On Wed, Jul 29, 2015 at 10:47 AM, Linus Torvalds <torva...@linux-foundation.org> wrote: > On Wed, Jul 29, 2015 at 10:36 AM, Brian Gerst <brge...@gmail.com> wrote: >> >> I think I remember now what the issue was. Since entering vm86 mode >> uses force_iret(), the work_pending code path was being taken. I had >> to move the call to save_v86_state out of here to handle_signal(), >> otherwise it would just restore the 32-bit regs and exit the syscall >> without ever entering vm86 mode. But that meant that the test for >> kernel CS was seeing the vm86 regs instead of 32-bit regs, and was >> failing because it didn't account for the VM bit (if the real-mode CS >> looked like RPL 0). A fault would get stuck in a loop because it >> couldn't exit to the signal handling code. > > Hmm. I think we'd want a big comment about that code then, and how it > is only used for user-space (including vm86 mode).
I think that a very tiny comment might be sufficient, because I'm planning to resubmit my patch series that removes all the work_xyz asm entirely as soon as Brian's patches land in -tip :) I've just been waiting for v86 mode to GTFO of the asm loop so the rest could be done in C. I had a small patch to deal with vm86, but Brian's is much better, so I decided to hold off. --Andy -- 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/
