On Tue, Nov 30, 2021 at 11:08PM +0100, andrey.konovalov@xxxxxxxxx wrote: > From: Andrey Konovalov <andreyknvl@xxxxxxxxxx> > > This patch adds vmalloc tagging support to HW_TAGS KASAN. > > The key difference between HW_TAGS and the other two KASAN modes > when it comes to vmalloc: HW_TAGS KASAN can only assign tags to > physical memory. The other two modes have shadow memory covering > every mapped virtual memory region. > > This patch makes __kasan_unpoison_vmalloc() for HW_TAGS KASAN: > > - Skip non-VM_ALLOC mappings as HW_TAGS KASAN can only tag a single > mapping of normal physical memory; see the comment in the function. > - Generate a random tag, tag the returned pointer and the allocation. > - Propagate the tag into the page stucts to allow accesses through > page_address(vmalloc_to_page()). > > The rest of vmalloc-related KASAN hooks are not needed: > > - The shadow-related ones are fully skipped. > - __kasan_poison_vmalloc() is kept as a no-op with a comment. > > Poisoning of physical pages that are backing vmalloc() allocations > is skipped via __GFP_SKIP_KASAN_UNPOISON: __kasan_unpoison_vmalloc() > poisons them instead. > > Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx> > Co-developed-by: Vincenzo Frascino <vincenzo.frascino@xxxxxxx> This is missing a Signed-off-by from Vincenzo.
