[ 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 '10.128.0.151' (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 syzkaller login: [ 38.072975] ================================================================== [ 38.080564] BUG: KASAN: use-after-free in refcount_dec_not_one+0x71/0x1d0 [ 38.087478] Read of size 4 at addr ffff8880aaa79b98 by task syz-executor405/8482 [ 38.094984] [ 38.096599] CPU: 1 PID: 8482 Comm: syz-executor405 Not tainted 4.19.211-syzkaller #0 [ 38.104469] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 38.113805] Call Trace: [ 38.116385] dump_stack+0x1fc/0x2ef [ 38.120007] print_address_description.cold+0x54/0x219 [ 38.125272] kasan_report_error.cold+0x8a/0x1b9 [ 38.129925] ? refcount_dec_not_one+0x71/0x1d0 [ 38.134503] kasan_report+0x8f/0xa0 [ 38.138113] ? refcount_dec_not_one+0x71/0x1d0 [ 38.142682] refcount_dec_not_one+0x71/0x1d0 [ 38.147075] ? refcount_dec_and_test_checked+0x20/0x20 [ 38.152332] ? nbd_config_put+0x5da/0x870 [ 38.156475] refcount_dec_and_mutex_lock+0x1c/0x80 [ 38.161392] nbd_genl_connect+0x11ee/0x1630 [ 38.165701] ? nbd_xmit_timeout+0x730/0x730 [ 38.170008] ? __sanitizer_cov_trace_switch+0x4b/0x80 [ 38.175187] ? validate_nla+0x270/0x820 [ 38.179159] ? nla_parse+0x1b2/0x290 [ 38.182862] genl_family_rcv_msg+0x642/0xc40 [ 38.187253] ? genl_rcv+0x40/0x40 [ 38.190685] ? genl_rcv_msg+0x12f/0x160 [ 38.194638] ? mutex_trylock+0x1a0/0x1a0 [ 38.198694] ? __radix_tree_lookup+0x216/0x370 [ 38.203266] genl_rcv_msg+0xbf/0x160 [ 38.206962] netlink_rcv_skb+0x160/0x440 [ 38.211006] ? genl_family_rcv_msg+0xc40/0xc40 [ 38.215568] ? netlink_ack+0xae0/0xae0 [ 38.219442] ? genl_rcv+0x15/0x40 [ 38.222888] genl_rcv+0x24/0x40 [ 38.226149] netlink_unicast+0x4d5/0x690 [ 38.230192] ? netlink_sendskb+0x110/0x110 [ 38.234419] ? _copy_from_iter_full+0x229/0x7c0 [ 38.239069] ? __phys_addr_symbol+0x2c/0x70 [ 38.243375] ? __check_object_size+0x17b/0x3e0 [ 38.247941] netlink_sendmsg+0x6c3/0xc50 [ 38.252001] ? aa_af_perm+0x230/0x230 [ 38.255783] ? nlmsg_notify+0x1f0/0x1f0 [ 38.259738] ? kernel_recvmsg+0x220/0x220 [ 38.263871] ? nlmsg_notify+0x1f0/0x1f0 [ 38.267829] sock_sendmsg+0xc3/0x120 [ 38.271533] ___sys_sendmsg+0x7bb/0x8e0 [ 38.275500] ? copy_msghdr_from_user+0x440/0x440 [ 38.280255] ? netlink_dump+0xc10/0xc10 [ 38.284221] ? nlmsg_notify+0x1f0/0x1f0 [ 38.288189] ? security_socket_recvmsg+0x8f/0xc0 [ 38.292926] ? __sys_recvfrom+0x2cd/0x3a0 [ 38.297053] ? __ia32_sys_send+0x100/0x100 [ 38.301295] ? __fdget+0x1a0/0x230 [ 38.304828] __x64_sys_sendmsg+0x132/0x220 [ 38.309053] ? __sys_sendmsg+0x1b0/0x1b0 [ 38.313104] ? entry_SYSCALL_64_after_hwframe+0x3e/0xbe [ 38.318465] ? trace_hardirqs_off_caller+0x6e/0x210 [ 38.323464] ? do_syscall_64+0x21/0x620 [ 38.327437] do_syscall_64+0xf9/0x620 [ 38.331582] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 38.336764] RIP: 0033:0x7fb69fdffb69 [ 38.340461] 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 [ 38.359362] RSP: 002b:00007ffe9f2348f8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e [ 38.367063] RAX: ffffffffffffffda RBX: 00007ffe9f234940 RCX: 00007fb69fdffb69 [ 38.374320] RDX: 0000000000000000 RSI: 0000000020000380 RDI: 0000000000000003 [ 38.381576] RBP: 0000000000000000 R08: 0000000000000000 R09: 00007fb69fe73ec0 [ 38.388829] R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe9f234930 [ 38.396104] R13: 0000000000009461 R14: 00007ffe9f23492c R15: 431bde82d7b634db [ 38.403542] [ 38.405159] Allocated by task 8476: [ 38.408774] kmem_cache_alloc_trace+0x12f/0x380 [ 38.413429] nbd_dev_add+0x44/0x890 [ 38.417158] nbd_genl_connect+0x4cc/0x1630 [ 38.421390] genl_family_rcv_msg+0x642/0xc40 [ 38.425879] genl_rcv_msg+0xbf/0x160 [ 38.429571] netlink_rcv_skb+0x160/0x440 [ 38.433612] genl_rcv+0x24/0x40 [ 38.436872] netlink_unicast+0x4d5/0x690 [ 38.440912] netlink_sendmsg+0x6c3/0xc50 [ 38.444958] sock_sendmsg+0xc3/0x120 [ 38.448653] ___sys_sendmsg+0x7bb/0x8e0 [ 38.452608] __x64_sys_sendmsg+0x132/0x220 [ 38.456832] do_syscall_64+0xf9/0x620 [ 38.460622] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 38.465786] [ 38.467391] Freed by task 8482: [ 38.470655] kfree+0xcc/0x210 [ 38.473750] nbd_put.part.0+0xfe/0x140 [ 38.477624] nbd_config_put+0x6a0/0x870 [ 38.481577] nbd_genl_connect+0x11bb/0x1630 [ 38.485878] genl_family_rcv_msg+0x642/0xc40 [ 38.490268] genl_rcv_msg+0xbf/0x160 [ 38.493958] netlink_rcv_skb+0x160/0x440 [ 38.498003] genl_rcv+0x24/0x40 [ 38.501263] netlink_unicast+0x4d5/0x690 [ 38.505304] netlink_sendmsg+0x6c3/0xc50 [ 38.509348] sock_sendmsg+0xc3/0x120 [ 38.513041] ___sys_sendmsg+0x7bb/0x8e0 [ 38.516993] __x64_sys_sendmsg+0x132/0x220 [ 38.521205] do_syscall_64+0xf9/0x620 [ 38.525003] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 38.530180] [ 38.531788] The buggy address belongs to the object at ffff8880aaa79ac0 [ 38.531788] which belongs to the cache kmalloc-512 of size 512 [ 38.544530] The buggy address is located 216 bytes inside of [ 38.544530] 512-byte region [ffff8880aaa79ac0, ffff8880aaa79cc0) [ 38.556390] The buggy address belongs to the page: [ 38.561301] page:ffffea0002aa9e40 count:1 mapcount:0 mapping:ffff88813bff0940 index:0x0 [ 38.569422] flags: 0xfff00000000100(slab) [ 38.573553] raw: 00fff00000000100 ffffea0002ab0748 ffffea0002a60008 ffff88813bff0940 [ 38.581412] raw: 0000000000000000 ffff8880aaa790c0 0000000100000006 0000000000000000 [ 38.589269] page dumped because: kasan: bad access detected [ 38.594958] [ 38.596564] Memory state around the buggy address: [ 38.601473] ffff8880aaa79a80: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb [ 38.608813] ffff8880aaa79b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 38.616149] >ffff8880aaa79b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 38.623485] ^ [ 38.627609] ffff8880aaa79c00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 38.634954] ffff8880aaa79c80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc [ 38.642288] ================================================================== [ 38.649623] Disabling lock debugging due to kernel taint [ 38.655393] Kernel panic - not syncing: panic_on_warn set ... [ 38.655393] [ 38.662763] CPU: 1 PID: 8482 Comm: syz-executor405 Tainted: G B 4.19.211-syzkaller #0 [ 38.672028] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 38.681379] Call Trace: [ 38.683970] dump_stack+0x1fc/0x2ef [ 38.687596] panic+0x26a/0x50e [ 38.690786] ? __warn_printk+0xf3/0xf3 [ 38.694670] ? preempt_schedule_common+0x45/0xc0 [ 38.699416] ? ___preempt_schedule+0x16/0x18 [ 38.703804] ? trace_hardirqs_on+0x55/0x210 [ 38.708106] kasan_end_report+0x43/0x49 [ 38.712062] kasan_report_error.cold+0xa7/0x1b9 [ 38.716710] ? refcount_dec_not_one+0x71/0x1d0 [ 38.721285] kasan_report+0x8f/0xa0 [ 38.724911] ? refcount_dec_not_one+0x71/0x1d0 [ 38.729472] refcount_dec_not_one+0x71/0x1d0 [ 38.733857] ? refcount_dec_and_test_checked+0x20/0x20 [ 38.739116] ? nbd_config_put+0x5da/0x870 [ 38.743251] refcount_dec_and_mutex_lock+0x1c/0x80 [ 38.748163] nbd_genl_connect+0x11ee/0x1630 [ 38.752463] ? nbd_xmit_timeout+0x730/0x730 [ 38.756766] ? __sanitizer_cov_trace_switch+0x4b/0x80 [ 38.761937] ? validate_nla+0x270/0x820 [ 38.765896] ? nla_parse+0x1b2/0x290 [ 38.769603] genl_family_rcv_msg+0x642/0xc40 [ 38.773991] ? genl_rcv+0x40/0x40 [ 38.777422] ? genl_rcv_msg+0x12f/0x160 [ 38.781374] ? mutex_trylock+0x1a0/0x1a0 [ 38.785424] ? __radix_tree_lookup+0x216/0x370 [ 38.789991] genl_rcv_msg+0xbf/0x160 [ 38.793684] netlink_rcv_skb+0x160/0x440 [ 38.797723] ? genl_family_rcv_msg+0xc40/0xc40 [ 38.802299] ? netlink_ack+0xae0/0xae0 [ 38.806167] ? genl_rcv+0x15/0x40 [ 38.809599] genl_rcv+0x24/0x40 [ 38.812858] netlink_unicast+0x4d5/0x690 [ 38.816904] ? netlink_sendskb+0x110/0x110 [ 38.821118] ? _copy_from_iter_full+0x229/0x7c0 [ 38.825764] ? __phys_addr_symbol+0x2c/0x70 [ 38.830064] ? __check_object_size+0x17b/0x3e0 [ 38.834624] netlink_sendmsg+0x6c3/0xc50 [ 38.838665] ? aa_af_perm+0x230/0x230 [ 38.842444] ? nlmsg_notify+0x1f0/0x1f0 [ 38.846394] ? kernel_recvmsg+0x220/0x220 [ 38.850537] ? nlmsg_notify+0x1f0/0x1f0 [ 38.854489] sock_sendmsg+0xc3/0x120 [ 38.858180] ___sys_sendmsg+0x7bb/0x8e0 [ 38.862132] ? copy_msghdr_from_user+0x440/0x440 [ 38.866880] ? netlink_dump+0xc10/0xc10 [ 38.870837] ? nlmsg_notify+0x1f0/0x1f0 [ 38.874791] ? security_socket_recvmsg+0x8f/0xc0 [ 38.879525] ? __sys_recvfrom+0x2cd/0x3a0 [ 38.883652] ? __ia32_sys_send+0x100/0x100 [ 38.887866] ? __fdget+0x1a0/0x230 [ 38.891401] __x64_sys_sendmsg+0x132/0x220 [ 38.895626] ? __sys_sendmsg+0x1b0/0x1b0 [ 38.899674] ? entry_SYSCALL_64_after_hwframe+0x3e/0xbe [ 38.905022] ? trace_hardirqs_off_caller+0x6e/0x210 [ 38.910030] ? do_syscall_64+0x21/0x620 [ 38.913988] do_syscall_64+0xf9/0x620 [ 38.917794] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 38.922969] RIP: 0033:0x7fb69fdffb69 [ 38.926662] 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 [ 38.945549] RSP: 002b:00007ffe9f2348f8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e [ 38.953244] RAX: ffffffffffffffda RBX: 00007ffe9f234940 RCX: 00007fb69fdffb69 [ 38.960516] RDX: 0000000000000000 RSI: 0000000020000380 RDI: 0000000000000003 [ 38.967778] RBP: 0000000000000000 R08: 0000000000000000 R09: 00007fb69fe73ec0 [ 38.975037] R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe9f234930 [ 38.982289] R13: 0000000000009461 R14: 00007ffe9f23492c R15: 431bde82d7b634db [ 38.989726] Kernel Offset: disabled [ 38.993364] Rebooting in 86400 seconds..