Il 26/04/2013 23:07, Paul Moore ha scritto: >> > 3. Debugging and/or learning mode - third party libraries still have the >> > problem of interfering in the Qemu's signal mask. According to some >> > previous discussions, perhaps patch all external libraries that mass up >> > with this mask (spice, for example) is a way to solve it. But not sure >> > if it worth the time spent. Would like to hear you guys. > I think patching all the libraries is a losing battle, I think we need to > pursue alternate debugging techniques.
It is really only about patching libraries that create threads _and_ block all signals in the newly-created thread (to not interfere with the program's own handling of the signals). In this case, the per-thread signals (SIGFPE/SIGSEGV/SIGBUS/SIGSYS/SIGILL) should be left unblocked, but SIGSYS is often forgotten. I don't think there are many libraries like this, but fixing SPICE at least should definitely be welcome. In fact QEMU's own util/qemu-thread-posix.c does not unblock those signals. Eduardo, can you submit a patch for that? Paolo
