On Wed, Apr 02, 2025 at 05:06:59PM -0700, Peter Collingbourne wrote: > The call to read_word_at_a_time() in sized_strscpy() is problematic > with MTE because it may trigger a tag check fault when reading > across a tag granule (16 bytes) boundary. To make this code > MTE compatible, let's start using load_unaligned_zeropad() > on architectures where it is available (i.e. architectures that > define CONFIG_DCACHE_WORD_ACCESS). Because load_unaligned_zeropad() > takes care of page boundaries as well as tag granule boundaries, > also disable the code preventing crossing page boundaries when using > load_unaligned_zeropad(). > > Signed-off-by: Peter Collingbourne <pcc@xxxxxxxxxx> > Link: https://linux-review.googlesource.com/id/If4b22e43b5a4ca49726b4bf98ada827fdf755548 > Fixes: 94ab5b61ee16 ("kasan, arm64: enable CONFIG_KASAN_HW_TAGS") > Cc: stable@xxxxxxxxxxxxxxx Up to you if you want to keep the panic behaviour on unmapped pages. Either way: Reviewed-by: Catalin Marinas <catalin.marinas@xxxxxxx>
