On 03/09, Borislav Petkov wrote: > > On Mon, Mar 09, 2015 at 03:34:36PM +0100, Oleg Nesterov wrote: > > The patch only fixes the problem with irqs disabled, I tested this. > > > > The problem with fpu_init/XRSTORS is another thing... > > Yet another thing?! Oh boy.
Well, this is the same thinhg reported by Dave ;) > So first Dave reported the #GP, which got fixed by Quentin's patch. It is not fixed by Quentin's patch. This patch "fixes" the problem in a sense that the kernel won't crash after restore_fpu_checking() triggers #GP. Before this patch do_general_protection()->fixup_exception() does not work in this case and the kernel panics. But restore_fpu_checking() should not trigger #GP (and fail). And just in case... tip/x86/fpu still won't work even with the patch from Quentin. Again, the kernel won't crash, but /sbin/init will be killed by SIGSEGV I guess. Because restore_fpu_checking() will fail. I'll change flush_thread() to rely on init_xstate_buf, I was going to do this anyway. But this too doesn't fix the problem: fpu_finit() is buggy on Dave's machine. Oleg. -- 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/
