On Fri, Feb 10, 2017 at 3:52 AM, Dmitry Safonov <dsafonov@xxxxxxxxxxxxx> wrote: > Kernel erases R8..R11 registers prior returning to userspace > from int80: https://lkml.org/lkml/2009/10/1/164 > > GCC can reuse this registers and doesn't expect them to change > during syscall invocation. I met this kind of bug in CRIU once > gcc 6.1 and clang stored local variables in those registers > and the kernel zerofied them during syscall: > https://github.com/xemul/criu/commit/990d33f1a1cdd17bca6c2eb059ab3be2564f7fa2 > > By that reason I suggest to add those registers to clobbers > in selftests. Seems reasonable, but presumably INT80_CLOBBERS should be defined the same way in all the tests. IOW, if the "flags" clobber is actually needed, it should be "flags", INT80_CLOBBERS (possibly without the comma if it's problematic). -- To unsubscribe from this list: send the line "unsubscribe linux-kselftest" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
