From patchwork Mon May 10 15:32:11 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthew Wilcox X-Patchwork-Id: 12248549 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B36DCC433B4 for ; Mon, 10 May 2021 15:33:11 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 2B83B61108 for ; Mon, 10 May 2021 15:33:11 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2B83B61108 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 94BC36B0036; Mon, 10 May 2021 11:33:10 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 922606B0072; Mon, 10 May 2021 11:33:10 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7C3526B0073; Mon, 10 May 2021 11:33:10 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0068.hostedemail.com [216.40.44.68]) by kanga.kvack.org (Postfix) with ESMTP id 606C36B0036 for ; Mon, 10 May 2021 11:33:10 -0400 (EDT) Received: from smtpin16.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 1BD2AA74C for ; Mon, 10 May 2021 15:33:10 +0000 (UTC) X-FDA: 78125714940.16.6D1D511 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf26.hostedemail.com (Postfix) with ESMTP id BF02E40002E8 for ; Mon, 10 May 2021 15:32:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Content-Transfer-Encoding:MIME-Version: Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To:Content-Type:Content-ID: Content-Description:In-Reply-To:References; bh=2eNTXpQfHJ0OdyPVOxt21lm4q6iYqitgx5VeCGzxOCQ=; b=sM/k0UKsyO7B4HEs9hq/HAnpkj NcDVQIakATA8zV7KnFRlQSzPnXg8e/j6+vnAzKpGDI1LS70LYJalgcYVBqqVA3dCDwiafIDQEsyju U2sxPc8bG+lM4Zv8/afaG0rbyU7H2m2Ut8yALSQnGh4g0a4o5g+THGH//mTihC9C0b0Rd8vxi/BLq gn96gS7QQPNNhi33WI6Px7IhzV4vHK1XiZp+oOuVlvmsd45ZOl+2hNmuBBYS+55HXMsTUip1+i8ZB v5c9y9w+6ci7JyCT4xDk0DuJAH97fNDSxg3kUcMDTzj15RK+I8B4o8Ighrux7aETbdmPtMLfLwZvc M1kK+xxQ==; Received: from willy by casper.infradead.org with local (Exim 4.94 #2 (Red Hat Linux)) id 1lg7tF-006JVj-9w; Mon, 10 May 2021 15:32:22 +0000 From: "Matthew Wilcox (Oracle)" To: linux-mm@kvack.org Cc: "Matthew Wilcox (Oracle)" , stable@vger.kernel.org, Ilias Apalodimas , Jesper Dangaard Brouer , Vlastimil Babka Subject: [PATCH] mm: Fix struct page layout on 32-bit systems Date: Mon, 10 May 2021 16:32:11 +0100 Message-Id: <20210510153211.1504886-1-willy@infradead.org> X-Mailer: git-send-email 2.30.2 MIME-Version: 1.0 Authentication-Results: imf26.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b="sM/k0UKs"; dmarc=none; spf=none (imf26.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: BF02E40002E8 X-Stat-Signature: z7z8up655ms9xxy5ozoxdbqp8r98dfgb Received-SPF: none (infradead.org>: No applicable sender policy available) receiver=imf26; identity=mailfrom; envelope-from=""; helo=casper.infradead.org; client-ip=90.155.50.34 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1620660775-14933 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 32-bit architectures which expect 8-byte alignment for 8-byte integers and need 64-bit DMA addresses (arm, mips, ppc) had their struct page inadvertently expanded in 2019. When the dma_addr_t was added, it forced the alignment of the union to 8 bytes, which inserted a 4 byte gap between 'flags' and the union. Fix this by storing the dma_addr_t in one or two adjacent unsigned longs. This restores the alignment to that of an unsigned long. We always store the low bits in the first word to prevent the PageTail bit from being inadvertently set on a big endian platform. If that happened, get_user_pages_fast() racing against a page which was freed and reallocated to the page_pool could dereference a bogus compound_head(), which would be hard to trace back to this cause. Fixes: c25fff7171be ("mm: add dma_addr_t to struct page") Cc: stable@vger.kernel.org Signed-off-by: Matthew Wilcox (Oracle) Acked-by: Ilias Apalodimas Acked-by: Jesper Dangaard Brouer Acked-by: Vlastimil Babka --- include/linux/mm_types.h | 4 ++-- include/net/page_pool.h | 12 +++++++++++- net/core/page_pool.c | 12 +++++++----- 3 files changed, 20 insertions(+), 8 deletions(-) diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 6613b26a8894..5aacc1c10a45 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -97,10 +97,10 @@ struct page { }; struct { /* page_pool used by netstack */ /** - * @dma_addr: might require a 64-bit value even on + * @dma_addr: might require a 64-bit value on * 32-bit architectures. */ - dma_addr_t dma_addr; + unsigned long dma_addr[2]; }; struct { /* slab, slob and slub */ union { diff --git a/include/net/page_pool.h b/include/net/page_pool.h index 6d517a37c18b..b4b6de909c93 100644 --- a/include/net/page_pool.h +++ b/include/net/page_pool.h @@ -198,7 +198,17 @@ static inline void page_pool_recycle_direct(struct page_pool *pool, static inline dma_addr_t page_pool_get_dma_addr(struct page *page) { - return page->dma_addr; + dma_addr_t ret = page->dma_addr[0]; + if (sizeof(dma_addr_t) > sizeof(unsigned long)) + ret |= (dma_addr_t)page->dma_addr[1] << 16 << 16; + return ret; +} + +static inline void page_pool_set_dma_addr(struct page *page, dma_addr_t addr) +{ + page->dma_addr[0] = addr; + if (sizeof(dma_addr_t) > sizeof(unsigned long)) + page->dma_addr[1] = upper_32_bits(addr); } static inline bool is_page_pool_compiled_in(void) diff --git a/net/core/page_pool.c b/net/core/page_pool.c index 9ec1aa9640ad..3c4c4c7a0402 100644 --- a/net/core/page_pool.c +++ b/net/core/page_pool.c @@ -174,8 +174,10 @@ static void page_pool_dma_sync_for_device(struct page_pool *pool, struct page *page, unsigned int dma_sync_size) { + dma_addr_t dma_addr = page_pool_get_dma_addr(page); + dma_sync_size = min(dma_sync_size, pool->p.max_len); - dma_sync_single_range_for_device(pool->p.dev, page->dma_addr, + dma_sync_single_range_for_device(pool->p.dev, dma_addr, pool->p.offset, dma_sync_size, pool->p.dma_dir); } @@ -195,7 +197,7 @@ static bool page_pool_dma_map(struct page_pool *pool, struct page *page) if (dma_mapping_error(pool->p.dev, dma)) return false; - page->dma_addr = dma; + page_pool_set_dma_addr(page, dma); if (pool->p.flags & PP_FLAG_DMA_SYNC_DEV) page_pool_dma_sync_for_device(pool, page, pool->p.max_len); @@ -331,13 +333,13 @@ void page_pool_release_page(struct page_pool *pool, struct page *page) */ goto skip_dma_unmap; - dma = page->dma_addr; + dma = page_pool_get_dma_addr(page); - /* When page is unmapped, it cannot be returned our pool */ + /* When page is unmapped, it cannot be returned to our pool */ dma_unmap_page_attrs(pool->p.dev, dma, PAGE_SIZE << pool->p.order, pool->p.dma_dir, DMA_ATTR_SKIP_CPU_SYNC); - page->dma_addr = 0; + page_pool_set_dma_addr(page, 0); skip_dma_unmap: /* This may be the last page returned, releasing the pool, so * it is not safe to reference pool afterwards.