kasan: reset page tags properly with sampling
The implementation of page_alloc poisoning sampling assumed that tag_clear_highpage resets page tags for __GFP_ZEROTAGS allocations. However, this is no longer the case since commit 70c248ac ("mm: kasan: Skip unpoisoning of user pages"). This leads to kernel crashes when MTE-enabled userspace mappings are used with Hardware Tag-Based KASAN enabled. Reset page tags for __GFP_ZEROTAGS allocations in post_alloc_hook(). Also clarify and fix related comments. [andreyknvl@google.com: update comment] Link: https://lkml.kernel.org/r/5dbd866714b4839069e2d8469ac45b60953db290.1674592780.git.andreyknvl@google.com Link: https://lkml.kernel.org/r/24ea20c1b19c2b4b56cf9f5b354915f8dbccfc77.1674592496.git.andreyknvl@google.com Fixes: 44383cef ("kasan: allow sampling page_alloc allocations for HW_TAGS") Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Reported-by: Peter Collingbourne <pcc@google.com> Tested-by: Peter Collingbourne <pcc@google.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Marco Elver <elver@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Showing
Please register or sign in to comment