 002b:00007ffc2fc85908 EFLAGS: 00000246 ORIG_RAX: 000000000000002e [ 37.735896] RAX: ffffffffffffffda RBX: 00000000000f4240 RCX: 00000000004407c9 [ 37.743297] RDX: 0000000000000000 RSI: 00000000200002c0 RDI: 0000000000000004 [ 37.750563] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000001 [ 37.757831] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000000090c9 [ 37.765086] R13: 00007ffc2fc8591c R14: 00007ffc2fc85930 R15: 00007ffc2fc85920 [ 37.772442] [ 37.774075] Allocated by task 8180: [ 37.777809] kmem_cache_alloc_trace+0x12f/0x380 [ 37.782479] nbd_dev_add+0x44/0x890 [ 37.786124] nbd_genl_connect+0x4cc/0x1630 [ 37.790367] genl_family_rcv_msg+0x642/0xc40 [ 37.794889] genl_rcv_msg+0xbf/0x160 [ 37.798685] netlink_rcv_skb+0x160/0x440 [ 37.802735] genl_rcv+0x24/0x40 [ 37.806012] netlink_unicast+0x4d5/0x690 [ 37.810062] netlink_sendmsg+0x6bb/0xc40 [ 37.814120] sock_sendmsg+0xc3/0x120 [ 37.817862] ___sys_sendmsg+0x7bb/0x8e0 [ 37.821823] __x64_sys_sendmsg+0x132/0x220 [ 37.826070] do_syscall_64+0xf9/0x620 [ 37.829885] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 37.835054] [ 37.836664] Freed by task 8184: [ 37.840025] kfree+0xcc/0x210 [ 37.843121] nbd_put.part.0+0xfe/0x140 [ 37.847005] nbd_config_put+0x6a0/0x870 [ 37.851240] nbd_genl_connect+0x11bb/0x1630 [ 37.855690] genl_family_rcv_msg+0x642/0xc40 [ 37.860264] genl_rcv_msg+0xbf/0x160 [ 37.863973] netlink_rcv_skb+0x160/0x440 [ 37.868029] genl_rcv+0x24/0x40 [ 37.871291] netlink_unicast+0x4d5/0x690 [ 37.875336] netlink_sendmsg+0x6bb/0xc40 [ 37.879383] sock_sendmsg+0xc3/0x120 [ 37.883106] ___sys_sendmsg+0x7bb/0x8e0 [ 37.887066] __x64_sys_sendmsg+0x132/0x220 [ 37.891369] do_syscall_64+0xf9/0x620 [ 37.895193] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 37.900370] [ 37.901989] The buggy address belongs to the object at ffff8880a3249800 [ 37.901989] which belongs to the cache kmalloc-512 of size 512 [ 37.914700] The buggy address is located 216 bytes inside of [ 37.914700] 512-byte region [ffff8880a3249800, ffff8880a3249a00) [ 37.926591] The buggy address belongs to the page: [ 37.931519] page:ffffea00028c9240 count:1 mapcount:0 mapping:ffff88813bff0940 index:0x0 [ 37.939878] flags: 0xfff00000000100(slab) [ 37.944054] raw: 00fff00000000100 ffffea0002a9d608 ffffea00028ce208 ffff88813bff0940 [ 37.951929] raw: 0000000000000000 ffff8880a3249080 0000000100000006 0000000000000000 [ 37.960132] page dumped because: kasan: bad access detected [ 37.965855] [ 37.967551] Memory state around the buggy address: [ 37.972562] ffff8880a3249780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 37.979919] ffff8880a3249800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 37.987424] >ffff8880a3249880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 37.994776] ^ [ 38.001006] ffff8880a3249900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 38.008464] ffff8880a3249980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 38.015824] ================================================================== [ 38.023180] Disabling lock debugging due to kernel taint [ 38.030510] Kernel panic - not syncing: panic_on_warn set ... [ 38.030510] [ 38.038000] CPU: 1 PID: 8184 Comm: syz-executor167 Tainted: G B 4.19.194-syzkaller #0 [ 38.050329] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 38.059903] Call Trace: [ 38.062504] dump_stack+0x1fc/0x2ef [ 38.066231] panic+0x26a/0x50e [ 38.069429] ? __warn_printk+0xf3/0xf3 [ 38.073327] ? preempt_schedule_common+0x45/0xc0 [ 38.078104] ? ___preempt_schedule+0x16/0x18 [ 38.082524] ? trace_hardirqs_on+0x55/0x210 [ 38.086923] kasan_end_report+0x43/0x49 [ 38.090926] kasan_report_error.cold+0xa7/0x1b9 [ 38.095598] ? refcount_dec_not_one+0x71/0x1d0 [ 38.100180] kasan_report+0x8f/0xa0 [ 38.103807] ? refcount_dec_not_one+0x71/0x1d0 [ 38.108389] refcount_dec_not_one+0x71/0x1d0 [ 38.112783] ? refcount_dec_and_test_checked+0x20/0x20 [ 38.118048] ? nbd_config_put+0x5da/0x870 [ 38.122239] refcount_dec_and_mutex_lock+0x1c/0x80 [ 38.127347] nbd_genl_connect+0x11ee/0x1630 [ 38.131839] ? nbd_xmit_timeout+0x730/0x730 [ 38.136150] ? __sanitizer_cov_trace_switch+0x4b/0x80 [ 38.141327] ? validate_nla+0x270/0x820 [ 38.145289] ? nla_parse+0x1b2/0x290 [ 38.148988] genl_family_rcv_msg+0x642/0xc40 [ 38.153401] ? genl_rcv+0x40/0x40 [ 38.156835] ? genl_rcv_msg+0x12f/0x160 [ 38.160792] ? mutex_trylock+0x1a0/0x1a0 [ 38.164838] ? __radix_tree_lookup+0x216/0x370 [ 38.169462] genl_rcv_msg+0xbf/0x160 [ 38.173183] netlink_rcv_skb+0x160/0x440 [ 38.177236] ? genl_family_rcv_msg+0xc40/0xc40 [ 38.181811] ? netlink_ack+0xae0/0xae0 [ 38.185685] ? genl_rcv+0x15/0x40 [ 38.189273] genl_rcv+0x24/0x40 [ 38.192584] netlink_unicast+0x4d5/0x690 [ 38.196629] ? netlink_sendskb+0x110/0x110 [ 38.200851] ? _copy_from_iter_full+0x229/0x7c0 [ 38.205513] ? __phys_addr_symbol+0x2c/0x70 [ 38.209874] ? __check_object_size+0x17b/0x3e0 [ 38.214512] netlink_sendmsg+0x6bb/0xc40 [ 38.218563] ? aa_af_perm+0x230/0x230 [ 38.222371] ? nlmsg_notify+0x1a0/0x1a0 [ 38.226448] ? kernel_recvmsg+0x220/0x220 [ 38.230591] ? nlmsg_notify+0x1a0/0x1a0 [ 38.234563] sock_sendmsg+0xc3/0x120 [ 38.238268] ___sys_sendmsg+0x7bb/0x8e0 [ 38.242230] ? copy_msghdr_from_user+0x440/0x440 [ 38.247202] ? netlink_dump+0xc10/0xc10 [ 38.251225] ? nlmsg_notify+0x1a0/0x1a0 [ 38.255188] ? security_socket_recvmsg+0x8f/0xc0 [ 38.259944] ? __sys_recvfrom+0x2cd/0x3a0 [ 38.264073] ? __ia32_sys_send+0x100/0x100 [ 38.268300] ? __fdget+0x1a0/0x230 [ 38.271826] __x64_sys_sendmsg+0x132/0x220 [ 38.276049] ? __sys_sendmsg+0x1b0/0x1b0 [ 38.280114] ? entry_SYSCALL_64_after_hwframe+0x3e/0xbe [ 38.285602] ? trace_hardirqs_off_caller+0x6e/0x210 [ 38.290622] ? do_syscall_64+0x21/0x620 [ 38.294591] do_syscall_64+0xf9/0x620 [ 38.298383] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 38.303644] RIP: 0033:0x4407c9 [ 38.306832] Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 14 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48 [ 38.325873] RSP: 002b:00007ffc2fc85908 EFLAGS: 00000246 ORIG_RAX: 000000000000002e [ 38.333582] RAX: ffffffffffffffda RBX: 00000000000f4240 RCX: 00000000004407c9 [ 38.341010] RDX: 0000000000000000 RSI: 00000000200002c0 RDI: 0000000000000004 [ 38.348375] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000001 [ 38.355636] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000000090c9 [ 38.362911] R13: 00007ffc2fc8591c R14: 00007ffc2fc85930 R15: 00007ffc2fc85920 [ 38.370751] Kernel Offset: disabled [ 38.374383] Rebooting in 86400 seconds..