Re: [PATCH AUTOSEL for 4.9 04/52] x86/selftests: Add clobbers for int80 on x86_64

2017-11-30 Thread alexander . levin
On Wed, Nov 29, 2017 at 05:42:25PM +, Dmitry Safonov wrote: >Hi Sasha, > >I would object including this to stable tree: >1. It's selftest fixup >2. I have never saw selftests failing because of it (but it's possible) >I saw this in CRIU (Checkpoint Restore In Userspace) project >trigger

[PATCH AUTOSEL for 4.9 04/52] x86/selftests: Add clobbers for int80 on x86_64

2017-11-29 Thread alexander . levin
From: Dmitry Safonov [ Upstream commit 2a4d0c627f5374f365a873dea4e10ae0bb437680 ] Kernel erases R8..R11 registers prior returning to userspace from int80: https://lkml.org/lkml/2009/10/1/164 GCC can reuse these registers and doesn't expect them to change during syscall invocation. I met this

Re: [PATCH AUTOSEL for 4.9 04/52] x86/selftests: Add clobbers for int80 on x86_64

2017-11-29 Thread Dmitry Safonov
Hi Sasha, I would object including this to stable tree: 1. It's selftest fixup 2. I have never saw selftests failing because of it (but it's possible) I saw this in CRIU (Checkpoint Restore In Userspace) project triggering, so I've fixed the selftests, mostly for documentation reasons