linux-kernel - [PATCH v4 3/5] udmabuf: fix vmap

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20240822084342.1574914-4-link@vivo.com>
Date: Thu, 22 Aug 2024 16:43:35 +0800
From: Huan Yang <link@...o.com>
To: Sumit Semwal <sumit.semwal@...aro.org>,
	Christian König <christian.koenig@....com>,
	Gerd Hoffmann <kraxel@...hat.com>,
	linux-media@...r.kernel.org,
	dri-devel@...ts.freedesktop.org,
	linaro-mm-sig@...ts.linaro.org,
	linux-kernel@...r.kernel.org
Cc: opensource.kernel@...o.com,
	Huan Yang <link@...o.com>,
	Vivek Kasireddy <vivek.kasireddy@...el.com>
Subject: [PATCH v4 3/5] udmabuf: fix vmap_udmabuf error page set

Currently vmap_udmabuf set page's array by each folio.
But, ubuf->folios is only contain's the folio's head page.

That mean we repeatedly mapped the folio head page to the vmalloc area.

Due to udmabuf can use hugetlb, if HVO enabled, tail page may not exist,
so, we can't use page array to map, instead, use pfn array.

By this, we removed page usage in udmabuf totally.

Suggested-by: Vivek Kasireddy <vivek.kasireddy@...el.com>
Signed-off-by: Huan Yang <link@...o.com>
---
 drivers/dma-buf/Kconfig   |  1 +
 drivers/dma-buf/udmabuf.c | 22 +++++++++++++++-------
 2 files changed, 16 insertions(+), 7 deletions(-)

diff --git a/drivers/dma-buf/Kconfig b/drivers/dma-buf/Kconfig
index b46eb8a552d7..fee04fdb0822 100644
--- a/drivers/dma-buf/Kconfig
+++ b/drivers/dma-buf/Kconfig
@@ -36,6 +36,7 @@ config UDMABUF
 	depends on DMA_SHARED_BUFFER
 	depends on MEMFD_CREATE || COMPILE_TEST
 	depends on MMU
+	select VMAP_PFN
 	help
 	  A driver to let userspace turn memfd regions into dma-bufs.
 	  Qemu can use this to create host dmabufs for guest framebuffers.
diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c
index 1bad4576d492..0bbc9df36c0a 100644
--- a/drivers/dma-buf/udmabuf.c
+++ b/drivers/dma-buf/udmabuf.c
@@ -96,21 +96,29 @@ static int mmap_udmabuf(struct dma_buf *buf, struct vm_area_struct *vma)
 static int vmap_udmabuf(struct dma_buf *buf, struct iosys_map *map)
 {
 	struct udmabuf *ubuf = buf->priv;
-	struct page **pages;
+	unsigned long *pfns;
 	void *vaddr;
 	pgoff_t pg;
 
 	dma_resv_assert_held(buf->resv);
 
-	pages = kvmalloc_array(ubuf->pagecount, sizeof(*pages), GFP_KERNEL);
-	if (!pages)
+	/**
+	 * HVO may free tail pages, so just use pfn to map each folio
+	 * into vmalloc area.
+	 */
+	pfns = kvmalloc_array(ubuf->pagecount, sizeof(*pfns), GFP_KERNEL);
+	if (!pfns)
 		return -ENOMEM;
 
-	for (pg = 0; pg < ubuf->pagecount; pg++)
-		pages[pg] = &ubuf->folios[pg]->page;
+	for (pg = 0; pg < ubuf->pagecount; pg++) {
+		unsigned long pfn = folio_pfn(ubuf->folios[pg]);
 
-	vaddr = vm_map_ram(pages, ubuf->pagecount, -1);
-	kvfree(pages);
+		pfn += ubuf->offsets[pg] >> PAGE_SHIFT;
+		pfns[pg] = pfn;
+	}
+
+	vaddr = vmap_pfn(pfns, ubuf->pagecount, PAGE_KERNEL);
+	kvfree(pfns);
 	if (!vaddr)
 		return -EINVAL;
 
-- 
2.45.2