Warning: Permanently added '10.128.0.255' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 75.905323][ T9611] IPVS: ftp: loaded support on port[0] = 21 [ 75.941528][ T9611] netlink: 16 bytes leftover after parsing attributes in process `syz-executor670'. [ 75.995104][ T9611] ------------[ cut here ]------------ [ 76.000623][ T9611] refcount_t: underflow; use-after-free. [ 76.006826][ T9611] WARNING: CPU: 0 PID: 9611 at lib/refcount.c:28 refcount_warn_saturate+0x1d1/0x1e0 [ 76.019937][ T9611] Kernel panic - not syncing: panic_on_warn set ... [ 76.028754][ T9611] CPU: 0 PID: 9611 Comm: syz-executor670 Not tainted 5.6.0-rc5-syzkaller #0 [ 76.040930][ T9611] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 76.052402][ T9611] Call Trace: [ 76.056045][ T9611] dump_stack+0x188/0x20d [ 76.060503][ T9611] ? refcount_warn_saturate+0x1d0/0x1e0 [ 76.067097][ T9611] panic+0x2e3/0x75c [ 76.071267][ T9611] ? add_taint.cold+0x16/0x16 [ 76.077277][ T9611] ? __probe_kernel_read+0x188/0x1d0 [ 76.082769][ T9611] ? __warn.cold+0x14/0x35 [ 76.087178][ T9611] ? __warn+0xd5/0x1c8 [ 76.091630][ T9611] ? refcount_warn_saturate+0x1d1/0x1e0 [ 76.097397][ T9611] __warn.cold+0x2f/0x35 [ 76.102813][ T9611] ? refcount_warn_saturate+0x1d1/0x1e0 [ 76.108377][ T9611] report_bug+0x27b/0x2f0 [ 76.112694][ T9611] do_error_trap+0x12b/0x220 [ 76.117294][ T9611] ? refcount_warn_saturate+0x1d1/0x1e0 [ 76.123198][ T9611] do_invalid_op+0x32/0x40 [ 76.128105][ T9611] ? refcount_warn_saturate+0x1d1/0x1e0 [ 76.133771][ T9611] invalid_op+0x23/0x30 [ 76.137985][ T9611] RIP: 0010:refcount_warn_saturate+0x1d1/0x1e0 [ 76.144305][ T9611] Code: e9 db fe ff ff 48 89 df e8 7c 03 20 fe e9 8a fe ff ff e8 22 39 e3 fd 48 c7 c7 00 b1 51 88 c6 05 28 80 d2 06 01 e8 87 49 b5 fd <0f> 0b e9 af fe ff ff 0f 1f 84 00 00 00 00 00 41 56 41 55 41 54 55 [ 76.164846][ T9611] RSP: 0018:ffffc90001fc7d38 EFLAGS: 00010286 [ 76.171083][ T9611] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 [ 76.179674][ T9611] RDX: 0000000000000000 RSI: ffffffff815bfe61 RDI: fffff520003f8f99 [ 76.188238][ T9611] RBP: 0000000000000003 R08: ffff888094122180 R09: 0000000000000000 [ 76.196848][ T9611] R10: 0000000000000000 R11: 0000000000000000 R12: ffff8880909a6040 [ 76.204907][ T9611] R13: ffff8880909a6044 R14: 00000000000002ab R15: ffff8880990c1440 [ 76.213149][ T9611] ? vprintk_func+0x81/0x17e [ 76.217864][ T9611] ? refcount_warn_saturate+0x1d1/0x1e0 [ 76.223797][ T9611] free_nsproxy+0x445/0x4a0 [ 76.228893][ T9611] switch_task_namespaces+0xaa/0xc0 [ 76.234536][ T9611] do_exit+0xb2f/0x2dd0 [ 76.238778][ T9611] ? mm_update_next_owner+0x7a0/0x7a0 [ 76.244538][ T9611] ? up_read+0x1ab/0x750 [ 76.249011][ T9611] ? mark_held_locks+0x9f/0xe0 [ 76.254094][ T9611] ? down_read_non_owner+0x470/0x470 [ 76.259483][ T9611] ? handle_mm_fault+0x491/0xa10 [ 76.264426][ T9611] do_group_exit+0x125/0x340 [ 76.269024][ T9611] __x64_sys_exit_group+0x3a/0x50 [ 76.274221][ T9611] do_syscall_64+0xf6/0x7d0 [ 76.278739][ T9611] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 76.284622][ T9611] RIP: 0033:0x43f998 [ 76.288502][ T9611] Code: 24 38 80 f9 3a 0f 85 5f 01 00 00 48 8d 74 24 34 48 8d 7c 24 38 83 ea 01 89 54 24 34 e8 61 f8 ff ff 83 f8 3c 41 89 c1 0f 87 3d <01> 00 00 8b 4c 24 34 85 c9 0f 8e 59 01 00 00 48 8b 54 24 38 c7 44 [ 76.309178][ T9611] RSP: 002b:00007ffc3b8a0dd8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 76.317936][ T9611] RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 000000000043f998 [ 76.326014][ T9611] RDX: 0000000000000001 RSI: 000000000000003c RDI: 0000000000000001 [ 76.333975][ T9611] RBP: 00000000004bfa10 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 76.341953][ T9611] R10: 0000000120080522 R11: 0000000000000246 R12: 0000000000000001 [ 76.349915][ T9611] R13: 00000000006d11c0 R14: 0000000000000000 R15: 0000000000000000 [ 76.359950][ T9611] Kernel Offset: disabled [ 76.364339][ T9611] Rebooting in 86400 seconds..