Qt-interest Archive, August 2006
qCompress crash
Message 1 in thread
Hello,
I am using qCompress in my application and detect a crash in qCompress
when using it a lot.
Attached a code sample that reproduce the issue.
The application was compiled using msvc-7.1.
I use the application with following parameters, and the access
violation appear during the third compression.
Try to compress 10 times 500000000 bytes:
qCompress.exe 10 500000000
output:
--> Compressing 500000000 bytes...
--> Compressed fine. Compressed size: 485999
--> Compressed fine. Compressed size: 485999
--> CRASH...
The crash appear all the time, but with different parameters according
to computer configuration.
So fill free to use different parameters in order to reproduce the issue.
Could someone try my sample and report me the result please.
Thanks
Templie Cédric
#include <stdlib.h>
#include <stdlib.h>
#include <QtCore/QByteArray>
#include <QtCore/QList>
void main( int argc, char *argv[] )
{
// The number of the passes to perform
int tasksNumber = 0;
// The the size of the buffer that should be generated
int taskSize = 1024;
// check if no parameters were passed
if( argc == 1 )
{
qDebug( "Pass the task number and size" );
return;
}
// get the command line parameter which indicates the number of tasks to be created
if( argc > 1 )
{
char* parameter = argv[1];
tasksNumber = atoi(parameter);
}
// get the command line parameter which indicates the size of the task that should be generated
if( argc > 2 )
{
char* parameter = argv[2];
taskSize = atoi( parameter );
}
// the list to store compressed QByteArrays
QList<QByteArray> compressedArrayList;
// buffers to store the plain data
QByteArray uncompressedData;
// create the message of needed size
uncompressedData.fill( 'd', taskSize );
// check the generated byte array
if( !uncompressedData.isEmpty() )
{
qDebug( "Compressing %d bytes...", uncompressedData.size() );
// generate the needed number of byte arays
while( tasksNumber )
{
// the compressed data which should be decompressed
QByteArray compressedData;
// compress it
compressedData = qCompress( uncompressedData );
// put the array in the list
compressedArrayList << compressedData;
// check the result
if( !compressedData.isEmpty() )
{
qDebug( "Compressed fine. Compressed size: %d", compressedData.size() );
}
else
{
qDebug( "Error: Compress failed!" );
}
// decrement the tasks number that is left to perform
tasksNumber--;
}
}
else
{
qDebug( "Error: plain data could not be generated!" );
}
qDebug( "All tasks generated." );
}
Message 2 in thread
I forgot to mention that I use Qt 4.1.4
Templie Cédric
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Message 3 in thread
On Thursday 17 August 2006 08:54, Templie Cédric wrote:
> I am using qCompress in my application and detect a crash in qCompress
> when using it a lot.
I can reproduce the crash on Linux. Here's a backtrace:
#0 0x00346ecc in deflateParams () from /usr/lib/libz.so.1
No symbol table info available.
#1 0x00345fd0 in deflate () from /usr/lib/libz.so.1
No symbol table info available.
#2 0x00343bd7 in compress2 () from /usr/lib/libz.so.1
No symbol table info available.
#3 0x009f2554 in qCompress (data=0x97f7f018 'd' <repeats 200 times>..., nbytes=500000000,
compressionLevel=-1) at tools/qbytearray.cpp:373
len = 505000013
bazip = {static shared_null = {ref = {atomic = 2}, alloc = 0, size = 0,
data = 0x804a560 "", array = ""}, static shared_empty = {ref = {atomic = 1}, alloc = 0,
size = 0, data = 0xb5a238 "", array = ""}, d = 0x97e00470}
res = 134516552
#4 0x08048d97 in qCompress (data=@0xbfc86014, compressionLevel=-1)
at /gel/culbute/usr/perreaul//include/QtCore/qbytearray.h:507
No locals.
#5 0x080489f9 in main (argc=3, argv=0xbfc860d4) at qCompressTest.cpp:52
compressedData = {static shared_null = {ref = {atomic = 2}, alloc = 0, size = 0,
data = 0x804a560 "", array = ""}, static shared_empty = {ref = {atomic = 1}, alloc = 0,
size = 0, data = 0xb5a238 "", array = ""}, d = 0x804a550}
tasksNumber = 6
taskSize = 500000000
compressedArrayList = {{p = {static shared_null = {ref = {atomic = 2}, alloc = 0,
begin = 0, end = 0, sharable = 1, array = {0x0}}, d = 0x8fab0f0}, d = 0x8fab0f0}}
uncompressedData = {static shared_null = {ref = {atomic = 2}, alloc = 0, size = 0,
data = 0x804a560 "", array = ""}, static shared_empty = {ref = {atomic = 1}, alloc = 0,
size = 0, data = 0xb5a238 "", array = ""}, d = 0x97f7f008}
--
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Message 4 in thread
Templie Cédric wrote:
> Hello,
>
> I am using qCompress in my application and detect a crash in qCompress
> when using it a lot.
>
> Attached a code sample that reproduce the issue.
>
> The application was compiled using msvc-7.1.
>
> I use the application with following parameters, and the access
> violation appear during the third compression.
>
> Try to compress 10 times 500000000 bytes:
> qCompress.exe 10 500000000
>
> output:
> --> Compressing 500000000 bytes...
> --> Compressed fine. Compressed size: 485999
> --> Compressed fine. Compressed size: 485999
> --> CRASH...
>
> The crash appear all the time, but with different parameters according
> to computer configuration.
> So fill free to use different parameters in order to reproduce the issue.
>
> Could someone try my sample and report me the result please.
This is on Linux with system libz, not the one bundled. With the Qt 4.2
preview I also get a crash, but in Qt not libz like Simon
Program terminated with signal 11, Segmentation fault.
#0 0xa74b46db in QBasicAtomic::init (this=0x0, x=1) at
../../include/QtCore/../../src/corelib/thread/qatomic.h:66
66 { atomic = x; }
(gdb) bt
#0 0xa74b46db in QBasicAtomic::init (this=0x0, x=1) at
../../include/QtCore/../../src/corelib/thread/qatomic.h:66
#1 0xa74b9865 in QByteArray::resize (this=0xafa3af84, size=505000017)
at tools/qbytearray.cpp:1296
#2 0xa74bb04d in qCompress (data=0x89486018 'd' <repeats 200 times>...,
nbytes=500000000, compressionLevel=-1) at tools/qbytearray.cpp:370
#3 0x08048d97 in qCompress (data=@0xafa3b014, compressionLevel=-1)
at
/home/adamm/work/src/qt/qt-x11-preview-commercial-src-4.2.0-tp1/include/QtCore/../../src/corelib/tools/qbytearray.h:505
#4 0x080489f9 in main (argc=3, argv=0xafa3b0c4) at t.cpp:52
t.cpp:52 is the qCompress line.
- Adam
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