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Andrey Ryabinin
caf55fef61
kasan_non_canonical_hook() derives orig_addr from kasan_shadow_to_mem(), but the pointer tag may remain in the top byte. In SW_TAGS mode this tagged address is compared against PAGE_SIZE and TASK_SIZE, which leads to incorrect bug classification. As a result, NULL pointer dereferences may be reported as "wild-memory-access". Strip the tag before performing these range checks and use the untagged value when reporting addresses in these ranges. Before: [ ] Unable to handle kernel paging request at virtual address ffef800000000000 [ ] KASAN: maybe wild-memory-access in range [0xff00000000000000-0xff0000000000000f] After: [ ] Unable to handle kernel paging request at virtual address ffef800000000000 [ ] KASAN: null-ptr-deref in range [0x0000000000000000-0x000000000000000f] Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Andrey Ryabinin <[email protected]> Cc: Alexander Potapenko <[email protected]> Cc: Andrey Konovalov <[email protected]> Cc: Dmitry Vyukov <[email protected]> Cc: Maciej Wieczor-Retman <[email protected]> Cc: Vincenzo Frascino <[email protected]> Signed-off-by: Andrew Morton <[email protected]>