我也想学习 https://ws3.sinaimg.cn/bmiddle/62e721e4gw1et02cofvqxj200k00k3y9.jpg

@didida #14
我看是有的
127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4
::1 localhost localhost.localdomain localhost6 localhost6.localdomain6

有那么重要吗？为何要如此执着

加一

每天精精神神的写代码不挺好的吗？你们究竟想咋滴？

战略性马克

多运动，然后晚上提前两个小时洗澡，然后看会书让自己心静下来，然后睡觉。个人觉得会有一点效果吧

花钱买的都是吃灰，免费给你就能不吃灰了？

2 楼没毛病

@xiaket #2 cmd + k 好用，有时候并不是想要 clear 那样的假清除

不同女朋友不同爱好,我不了解你女朋友,而且我也没有女朋友.
我不知道你女朋友化不化妆.
PS:我知道你有女朋友了.你的狗粮就是送给我的礼物

@tempdban #9 你说的 core 一下是啥子意思？我是个 Linux 新手

@tempdban #8 strace iptalbes -t nat -nL 这条命令我在 5 楼的回复中已经用过了，知道了卡在了 getsocketopt 这个系统调用处，但是还是不知道卡着的原因。。。而 cat /proc/16523/stack 的输出如下：
[<ffffffff8108b6d1>] call_usermodehelper_exec+0x111/0x1a0
[<ffffffff8108bb5b>] __request_module+0x18b/0x2b0
[<ffffffffa03c096f>] get_info+0x1ef/0x250 [ip_tables]
[<ffffffffa03c199f>] do_ipt_get_ctl+0x6f/0x3a0 [ip_tables]
[<ffffffff8152ebe8>] nf_getsockopt+0x68/0x90
[<ffffffff8153e5a0>] ip_getsockopt+0xa0/0xd0
[<ffffffff815617c5>] raw_getsockopt+0x25/0x50
[<ffffffff814e5ba4>] sock_common_getsockopt+0x14/0x20
[<ffffffff814e4f17>] SyS_getsockopt+0x77/0xf0
[<ffffffff81614a29>] system_call_fastpath+0x16/0x1b
[<ffffffffffffffff>] 0xffffffffffffffff
这些输出我个 Linux 渣渣看不懂啊( Ĭ ^ Ĭ )

@ryd994 #3 大概看了下 dmesg 的输出，好像也没相关信息。。

@tempdban #2 不好意思，上面给你贴的命令 cat /proc/16523/status 的输出中 pid 不是 16523，是因为我又重新运行命令 iptables -t nat -nL 生成的进程 id 是 17357。。。

@wd #1 我运行了命令：strace -p 16523，就输出了一句：Process 16523 attached ,然后就再也没有输出了，strace 命令本身的进程 id 是 22098，然后我又看了下 strace 命令本身的进程状态：cat /proc/22098/status，输出的是：
State: S (sleeping)
然后我把之前 iptables 命令起的进程杀掉后又运行了命令：strace iptables -t nat -nL，输出如下：
execve("/sbin/iptables", ["iptables", "-t", "nat", "-nL"], [/* 24 vars */]) = 0
brk(0) = 0x2387000
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f66473f7000
access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=82284, ...}) = 0
mmap(NULL, 82284, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f66473e2000
close(3) = 0
open("/lib64/libip4tc.so.0", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0`\31\0\0\0\0\0\0"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0755, st_size=32816, ...}) = 0
mmap(NULL, 2126600, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f6646fcf000
mprotect(0x7f6646fd5000, 2097152, PROT_NONE) = 0
mmap(0x7f66471d5000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x6000) = 0x7f66471d5000
close(3) = 0
open("/lib64/libip6tc.so.0", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\340\32\0\0\0\0\0\0"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0755, st_size=32864, ...}) = 0
mmap(NULL, 2126632, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f6646dc7000
mprotect(0x7f6646dce000, 2093056, PROT_NONE) = 0
mmap(0x7f6646fcd000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x6000) = 0x7f6646fcd000
close(3) = 0
open("/lib64/libxtables.so.10", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\2403\0\0\0\0\0\0"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0755, st_size=53520, ...}) = 0
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f66473e1000
mmap(NULL, 2149016, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f6646bba000
mprotect(0x7f6646bc5000, 2097152, PROT_NONE) = 0
mmap(0x7f6646dc5000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0xb000) = 0x7f6646dc5000
close(3) = 0
open("/lib64/libm.so.6", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0pS\0\0\0\0\0\0"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0755, st_size=1139680, ...}) = 0
mmap(NULL, 3150136, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f66468b8000
mprotect(0x7f66469b9000, 2093056, PROT_NONE) = 0
mmap(0x7f6646bb8000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x100000) = 0x7f6646bb8000
close(3) = 0
open("/lib64/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P%\2\0\0\0\0\0"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0755, st_size=2173512, ...}) = 0
mmap(NULL, 3981792, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f66464eb000
mprotect(0x7f66466ae000, 2093056, PROT_NONE) = 0
mmap(0x7f66468ad000, 24576, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x1c2000) = 0x7f66468ad000
mmap(0x7f66468b3000, 16864, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7f66468b3000
close(3) = 0
open("/lib64/libdl.so.2", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0`\16\0\0\0\0\0\0"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0755, st_size=19776, ...}) = 0
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f66473e0000
mmap(NULL, 2109744, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f66462e7000
mprotect(0x7f66462e9000, 2097152, PROT_NONE) = 0
mmap(0x7f66464e9000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x2000) = 0x7f66464e9000
close(3) = 0
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f66473df000
mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f66473dd000
arch_prctl(ARCH_SET_FS, 0x7f66473dd740) = 0
mprotect(0x7f66468ad000, 16384, PROT_READ) = 0
mprotect(0x7f66464e9000, 4096, PROT_READ) = 0
mprotect(0x7f6646bb8000, 4096, PROT_READ) = 0
mprotect(0x7f6646dc5000, 4096, PROT_READ) = 0
mprotect(0x7f6646fcd000, 4096, PROT_READ) = 0
mprotect(0x7f66471d5000, 4096, PROT_READ) = 0
mprotect(0x613000, 4096, PROT_READ) = 0
mprotect(0x7f66473f8000, 4096, PROT_READ) = 0
munmap(0x7f66473e2000, 82284) = 0
socket(PF_LOCAL, SOCK_STREAM, 0) = 3
bind(3, {sa_family=AF_LOCAL, sun_path=@"xtables"}, 10) = 0
socket(PF_INET, SOCK_RAW, IPPROTO_RAW) = 4
fcntl(4, F_SETFD, FD_CLOEXEC) = 0
getsockopt(4, SOL_IP, 0x40 /* IP_??? */,
输出的好像是 Linux 的系统调用信息吧，不知道为啥会卡在 getsockopt 这个调用这里。。。

@tempdban #2 运行命令 cat /proc/16523/status 后，输出如下：
``` bash
Name: iptables
State: D (disk sleep)
Tgid: 17357
Ngid: 0
Pid: 17357
PPid: 8171
TracerPid: 6117
Uid: 0 0 0 0
Gid: 0 0 0 0
FDSize: 256
Groups: 0
VmPeak: 16196 kB
VmSize: 16112 kB
VmLck: 0 kB
VmPin: 0 kB
VmHWM: 548 kB
VmRSS: 508 kB
VmData: 468 kB
VmStk: 136 kB
VmExe: 80 kB
VmLib: 3072 kB
VmPTE: 48 kB
VmSwap: 0 kB
Threads: 1
SigQ: 2/63168
SigPnd: 0000000000040000
ShdPnd: 0000000000000000
SigBlk: 0000000000000000
SigIgn: 0000000000000000
SigCgt: 0000000000000000
CapInh: 0000000000000000
CapPrm: 0000001fffffffff
CapEff: 0000001fffffffff
CapBnd: 0000001fffffffff
Seccomp: 0
Cpus_allowed: ffffff
Cpus_allowed_list: 0-23
Mems_allowed: 00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000003
Mems_allowed_list: 0-1
voluntary_ctxt_switches: 1
nonvoluntary_ctxt_switches: 1
```
我看到网上别人解释 State: D (disk sleep) 的意思是进程在等待磁盘 IO （这里说磁盘 IO，也可能是网络 IO 吧），然后我运行命令：ll /proc/16523/fd/ ，看了下该进程打开的文件句柄，输出如下：
``` bash
lrwx------ 1 root root 64 Aug 13 10:10 0 -> /dev/pts/0
lrwx------ 1 root root 64 Aug 13 10:10 1 -> socket:[836197772]
lrwx------ 1 root root 64 Aug 13 10:10 2 -> socket:[836197773]
``` bash
然后我又看了这个解释 socket:[number] 的博客：[https://blog.csdn.net/lkkey80/article/details/16856063]( https://blog.csdn.net/lkkey80/article/details/16856063)，我又运行 cat /proc/net/unix | grep 836197772，找到了 836197772：
``` bash
Num RefCount Protocol Flags Type St Inode Path
ffff880471dd9680: 00000002 00000000 00000000 0001 01 836197772 @xtables
```
运行 cat /proc/net/raw | grep 836197773 找到了 836197773：
``` bash
sl local_address rem_address st tx_queue rx_queue tr tm->when retrnsmt uid timeout inode ref pointer drops
255: 00000000:00FF 00000000:0000 07 00000000:00000000 00:00000000 00000000 0 0 836197773 2 ffff880471ddf440 0
```
（/proc/net/tcp 和 /proc/net/udp 这两个文件我也看了，没有 836197772 和 836197773 这两个 inode 的信息）。现在，到这里了，/proc/net/unix 和 /proc/net/raw 这两个文件的信息我看不太懂，接下来该怎么排查呢？

挺一楼