GetInt coredump

[lonelymemo]

这是我的代码（原谅没有试用FindMember来获取，偷懒测试）
if(root.Parse(result.c_str()).HasParseError())
{
WRN("parse json got err %d.\n",root.GetParseError());
return -1;
}
if (root[“retcode”]!= 0) { //core 在这一行，
WRN("curl retcode=%d errmsg=%s\n", root[“retcode”], root["errmsg"].GetString());
return -1;
}
gdb 显示的结果：#0 0x000000000041cfb6 in rapidjson::GenericValuerapidjson::UTF8<char, rapidjson::MemoryPoolAllocatorrapidjson::CrtAllocator >::GetInt (
this=0x10) at rapidjson/document.h:1645 //这里段错误
照源码来看，无论如何也不应该是段错误，如果json里面没有‘retcode’或者‘retcode’类型不是int，都应该在RAPIDJSON_ASSERT上core（实际上json是有这个字段的，并且类型也是int）。
这里到底是什么原因导致的呢？请教
附：json
{
"errmsg": "Transportendpointisnotconnected",
"results": [
null
],
"retcode": -1
}

[miloyip]

不能重现：

#include "rapidjson/document.h"
#include <cstdio>

using namespace rapidjson;

int main() {
    const char json[] = "{\"errmsg\":\"Transportendpointisnotconnected\",\"results\":[null],\"retcode\":-1}";
    Document root;
    root.Parse(json);
    if (root["retcode"] != 0) {
        printf("curl retcode=%d errmsg=%s\n", root["retcode"].GetInt(), root["errmsg"].GetString());
    }
}

$ g++ -I ~/github/rapidjson/include a.cpp
$ ./a.out
curl retcode=-1 errmsg=Transportendpointisnotconnected

[lonelymemo]

我自己也被迷惑了，不知道是不是其他的原因导致的；目前从coredump看到的情况是这样的。gdb 结果
Program terminated with signal 11, Segmentation fault.
#0 0x000000000041cfb6 in rapidjson::GenericValuerapidjson::UTF8<char, rapidjson::MemoryPoolAllocatorrapidjson::CrtAllocator >::GetInt (
this=0x10) at rapidjson/document.h:1645
1645 rapidjson/document.h: No such file or directory.
Missing separate debuginfos, use: debuginfo-install cyrus-sasl-lib-2.1.26-17.el7.x86_64 glibc-2.17-55.tl2.7.x86_64 keyutils-libs-1.5.8-3.el7.x86_64 krb5-libs-1.11.3-49.el7.x86_64 libcom_err-1.42.9-4.el7.x86_64 libcurl-7.29.0-19.el7.x86_64 libgcc-4.8.2-16.2.el7_0.x86_64 libidn-1.28-3.el7.x86_64 libselinux-2.2.2-6.el7.x86_64 libssh2-1.4.3-8.el7.x86_64 libstdc++-4.8.2-16.2.el7_0.x86_64 mariadb-libs-5.5.41-2.el7_0.x86_64 nspr-4.10.6-1.el7_0.x86_64 nss-3.16.2.3-2.el7_0.x86_64 nss-softokn-freebl-3.16.2.3-1.el7_0.x86_64 nss-util-3.16.2.3-1.el7_0.x86_64 openldap-2.4.39-3.el7.x86_64 openssl-libs-1.0.1e-51.tl2.5.x86_64 pcre-8.32-12.el7.x86_64 xz-libs-5.1.2-8alpha.el7.x86_64 zlib-1.2.7-13.el7.x86_64
(gdb) bt
#0 0x000000000041cfb6 in rapidjson::GenericValuerapidjson::UTF8<char, rapidjson::MemoryPoolAllocatorrapidjson::CrtAllocator >::GetInt (
this=0x10) at rapidjson/document.h:1645
#1 0x0000000000439016 in Dispatch_Proc::get_featuredata_by_id (this=0x7ffdcf006760,
apisvr="http://anm.interface1.oa.com/cgi-bin/netman2.0/core_v2/getfeaturedatabyid_inbulk_v2.cgi",
params="user_id=15&user_rtx=devinzeng&data={%22features%22:[{%22id%22:2037343130,%22day%22:%222016-09-01%22},{%22id%22:2037343131,%22day%22:%222016-09-01%22},{%22id%22:2037343021,%22day%22:%222016-09-01%22},{"..., timesecond=1472724048, last_update_time=1472723448)
at dispatch_proc.cpp:2069
#2 0x0000000000448dc8 in Dispatch_Proc::update_zone (this=0x7ffdcf006760) at dispatch_proc.cpp:2233
#3 0x0000000000449d49 in Dispatch_Proc::calc_video_gslb (this=0x7ffdcf006760) at dispatch_proc.cpp:2454
#4 0x000000000044b433 in Dispatch_Proc::run (this=0x7ffdcf006760) at dispatch_proc.cpp:4058
#5 0x000000000047a0a1 in main (ac=3, av=0x7ffdcf008208) at dispatch_svr.cpp:67
(gdb) f 1
#1 0x0000000000439016 in Dispatch_Proc::get_featuredata_by_id (this=0x7ffdcf006760,
apisvr="http://anm.interface1.oa.com/cgi-bin/netman2.0/core_v2/getfeaturedatabyid_inbulk_v2.cgi",
params="user_id=15&user_rtx=devinzeng&data={%22features%22:[{%22id%22:2037343130,%22day%22:%222016-09-01%22},{%22id%22:2037343131,%22day%22:%222016-09-01%22},{%22id%22:2037343021,%22day%22:%222016-09-01%22},{"..., timesecond=1472724048, last_update_time=1472723448)
at dispatch_proc.cpp:2069
2069 dispatch_proc.cpp: No such file or directory.
(gdb) p result
$1 = "{"errmsg":"Transport endpoint is not connected","results":[null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,n"...
(gdb) p root
$2 = {rapidjson::GenericValue<rapidjson::UTF8<char, rapidjson::MemoryPoolAllocatorrapidjson::CrtAllocator >> = {
static kDefaultArrayCapacity = <error reading variable: No global symbol "rapidjson::GenericValue<rapidjson::UTF8, rapidjson::MemoryPoolAllocatorrapidjson::CrtAllocator >::kDefaultArrayCapacity".>,
static kDefaultObjectCapacity = <error reading variable: No global symbol "rapidjson::GenericValue<rapidjson::UTF8, rapidjson::MemoryPoolAllocatorrapidjson::CrtAllocator >::kDefaultObjectCapacity".>, data_ = {s = {length = 3, hashcode = 3,
str = 0x3000082d7f370 <Address 0x3000082d7f370 out of bounds>}, ss = {str = "\003\000\000\000\003\000\000\000p\363\327\202\000"}, n = {
i = {i = 3, padding = "\003\000\000"}, u = {u = 3, padding2 = "\003\000\000"}, i64 = 12884901891, u64 = 12884901891,
d = 6.3659873743780139e-314}, o = {size = 3, capacity = 3, members = 0x3000082d7f370}, a = {size = 3, capacity = 3,
elements = 0x3000082d7f370}, f = {payload = "\003\000\000\000\003\000\000\000p\363\327\202\000", flags = 3}}},
static kDefaultStackCapacity = 1024, allocator_ = 0x7d924a70, ownAllocator_ = 0x7d924a70, stack_ = {allocator_ = 0x28631f0,
ownAllocator_ = 0x28631f0, stack_ = 0x0, stackTop_ = 0x0, stackEnd_ = 0x0, initialCapacity_ = 1024}, parseResult_ = {
code_ = rapidjson::kParseErrorNone, offset_ = 0}}
(gdb) se
search section select-frame set
(gdb) set print elements 0
(gdb) p result
$3 = "{"errmsg":"Transport endpoint is not connected","results":[null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null],"retcode":-1}\n"
(gdb)

[miloyip]

this=0x10 是错的指针。会不会是 root 的生命周期有问题？

[lonelymemo]

root是一个局部变量，函数调用时申请的，非指针不存在提前释放。

[miloyip]

你试试 valgrind 跑一下，看看有没有非法的内存访问？

[lonelymemo]

嗯，正准备搞一搞试试

[miloyip]

有进展么？

[nuoqish]

我也遇到同样的问题，当rapidjson和libcurl同时使用时会随机coredump，目前还在找原因，不知道有没有最新进展？