How to prevent crash when invoke fwrite with different file in multi-thread?

Question

How to prevent crash when invoke fwrite with different file in multi-thread?

Ace Wang 1

My app keep crash when fwirte without way to reproduce.

My code is like this:

FILE *fp = fopen(tempFileName.c_str(), "wb");  
if (fp) {  
	fwrite(jsonString.c_str(), 1, jsonString.length(), fp);  
	fclose(fp);  
  
	remove(_filename.c_str());  
	// move temp file to overwitten original one;  
	rename(tempFileName.c_str(), _filename.c_str());

crash stack like this:

CrashRpt!Ordinal10+0x70fd  
CrashRpt!Ordinal10+0x4224  
CrashRpt!Ordinal10+0x5064  
ucrtbase!invalid_parameter+0x145  
ucrtbase!invalid_parameter_noinfo+0x9  
ucrtbase!_isatty+0x3afa0  
ucrtbase!__acrt_stdio_begin_temporary_buffering_nolock+0x19  
ucrtbase!<lambda_96f4279ff90247a4c5c5d9824f56f8c1>::operator()+0x20  
ucrtbase!__crt_seh_guarded_call<unsigned __int64>::operator()<<lambda_bdbcead8b570fa3d5ec6d9679862a6e5>,<lambda_96f4279ff90247a4c5c5d9824f56f8c1> & __ptr64,<lambda_4606be27f17b5e5579e09050fab91818> >+0x2b  
ucrtbase!fwrite+0x67

detail of ucrtbase as follow
0:020> lmvm ucrtbase
Browse full module list
start end module name
00007ffab3c80000 00007ffab3d7a000 ucrtbase (pdb symbols) c:\symbols\ucrtbase.pdb\9FB5798C91EBCA528CADC890FF6E04FF1\ucrtbase.pdb
Loaded symbol image file: ucrtbase.dll
Image path: C:\Windows\System32\ucrtbase.dll
Image name: ucrtbase.dll
Browse all global symbols functions data
Image was built with /Brepro flag.
Timestamp: 48AC8393 (This is a reproducible build file hash, not a timestamp)
CheckSum: 0010252D
ImageSize: 000FA000
File version: 6.2.17763.1490
Product version: 10.0.17763.1490
File flags: 0 (Mask 3F)
File OS: 40004 NT Win32
File type: 2.0 Dll
File date: 00000000.00000000
Translations: 0409.04b0
Information from resource tables:
CompanyName: Microsoft Corporation
ProductName: Microsoft® Windows® Operating System
InternalName: ucrtbase.dll
OriginalFilename: ucrtbase.dll
ProductVersion: 10.0.17763.1490
FileVersion: 10.0.17763.1490 (WinBuild.160101.0800)
FileDescription: Microsoft® C Runtime Library
LegalCopyright: © Microsoft Corporation. All rights reserved.

Viorel 122.6K Reputation points

2023-01-09T10:30:01.257+00:00

Which of these variables are used by different threads?
Ace Wang 1 Reputation point

2023-01-10T01:15:22.607+00:00

the _filename would be access by different thread. but there has critical section to make sure the parameter thread safe.
other variables are temporary use.

the frame data is like [Desensitized]:

0:020> dx Debugger.Sessions[0].Processes[2336].Threads[6804].Stack.Frames[25].SwitchTo();dv /t /v
Debugger.Sessions[0].Processes[2336].Threads[6804].Stack.Frames[25].SwitchTo()
0000005b7e2be960 class std::basic_string<char,std::char_traits<char>,std::allocator<char> > * path = 0x0000005b7e2be9c0 "C:/Users/aaadmin/AppData/Roaming/FFF/1454117609475/client_info/alert_events.json"
0000005b7e2be968 class std::basic_string<char,std::char_traits<char>,std::allocator<char> > * buffer = 0x0000005b7e2be9a0 "{
"xxxxyyyAlertEventsList": [
"AAMkAGU3MzBhZDFlLWQ0YTYtNDI3OS1hODc0LTAzZDY3ZTNhYzAyMgFRAAgI2t74eZ4AAEYAAAAAha43j_1ROUWTZCjiN-16KwcALQev6pjp1UqGfleeHJc6CwACMkhQEQAALQev6pjp1UqGfleeHJc6CwACMkjQjgAAEA==",
"AAMkAGU3MzBhZDFlLWQ0YTYtNDI3OS1hODc0LTAzZDY3ZTNhYzAyMgBGAAAAAACFrjeP7VE5RZNkKOI3-XorBwAtB6-qmOnVSoZ_V54clzoLAAIySFARAAAtB6-qmOnVSoZ_V54clzoLAAI8MVKRAAA="
]
}"
0000005b7e2be770 class std::basic_ofstream<char,std::char_traits<char> > file = class std::basic_ofstream<char,std::char_traits<char> > 0000005b7e2be880 class std::basic_string<char,std::char_traits<char>,std::allocator<char> > tempPath = "C:/Users/aaadmin/AppData/Roaming/FFF/1454117609475/client_info/alert_events.json_temp"
Viorel 122.6K Reputation points

2023-01-10T11:21:23.473+00:00

For some reasons the fp variable is detected as invalid inside the _isatty function, which is invoked by fwrite. Maybe it was corrupted by some parallel threads or invalid memory usage, and it is not clear if you shown the real code. Maybe you should give more details to understand or reproduce the problem. Or maybe the critical section objects do not protect the whole critical sections.

Ace Wang 1

code.txt

full function as attachment 


the macro SYNCHRONIZED could expend to:
        auto mutexLock = std::make_shared<std::lock_guard<std::mutex>>(*_mutex);
and the _mutex is a member variable type is std::shared_ptr<std::mutex>


the class JsonStorage help deal with json string and save to file .
would bind one file for each JsonStorage  object. 

**The following facts need to be clarified**

 1. Each JsonStorage object bound different json file.
 2. One JsonStorage object could be access in some different threads.
 3. This code is used in cross platform , the problem is happened in windows part.
 4. We cannot reproduce in our dev/qa environment.  Only one customer has this issue. maybe you could help check ucrtbase.dll version  6.2.17763.1490 ,could lead to this issue.

Minxin Yu 13,501 Reputation points Microsoft External Staff

2023-01-12T02:09:43.7966667+00:00

Only one customer has this issue

Do you mean that some Windows customers can use the program well?
Ace Wang 1 Reputation point

2023-01-12T03:38:17.6+00:00

yes , only one customer has this issue. some others and all our develop/qa environments are work well.

So i suspect that the system dll has some different (C:\Windows\System32\ucrtbase.dll)

our package has release a specific ucrtbase.dll in our install path . but seems not be load.
Viorel 122.6K Reputation points

2023-01-12T11:34:14.2866667+00:00

Make sure that the _mutex members of all objects point to the same shared unique object.

The definition of SYNCHRONIZED probably can be simplified to const std::lock_guard<std::mutex> mutexLock( *_mutex ), though the current implementation should work too.

Maybe there are pointer issues in other parts that affect the memory.

Your answer

Viorel 122.6K Reputation points

2023-01-09T10:30:01.257+00:00

Which of these variables are used by different threads?
Ace Wang 1 Reputation point

2023-01-10T01:15:22.607+00:00

the _filename would be access by different thread. but there has critical section to make sure the parameter thread safe.
other variables are temporary use.

the frame data is like [Desensitized]:

0:020> dx Debugger.Sessions[0].Processes[2336].Threads[6804].Stack.Frames[25].SwitchTo();dv /t /v
Debugger.Sessions[0].Processes[2336].Threads[6804].Stack.Frames[25].SwitchTo()
0000005b7e2be960 class std::basic_string<char,std::char_traits<char>,std::allocator<char> > * path = 0x0000005b7e2be9c0 "C:/Users/aaadmin/AppData/Roaming/FFF/1454117609475/client_info/alert_events.json"
0000005b7e2be968 class std::basic_string<char,std::char_traits<char>,std::allocator<char> > * buffer = 0x0000005b7e2be9a0 "{
"xxxxyyyAlertEventsList": [
"AAMkAGU3MzBhZDFlLWQ0YTYtNDI3OS1hODc0LTAzZDY3ZTNhYzAyMgFRAAgI2t74eZ4AAEYAAAAAha43j_1ROUWTZCjiN-16KwcALQev6pjp1UqGfleeHJc6CwACMkhQEQAALQev6pjp1UqGfleeHJc6CwACMkjQjgAAEA==",
"AAMkAGU3MzBhZDFlLWQ0YTYtNDI3OS1hODc0LTAzZDY3ZTNhYzAyMgBGAAAAAACFrjeP7VE5RZNkKOI3-XorBwAtB6-qmOnVSoZ_V54clzoLAAIySFARAAAtB6-qmOnVSoZ_V54clzoLAAI8MVKRAAA="
]
}"
0000005b7e2be770 class std::basic_ofstream<char,std::char_traits<char> > file = class std::basic_ofstream<char,std::char_traits<char> > 0000005b7e2be880 class std::basic_string<char,std::char_traits<char>,std::allocator<char> > tempPath = "C:/Users/aaadmin/AppData/Roaming/FFF/1454117609475/client_info/alert_events.json_temp"
Viorel 122.6K Reputation points

2023-01-10T11:21:23.473+00:00

For some reasons the fp variable is detected as invalid inside the _isatty function, which is invoked by fwrite. Maybe it was corrupted by some parallel threads or invalid memory usage, and it is not clear if you shown the real code. Maybe you should give more details to understand or reproduce the problem. Or maybe the critical section objects do not protect the whole critical sections.
Ace Wang 1 Reputation point

2023-01-11T05:55:31.98+00:00

code.txt

full function as attachment the macro SYNCHRONIZED could expend to: auto mutexLock = std::make_shared<std::lock_guard<std::mutex>>(*_mutex); and the _mutex is a member variable type is std::shared_ptr<std::mutex> the class JsonStorage help deal with json string and save to file . would bind one file for each JsonStorage object. **The following facts need to be clarified** 1. Each JsonStorage object bound different json file. 2. One JsonStorage object could be access in some different threads. 3. This code is used in cross platform , the problem is happened in windows part. 4. We cannot reproduce in our dev/qa environment. Only one customer has this issue. maybe you could help check ucrtbase.dll version 6.2.17763.1490 ,could lead to this issue.
Minxin Yu 13,501 Reputation points Microsoft External Staff

2023-01-12T02:09:43.7966667+00:00

Only one customer has this issue

Do you mean that some Windows customers can use the program well?
Ace Wang 1 Reputation point

2023-01-12T03:38:17.6+00:00

yes , only one customer has this issue. some others and all our develop/qa environments are work well.

So i suspect that the system dll has some different (C:\Windows\System32\ucrtbase.dll)

our package has release a specific ucrtbase.dll in our install path . but seems not be load.
Viorel 122.6K Reputation points

2023-01-12T11:34:14.2866667+00:00

Make sure that the _mutex members of all objects point to the same shared unique object.

The definition of SYNCHRONIZED probably can be simplified to const std::lock_guard<std::mutex> mutexLock( *_mutex ), though the current implementation should work too.

Maybe there are pointer issues in other parts that affect the memory.

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How to prevent crash when invoke fwrite with different file in multi-thread?

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