From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 7A334CCF9F8 for ; Mon, 3 Nov 2025 15:16:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=vUcpx5Qe0legPw/0+w+dnAdYl2CDGyyRFIFqnaHMwOI=; b=ZFSwk22/o09vYWGdnrMURq9AOJ wkWMbkP205+eWohG2NL5yY+7MIxmbzYuPUofft4K3i3t1HRZpD7OKgc0CHEeuy2e/PKD82kE0C4QR Wg9dlS5H024j8e2gd03yUsspZV6WqowmWC2rixWfIaYioa7O6K7zdZNTBC2BHnHjHxJp3pS9fOnkJ mqROTpBF+ACUXq4kllh+armnr+AMkEsuzeuyAVfzCG0iQ242QnxB2rNZ+ZV5xf5u5c4RGdJZvjDJB dgq8OvCpqRCx0LknYRKYXAG95X1QqIr5TOOJ4p+gt/zgaFyMTyEBtqeDAj2invLcQs6dj5nyIbahd kMy54KFw==; 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charset=us-ascii Content-Disposition: inline In-Reply-To: <20251103061306.82034-1-dev.jain@arm.com> X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon, Nov 03, 2025 at 11:43:06AM +0530, Dev Jain wrote: > Post a166563e7ec3 ("arm64: mm: support large block mapping when rodata=full"), > __change_memory_common has a real chance of failing due to split failure. > Before that commit, this line was introduced in c55191e96caa, still having > a chance of failing if it needs to allocate pagetable memory in > apply_to_page_range, although that has never been observed to be true. > In general, we should always propagate the return value to the caller. > > Cc: stable@vger.kernel.org > Fixes: c55191e96caa ("arm64: mm: apply r/o permissions of VM areas to its linear alias as well") > Signed-off-by: Dev Jain > --- > Based on Linux 6.18-rc4. > > arch/arm64/mm/pageattr.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/arch/arm64/mm/pageattr.c b/arch/arm64/mm/pageattr.c > index 5135f2d66958..b4ea86cd3a71 100644 > --- a/arch/arm64/mm/pageattr.c > +++ b/arch/arm64/mm/pageattr.c > @@ -148,6 +148,7 @@ static int change_memory_common(unsigned long addr, int numpages, > unsigned long size = PAGE_SIZE * numpages; > unsigned long end = start + size; > struct vm_struct *area; > + int ret; > int i; > > if (!PAGE_ALIGNED(addr)) { > @@ -185,8 +186,10 @@ static int change_memory_common(unsigned long addr, int numpages, > if (rodata_full && (pgprot_val(set_mask) == PTE_RDONLY || > pgprot_val(clear_mask) == PTE_RDONLY)) { > for (i = 0; i < area->nr_pages; i++) { > - __change_memory_common((u64)page_address(area->pages[i]), > + ret = __change_memory_common((u64)page_address(area->pages[i]), > PAGE_SIZE, set_mask, clear_mask); > + if (ret) > + return ret; Hmm, this means we can return failure half-way through the operation. Is that something callers are expecting to handle? If so, how can they tell how far we got? Will