kfence: fix is_kfence_address() for addresses below KFENCE_POOL_SIZE
Originally the addr != NULL check was meant to take care of the case where __kfence_pool == NULL (KFENCE is disabled). However, this does not work for addresses where addr > 0 && addr < KFENCE_POOL_SIZE. This can be the case on NULL-deref where addr > 0 && addr < PAGE_SIZE or any other faulting access with addr < KFENCE_POOL_SIZE. While the kernel would likely crash, the stack traces and report might be confusing due to double faults upon KFENCE's attempt to unprotect such an address. Fix it by just checking that __kfence_pool != NULL instead. Link: https://lkml.kernel.org/r/20210818130300.2482437-1-elver@google.com Fixes: 0ce20dd8 ("mm: add Kernel Electric-Fence infrastructure") Signed-off-by:Marco Elver <elver@google.com> Reported-by:
Kuan-Ying Lee <Kuan-Ying.Lee@mediatek.com> Acked-by:
Alexander Potapenko <glider@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: <stable@vger.kernel.org> [5.12+] Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
parent
57f29762
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