Re: [Pykaraoke-discuss] pycdg segfault on amd64
On 2/1/07, Kelvin Lawson [EMAIL PROTECTED] wrote: Hi Daniel, This problem was indeed happening with multiple .cdg files, though I can't say if it applied to them all. Because pykaraoke worked with the same files on x86 without incident, however, I doubt that corrupted/rogue data is the issue. I'll send you a private e-mail re: obtaining the OGG+CDG files in question for testing purposes. I tried these CDGs on my AMD64 and they worked fine. I guess it's system dependent whether the out of bounds array access will hit somewhere that will cause a seg fault. I suspect this is either a numeric thing or a pygame thing -- aren't there some compiled bits in those libraries for speed purposes on some systems? I recall having a 64-bit problem myself when I was first mucking with PyKaraoke myself ;) - Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier. Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnkkid=120709bid=263057dat=121642___ Pykaraoke-discuss mailing list Pykaraoke-discuss@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/pykaraoke-discuss
Re: [Pykaraoke-discuss] pycdg segfault on amd64
Hey Will, I suspect this is either a numeric thing or a pygame thing -- aren't there some compiled bits in those libraries for speed purposes on some systems? I recall having a 64-bit problem myself when I was first mucking with PyKaraoke myself ;) Yep I believe that one was a pygame vs 64-bit bug. In this case there are no libraries involved, however. It's just our own C module _pycdgAux.c which is reading the CDG bytes read directly from the CDG file. The problem is that it's reading an x,y offset from the CDG file which is outside of the 300x216 screen size, i.e. the data in the file at this location isn't a perfect rip of the original CDG command. The C code was then using this x,y offset to index into an array sized at 300x216. This was what caused the seg fault that Daniel sent the debug info on. It won't necessarily cause a seg fault on all machines though, as I found on my PC. It would have just been stomping on some memory somewhere that it probably shouldn't :-) It turns out that both of these files fail when using the pure Python implementation of pycdg as well, for the same reason: array index out of bounds. I'd better fix that one up too. The lesson here is to sanity-check the CDG commands as they aren't always perfectly ripped. Kelvin. - Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier. Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnkkid=120709bid=263057dat=121642 ___ Pykaraoke-discuss mailing list Pykaraoke-discuss@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/pykaraoke-discuss
Re: [Pykaraoke-discuss] pycdg segfault on amd64
Hi Kelvin, I patched the code as you indicated, and the segfaults are gone. This problem was indeed happening with multiple .cdg files, though I can't say if it applied to them all. Because pykaraoke worked with the same files on x86 without incident, however, I doubt that corrupted/rogue data is the issue. I'll send you a private e-mail re: obtaining the OGG+CDG files in question for testing purposes. --Daniel (Please Cc: any replies to me) On Thu, 2007 Feb 01 00:15:25 +, Kelvin Lawson wrote: Hi Daniel, I've been moving house the last couple of weeks so have just got round to looking into this. I originally thought this looked like a sizeof(int) discrepancy somewhere. I thought perhaps one component (pygame, SDL or _pycdgAux.c) had been built as 32-bit, or perhaps one of the underlying libraries is not 64-bit safe in some places. Anyway, on looking into it further I see that the row_index value is 378 (thanks for all the excellent debug info by the way). This is an invalid index into the array, as the CDG screen width and hence cdgSurfarray[][] is only max 300. For some reason this line in cdgTileBlockCommon() is reading an attempt to set pixel offset 378: row_index = ((packd-data[3] 0x3f) * 6); CDG rips occasionally contain corrupted bytes, so I could well imagine that this could happen on the odd CDG file but it sounds like this probably happens on all files (please correct me if I'm wrong there). Whether it's corrupted data or not, we really should be range-checking the row and column index here anyway. Could you try adding the following lines in cdgTileBlockCommon() please: // 2 lines of current code below column_index = ((packd-data[2] 0x1f) * 12); row_index = ((packd-data[3] 0x3f) * 6); // Enter the following 4 lines if (column_index (CDG_FULL_HEIGHT - 12)) column_index = (CDG_FULL_HEIGHT - 12); if (row_index (CDG_FULL_WIDTH - 6)) row_index = (CDG_FULL_WIDTH - 6); If it's rogue data, then hopefully this will fix the seg fault. If it's not rogue data and somehow we're reading the CDG data out incorrectly, well we'll find that out. I hope you don't mind trying this out - I do actually have an AMD64 machine here but unfortunately I can't reproduce the problem. Perhaps if you could send the offending cdg+ogg files I could reproduce it. Many thanks, Kelvin. -- NAME = Daniel Richard G. ## Remember, skunks _\|/_ meef? EMAIL1 = [EMAIL PROTECTED]## don't smell bad---(/o|o\) / EMAIL2 = [EMAIL PROTECTED] ## it's the people who(^), WWW= http://www.**.org/ ## annoy them that do!/ \ -- (** = site not yet online) - Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier. Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnkkid=120709bid=263057dat=121642 ___ Pykaraoke-discuss mailing list Pykaraoke-discuss@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/pykaraoke-discuss
