From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1033019AbdI0Bll (ORCPT ); Tue, 26 Sep 2017 21:41:41 -0400 Received: from mailgw01.mediatek.com ([210.61.82.183]:30717 "EHLO mailgw01.mediatek.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1033005AbdI0Blk (ORCPT ); Tue, 26 Sep 2017 21:41:40 -0400 X-UUID: 12f224c4295d4392a17fa0e6e34988bf-20170927 From: To: Robin Murphy , Andrew Morton CC: , , , , , Miles Chen Subject: [PATCH v2] dma-debug: fix incorrect pfn calculation Date: Wed, 27 Sep 2017 09:41:33 +0800 Message-ID: <1506476493-28949-1-git-send-email-miles.chen@mediatek.com> X-Mailer: git-send-email 1.9.1 MIME-Version: 1.0 Content-Type: text/plain X-MTK: N Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Miles Chen dma-debug report the following warning: [name:panic&]WARNING: CPU: 3 PID: 298 at kernel-4.4/lib/dma-debug.c:604 debug _dma_assert_idle+0x1a8/0x230() DMA-API: cpu touching an active dma mapped cacheline [cln=0x00000882300] CPU: 3 PID: 298 Comm: vold Tainted: G W O 4.4.22+ #1 Hardware name: MT6739 (DT) Call trace: [] dump_backtrace+0x0/0x1d4 [] show_stack+0x14/0x1c [] dump_stack+0xa8/0xe0 [] warn_slowpath_common+0xf4/0x11c [] warn_slowpath_fmt+0x60/0x80 [] debug_dma_assert_idle+0x1a8/0x230 [] wp_page_copy.isra.96+0x118/0x520 [] do_wp_page+0x4fc/0x534 [] handle_mm_fault+0xd4c/0x1310 [] do_page_fault+0x1c8/0x394 [] do_mem_abort+0x50/0xec I found that debug_dma_alloc_coherent() and debug_dma_free_coherent() assume that dma_alloc_coherent() always returns a linear address. However it's possible that dma_alloc_coherent() returns a non-linear address. So we cannot calculate a pfn by page_to_pfn(virt_to_page(virt)). Fix this by calculating pfn for linear and non-linear addresses. Signed-off-by: Miles Chen --- lib/dma-debug.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/lib/dma-debug.c b/lib/dma-debug.c index ea4cc3d..381f2ac 100644 --- a/lib/dma-debug.c +++ b/lib/dma-debug.c @@ -1497,7 +1497,8 @@ void debug_dma_alloc_coherent(struct device *dev, size_t size, entry->type = dma_debug_coherent; entry->dev = dev; - entry->pfn = page_to_pfn(virt_to_page(virt)); + entry->pfn = is_vmalloc_addr(virt) ? vmalloc_to_pfn(virt) : + page_to_pfn(virt_to_page(virt)), entry->offset = offset_in_page(virt); entry->size = size; entry->dev_addr = dma_addr; @@ -1513,7 +1514,8 @@ void debug_dma_free_coherent(struct device *dev, size_t size, struct dma_debug_entry ref = { .type = dma_debug_coherent, .dev = dev, - .pfn = page_to_pfn(virt_to_page(virt)), + .pfn = is_vmalloc_addr(virt) ? vmalloc_to_pfn(virt) : + page_to_pfn(virt_to_page(virt)), .offset = offset_in_page(virt), .dev_addr = addr, .size = size, -- 1.9.1