On 30.09.2014 21:40, Andy Lutomirski wrote: > what would happen. Apparently Wine sometimes does this (!), and, if > an IRET return happens, Wine will segfault. > > I think that Wine should be fixed to stop setting NT when a syscall > happens, but handling NT more gracefully is still nice. >
Just to give some more background about this issue: Wine has no influence if the NT flag is set or not - as Wine doesn't trace each individual opcode, there is no chance to know, if a Windows program messes up the EFLAGS. This happens in closed source Windows applications, so its not really Wines fault. I think the current approach should be fine, but if other people prefer one of the solutions without additional overhead on syscall entry: At least for Wine it would also be absolutely fine, when the application would just get a proper signal (if adding the retry IRET is too complicated). I've attached the url to an additional example program, which shows that currently the signal handler is unable to process such a fault, and a proof-of-concept patch to clear the NT flags at least for the signal handler. Such a patch doesn't fix the potential issues with EFI though. Example program: http://ix.io/ezl Proof-of-concept patch: http://ix.io/ezm Regards, Sebastian -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
