MobileRead Forums - View Single Post

KevinH · 10-29-2010, 12:41 PM

Hi,

I wonder ... if thread 3 was doing the following:

const QString &atrribute_value = Utility::URLDecodePath( XtoQ( attribute.getValue() ) );

at the same time that thread 4 was doing

attribute.setValue( QtoX( Utility::URLEncodePath( new_path ) ) );

and the attribute itself was the same and if setValue released/freed memory to rpelace it with a new piece at the same time that the first thread was trying to read it, you might end up with a segfault.

Again, this is all a big guess on my part. Only Valloric will know for sure if this guess is all wet or not.

If I knew where the attribute.setValue and getValue routines were in the source code and if there was a lock involved at that point (grab a lock before reading the value to prevent another thread from changing it underneath you), I would know more.

10-29-2010, 12:41 PM	#16
KevinH Sigil Developer Posts: 8,883 Karma: 6120478 Join Date: Nov 2009 Device: many	Hi, I wonder ... if thread 3 was doing the following: const QString &atrribute_value = Utility::URLDecodePath( XtoQ( attribute.getValue() ) ); at the same time that thread 4 was doing attribute.setValue( QtoX( Utility::URLEncodePath( new_path ) ) ); and the attribute itself was the same and if setValue released/freed memory to rpelace it with a new piece at the same time that the first thread was trying to read it, you might end up with a segfault. Again, this is all a big guess on my part. Only Valloric will know for sure if this guess is all wet or not. If I knew where the attribute.setValue and getValue routines were in the source code and if there was a lock involved at that point (grab a lock before reading the value to prevent another thread from changing it underneath you), I would know more.