On Tue, Feb 15, 2022 at 09:01:54PM -0500, Brian Geffon wrote:
On Tue, Feb 15, 2022 at 4:42 PM Dave Hansen dave.hansen@intel.com wrote:
On 2/15/22 13:32, Brian Geffon wrote:
How was this tested, and what do the maintainers of this subsystem think? And will you be around to fix the bugs in this when they are found?
This has been trivial to reproduce, I've used a small repro which I've put here: https://gist.github.com/bgaff/9f8cbfc8dd22e60f9492e4f0aff8f04f , I also was able to reproduce this using the protection_keys self tests on a 11th Gen Core i5-1135G7.
I've got an i7-1165G7, but I'm not seeing any failures on a 5.11 distro kernel.
Hi Dave, I suspect the reason you're not seeing it is toolchain related, I'm building with clang 14.0.0 and it produces the sequence of instructions which use the cached value. Let me know if there is anything I can do to help you investigate this further.
Do older versions of clang have this problem?
thanks,
greg k-h