On Sunday, 28 August 2022 23:07:38 CEST Adam Lackorzynski wrote: > On Sun Aug 21, 2022 at 00:18:57 +0200, Paul Boddie wrote: > > > > I just spent quite some time seeing errors like this... > > > > ext2svr | L4Re[rm]: mapping for page fault failed with error -39 at > > 0x1002fbc00 pc=0x10b7804 > > ext2svr | L4Re: rom/ext2_server: Unhandled exception: PC=0x10b7804 > > PFA=0x1002fbc00 LdrFlgs=0x0 > > > > -39 being -L4_EBADPROTO (unsupported protocol), of course. > > > > And then I remembered that there was some curious IPC-related problem I > > had encountered a while ago. It turns out that it was this again, and > > since I had obtained a fresh checkout of the L4Re code and had forgotten > > that this could be a problem, I had revived it! Introducing my workaround > > eliminated the error. > > > > Do you have any ideas as to why the first message register gets corrupted? > > No, still not. Any chance I could see a small example of this?
I'll try and package up what I've been doing so that it can be more readily investigated. I was actually in the middle of this packaging process when I discovered the problem once again. Ideally, I would be able to make a very compact example that exhibits this behaviour, but it would probably need a bit of extra contemplation about why it occurs. Obviously, the region manager provided by the l4re binary is trying to send requests to a dataspace, but it is somehow producing the wrong IPC opcodes, and it does so after a number of requests have occurred. On this most recent occasion, the number of requests was reproducible, so I wonder a bit about that (and about my own code's involvement in it occurring, of course). Anyway, I'll try and get something out there to look at in the next few days. Sorry not to have done that already, but I just wondered if there had been any insights into the matter, discoveries related to the code, and so on. Thanks once again, Paul _______________________________________________ l4-hackers mailing list l4-hackers@os.inf.tu-dresden.de https://os.inf.tu-dresden.de/mailman/listinfo/l4-hackers
