Hi Mathias, On Monday 19 September 2005 17:45, Mathias Krause wrote: > I've got a problem with a hybrid Linux Task. I want to create a little > tool to tranfser data between two L4Linuxes easily. A tool similar to > the famous netcat but using IPC instead of UDP/TCP. So far so good. > Server is listen for client and client is sending data to the server > (using long IPC transfering data as dwords). The problem is that the > data doesn't arrive at the server task. There only an empty IPC message > gets received (no IPC error).
Try to debug this issue using the kernel debugger. What does the IPC log say (options I* and IR+, what msgdope is displayed)? > After I've played around a while with debug messages I got strange > results. Using debug messages (simple printf()) inbetween and the > transfer succedes! > > Digging a little deeper got me to the point that it must be a problem > with the compiler. Using 'gcc -O0' generates working code too - 'gcc -O2' > doesn't. Trying another compiler (gcc version 4.0.1 (Debian 4.0.1-2)) > with -O2 got me also working code. Maybe the compiler optimizes some code away. I assume that you tried the last version of L4Linux 2.6 -- Adam changed many things to get hybrid tasks working. > So my question is if really my gcc (version 3.3.5 (Debian 1:3.3.5-13)) > is broken or the includes under l4/l4sys/.../ipc.h. Maybe the inline > assembly isn't that clean? But just a guess. My GNU assembly knowlegde > isn't that good. We cannot guarantee that the bindings are bug-free but they have been tested for a long time. Do you use any special compiler switches besides -O2? Do you use -fomit-frame-pointer? Try without. Do you use -fstrict- aliasing? Try with -fno-strict-aliasing as defined in l4/mk/binary.inc. > PS: I'm runing Debian sarge over here. Should be fine. Actually I use gcc-3.4 but have used gcc-3.3 for a long time. gcc-4 is still not supported for the L4env tree. If nothing helps you could send me the source/binary so I'm able to investigate a little bit more. Frank -- ## Dept. of Computer Science, Dresden University of Technology, Germany ## ## http://os.inf.tu-dresden.de/~fm3 ##
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