From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mta0.migadu.com (out-82.mta0.migadu.com [91.218.175.82]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8C4D5A95E for ; Thu, 17 Sep 2026 12:10:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.82 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789647061; cv=none; b=RY+x9KMtADyBEOXaI3n7QBb5TVjvQSgetk8JOjl2QFiA60sfUo/J4iwFLiASezizUX15uQtbhZqwg8GC0HBw2LKa0nUOkeb/OdMzzf4rxQd9pK7YUxFGkJIZKXv62kSsr1bWbMrgeoJgvSKv2gEsuNLWcgKgFTf94al836D3AmY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789647061; c=relaxed/simple; bh=47vcZ904lW3a6rNy/Fy96vjfGFEJ8yr3KRqKx1ywsiU=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=Yv1T77MurGEM8/iF7m3ABG9oBkDgziy2gXcz7Lxvpi42YraVk1mqSXF0WMck3pNAkY8izw5P+lk7si+sumbLvmMWnrEmb0LrTT2tPCexn7UGBHLM03YW/J/Rw6mntMbnF6v7NqPSXvqnkxz/EXKd6SSq30caRy84rFES20nMdLg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=u1YnfjAG; arc=none smtp.client-ip=91.218.175.82 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="u1YnfjAG" X-Envelope-To: linux-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=47vcZ904lW3a6rNy/Fy96vjfGFEJ8yr3KRqKx1ywsiU=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1789647035; v=1; x=1790251835; b=u1YnfjAGiN5FUhnln2+X/676E2irZhLeKYEPvFPpUaHzWhYAYIheDL21c0PBRGXXBpoc/oD4 SMnPtdlGZ1+xn2iCciyZbvjqQQZfOCHJLS2iHBIzlUxKuQ32z/Jy3f+L+vSNgX1pARRhBiRRhOm ptcY+6DhH8x9L9kQI2AR+m5I= X-Envelope-To: linux-kernel@vger.kernel.org Received: by smtp.migadu.com with ESMTPS id 44dfbe1cd77953d7; Thu, 17 Sep 2026 12:10:18 +0000 X-Mizu-Trace-ID: 44dfbe1cd77953d7 X-Migadu-Flow: FLOW_OUT From: Lance Yang To: akpm@linux-foundation.org, david@kernel.org Cc: ziy@nvidia.com, baolin.wang@linux.alibaba.com, liam@infradead.org, nico.pache@linux.dev, ryan.roberts@arm.com, dev.jain@arm.com, baohua@kernel.org, lance.yang@linux.dev, usama.arif@linux.dev, kas@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH 1/1] mm/huge_memory: disallow raw PMD mappings of the huge zero page Date: Thu, 17 Sep 2026 20:10:10 +0800 Message-ID: <20260917121010.60966-1-lance.yang@linux.dev> X-Mailer: git-send-email 2.49.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit vm_mixed_zeropage_allowed() validates zeropage insertion into VM_MIXEDMAP VMAs. No in-tree user needs to insert the huge zero page through vmf_insert_pfn_pmd(). Return VM_FAULT_SIGBUS if vmf_insert_pfn_pmd() is asked to map it. Link: https://lore.kernel.org/linux-mm/f76beaf8-351a-4b22-b362-a945a5e1af6a@kernel.org/ Suggested-by: Kiryl Shutsemau Suggested-by: David Hildenbrand Signed-off-by: Lance Yang --- mm/huge_memory.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index bfd972b997f9..c02f21ce4f4c 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1728,6 +1728,9 @@ vm_fault_t vmf_insert_pfn_pmd(struct vm_fault *vmf, unsigned long pfn, (VM_PFNMAP|VM_MIXEDMAP)); BUG_ON((vma->vm_flags & VM_PFNMAP) && vma_is_cow_mapping(vma)); + if (unlikely(is_huge_zero_pfn(pfn))) + return VM_FAULT_SIGBUS; + pfnmap_setup_cachemode_pfn(pfn, &pgprot); return insert_pmd(vma, addr, vmf->pmd, fop, pgprot, write); -- 2.39.3 (Apple Git-146)