Re: [PATCHv3] x86/selftests: add clobbers for int80 on x86_64

2017-02-17 Thread Andy Lutomirski
On Mon, Feb 13, 2017 at 2:18 PM, wrote: > On February 13, 2017 11:06:04 AM PST, Andy Lutomirski > wrote: >>On Mon, Feb 13, 2017 at 2:13 AM, Dmitry Safonov >> wrote: >>> Kernel erases R8..R11 registers prior returning to userspace >>> from int80: https://lkml.org/lkml/2009/10/1/164 >>> >>> GCC c

Re: [PATCHv3] x86/selftests: add clobbers for int80 on x86_64

2017-02-13 Thread hpa
On February 13, 2017 11:06:04 AM PST, Andy Lutomirski wrote: >On Mon, Feb 13, 2017 at 2:13 AM, Dmitry Safonov > 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 c

Re: [PATCHv3] x86/selftests: add clobbers for int80 on x86_64

2017-02-13 Thread Ingo Molnar
* Andy Lutomirski wrote: > On Mon, Feb 13, 2017 at 2:13 AM, Dmitry Safonov > 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 inv

Re: [PATCHv3] x86/selftests: add clobbers for int80 on x86_64

2017-02-13 Thread Andy Lutomirski
On Mon, Feb 13, 2017 at 2:13 AM, Dmitry Safonov 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 onc