From nobody Sun Feb 8 21:32:30 2026 Received: from mail.ispras.ru (mail.ispras.ru [83.149.199.84]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B5F5A20125B for ; Wed, 27 Nov 2024 18:59:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=83.149.199.84 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732733999; cv=none; b=REBJ0TOl7H6w/FFwbvpo7CN5YoVgh9rbgytbjYCCGwfK3bfaIqcIacFl+s4uPD3H8V5JancVTo7FroWapUrnOEdBOzH80I9xsYAMkkxtSPgULxJAoDbD3GtssKIrgxF3zwee6T2G0EkSY8RxJNIlU5vQR1Q3uQAEiPzi8Aju5d0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732733999; c=relaxed/simple; bh=Q9lD0FFdsE2KuX9EExX2wAlkFfqAIiMM16sS73q7On4=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=TpvJ5r/EmBZ0DF44v6/Ngbk/wBJJtfpqoEhOCtfHAbprFO4w9Gxo1TzCRKPwYiQjfmUqMKAVeBSe/1BZwLRrS7IlGNLX7hyqjESW1+oKHKT4rwEYn0gTUn7/Rsf9KFpQLzbSuAuOByqP3fE8p/n/2C6jZ1pS+mAfsU5mMiAhyC0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=ispras.ru; spf=pass smtp.mailfrom=ispras.ru; dkim=pass (1024-bit key) header.d=ispras.ru header.i=@ispras.ru header.b=Z6mYFFjA; arc=none smtp.client-ip=83.149.199.84 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=ispras.ru Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ispras.ru Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=ispras.ru header.i=@ispras.ru header.b="Z6mYFFjA" Received: from fpc.intra.ispras.ru (unknown [10.10.165.4]) by mail.ispras.ru (Postfix) with ESMTPSA id EDCD2518E76F; Wed, 27 Nov 2024 18:59:51 +0000 (UTC) DKIM-Filter: OpenDKIM Filter v2.11.0 mail.ispras.ru EDCD2518E76F DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ispras.ru; s=default; t=1732733992; bh=IbWtycDxvF+2Dy4hwBe4BTV3k5eyFHoRBLH861A4gOI=; h=From:To:Cc:Subject:Date:From; b=Z6mYFFjAn6JgbSPD5vF9Vm0kclH6Et4l/3KZmgaE7c7JVyqPY0YIPQtlTJn8wpS8D bukRG+IeNWgKspQ/zepNoe3iv7PR1vfotYqd/KG15qx7I0xBkRhcMllYWO2UQdF6jc 2NiyBgbhYUPhbKBDy8WUdwdDSTue8A923iKGjZPs= From: Fedor Pchelkin To: Christoph Hellwig Cc: Fedor Pchelkin , Marek Szyprowski , Robin Murphy , iommu@lists.linux.dev, linux-kernel@vger.kernel.org, lvc-project@linuxtesting.org Subject: [PATCH] dma-debug: fix physical address calculation for struct dma_debug_entry Date: Wed, 27 Nov 2024 21:59:26 +0300 Message-Id: <20241127185926.168102-1-pchelkin@ispras.ru> X-Mailer: git-send-email 2.39.5 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Offset into the page should also be considered while calculating a physical address for struct dma_debug_entry. page_to_phys() just shifts the value PAGE_SHIFT bits to the left so offset part is zero-filled. An example (wrong) debug assertion failure with CONFIG_DMA_API_DEBUG enabled which is observed during systemd boot process after recent dma-debug changes: DMA-API: e1000 0000:00:03.0: cacheline tracking EEXIST, overlapping mapping= s aren't supported WARNING: CPU: 4 PID: 941 at kernel/dma/debug.c:596 add_dma_entry CPU: 4 UID: 0 PID: 941 Comm: ip Not tainted 6.12.0+ #288 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-debian-1= .16.2-1 04/01/2014 RIP: 0010:add_dma_entry kernel/dma/debug.c:596=20 Call Trace: debug_dma_map_page kernel/dma/debug.c:1236=20 dma_map_page_attrs kernel/dma/mapping.c:179 e1000_alloc_rx_buffers drivers/net/ethernet/intel/e1000/e1000_main.c:4616 ... Found by Linux Verification Center (linuxtesting.org). Fixes: 9d4f645a1fd4 ("dma-debug: store a phys_addr_t in struct dma_debug_en= try") Signed-off-by: Fedor Pchelkin --- kernel/dma/debug.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/kernel/dma/debug.c b/kernel/dma/debug.c index 295396226f31..27ade2bab531 100644 --- a/kernel/dma/debug.c +++ b/kernel/dma/debug.c @@ -1219,7 +1219,7 @@ void debug_dma_map_page(struct device *dev, struct pa= ge *page, size_t offset, =20 entry->dev =3D dev; entry->type =3D dma_debug_single; - entry->paddr =3D page_to_phys(page); + entry->paddr =3D page_to_phys(page) + offset; entry->dev_addr =3D dma_addr; entry->size =3D size; entry->direction =3D direction; @@ -1400,7 +1400,8 @@ void debug_dma_alloc_coherent(struct device *dev, siz= e_t size, entry->type =3D dma_debug_coherent; entry->dev =3D dev; entry->paddr =3D page_to_phys((is_vmalloc_addr(virt) ? - vmalloc_to_page(virt) : virt_to_page(virt))); + vmalloc_to_page(virt) : virt_to_page(virt))) + + offset_in_page(virt); entry->size =3D size; entry->dev_addr =3D dma_addr; entry->direction =3D DMA_BIDIRECTIONAL; @@ -1424,7 +1425,8 @@ void debug_dma_free_coherent(struct device *dev, size= _t size, return; =20 ref.paddr =3D page_to_phys((is_vmalloc_addr(virt) ? - vmalloc_to_page(virt) : virt_to_page(virt))); + vmalloc_to_page(virt) : virt_to_page(virt))) + + offset_in_page(virt); =20 if (unlikely(dma_debug_disabled())) return; --=20 2.39.5