On Wed, Feb 09, 2022 at 03:22:35PM +0000, Joey Gouly wrote:
> These can be used to place an MTE tag at an address that is not at a
> page size boundary.
>
> The kernel prior to 295cf156231c ("arm64: Avoid premature usercopy failure"),
> would infinite loop if an MTE tag was placed not at a PAGE_SIZE boundary.
> This is because the kernel checked if the pages were readable by checking the
> first byte of each page, but would then fault in the middle of the page due
> to the MTE tag.
>
> Signed-off-by: Joey Gouly <joey.gouly@xxxxxxx>
> Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
> Cc: Will Deacon <will@xxxxxxxxxx>
> Cc: Mark Brown <broonie@xxxxxxxxxx>
> Cc: Shuah Khan <shuah@xxxxxxxxxx>
> Reviewed-by: Mark Brown <broonie@xxxxxxxxxx>
> Tested-by: Mark Brown <broonie@xxxxxxxxxx>
> Reviewed-by: Shuah Khan <skhan@xxxxxxxxxxxxxxxxxxx>
Reviewed-by: Catalin Marinas <catalin.marinas@xxxxxxx>
